GNS SCIENCE REPORT 2007/23

July 2007

Abondoned oil and gas wells - a reconnaissance study of an unconventional geothermal resource

A. G. Reyes

Abandoned oil and gas wells - a reconnaissance study of an unconventional geothermal resource

A. G. Reyes

GNS Science Report 2007/23July 2007

GNS Science

A. G. Reyes, GNS Science, 1 Fairway Drive, Avalon, PO Box 30368, Lower Hutt

© Institute of Geological and Nuclear Sciences Limited, 2007 ISSN 1177-2425 ISBN 978-0-478-09988-1

BIBLIOGRAPHIC REFERENCE

Reyes A.G. 2007. Abandoned oil and gas wells – a reconnaissance study of an unconventional geothermal resource, GNS Science Report 2007/23 41 p.

GNS Science Report 2007/23 i

CONTENTS ABSTRACT.............................................................................................................................................iii

KEYWORDS ...........................................................................................................................................iii

1.0 INTRODUCTION.........................................................................................................................1

1.1 Geothermal Resources in New Zealand ....................................................................... 1 1.2 Objectives of Study........................................................................................................ 2

2.0 ABANDONED OIL AND GAS WELLS IN OTHER COUNTRIES ..............................................4

3.0 ABANDONED OIL AND GAS WELLS IN NEW ZEALAND ......................................................4

3.1 Distribution and Dates of Completion............................................................................ 4 3.2 Well Depths and Estimated Bottom hole Temperatures ............................................... 7 3.3 Reasons for abandoning wells .................................................................................... 14

4.0 HARNESSING GEOTHERMAL ENERGY FROM ABANDONED HYDROCARBON WELLS14

4.1 Geothermal Potential Projections................................................................................ 14 4.2 Sedimentary basins and other areas outside the Taupo Volcanic Zone..................... 16

5.0 CURRENT GEOTHERMAL USE OF ABANDONED HYDROCARBON WELLS....................18

6.0 INITIAL STEPS FOR USE OF WELLS ....................................................................................20

7.0 RECOMMENDATIONS FOR FUTURE WORK ........................................................................23

8.0 SUMMARY AND CONCLUSIONS ...........................................................................................24

9.0 ACKNOWLEDGMENTS ...........................................................................................................25

10.0 REFERENCES..........................................................................................................................25

FIGURES Figure 1 Temperature, depth and permeability ranges of conventional and unconventional

sources of geothermal energy in New Zealand.................................................................2

Figure 2 Distribution of conventional and unconventional geothermal resources in New Zealand.. ............................................................................................................................3

Figure 3 Distribution of offshore and onshore abandoned wells in various hydrocarbon basins. ...5

Figure 4 Number of offshore and onshore abandoned wells in hydrocarbon basins and non-basins of New Zealand. .....................................................................................................5

Figure 5 Map showing the distribution of abandoned oil and gas wells with date of drilling completion and the general location of sedimentary basins..............................................6

Figure 6 Drilled vertical depths of abandoned onshore hydrocarbon wells. ....................................8

Figure 7 Estimated bottom hole temperatures in abandoned onshore hydrocarbon wells. ............9

Figure 8 Temperature ranges of abandoned oil and gas wells .....................................................13

Figure 9 Depth vs estimated bottom hole temperatures of offshore and onshore abandoned hydrocarbon wells and possible geothermal uses...........................................................14

Figure 10 Depth vs formation pressure in Taranaki wells ...............................................................17

Figure 11 Possible geothermal uses of abandoned hydrocarbon wells. .........................................15

Figure 12 Map showing areas where temperatures >120oC could be intersected at >3200m........17

Figure 13 Direct heat use of 29oC waters from well Bonithon-1, New Plymouth.............................18

Figure 14 A. Bonithon-1 in New Plymouth B. Kotuku borehole forming a pseudo-warm spring. ...18

GNS Science Report 2007/23 ii

Figure 15 Distribution of abandoned onshore hydrocarbon wells in Taranaki showing (A) vertical depths and (B) estimated bottomhole temperatures with roads and population centres. ............................................................................................................................21

Figure 16 Abandoned hydrocarbon wells in Taranaki (squares) that may be converted for geothermal use.. ..............................................................................................................22

TABLES

Table 1 Number of wells within a range of temperatures .............................................................15

Table 2 Potential energy from wells .............................................................................................16

Table 3 Potential energy from drilling new wells in high heat flow regions ..................................22

Table 4 Proposed wells for a 0.5 to 1 MWe pilot geothermal plant in Taranaki ...........................23

Table 5 Main points of presentations during the Oil and Gas conference held in March 2006....29

Table 6 Basic well data.................................................................................................................32

APPENDICES

Appendix 1 Notes on the Geothermal Energy Generation in Oil and Gas Settings Conference .......27

Appendix 2 Abandoned onshore hydrocarbon wells in New Zealand................................................31

GNS Science Report 2007/23 iii

ABSTRACT

There are 349 abandoned onshore oil and gas wells in New Zealand that can potentially be harnessed for geothermal energy for direct usage of heat, power production and development as pseudo hot spring systems for tourism. Well depths range from 17 to 5064m vertical. Estimated bottom hole temperatures range from ambient temperatures (about 12 to 18oC) to 172oC. Of these wells 65% are located in the North Island, the rest in South Island. Taranaki, the only oil and gas producing hydrocarbon basin in the country, has the largest number of abandoned oil and gas wells at 140 or about 40% of all onshore wells.

The use of abandoned hydrocarbon wells for direct heat utilisation and power generation could add another 6.1 PJ to the geothermal energy potential of New Zealand. Of these 1.4 PJ is for use with ground source heat pumps from 123 wells with bottomhole temperatures of <30oC drilled to depths of 17m to 686m for space heating and heating of domestic water; 4.54 PJ for other direct heat uses from 206 wells with temperatures of 31-120oC; and 0.15 PJ from 20 wells with bottomhole temperatures of 120-172oC drilled to 3131-5064m. The total power that could be produced from the 20 high temperature wells, assuming a flow of about 4 L s-1 and a capacity factor of 10% is 4772 kWe (kilowatt electric) or an average of about 238 kWe per well.

The requisite temperature may be present in abandoned hydrocarbon wells for a wide range of geothermal energy uses but there are many geoscientific, technical and non technical problems to be considered before oil and gas wells can be used for geothermal power generation or cogeneration of geothermal and hydrocarbon energy. However New Zealand has the available expertise in the geothermal and oil and gas industries and access to the requisite technology, making this scheme of converting old hydrocarbon wells for geothermal use viable.

Taranaki has a large energy-intensive dairy industry that would benefit from the cogeneration of geothermal and oil and gas wells and the conversion of abandoned oil and gas wells for geothermal use. Possible sites for a 200 kWe binary cycle pilot plant have been selected, preferably using two wells, one for production and the other for reinjection of waste fluids.

KEYWORDS

Geothermal, oil and gas, hydrocarbon, direct heat, power, binary cycle.

GNS Science Report 2007/23 1

1.0 INTRODUCTION

With the technological advances in the last 20 years the definition of an economically viable geothermal resource has broadened to a resource that extracts heat from the rock or circulating aquifer waters at temperatures ranging from as low as 4oC (Lund and Freeston, 2001) to as high as sub-magmatic (400oC) and from about 15m to >3500m depths. At shallow depths and temperatures of 10-35oC heat can be harnessed from the ground or circulating water in boreholes or warm water in abandoned mines using ground source heat pumps (Lund et al, 2005). In Central and Northern Europe, for example, all heat energy stored below about 15m from the surface is considered geothermal energy (Rybach and Sanner, 2000).

For some of the unconventional sources of geothermal energy, such as heat from sedimentary basins and hot dry rock (HDR), permeability or the volume of circulating fluids may be too low to economically extract heat. To increase the productivity and lifetime of these marginal geothermal sources for power generation, enhanced or engineered geothermal systems (EGS) technology may be required where, essentially, low permeability hot rock at depth is artificially fractured and fluid is introduced into the newly-fractured rock where it is heated by conduction. The heated fluids are recirculated to the surface by pumps and the heat extracted by a heat exchanger (e.g. Smith, 1983; White, 1983).

1.1 GEOTHERMAL RESOURCES IN NEW ZEALAND

There are conventional and non-conventional sources of geothermal energy for power generation and direct heat utilisation in New Zealand (Figure 1) ranging in temperature from about 12 to 15oC at about 15m to as high as >330oC at >3,500m. Power can be generated by steam turbines or by binary cycle systems using the Organic Rankine Cycle (ORC) where the working organic fluid has a low boiling temperature such as isopentane, or the Kalina Cycle which uses ammonia/water.

The newest system is called the NE (Natural Energy) Engine that operates on hot and cold water and uses liquid CO2 as a working fluid in the heat exchanger engine (www.fossil.energy.gov).

Conventional sources include (1) high enthalpy hot spring systems in the Taupo Volcanic Zone (TVZ) and Ngawha in Northland some of which are now harnessed for power production, (2) waste-water from high enthalpy power-generating systems such as Wairakei, Mokai, Ohaaki-Broadlands, Kawerau, Rotokawa and Ngawha and (3) hot spring systems outside the Taupo Volcanic Zone and Ngawha and including springs in the North Island, islands in the Bay of Plenty and Hauraki Gulf and in the South Island (Figure 2).

Nonconventional sources of geothermal energy include: (1) most of the TVZ outside high enthalpy geothermal systems, where thermal gradients range from 40oC/km to >50oC/km but permeability low, (2) 12oC to 170oC waters in abandoned oil and gas (hydrocarbon) wells, (3) heated waters in abandoned flooded coal and mineral mines, (4) conductive heat from shallow depths (<250m) for ground source heat pump harnessing, (5) conductive heat at depth in high-heat flow (>70 mW/m2) sedimentary basins, metamorphic terrain and rapidly rising regions of the country such as the Raukumara Peninsula (Mazengarb and Speden, 2000) and the Southern Alps (Allis and Shi, 1995) and regions outside high heat flow regions. The location of some of the nonconventional heat sources available in New Zealand are shown in Figure 2.

GNS Science Report 2007/23 2

Figure 1. Temperature, depth and permeability ranges of conventional and unconventional sources of geothermal energy in New Zealand. The temperature and depth range of abandoned oil and gas wells in New Zealand are highlighted in red.

Geothermal energy in this country is associated with power generation in the Taupo Volcanic Zone and Ngawha where volcanism is recent. New Zealand has a total installed power generating capacity of 435 MWe provided by six geothermal systems in the Taupo Volcanic Zone and one at Ngawha in Northland, where a binary plant produces 9 MWe (http://www.crownminerals.govt.nz).

The installed capacity for direct usage of geothermal energy in the country is 448 MWt (White, 2006), 62% of which is produced from waste water and waste steam or dedicated wells in the power-generating Kawerau, Mokai, Ohaaki-Broadlands and Wairakei geothermal systems. About 170 MWt is used for bathing in more than 30 commercial swimming pools and in ad hoc holes dug for hot water at the edges of rivers or at tide level along the sea shore, space-heating, fruit irrigation, plant or fish cultivation, and health and beauty therapy.

1.2 OBJECTIVES OF STUDY

This is reconnaissance study on the potential of extracting geothermal energy from abandoned oil and gas wells and regions outside the Taupo Volcanic Zone (TVZ) and Ngawha. Assumptions are broad and conservative, calculations are basic.

GNS Science Report 2007/23 3

Figure 2. Distribution of conventional and nonconventional geothermal resources in New Zealand including hot springs, abandoned oil and gas wells, abandoned flooded underground coal and mineral mines and stored heat in the rock. Conductive heat flow contours are from Allis et al, 1998.

GNS Science Report 2007/23 4

2.0 ABANDONED OIL AND GAS WELLS IN OTHER COUNTRIES

The idea of using abandoned oil and gas (hydrocarbon) wells and drilling wells in sedimentary basins to produce geothermal energy is not new. Low enthalpy geothermal resources in sedimentary basins in France have been tapped by wells for district heating since 1969. At present there are 41 plants in the Paris basin including 15 in the Aquitane basin and five in other regions producing hot water for a total of 200,000 households and supplanting about 170,000 TOE (Laplaige et al, 2000). Albania, Poland, Germany, Switzerland, USA, France and Australia are exploring the possibility of recovering heat from hydrocarbon wells (e.g., Bodvarrsson and Reistad, 1983; White, 1983; Barbacki, 2000; Schellshmidt et al, 2000; Lund et al, 2005).

In the USA abandoned hydrocarbon wells, in regions of high heat flow (>75 mW/m2) and sufficient water flow such as Texas and Oklahoma, are estimated to have a power generating potential at the gigawatt level (Appendix 2). Using the existing wells minimises the initial costs of geothermal power production. The main capital funding input is fitting existing wells with heat exchangers and small power plants (McKenna et al, 2005). In March 2006, the Southern Methodist University in Texas held the first conference on the potential of harnessing geothermal power from abandoned hydrocarbon wells (Appendix 1).

3.0 ABANDONED OIL AND GAS WELLS IN NEW ZEALAND

Although the number of abandoned hydrocarbon wells in New Zealand is <1% that of the USA several factors indicate that abandoned oil and gas wells can be harnessed for geothermal energy, including (1) bottomhole temperatures >50oC in more than 150 wells drilled to depths >625m, (2) the presence of nonsaline or saline waters in most of the abandoned wells that may be discharged using artesian pressures inherent in the wells or through downhole pumps, (3) over pressuring in some wells in Taranaki (King and Thrasher, 1996), the East Coast (Field et al) and Northland (Isaac et al) indicate that some wells are artesian and will flow without the need for well stimulation or hydrofracturing, (4) mud losses during drilling indicate permeability in several wells e.g., Kiakia-1/1A in the East Coast, and (4) large areas of high heat flow cover parts of the Northland, Taranaki, Wanganui and East Coast basins in the North Island and parts of the West Coast basin of the South Island (Figures 2 and 3) where the surface conductive heat flow of >70 mW/m2 indicate thermal gradients of >33oC/km.

3.1 DISTRIBUTION AND DATES OF COMPLETION

There are about 450 onshore and offshore abandoned hydrocarbon wells in New Zealand (Figure 3). Of these wells, 349 are onshore with the offshore wells drilled mostly in waters <150m deep.

Thirty-six of the onshore wells were drilled out of basins and the rest are located in eight of the 18 hydrocarbon basins in the country (Figures 3 and 4). Of the onshore wells, 65% are located in the North Island and the rest in the South Island. The highest number of abandoned hydrocarbon wells, at 140, are found in Taranaki, the only basin producing oil and gas in the country.

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Figure 3. Distribution of offshore and onshore abandoned wells in various hydrocarbon basins (data from http://www.crownminerals.govt.nz).

Figure 4. Number of offshore and onshore abandoned wells in New Zealand.

GNS Science Report 2007/23 6

Figure 5. Map showing the distribution of abandoned oil and gas wells with date of drilling completion and the general location of sedimentary basins (data from http://www.crownminerals.govt.nz). Active fault lines are shown as grey lines (data from www.gns.cri.nz). Red line defines the boundaries of the Taupo Volcanic Zone.

GNS Science Report 2007/23 7

The onshore wells were drilled from 1866 to 2005 with the two late-19th century ones located in Taranaki (Figure 5). The completion dates of 93 wells are unknown. Of those with known dates, 19 wells drilled from 1903-1944 are located in Taranaki, 16 in the East Coast of North Island, two in the Wanganui basin, 15 in the West Coast of South Island and one in Canterbury. These were drilled to depths of 19 to 3331m. Thirty-four wells were drilled before 1970, 33 before 1980, 68 before 1990, 41 from 1990-1999 and 27 after 2000. The date of completion nearly a century ago does not preclude development. For example, Bonithon-1, a well used today for the Taranaki baths in New Plymouth was drilled in 1908. However, Bonithon-2 sited nearby and drilled nearly at the same time could not be located. Well diameters below the production casing shoe range from about 2.5” to 12”. A liner is sometimes installed and sometimes perforated. However, the liner is retrieved prior to abandoning the wells. Hence the age of the boreholes may, however, affect the degree of cave-ins in wells without liners.

3.2 WELL DEPTHS AND ESTIMATED BOTTOM HOLE TEMPERATURES

Abandoned wells have total vertical depths ranging from 17m to 5064m (Figure 6). Twelve of the 13 wells drilled deeper than 4000m are located in Taranaki e.g., Inglewood-1 (5061m) and Cardiff-1 (5064m). The one well deeper than 4000m outside Taranaki is located in the East Coast i.e., Rere-1 (4351m; Figure 2).

Down hole temperatures, after the well had stabilised after drilling, are often not measured in hydrocarbon wells although temperatures during or just a few hours after drilling have been measured in some wells.

Since stable downhole temperatures are not available for most wells, bottom hole temperatures are roughly estimated using published surface conductive heat flow data (Funnell et al, 1996; King and Thrasher, 1996; Funnell and Allis, 1997; Field et al, 1997; Allis et al, 1998, Cook et al, 1999) and converted to thermal gradient, in oC/km, using a factor of 2.1 (Funnell, pers. comm., 2003) and an average surface temperature of 15oC. In two wells, Kowai-1 and Hohonu-1, the bottom temperatures measured a few hours after drilling are higher by 8oC and 3oC, respectively than calculated bottomhole temperatures, i.e., 60oC vs 52oC for Hohonu-1 and 52oC vs 49oC for Kowai-1. Thus calculated bottomhole temperatures are most likely minimum values. Homogenisation temperatures in the latest aqueous fluid inclusions in quartz in abandoned and active hydrocarbon wells in Taranaki are often about +10oC of the estimated bottomhole temperatures (Reyes unpublished data, Reyes, 1998).

The estimated bottomhole temperatures in the onshore abandoned hydrocarbon wells range from ambient to as high as 172oC at 4451m in well New Plymouth-2 in Taranaki (Figures 7 and 8; Table 1). About 34% of all the onshore wells (120) have bottom hole temperatures of <30oC suitable for harnessing with ground source heat pumps (Figure 8).

Temperatures of 30-100oC were intersected in 57% (199) of the onshore wells and another 18 wells (5%) have estimated bottomhole temperatures of 100-120oC, suitable for other direct uses of heat. Except for four wells, all wells with bottomhole temperatures of 120-172oC are located in Taranaki (Figure 7). The four wells outside Taranaki are: Waimamaku-2 in Northland (124oC), Rere-1 in the East Coast (147oC), Bounty-1 (131oC) and Kokiri-1 (122oC) in the West Coast, South Island (Figures 2 and 7).

GNS Science Report 2007/23 8

Figure 6. Drilled vertical depths of abandoned onshore hydrocarbon wells. Grey lines are active faults (www.gns.cri.nz) and the red line defines the boundaries of the Taupo Volcanic Zone.

GNS Science Report 2007/23 9

Figure 7. Estimated bottom hole temperatures in abandoned onshore hydrocarbon wells. Grey lines are active faults (www.gns.cri.nz) and the red line defines the boundaries of the Taupo Volcanic Zone.

GNS Science Report 2007/23 10

Figure 8. Temperatures ranges of onshore and offshore abandoned oil and gas wells.

In contrast to onshore wells about 92% of abandoned offshore wells (97 wells) have bottomhole temperatures >50oC (Figure 8) because these are all drilled deeper than 700m. One offshore well, Clipper-1 in the Great South basin, has a calculated bottomhole temperature of nearly 185oC at 4742m.

A plot of total depth versus estimated bottom hole temperatures (Figure 9) show three onshore wells with thermal gradients higher than most wells: Rotokautuku-1 in the East Cape, Bounty-1 in the West Coast and New Plymouth-2 in Taranaki (Figures 2 and 9). Rotokautuku-1 is located in a region of active landmass uplift in the Raukumara Peninsula where the surface heat flow is high at 170 mW/m2 believed to be caused by the advection of rising hot fluids from depth (Field et al, 1997). The thermal gradient in Rotokautuku is about 80oC/km.

Well Bounty-1 in the West Coast is 3131m deep, drilled in an isolated region with a heat flow of 80 mW/m2 heat flux (Figure 3) where the landmass is rapidly rising (Allis and Shi, 1995). Well New Plymouth-2 is drilled to 4451m in a region of 70 mW/m2 heat flux and is located near the Pliocene to Quaternary Sugar Loaf Islands and Paritutu volcanic centres which may still possess vestigial heat at depth.

The thermal gradient is about 40oC/km in wells Bounty-1 and New Plymouth-2. The three offshore wells with the highest thermal gradients at 40-50oC/km are wells Takapu-1 and Clipper-1 in the Great South basin and well Cook-1 in offshore Taranaki.

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Num

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of w

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with

in a

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Num

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f w

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B

HT(

o C)

rang

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(m)

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30-5

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80-1

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100-

120o C

>120

o C

Nor

th Is

land

N

orth

land

10

17

-127

4

4-33

57

5

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1

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72

48-

5064

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27

36

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295-

3495

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66

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1696

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123

76

68

43

19

20

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P

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tial e

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y in

kW

from

oil

and

gas

wel

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ssum

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flow

of 4

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CF)

use

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Bas

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kW

kW

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7 kW

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F=0.

1

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30-5

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50-8

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10

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31

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38

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95

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400

1,50

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610

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18

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500

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500

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250

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200

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9,24

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25

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55

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59

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43

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300

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550

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0 -

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290

0.0

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19

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10

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19

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4,

300

3,70

0 4,

320

39,5

50

432

Tota

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,500

51

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75

,100

63

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34

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47

,720

18

8,44

0 4,

772

GNS Science Report 2007/23 14

3.3 REASONS FOR ABANDONING WELLS

Most wells were abandoned because of low or total lack of hydrocarbon shows. The reservoirs are, instead, often saturated with fresh or saline waters and are a boon to geothermal exploitation. Others were abandoned because of drilling problems e.g., swelling clays and oil and sand bursts.

Abandoned wells are plugged. In most cases liners are not installed or are pulled out upon abandonment. Hence cave-ins may occur in some older wells.

Permeability is apparently present in most of the wells as indicated by the discharge of water from some wells; however the water level in the wells is unknown. In Taranaki, there is a widespread zone of over pressuring with respect to the hydrostatic gradient at >3000m (King and Thrasher, 1996) indicating that these wells may be artesian (Figure 10) and hence will flow without the need for downhole heat pumps.

Figure 10. Depth versus formation pressure derived from measured values or mud weights in several Taranaki wells showing over pressuring with respect to hydrostatic pressure at about >3km depths (Figure 6.12 of King and Thrasher, 1996)

4.0 HARNESSING GEOTHERMAL ENERGY FROM ABANDONED HYDROCARBON WELLS

4.1 GEOTHERMAL POTENTIAL PROJECTIONS

As shown in Figures 9 and 11 geothermal energy from abandoned oil and gas wells can be harnessed for direct heat using ground source heat pumps at temperatures of about <30oCfor space heating and heating water for domestic use. Wells with bottomhole temperatures from 30o to 120oC can be harnessed for other direct heat uses, and wells with waters >120oCand sufficient water flow can potentially be used for power generation.

There are 123 onshore wells with bottomhole temperatures <30oC (Table 1) that can potentially yield a total of 31,150 kWt (44,500 x 0.7=31,500) as shown in Table 2. On the other hand, if a 6 kW capacity closed loop ground source heat pump system is installed in each well, then a total of 738 kWt can be produced.

GNS Science Report 2007/23 15

Figure 11. Possible geothermal uses of abandoned hydrocarbon wells. Grey lines are active faults (www.gns.cri.nz) and the red line defines the boundaries of the Taupo Volcanic Zone.

GNS Science Report 2007/23 16

Assuming a flow of 4 L s-1, the 206 wells with bottomhole temperatures of 30 to 120oC can potentially produce 166,754 kWt of energy (238,220 x 0.7 = 166,754) for various direct heat uses.

For the 20 wells with temperatures of 120-172oC, the hot fluids can be used to generate power using a down hole heat pump (to enhance the flow rate and keep the resource under pressure to prevent formation of a vapour phase (Hance, 2005) and a binary cycle system. A down hole pump can be used up to about 200oC (Hance, 2005) which is well above the highest temperatures in the abandoned wells. The total power that could be produced from these wells, assuming a flow of about 4 L s-1 and a capacity factor of 10% is 4,772 kWe (kilowatt electric) or an average of about 238 kWe per well.

The use of abandoned hydrocarbon wells for direct heat utilisation and power generation could add another 6.1 PJ to the geothermal energy potential of New Zealand. Of these 1.4 PJ is for use with ground source heat pumps from 123 wells with bottomhole temperatures of <30oC drilled to depths of 17m to 686m; 4.54 PJ for other direct heat uses from 206 wells with temperatures of 31-120oC; and 0.15 PJ from 20 wells at temperatures of 120-172oCdrilled to 3131-5064m.

4.2 SEDIMENTARY BASINS AND OTHER AREAS OUTSIDE THE TAUPO VOLCANIC ZONE

The region with surface conductive heat flow of >70 mW/m2 (>33oC/km), outside the Taupo Volcanic Zone, Ngawha and land administered by the Department of Conservation, covers an area of about 31,520km2 or about 12% of the New Zealand landmass (Figure 12). In these regions, a temperature of 120oC will be intersected at about 2,600m in Northland and the Coromandel and at least 3,200m in the rest of the North Island and in South Island (Figures 2 and 12; Table 3).

Drilling new wells in these areas is dependent on accessibility (access factor) dictated by topography (e.g., slip-prone rugged Alpine slopes are problematic), land usage (e.g., national parks, private property, Maori-owned may not be accessible for drilling) and geology (e.g. proximity to faults may contribute to permeability at depth and are therefore attractive for drilling; areas best drilled for coal, hydrocarbons or precious metals may not be immediately accessible for deep drilling; regions with swelling clays or highly silicified rocks may cause drilling problems). The success rate of 0.40, used in Table 3, is the lowest success rate in exploration geothermal drilling in New Zealand, based on the percentage of geothermal wells that would successfully produce 1 MWe per five wells drilled (Barr et al, 1984).

Assuming that the areas to be drilled, at 2 wells/100 km2, have enough permeability where heated water circulates, the temperature of extraction is 100oC, and the drilled wells will have a flow of at least 4 L s-1 then another 21,100 kWe can be potentially produced or 0.67 PJ of geothermal energy generated (Table 3).

However, before drilling new deep wells in high heat flow regions outside the Taupo Volcanic Zone and Ngawha, geothermal energy from existing abandoned hydrocarbon wells should be explored first.

GNS Science Report 2007/23 17

Figure 12. Map showing areas where temperatures >120oC could be intersected at >3200m. Blue areas are under the jurisdiction of the Department of Conservation and cannot be drilled.

GNS Science Report 2007/23 18

5.0 CURRENT GEOTHERMAL USE OF ABANDONED HYDROCARBON WELLS

In Taranaki, warm bicarbonate water (27oC) from the 910m deep Bonithon-1, an abandoned hydrocarbon well drilled in 1908, is heated to 33-38oC by gas and fed into the therapy and private pools of a commercial spa enterprise. The bore water is also bottled and sold as therapeutic mineral water (Figure 13). In Kotuku, West Coast, a leaking hydrocarbon well discharged 21oC (ambient temperature=13oC) effervescent bicarbonate waters at 3 kg s-1 for years and formed a pseudo warm spring pool that could be used as a tourist attraction (Figure 14). However in early 2006 the well ceased to flow due probably to sealing by carbonate deposition and the lowered water level caused by drought in the region. A warm spring in Lake Omapere, Northland was also originally a well. These examples show that it is possible to harness abandoned hydrocarbon wells for direct utilisation of heat or turn them into “pseudo hot springs” for tourism.

Despite the projections of extracting gigawatts of geothermal power from abandoned hydrocarbon wells in the Gulf regions of the USA, only one hydrocarbon well is producing 1.5 MWe of geothermal power, located in a geopressured sedimentary basin in Pleasant Bayou, Louisiana (Campbell and Hattar, 1990; Griggs, 2005).

The well is 5030m deep, and intersected a leaky fault, a fault that leaks due to pressure differentials in the reservoir. Wellhead pressure is 20.7 MPa. Fluids contain 87% CH4. The hybrid cycle power plant is equipped with a pressure reduction turbine, with the gas providing 690 kW, the binary cycle turbine 535 kW and a parasitic load of 270 kW. Problems with corrosive saline solutions were solved by using 16 gauge steel; scaling problems from 130,000 mg/kg TDS waters by using inhibitors, and carbon fouling by regularly shutting and opening the plant (www.smu.edu/geothermal/Oil&Gas/Oil&Gas_SMUmeeting_summary; Appendix 1).

Figure 13. Direct heat use of 29oC waters from well Bonithon-1, New Plymouth

Figure 14. Kotuku borehole forming a pseudo-warm spring (21oC) in 2003. Flow is 3 kg/s (photo by A.G.Reyes).

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Tabl

e 3.

D

rillin

g ne

w w

ells

in r

egio

ns w

ith h

eat

flow

>70

mW

/m2 w

here

the

geo

ther

mal

gra

dien

t is

>33

o C/k

m.

Two

wel

ls a

re p

ropo

sed

for

each

100

km

2 are

a. O

ne is

for

pr

oduc

tion,

the

othe

r for

rein

ject

ion.

CF=

con

vers

ion

fact

or

Reg

ion

Ther

mal

gr

adie

nt

(o C/k

m)

Are

a in

km

2Te

mpe

ratu

re

at d

epth

Te

mpe

ratu

re

of e

xtra

ctio

n (o C

)En

thal

py

(kJ/

kg)

Flow

(k

g/s)

2w

ells

/100

km

2Su

cces

s N

o. o

f w

ells

for

pow

er

gene

ratio

n kW

kW

e

(0

.1 C

F)

TJ

PJ

3,

200m

N

orth

Isla

nd

33

7,86

5 12

0o C

100

419

4 15

7 0.

4 31

52

,727

5,

273

166

0.17

So

uth

Isla

nd

33

18,8

00

120o C

10

0 41

9 4

376

0.4

75

126,

035

12,6

04

398

0.40

2,

600m

C

orom

ande

l 40

1,

610

120o C

10

0 41

9 4

32

0.4

6 10

,793

1,

079

34

0.03

N

orth

land

40

3,

245

120o C

10

0 41

9 4

65

0.4

13

21,7

54

2,17

5 69

0.

07

TOTA

L

31,5

20

125

21

,131

66

7 0.

67

GNS Science Report 2007/23 20

In New Zealand temperature may be present but there are many technical and non technical problems to be considered when converting oil and gas wells for geothermal extraction e.g.,

1. Marginal permeability and fluid flow in a number of oil and gas wells may require hydrofracturing and/or well stimulation,

2. The state of the casing and grouting jobs of wells drilled before 1980, which comprise about 45% of the onshore wells, may not be satisfactory and the wells not usable,

3. Wells are filled and plugged when abandoned and will require drilling out the fills and cement before use,

4. Some wells may be difficult to locate because all surface traces are covered (Funnell, pers comm. 2007),

5. Oil fouling of geothermal turbines is possible when producing some wells for geothermal power,

6. Liner tubings may need to be converted to slotted liners (or the tubings perforated),

7. Liners have either been pulled out or not installed at all and rock may have caved-in in some wells,

8. Casing corrosion, whether internally or externally induced, is probable,

9. Access to the wells owned by oil companies, Maori tribes, other private owners or the New Zealand government,

10. Acceptance and support of the government to the idea of converting hydrocarbon wells for geothermal use.

In Taranaki cogeneration and colocation of geothermal and hydrocarbon energy sources may affect reinjection strategies because water reinjection may hasten water flooding in structurally or stratigraphically-connected hydrocarbon-bearing zones in nearby producing gas and condensate wells. Other factors that should be considered include finding methods of stimulating water flow in abandoned oil and gas wells, determining the type of binary cycle system to be used (Rankine, Kalina or NE Engine) and the feasibility of using hybrid power plant systems to cogenerate power from geothermal fluids and methane from the same well, and later, investigating EGS (Enhanced or Engineered Geothermal Systems) technology to exploit deep oil and gas wells.

6.0 INITIAL STEPS FOR USE OF WELLS

A pilot plant could be set up in Taranaki to demonstrate the viability of this hydrocarbon-to-geothermal energy scheme. Taranaki has the most number of abandoned hydrocarbon wells with some of the highest estimated bottom hole temperatures and artesian pressures below 3000m (Figures 15A and B). It is the centre of oil, gas and petrochemical production in the country. It is one of the most energy-hungry regions of the country that could benefit from cogeneration and colocation of hydrocarbon and geothermal energy sources to support its dairying, horticultural and food processing industries. Low temperature wells could be harnessed to provide heat for space heating of dairy farm buildings, milk pasteurisation, greenhouses, swimming pools and spas. Higher temperature wells (16 wells) can be used for power generation.

GNS Science Report 2007/23 21

The 16 high temperature wells selected for possible geothermal power generation (Figure 15) have estimated bottom hole temperatures 120oC to 172oC, drilled to >3100m and are mostly artesian. However four of these (with yellow crosses) were drilled prior to 1980 and the state of the casing, liners and grouting jobs is uncertain and need to be examined. All 16 wells have been plugged with cement upon abandonment.

For a binary cycle pilot plant with a capacity of about 200 kW five wells were selected based on their bottomhole temperatures, proximity to a population centre or an industrial complex such as Fonterra and proximity to another abandoned well that can be possibly used as a reinjection well. These wells include Tipoka-1, Te Kiri-1, Toko-1, New Plymouth-2 or Inglewood-1 (Table 4), listed according to priority, and shown in Figure 16. A downhole pump may be needed in some wells to increase or sustain fluid flow. Electricity generated from Tipoka-1 or Te Kiri-1 can be used by nearby dairy farms or Fonterra while other wells such as from Toko-1, New Plymouth-2 and Inglewood-1 may supplement electricity from the grid for Stratford, New Plymouth and Inglewood, respectively. Other wells with bottomhole temperatures >120oC near Stratford are Wharehuia-1, Piakau-1 and Waihapa-1. Another well that could be harnessed in Inglewood is Tauteka-1. Cardiff-1, a well with a bottomhole temperature of 153oC may be reactivated as a source of hydrocarbons and hence not included in the list.

More geoscientific studies need to be done on these wells before any power harnessing could be done. The effect of drawing out large volumes of hot water on nearby actively-producing hydrocarbon wells is not known.

Figure 15. Distribution of abandoned onshore hydrocarbon wells in Taranaki showing (A) vertical depths and (B) estimated bottomhole temperatures with roads and population centres. Haloed wells may be used for geothermal power production.

A B

GNS Science Report 2007/23 22

Figure 16. Abandoned hydrocarbon wells in Taranaki (squares) that may be converted for geothermal use. All plotted abandoned hydrocarbon wells have estimated bottom hole temperatures (BHT) >120oC and depths from 3131 – 5064m.

GNS Science Report 2007/23 23

Table 4. Proposed wells for 200 kWe pilot geothermal plant in Taranaki. Refer to Appendix 3 for well details. BHT= bottom hole temperature.

Well Priority Estimated

kWe Comments

Tipoka-1 1 240 Tipoka-1 fluids (BHT= 142oC at 4360m) can be reinjected in Tipoka-2, 1.1 km away, which has BHT= 88oC at 2504m. Power can be used by nearby dairy farms.

Te Kiri-1 2 260 Well (154oC at 4710m) near dairy farms associated with Fonterra. There may be a need to drill a nearby reinjection well

Toko-1 3 250

Fluids from Toko-1 with BHT=150oC at 4900m can be reinjected into Toko-2 with BHT = 103oC at 3200m, 1.2km away. There is a seal between the Mangahewa Fm in Toko-1 and the shallower Tikorangi Fm in Toko-2. Power can be used for Stratford. Other wells near Stratford that can be used for power generation are: Wharehuia-1 (114oC at 3595m) with fluids reinjected into Piakau-1 1.0km away or Waihapa-1 (144oC at 4942m) using Waihapa-2, 1.8km away, as a reinjection well

New Plymouth-2 4 290

Highest BHT of all onshore wells at 172oC; located in middle of New Plymouth. Fluids can be reinjected in numerous adjacent abandoned wells. This was drilled before 1980 and the state of the casings and grouts is unknown.

Inglewood-1 5 275

BHT= 164oC at 5061m. This was drilled before 1980. There may be a need to drill a nearby reinjection well. The nearest abandoned well that could be used for reinjection is Ngatoro-1 about 2.1km away. Power can be used by Inglewood. Another well near Inglewood is Manganui-1 (131oC at 3753m) with Tauteka-1, 830m away, as a reinjection well

7.0 RECOMMENDATIONS FOR FUTURE WORK

This is merely a reconnaissance study whose main goal is to present an idea and the basic data of wells that could be used for geothermal energy purposes. Before any wells could be used the following studies should be done:

1. Review all literature on wells regarding water reservoirs, fault and stratigraphic permeability, stratigraphic connectivity among abandoned and actively-producing wells, downhole pressure and temperature measurements and geology.

2. Determine the state of the casing/tubings, liners and cementing jobs of selected wells.

3. Determine the corrosion state of the well pipes.

4. Measure downhole temperatures of selected wells.

5. Determine flow rates of well discharges and methods of stimulating water flow.

6. Find out if hydrofracturing is necessary or possible to enhance permeability.

7. Find out the maximum working temperatures of down hole pumps.

8. Determine fluid discharge chemistry to find out if a hybrid plants can be used to tap both gas and geothermal fluids, predict fouling problems to the plant, determine ways of disposing well fluids (use a reinjection well or dispose fluids into the waterways?).

9. Determine fluid pathways and temperatures using petrological and geochemical methods.

GNS Science Report 2007/23 24

10. Determine how geothermal production will affect the hydrocarbon reservoirs.

11. Study the economic viability of converting extant hydrocarbon wells for geothermal direct heat use or for power production.

8.0 SUMMARY AND CONCLUSIONS

The 349 abandoned onshore oil and gas wells in New Zealand have total vertical depths of 17 to 5064m and estimated bottom hole temperatures ranging from ambient temperatures (about 12 to 18oC) to 172oC. Of these wells 65% are located in the North Island, the rest in South Island. Taranaki, the only oil and gas producing hydrocarbon basin in the country, has the largest number of abandoned oil and gas wells at 140 or about 40% of all onshore wells and also contains 16 of the 20 wells with bottomhole temperatures >120oC.

Thus the use of abandoned hydrocarbon wells for direct heat utilisation and power generation could add another 6.1 PJ to the geothermal energy potential of New Zealand. Of these 1.4 PJ is for use with ground source heat pumps from 123 wells with bottomhole temperatures of <30oC drilled to depths of 17m to 686m for space heating and heating of domestic water; 4.54 PJ for other direct heat uses from 206 wells with temperatures of 31-120oC; and 0.15 PJ from 20 wells with bottomhole temperatures of 120-172oC drilled to 3131-5064m. The total power that could be produced from the 20 high temperature wells, assuming a flow of about 4 L s-1 and a capacity factor of 10% is 4,772 kWe (kilowatt electric) or an average of about 238 kWe per well.

Taranaki has a large energy-intensive dairy industry that would benefit from the cogeneration of geothermal and oil and gas wells and the conversion of abandoned oil and gas wells for geothermal use. Possible sites for a 200 kWe binary cycle pilot plant have been selected using wells with bottomhole temperatures >120oC and include, with decreasing priority, Tipoka-1, Te Kiri-1, Toko-1, New Plymouth-2 or Inglewood-1. The selected wells are either near dairy farms or an industrial complex like Fonterra or within a population centre such as Stratford, new Plymouth and Inglewood. Three of the sites are within a 1.8 km radius from another abandoned well, but with lower temperatures, that can be used for reinjection. Well Inglewood-1, however, is 2.1 km from the nearest abandoned well and a reinjection may need to be drilled nearer the well and there is no nearby well for Te Kiri-1.

New wells in high heat flow regions of the country, outside the Taupo Volcanic Zone, Ngawha and Department of Conservation land, may provide another 0.67 PJ of energy assuming production of energy from waters extracted at 100oC and a flow of about 4 L s-1.However, these will only be drilled once the viability of geothermal power outside the Taupo Volcanic Zone and Ngawha have been proven by harnessing geothermal energy from abandoned hydrocarbon wells.

The requisite temperature may be present in abandoned hydrocarbon wells for a wide range of geothermal energy uses but there are many geoscientific, technical and non technical problems to be considered before oil and gas wells can be used for geothermal power generation or cogeneration of geothermal and hydrocarbon energy. However New Zealand has the available expertise in the geothermal and oil and gas industries and access to the requisite technology, making this scheme of converting old hydrocarbon wells for geothermal use viable.

GNS Science Report 2007/23 25

Converting at least a pair of abandoned hydrocarbon wells (one for production the other for reinjection) in Taranaki for use in a 200 kWe pilot plant may prove the viability of this scheme.

9.0 ACKNOWLEDGMENTS

Thank you to D. Darby and E. Mroczek for reviewing the report whose comments and suggestions have contributed to the improvement of the report. Discussions with D. Darby, E Mroczek, and J. Callan and speakers of the conference on Geothermal Energy Generation in Oil and Gas Settings Conference held in the Southern Methodist University, Texas in 13-14 March 2006 have helped in writing this report. Thank you to K. Hunt for her expert word processing.

10.0 REFERENCES

Allis R G and Shi Y (1995) New insights to temperature and pressure beneath the central southern Alps, New Zealand. NZ J Geol Geophysics, 38, 585-592.

Allis R G, Funnell R and Zhan X (1998) From basins to mountains and back again: NZ basin evolution since 10 Ma. Proceedings 9th International Symposium on Water-Rock Interaction, Taupo New Zealand, 3-7.

Barbacki A (2000) The use of abandoned oil and gas wells in Poland for recovering geothermal heat. Proceedings World Geothermal Congress 2000, Kyushu Japan, 3361-3365.

Barr H, Grant M A and Mclachlan R (1984) Proving and development of geothermal fields, DSIR Report 116, Wellington New Zealand.

Barry J M, Duff S W and MacFarlan D A B (1994) Coal resources of New Zealand. Coal report series CR3132, NZ Ministry of Commerce, 73 p.

Bodvarrsson G and Reistad G M (1983) Forced geoheat recovery for moderate temperature uses. J Volcanol and Geoth Res, 15, 247-267.

Campbell R G and Hattar M M (1990) Operation of a geopressured hybrid power system at Pleasant Bayou. Proceedings Energy Conversion Engineering Conference, 1990, IECEC-90 25th Intersociety, 91-101.

Cook R A, Sutherland, R, Zhu H and others (1999) Cretaceous-Cenozoic geology and petroleum systems of the Great South basin, New Zealand. Institute of Geological and Nuclear Sciences Monograph 20, Lower Hutt New Zealand, 188 p.

Dunstall M (2005) 2000-2005 New Zealand country update. Proceedings World Geothermal Congress 2005, Turkey.

Field B D, Uruski C I and others (1997) Cretaceous-Cenozoic geology and petroleum systems of the East Coast region, New Zealand. Institute of Geological and Nuclear Sciences Monograph 19, Lower Hutt New Zealand, 301 p.

Funnell R and Allis R G (1997) Hydrocarbon maturation potential of offshore Canterbury and Great South basins. Proceedings New Zealand Petroleum Conference, 22-30.

Funnell R, Chapman D, Allis R and Armstrong P (1996) Thermal state of the Taranaki Basin, New Zealand. JGR, V 101 (B11), 25197-25215.

Griggs J (2005) A reevaluation of geopressured-geothermal aquifers as an energy source. Proceedings 30th workshop on geothermal reservoir engineering, Stanford University, California.

Hance C N (2005) Factors affecting costs of geothermal power development. Geothermal Energy Association for the US Department of Energy, 61 p.

GNS Science Report 2007/23 26

Isaac M J, Herzer R H, Brook F J and Hayward B W (1994) Cretaceous and Cenozoic sedimentary basins of Northland, New Zealand, Inst. of Geol and Nuclear Sciences Monograph 8, 203 p.

King P R and Thrasher G P (1996) Cretaceous-Cenozoic geology and petroleum systems of the Taranaki Basin, New Zealand. Institute of Geological and Nuclear Sciences Monograph 13, Lower Hutt New Zealand, 243 p.

Klein C W, Lovekin J W and Sanyal S K (2004) New geothermal site identification and qualification. GeothermEx Inc. report.

Laplaige P, Jaudin F, Desplan A and Demange J (2000) the French geothermal experience review and perspectives. Proceedings World Geothermal Congress 2000, Kyushu Japan, 283-294.

Lund, J, Freeston D H and Boyd T L (2005) World-wide direct uses of geothermal energy 2005. Proceedings World Geothermal Congress 2005, Turkey.

Mazengarb C and Speden I G (2000) Geology of the Raukumara area. Institute of Geological and Nuclear Sciences 1:250,000 Geological Map 6.

Mckenna J, Blackwell D, Moyes C and Patterson D P (2005) Geothermal electric power supply possible from Gulf Coast, midcontinent oil field waters. Oil and Gas Journal, 34-39.

Rybach L and Sanner B (2000) Ground source heat pump systems, the European experience. GHC Bull, 16-26.

Reyes A G (2001) Mineral alteration in a low-enthalpy hydrocarbon well, Taranaki, New Zealand. Proceedings 23rd New Zealand Geothermal Workshop.

Schellschmidt R, Clauser C, and Sanner B (2000) Geothermal energy use in Germany at the turn of the millenium. Proceedings World Geothermal Congress 2000, Kyushu Japan, 427-432.

Smith M (1983) A history of hot dry rock geothermal energy systems. J Volcanol and Geoth Res, 15, 1-20.

White A A L (1983) Sedimentary formations as sources of geothermal heat. J Volcanol and Geoth Res, 15, 269-284.

Websiteshttp://www.crownminerals.govt.nz

www.fossil.energy.gov

GNS Science Report 2007/23 27

APPENDIX 1

NOTES ON THE GEOTHERMALENERGY GENERATION IN OIL AND

GAS SETTINGS CONFERENCE

GNS Science Report 2007/23 28

APPENDIX 1 NOTES ON THE GEOTHERMAL ENERGY GENERATION IN OIL AND GAS SETTINGS CONFERENCE

The conference was held in March 2006 at the Southern Methodist University (SMU) in Texas, organised by D. Blackwell. The main point of the conference is the enormous potential of oil and gas settings in providing geothermal power. What oil and gas operators view as the death of a fossil fuel system is viewed as the source of another energy by the geothermal industry that also has the blessings of the environmentally conscious population.

Talks were about 75% technical, 25% laws and regulations affecting geothermal and oil and gas systems in the USA (main points of talks are in Table 4).

The most interesting talks and posters were centred on the heat flow map of the USA that SMU had published at the AAPG. The map making was led by David Blackwell of SMU. One of the main offshoots of this map is the reestimation of the geothermal potential of the USA using oil and gas wells and EGS technology (EGS= Enhanced or Engineered Geothermal Systems). The total conservative geothermal potential of the USA is 43,617,976 MWe. At present geothermal provides 8900 MWe of power to 24 countries world-wide.

The oil and gas operators view water flooding as the end of the field whereas geothermal operators see this phenomenon as the start of a new source of energy. Some of the problems in harnessing geothermal energy from oil and gas wells are not technical but include the lack of communication between people in the oil and gas and geothermal industries and the lack of overt support from the federal government. During the meeting the discussion panel decided to write a one-page white paper report on “Geothermal Energy Generation in Oil and gas Settings”, to be submitted to the government and oil and gas operators. Interestingly, the convenors sent nearly 15,000 invitations to oil and gas operators and technical people, government officials and the media to attend this conference (which is the first in the world and quite important for the future energy outlook of the USA, at least) but there were only 90 attendees, <10 are oil and gas operators, one government representative, and mostly geothermal people.

GN

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29

Tabl

e 5.

Mai

n po

ints

of p

rese

ntat

ions

dur

ing

the

Oil

and

Gas

con

fere

nce

held

in M

arch

200

6.

Spea

ker

Com

pany

/Age

ncy

Topi

c M

ain

Poin

ts o

f Tal

k

Ray

La

Sala

U

S D

OE

Geo

ther

mal

Te

chno

logi

es

Dep

t. of

Ene

rgy

Geo

ther

mal

Fo

cus

DO

E’s

geo

ther

mal

bud

get f

or 2

007:

$0.

00 y

et th

ey p

lan

to h

ave

40,0

00 M

We

from

ge

othe

rmal

by

2040

at <

US

$0.0

5/kw

h (=

NZ$

0.08

/kw

h; in

NZ

elec

trici

ty c

ost:

NZ$

0.06

3/kw

h). A

t pre

sent

US

A p

rodu

ces

2600

MW

e fro

m g

eoth

erm

al

Susa

nP

etty

B

lack

Mou

ntai

n Te

chno

logy

U

S 2

006

Enh

ance

d G

eoth

erm

al S

yste

m

Res

ourc

e E

valu

atio

n

Tota

l rec

over

able

ene

rgy

from

oil

& g

as w

ells

at >

80o C

incl

udin

g ov

erpr

essu

red

syst

ems:

43,

617,

976

MW

e @

20%

reco

very

, usi

ng O

RC

and

con

vent

iona

l ste

am

turb

ines

(lot

s of

ver

y co

nser

vativ

e as

sum

ptio

ns in

cal

cula

tions

) D

ubTa

ylor

S

tate

Ene

rgy

Con

serv

atio

n O

ffice

(S

EC

O)-

Texa

s R

enew

able

P

rogr

am

Texa

s R

enew

able

Pro

gram

an

d D

emon

stra

tion

Site

s Te

xas

is th

e 5th

larg

est e

nerg

y us

er in

the

wor

ld a

nd m

ost o

f the

ene

rgy

sour

ces

are

from

foss

il fu

els.

Loui

s C

apua

no

Ther

maS

ourc

e, In

c C

ompa

rison

bet

wee

n ge

othe

rmal

and

oil

& ga

s dr

illin

g

Maj

or d

iffer

ence

s: te

mpe

ratu

re, p

rodu

ctio

n pr

essu

res,

rock

form

atio

n ch

arac

teris

tics,

pr

oduc

tion

rate

s an

d ty

pes

of d

isch

arge

flui

ds; t

ubin

gs u

sed

in o

il &

gas

, slo

tted

liner

s in

geo

ther

mal

Pa

ulTh

omse

n O

RM

AT

Mod

ular

bin

ary

pow

er

gene

rato

rs

Bin

ary

and

flash

ste

am tu

rbin

es, m

odul

ar (m

ainl

y an

adv

ertis

ing

spie

l- pr

esen

tatio

n on

O

RM

AT

data

mos

t peo

ple

in th

e ge

othe

rmal

indu

stry

alre

ady

know

). Tu

rbin

e ef

ficie

ncy

is n

ow 8

8%.

Dav

idBl

ackw

ell

Sou

ther

n M

etho

dist

Uni

vers

ity

Geo

ther

mal

reso

urce

s in

se

dim

enta

ry b

asin

s D

iscu

ssed

wha

t fac

tors

SM

U c

onsi

dere

d in

mak

ing

heat

flow

map

of U

SA

(AA

PG

pu

blic

atio

n) e

.g.,

used

sev

eral

cor

rect

ion

fact

ors

to e

stim

ate

BH

T’s

at v

ario

us d

epth

s.

Sce

nario

s fo

r dev

elop

men

t of s

edim

enta

ry b

asin

s: c

o-pr

oduc

tion

of fl

uids

, ge

opre

ssur

ed fl

uids

, sed

imen

tary

EG

S (e

nhan

ced

geot

herm

al s

yste

ms)

W

illG

osno

ld

Uni

vers

ity o

f Nor

th D

akot

a, D

ept

of G

eol &

Geo

l. E

ngg

Nor

ther

n G

reat

Pla

ins

geot

herm

al re

sour

ces

Ano

mal

ousl

y hi

gh te

mpe

ratu

res

in th

is re

gion

par

tly d

ue to

bla

nket

ing

effe

ct o

f sha

les

and

heat

adv

ectio

n in

regi

onal

gro

undw

ater

flow

sys

tem

. B

erni

Kar

l C

hena

Hot

Spr

ings

Res

ort

Geo

ther

mal

ele

ctric

al

appl

icat

ion

in A

lask

a 74

o C w

ater

s fro

m w

ell u

sed

to p

rovi

de e

lect

ricity

for r

esor

t usi

ng O

RC

sys

tem

of

Uni

ted

Tech

nolo

gies

whe

re C

arrie

r air

cond

ition

ers

are

reen

gine

ered

as

reve

rse

chill

ers

(sm

alle

st m

odul

e is

200

kw).

Use

d th

erm

al w

ater

s ar

e ca

scad

ed fo

r use

in

gree

nhou

se, s

pace

hea

ting

and

an ic

e ho

use

(Kal

ina

cycl

e)

Dic

kB

enoi

t S

usta

inab

le S

olut

ions

S

calin

g an

d co

rrosi

on

abat

emen

t M

ain

prob

lem

s in

oil

& g

as w

ells

that

wou

ld b

e us

ed a

s ge

othe

rmal

wel

ls w

ould

be

carb

onat

e sc

alin

g an

d co

rrosi

on d

ue to

hyp

er s

alin

e flu

ids

M

ike

Shoo

kC

hevr

on-T

exac

o H

eat e

xtra

ctio

n fro

m

sedi

men

tary

form

atio

ns

Mod

elle

d se

vera

l sce

nario

s on

how

hea

t can

be

extra

cted

from

oil

& g

as w

ells

: bes

t ca

se is

a v

ertic

al w

ell d

ual d

oubl

et w

ith a

circ

ulat

ion

rate

of 6

.31

kg/s

. Inl

et T

(T o

f w

ater

bei

ng fe

d in

to w

ell)=

27o C

, fed

wat

er h

eate

d to

203

o C. T

here

is a

nee

d to

ba

lanc

e ci

rcul

atio

n ra

te a

nd te

mpe

ratu

res

for o

ptim

um e

nerg

y ef

ficie

ncy-

bes

t mod

el

is u

se o

f hor

izon

tal w

ells

but

mod

ellin

g st

udy

still

ongo

ing.

Geo

ther

mal

pro

duct

ion

from

mat

ure

wat

ered

-out

oil

& g

as fi

elds

and

from

fiel

ds w

ith o

n-go

ing

wat

er-fl

oodi

ng

Pre

ntic

eC

reel

Hal

libur

ton

Wel

l int

egrit

y to

ext

end

a w

ell’s

life

U

se o

f zon

ed s

eal f

oam

cem

ent e

xtol

led

beca

use

of it

s hi

gh s

treng

th, h

igh

visc

osity

an

d ex

celle

nt d

ispl

acem

ent p

rope

rties

, res

ultin

g to

bet

ter c

emen

ting

jobs

- the

key

to

long

live

s of

wel

ls

GN

S S

cien

ce R

epor

t 200

7/23

30

Spea

ker

Com

pany

/Age

ncy

Topi

c M

ain

Poin

ts o

f Tal

k

Tim

Sm

ith

Ele

men

t Mar

kets

LP

R

enew

able

Ene

rgy

Cre

dits

(R

EC

’s) f

or th

e G

ulf C

oast

S

tate

s

Reg

ulat

ions

in th

e U

SA

1R

EC

= 1M

Wh

of e

nerg

y

Gre

gM

ines

Idah

o N

atio

nal l

abor

ator

y C

ontri

buto

rs to

the

cost

of

geot

herm

al p

ower

pr

oduc

tion

Reg

ulat

ions

in th

e U

SA

Jaso

nM

cKen

na

Eng

inee

r res

earc

h an

d D

evel

opm

ent C

ente

r US

Arm

y C

orps

of E

ngin

eers

Geo

ther

mal

pot

entia

l in

milit

ary

faci

litie

s W

ater

/oil

ratio

cut

(wat

er-fl

oodi

ng) =

95%

. Thi

nkin

g of

usi

ng fl

oode

d oi

l & g

as s

yste

ms

in Ir

aq to

incr

ease

cou

ntry

’s e

nerg

y so

urce

bas

e

Ric

hard

E

rdla

cU

nive

rsity

of T

exas

Per

mia

n Ba

sin

CEE

D

Texa

s ge

othe

rmal

ene

rgy:

a

focu

s on

Per

mia

n ba

sin

and

Tran

s-P

ecos

regi

ons

7 po

ster

s pr

esen

ted

Mos

t int

eres

ting

post

er is

a n

ew s

yste

m fo

r har

ness

ing

ener

gy u

sing

the

mov

emen

t of

a m

agne

t in

a tu

be, b

y ei

ther

a te

mpe

ratu

re o

r pre

ssur

e gr

adie

nt- s

till i

n de

velo

pmen

t st

age

(Lar

ry S

hultz

of E

ncor

e C

lean

Ene

rgy)

R

icha

rd

Cam

pbel

l TI

C- T

he In

dust

rial C

ompa

ny

Res

ults

of t

he d

emon

stra

tion

pow

er p

lant

on

the

Ple

asan

t Ba

you

geop

ress

ured

re

sour

ce

Wel

l has

WH

P=

20.7

MP

a. F

luid

s ha

ve 8

7% C

H4.

A h

ybrid

cyc

le p

ower

pla

nt is

use

d,

equi

pped

with

a p

ress

ure

redu

ctio

n tu

rbin

e. G

as=

690

kW, b

inar

y cy

cle

turb

ine

= 53

5 kW

and

par

asiti

c lo

ad =

270

kW

. Hea

t exc

hang

er u

ses

the

Ran

kine

cyc

le. H

ybrid

sy

stem

has

a h

ighe

r effi

cien

cy th

an 2

pla

nts

oper

atin

g 2

diffe

rent

flui

ds. P

robl

ems

from

cor

rosi

ve b

rine

solv

ed b

y us

ing

16 g

auge

ste

el; s

calin

g fro

m 1

30,0

00 T

DS

w

ater

s by

usi

ng in

hibi

tors

; car

bon

foul

ing

by c

losi

ng th

en o

peni

ng p

lant

regu

larly

Jo

elR

enne

r Id

aho

Nat

iona

l Lab

orat

ory

Plea

sant

Bay

ou, T

X ge

opre

ssur

ed g

eoth

erm

al

rese

rvoi

r

Geo

pres

sure

d sy

stem

s: P

rang

e =

59.3

-91.

0MP

a, T

rang

e =

110-

180o C

. In

Ple

asan

t B

ayou

, TX

wel

l is

5030

m d

eep,

has

sal

t dom

es a

nd h

as in

ters

ecte

d a

leak

y fa

ult(l

eaka

ge in

faul

t due

to p

ress

ure

diffe

rent

ials

in re

serv

oir)

Ric

hard

E

rdla

cU

T P

erm

ian

Bas

in C

EE

D

Con

stra

ints

and

bes

t use

pr

actic

es: t

he im

porta

nce

of

Texa

s ge

othe

rmal

ele

ctric

al

ener

gy p

rodu

ctio

n

Mai

n th

esis

of t

alk

is to

ent

ice

oil &

gas

ope

rato

rs a

nd th

e Te

xas

gove

rnm

ent t

o us

e oi

l &

gas

wel

ls th

at a

re c

onsi

dere

d us

eles

s by

the

oil &

gas

indu

stry

for g

eoth

erm

al

prod

uctio

n. H

e em

phas

ised

that

wat

er in

an

oil &

gas

wel

l is

not a

liab

ility

but a

n as

set.

Enc

oura

ges

use

of p

inna

te d

rillin

g sy

stem

, ofte

n us

ed in

coa

l bed

CH

4ex

tract

ion,

to b

e ad

apte

d to

oil

& g

as c

um g

eoth

erm

al w

ells

. M

ark

Milli

can

Roc

ky M

ount

ain

Oilf

ield

Tes

ting

Cen

ter

Tea

Pot

Dom

e C

ase

Stu

dy,

Wyo

min

g Ta

p C

ambr

ian

sand

ston

e an

d P

re-C

ambr

ian

base

men

t for

geo

ther

mal

at T

= 1

20-

125o C

Susa

nP

etty

B

lack

Mou

ntai

n Te

chno

logy

G

eoth

erm

al p

ower

ge

nera

tion

pote

ntia

l- P

opla

r D

ome,

MT

In P

opla

r Dom

e, p

rese

nt o

il &

gas

wel

ls n

eed

to b

e de

epen

ed to

3-4

km

whe

re T

is a

s hi

gh a

s 13

5o C in

faul

t zon

e. 3

sce

nario

s fo

r exp

lorin

g ge

othe

rmal

ene

rgy

in o

il &

gas

sy

stem

s: (1

) use

wel

ls o

f opp

ortu

nity

(exi

stin

g w

ells

), (2

) enh

ance

d re

cove

ry, (

3) E

GS

te

chno

logy

. Som

e of

the

prob

lem

s: th

ere

is a

nee

d to

get

rid

of m

ost o

f the

oil

as th

is

wou

ld fo

ul u

p he

at e

xcha

nger

s (u

se d

ispe

rsan

ts),

may

nee

d el

ectri

c su

bmer

sibl

e pu

mps

, wel

l stim

ulat

ion,

per

fora

te o

il &

gas

wel

l tub

ings

. In

all h

er s

cena

rios,

Pet

ty

coul

d on

ly g

o do

wn

to $

US

0.06

88/k

wh

whi

ch is

30%

hig

her t

han

the

goal

of

US

$0.0

5/kw

h se

t by

DO

E

GNS Science Report 2007/23 31

APPENDIX 2

ABANDONED ONSHOREHYDROCARBON WELLS

IN NEW ZEALAND

GNS Science Report 2007/23 32

Table 6. Basic well data for onshore abandoned hydrocarbon wells in New Zealand. BHT= bottom hole temperature calculated from heat flow data, MWt = megawatt thermal, MWe = megawatt electrical, MWh = megawatt-hour (8766 hours/year), TJ = terajoules, PJ= petajoules. In the calculations, the BHT is the same as the extraction temperature.

Well Name DateCompleted

Total Depth

(m)BHT(oC) MW MWt

(CF=0.7) MWe

(CF=0.1) MWh TJ PJ

NORTH ISLANDEAST COAST Awatere-1 2/06/1998 2136.0 69.9 1.2 0.8 7192 25.9 0.03 Back Ormond Road-1 1/12/1992 301.1 24.0 0.4 0.3 2479 8.9 0.01 Back Ormond Road-2 21/12/1992 300.1 24.0 0.4 0.3 2479 8.9 0.01 Gisborne-1 27/10/1928 927.0 40.6 0.7 0.5 4222 15.2 0.02 Gisborne-2 23/03/1930 1192.0 46.8 0.8 0.6 4835 17.4 0.02 Hukarere-1 24/11/2001 3213.2 94.6 1.6 1.1 9769 35.2 0.04 Kauhauroa-2 8/11/1998 2131.0 69.8 1.2 0.8 7192 25.9 0.03 Kauhauroa-5 16/06/1999 1751.0 60.0 1.0 0.7 6161 22.2 0.02 Kereru-1 30/11/1996 1939.0 56.6 0.9 0.7 5743 20.7 0.02 Kiakia-1/1A 21/08/1998 2225.0 72.2 1.2 0.8 7388 26.6 0.03 Koranga-1 18/04/1978 273.0 20.9 0.4 0.2 2160 7.8 0.01 Mangaone-1 20/04/1961 1550.0 56.3 0.9 0.7 5743 20.7 0.02 Mason Ridge-1 23/06/1971 1880.0 58.0 1.0 0.7 5964 21.5 0.02 Minerva Borehole 283.0 23.8 0.4 0.3 2479 8.9 0.01 Morere-1 20/11/1941 2037.0 69.3 1.2 0.8 7093 25.5 0.03 Ongaonga-1 2/05/1971 1573.0 48.7 0.8 0.6 5032 18.1 0.02 Opoho-1 20/12/1998 2320.0 76.9 1.3 0.9 7903 28.5 0.03 Opoutama-1 17/08/1967 3658.5 112.6 1.9 1.3 11634 41.9 0.04 Peep-O-Day 13/01/1914 917.0 34.7 0.6 0.4 3608 13.0 0.01 Rakaiatai-1 19/06/1969 685.7 29.7 0.5 0.4 3093 11.1 0.01 Rere-1 4/04/1986 4351.0 149.7 2.5 0.3 2216 8.0 0.01 Rotokautuku-1 13/03/1972 625.1 65.6 1.1 0.8 6774 24.4 0.02 Rotokautuku-1 (Southern Cross) 145.0 21.2 0.4 0.2 2160 7.8 0.01

Rotokautuku-2 172.0 22.4 0.4 0.3 2258 8.1 0.01 Rotokautuku-4 114.0 19.9 0.3 0.2 2062 7.4 0.01 Rotokautuku-5 560.0 33.7 0.6 0.4 3510 12.6 0.01 Ruakituri-1 1/01/1962 2745.0 85.6 1.4 1.0 8836 31.8 0.03 Speedy-1 20/07/2000 876.0 33.8 0.6 0.4 3510 12.6 0.01 Speedy-1 876.0 33.8 0.6 0.4 3510 12.6 0.01 Takapau-1 23/05/1971 1059.0 37.7 0.6 0.4 3903 14.0 0.01 Tane-1 (Mangaone) 13/01/1914 917.0 34.7 0.6 0.4 3608 13.0 0.01 Taradale-1 1/01/1969 1660.7 57.7 1.0 0.7 5964 21.5 0.02 Tautane-1 29/07/2001 1328.9 43.5 0.7 0.5 4516 16.3 0.02 Te Hoe-1 30/07/1990 627.0 32.3 0.5 0.4 3289 11.8 0.01 Te Horo-1 23/05/1972 1829.3 76.0 1.3 0.9 7805 28.1 0.03 Te Karaka-1 152.0 19.7 0.3 0.2 2062 7.4 0.01 Te Puia-1 5/08/1972 2042.7 80.2 1.3 0.9 8223 29.6 0.03 Toi Flat-1 1/01/1991 55.0 16.2 0.3 0.2 1645 5.9 0.01 Totangi-1 24/11/1939 103.0 18.1 0.3 0.2 1865 6.7 0.01 Totangi-1A 1903 64.0 17.0 0.3 0.2 1743 6.3 0.01 Totangi-1B 24/11/1939 1737.0 68.8 1.2 0.8 7093 25.5 0.03 Totangi-2 1903 154.0 19.7 0.3 0.2 2062 7.4 0.01 Totangi-2A 1903 156.0 19.8 0.3 0.2 2062 7.4 0.01 Tuhara-1B 24/06/2002 2169.3 70.8 1.2 0.8 7290 26.2 0.03 Waewaepa-1 1/01/1991 124.0 17.7 0.3 0.2 1865 6.7 0.01 Waiapu-1 774.0 40.8 0.7 0.5 4222 15.2 0.02 Waiapu-2 994.0 44.8 0.8 0.5 4614 16.6 0.02 Waihihere-1 421.0 27.6 0.5 0.3 2872 10.3 0.01 Waingaromia Bore 403.0 27.1 0.5 0.3 2774 10.0 0.01 Waingaromia-2 27/05/2002 502.1 30.1 0.5 0.4 3093 11.1 0.01 Waipatiki-1 1921 1097.0 38.5 0.7 0.5 4001 14.4 0.01 Waipatiki-2 1912 966.0 35.7 0.6 0.4 3706 13.3 0.01 Waitangi Hill-1 64.0 17.0 0.3 0.2 1743 6.3 0.01 Waitangi Station-1 9/07/1972 2135.0 79.1 1.3 0.9 8124 29.2 0.03 Waitangi-1 3/04/1931 512.7 30.6 0.5 0.4 3191 11.5 0.01 Waitangi-1 (Gisborne Oil) 1909 450.0 28.9 0.5 0.3 2994 10.8 0.01 Waitangi-1 (Taranaki Oilfields) 1930 513.0 30.9 0.5 0.4 3191 11.5 0.01 Waitangi-2 1931 662.0 35.2 0.6 0.4 3608 13.0 0.01 Waitaria-1B 27/08/1997 1150.0 49.0 0.8 0.6 5032 18.1 0.02 Waitaria-2 14/03/2001 2548.1 90.2 1.5 1.1 9253 33.3 0.03 Westcott-1 1/01/1991 67.0 16.4 0.3 0.2 1645 5.9 0.01 Whakatu-1 7/02/2000 1455.0 46.2 0.8 0.5 4737 17.1 0.02 NORTHLAND 0.0Access Road 1963? 476.0 33.1 0.6 0.4 3387 12.2 0.01 Dargaville-1 1963? 248.0 23.3 0.4 0.3 2381 8.6 0.01 Dargaville-2 1963? 445.0 29.8 0.5 0.4 3093 11.1 0.01 Kaiaka-1 11/11/1957 625.0 35.8 0.6 0.4 3706 13.3 0.01 Kioreroa-1 148.0 21.0 0.4 0.2 2160 7.8 0.01

GNS Science Report 2007/23 33

Well Name DateCompleted

Total Depth

(m)BHT(oC) MW MWt

(CF=0.7) MWe

(CF=0.1) MWh TJ PJ

NORTH ISLANDNORTHLAND 0.0Kioreroa-2 109.0 19.4 0.3 0.2 1964 7.1 0.01 Kioreroa-3 54.0 17.1 0.3 0.2 1743 6.3 0.01 Northland-1 19/11/1972 625.9 38.8 0.7 0.5 4001 14.4 0.01 Waimamaku-1 1273.0 63.5 1.1 0.7 6480 23.3 0.02 Waimamaku-2 16/02/1972 3356.7 126.9 2.1 0.2 1872 6.7 0.01 NOT IN BASIN NORTH ISLAND Ardmore-1 137.0 19.6 0.3 0.2 1964 7.1 0.01 Great Barrier-1 226.0 24.7 0.4 0.3 2577 9.3 0.01 Great Barrier-2 92.0 18.9 0.3 0.2 1964 7.1 0.01 Horotiu Bore-1 137.0 19.2 0.3 0.2 1964 7.1 0.01 Horotiu Bore-2 137.0 19.2 0.3 0.2 1964 7.1 0.01 Horotiu Bore-3 195.0 20.9 0.4 0.2 2160 7.8 0.01 Horotiu Bore-4 229.0 22.0 0.4 0.3 2258 8.1 0.01 Horotiu-2 198.0 21.0 0.4 0.2 2160 7.8 0.01 Horotiu-5 198.0 21.0 0.4 0.2 2160 7.8 0.01 Kaiaua-1 2/02/1955 108.0 18.1 0.3 0.2 1865 6.7 0.01 Karaka-1 614.0 35.5 0.6 0.4 3706 13.3 0.01 Mangatawa-1 669.0 40.5 0.7 0.5 4222 15.2 0.02 Puketaha-1 24/10/1963 475.0 29.5 0.5 0.4 3093 11.1 0.01 Rangitaike-1 61.0 17.3 0.3 0.2 1743 6.3 0.01 Rangitaike-1A 479.0 33.2 0.6 0.4 3387 12.2 0.01 Rangitaike-2 194.0 22.4 0.4 0.3 2258 8.1 0.01 River Road-1 6/12/1963 789.0 39.0 0.7 0.5 4001 14.4 0.01 T.E. Weily-1 17/10/1966 1057.3 47.7 0.8 0.6 4934 17.8 0.02 Te Rapa-1 10/02/1964 1684.0 66.3 1.1 0.8 6774 24.4 0.02 Waikato-1 8/07/1971 1036.0 46.6 0.8 0.6 4835 17.4 0.02 Waikato-2 18/07/1971 1026.2 46.3 0.8 0.6 4835 17.4 0.02 Waikato-3 10/10/1972 320.1 24.8 0.4 0.3 2577 9.3 0.01 Waikato-4 29/11/1972 598.5 33.2 0.6 0.4 3387 12.2 0.01 Waikato-5 19/10/1972 1013.1 45.9 0.8 0.5 4737 17.1 0.02 Waiotapu-1 61.0 17.9 0.3 0.2 1865 6.7 0.01 Waiotapu-2 113.0 20.4 0.3 0.2 2062 7.4 0.01 Waipai-1 45.0 16.0 0.3 0.2 1645 5.9 0.01 TARANAKI Ahuroa-1 26/09/1986 3326.0 106.9 1.8 1.3 11021 39.7 0.04 Ahuroa-1A 11/10/1986 3153.0 102.1 1.7 1.2 10481 37.7 0.04 Ahuroa-2 10/12/1986 2465.0 83.1 1.4 1.0 8517 30.7 0.03 Bell Block-1 1/01/1913 1131.0 54.9 0.9 0.6 5645 20.3 0.02 Bell Block-2 8/02/1912 853.0 45.1 0.8 0.5 4614 16.6 0.02 Beta 208.0 21.9 0.4 0.3 2258 8.1 0.01 Blenheim-2 640.0 37.6 0.6 0.4 3903 14.0 0.01 Bonithon-1 1908 916.0 47.3 0.8 0.6 4835 17.4 0.02 Bonithon-2 1908 764.0 41.9 0.7 0.5 4320 15.6 0.02 Burgess-1 28/09/1989 3264.0 108.3 1.8 1.3 11217 40.4 0.04 Cape Egmont-1 17/11/1986 2435.0 84.6 1.4 1.0 8738 31.5 0.03 Cape Farewell-1 22/03/1986 2817.0 108.9 1.8 1.3 11217 40.4 0.04 Cardiff-1 21/08/1992 5064.0 152.5 2.6 1.8 0.3 2262 8.1 0.01 Carrington Road-1 1042.0 49.7 0.8 0.6 5130 18.5 0.02 Carrington Road-2 112.0 18.7 0.3 0.2 1964 7.1 0.01 Clematis-1 24/12/1999 1800.0 70.7 1.2 0.8 7290 26.2 0.03 Crusader-1 11/08/2000 2441.0 96.4 1.6 1.1 9867 35.5 0.04 Crusader-1A 19/09/2000 2060.0 83.7 1.4 1.0 8640 31.1 0.03 Cutters Bridge-1 48.0 16.8 0.3 0.2 1743 6.3 0.01 Devon-1 1/03/1943 2868.0 116.1 1.9 1.4 11953 43.0 0.04 Devon-2 16/07/1943 1883.0 77.8 1.3 0.9 8002 28.8 0.03 Dobson-1 682.0 37.7 0.6 0.4 3903 14.0 0.01 Dobson-2 611.0 35.4 0.6 0.4 3608 13.0 0.01 Durham-1 18/08/1989 2303.0 80.8 1.4 0.9 8321 30.0 0.03 Hu Road-1/1A 13/06/1991 3350.0 105.9 1.8 1.2 10898 39.2 0.04 Huinga-1, 1A, 1B 12/06/2002 4373.0 133.7 2.3 0.2 1974 7.1 0.01 Huiroa Bore 1500.0 56.4 0.9 0.7 5743 20.7 0.02 Inglewood-1 20/06/1963 5061.0 164.4 2.8 0.3 2430 8.7 0.01 Kaimiro-12 18/01/1996 835.0 40.8 0.7 0.5 4222 15.2 0.02 Kaimiro-14, 14A 14/02/1996 1843.0 76.4 1.3 0.9 7805 28.1 0.03 Kaipikari-1 10/10/1994 1854.0 70.6 1.2 0.8 7290 26.2 0.03 Kapuni-15 15/01/1992 4770.0 135.4 2.3 0.2 1992 7.2 0.01 Kiore-1 19/11/1964 536.6 30.3 0.5 0.4 3093 11.1 0.01 Koporongo-1 16/06/1971 590.9 31.6 0.5 0.4 3289 11.8 0.01 Makara-1 7/11/1984 2940.0 103.2 1.7 1.2 10603 38.2 0.04 Makara-1B 27/12/1984 2467.0 89.0 1.5 1.0 9155 33.0 0.03 Maketawa-1 30/10/2000 1135.4 47.4 0.8 0.6 4835 17.4 0.02 Makino-1, 1AA 17/02/2002 4100.0 116.5 1.9 1.4 11953 43.0 0.04 Makuri-1, 1A 18/08/1984 2500.0 86.4 1.4 1.0 8836 31.8 0.03

GNS Science Report 2007/23 34

Well Name DateCompleted

Total Depth

(m)BHT(oC) MW MWt

(CF=0.7) MWe

(CF=0.1) MWh TJ PJ

NORTH ISLANDTARANAKI Mangamahoe-1 29/10/1993 802.0 41.7 0.7 0.5 4222 15.2 0.02 Manganui-1 30/06/1982 3975.0 138.0 2.3 0.2 2037 7.3 0.01 Manganui-2 31/05/1984 3753.0 131.2 2.2 0.2 1932 7.0 0.01 Mangorei-1 2229.0 89.3 1.5 1.0 9155 33.0 0.03 McKee-13 28/01/1995 2278.0 80.1 1.3 0.9 8223 29.6 0.03 McKee-2B 8/07/2000 2237.0 78.9 1.3 0.9 8124 29.2 0.03 McKee-2C 15/06/2000 2316.0 81.2 1.4 0.9 8321 30.0 0.03 McKee-3 13/11/1981 2400.0 83.6 1.4 1.0 8640 31.1 0.03 McKee-6 6/05/1987 2227.0 78.6 1.3 0.9 8124 29.2 0.03 McKee-7 9/06/1987 2178.0 77.2 1.3 0.9 7903 28.5 0.03 Midhurst-1 14/02/1942 3330.8 105.4 1.8 1.2 10800 38.9 0.04 Moa Bore 140.0 18.5 0.3 0.2 1865 6.7 0.01 Mokoia-1 31/05/1989 3750.0 97.1 1.6 1.1 9965 35.9 0.04 Moturoa Bore 1329.0 59.3 1.0 0.7 6063 21.8 0.02 Moturoa-3 31/05/1933 658.0 38.2 0.6 0.4 3903 14.0 0.01 New Plymouth-1 15/04/1975 655.0 38.1 0.6 0.4 3903 14.0 0.01 New Plymouth-2 4/10/1965 4451.6 171.9 2.9 0.3 2553 9.2 0.01 Ngatoro-1 27/03/1984 4126.0 146.6 2.5 0.2 2170 7.8 0.01 Norfolk Road Bore 762.0 36.8 0.6 0.4 3804 13.7 0.01 Oakura-1 13/11/1998 3220.0 100.9 1.7 1.2 10382 37.4 0.04 Okoke Bore 11/07/1927 61.0 16.8 0.3 0.2 1743 6.3 0.01 Omata Bore-1 1930? 152.0 20.1 0.3 0.2 2062 7.4 0.01 Omata Bore-2 1930? 323.0 25.8 0.4 0.3 2675 9.6 0.01 Omata-1 1930? 960.0 47.0 0.8 0.6 4835 17.4 0.02 Onaero-1 14/12/1980 3590.0 124.4 2.1 0.2 1827 6.6 0.01 Oru-1 12/11/2005 1700.0 61.1 1.0 0.7 6259 22.5 0.02 Paritutu-1 24/09/1993 2400.0 95.0 1.6 1.1 9769 35.2 0.04 Patea East-1 11/08/2003 1082.5 39.2 0.7 0.5 4001 14.4 0.01 Patea-1 30/07/2003 1613.0 51.1 0.9 0.6 5253 18.9 0.02 Piakau-1 17/11/1986 2905.0 95.2 1.6 1.1 9769 35.2 0.04 Pohokura South-1 31/03/2001 3780.0 132.0 2.2 0.2 1946 7.0 0.01 Pouri-2 2/01/1997 2233.0 80.9 1.6 1.1 9793 35.3 0.04 Prospect Valley-1 29/09/1928 272.0 22.9 0.4 0.3 2258 8.1 0.01 Prospect Valley-2 430.0 27.5 0.5 0.3 2774 10.0 0.01 Pukearuhe-1 5/09/1986 3138.0 107.6 1.8 1.3 11119 40.0 0.04 Pukemai-1 10/07/1983 2293.0 83.8 1.4 1.0 8640 31.1 0.03 Pukemai-1A 24/07/1983 2432.0 88.0 1.5 1.0 9032 32.5 0.03 Pukemai-2 20/11/1983 2631.0 93.9 1.6 1.1 9671 34.8 0.03 Pukemai-3 6/03/1991 2098.0 77.9 1.3 0.9 8026 28.9 0.03 Ratapiko-1 21/01/2001 1597.0 62.1 1.1 0.7 6480 23.3 0.02 Rotary Bore 853.0 45.1 0.8 0.5 4614 16.6 0.02 Rotokare-1 23/02/1989 3232.7 102.7 1.7 1.2 10603 38.2 0.04 Salisbury-1 23/03/1996 2050.0 73.6 1.2 0.9 7609 27.4 0.03 Samuel Syndicate-1 283.0 24.4 0.4 0.3 2479 8.9 0.01 Samuel Syndicate-2 335.0 26.2 0.4 0.3 2675 9.6 0.01 Samuel Syndicate-3 468.0 30.6 0.5 0.4 3191 11.5 0.01 Samuel Syndicate-5 626.0 35.9 0.6 0.4 3706 13.3 0.01 Samuel Syndicate-6 92.0 18.1 0.3 0.2 1865 6.7 0.01 Samuel Syndicate-7 457.0 30.2 0.5 0.4 3093 11.1 0.01 Samuel Syndicate-8 625.0 35.8 0.6 0.4 3706 13.3 0.01 Samuel Syndicate-9 322.0 25.7 0.4 0.3 2675 9.6 0.01 Spotswood-1 925.0 45.8 0.8 0.5 4737 17.1 0.02 Standish-1 12/04/1993 1845.0 66.0 1.1 0.8 6774 24.4 0.02 Stent-1 5/09/2004 2710.0 93.7 1.6 1.1 9671 34.8 0.03 Taranaki Petroleum-1 (1866) 1866 94.0 18.1 0.3 0.2 1865 6.7 0.01 Taranaki Petroleum-2 (1866) 1866 97.0 18.2 0.3 0.2 1865 6.7 0.01 Taranaki Petroleum-4 511.0 33.0 0.6 0.4 3387 12.2 0.01 Tarata-1 7/05/1926 1527.0 60.8 1.0 0.7 6259 22.5 0.02 Tariki North-1 25/06/1987 2431.0 81.0 1.4 0.9 8321 30.0 0.03 Tariki North-1A 24/06/1987 3209.0 102.1 1.7 1.2 10382 37.4 0.04 Tariki-1 11/04/1986 3191.0 101.6 1.7 1.2 10382 37.4 0.04 Tariki-2 4/02/1987 3020.0 97.0 1.6 1.1 9965 35.9 0.04 Tariki-2A 10/03/1987 2564.5 84.6 1.4 1.0 8738 31.5 0.03 Tariki-4, 4C 1995 2777.0 90.4 1.5 1.1 9253 33.3 0.03 Tauteka-1 25/02/1983 2309.0 86.5 1.4 1.0 8836 31.8 0.03 Te Kiri-1 2/06/1986 4710.0 154.1 2.6 0.3 2276 8.2 0.01 Tikorangi-1 221.0 22.4 0.4 0.3 2258 8.1 0.01 Tipoka-1, 1A 21/10/1986 4359.0 141.6 2.4 0.2 2097 7.5 0.01 Tipoka-2 15/11/1993 2504.0 87.7 1.5 1.0 9057 32.6 0.03 Toetoe-1 11/09/1984 2310.0 84.3 1.4 1.0 8640 31.1 0.03 Toetoe-2 26/11/1984 2276.0 83.3 1.4 1.0 8517 30.7 0.03 Toetoe-2A, 2C 29/09/1987 1829.0 69.9 1.2 0.8 7192 25.9 0.03

GNS Science Report 2007/23 35

Well Name DateCompleted

Total Depth

(m)BHT(oC) MW MWt

(CF=0.7) MWe

(CF=0.1) MWh TJ PJ

NORTH ISLANDTARANAKI Toetoe-3 23/02/1985 2618.0 93.5 1.6 1.1 9671 34.8 0.03 Toetoe-4A, B, C 8/05/1997 2326.0 87.0 1.5 1.0 8934 32.2 0.03 Toetoe-5 27/12/1988 2536.0 93.5 1.6 1.1 9671 34.8 0.03 Toetoe-6A 31/10/1999 1817.0 69.5 1.2 0.8 7192 25.9 0.03 Toetoe-7 27/07/1989 2315.0 84.5 1.4 1.0 8738 31.5 0.03 Toetoe-8 15/10/1992 1986.0 74.6 1.3 0.9 7707 27.7 0.03 Toetoe-9 3/09/1992 2027.0 75.8 1.3 0.9 7805 28.1 0.03 Toko-1 31/08/1979 4900.0 150.3 2.5 0.3 2216 8.0 0.01 Toko-2 30/04/1994 3202.0 103.4 1.7 1.2 10603 38.2 0.04 Totara-1 14/06/1987 3965.0 132.1 2.2 0.2 1946 7.0 0.01 Tuhua-1 Re-entry 1994 2564.0 88.3 1.5 1.0 9032 32.5 0.03 Tuhua-2, 2A 24/09/1983 2529.0 87.3 1.5 1.0 8934 32.2 0.03 Tuhua-3A, B, C 31/08/1988 2125.0 78.8 1.3 0.9 8124 29.2 0.03 Tuhua-5A 6/02/1991 2509.0 86.7 1.5 1.0 8934 32.2 0.03 Tuhua-8 30/08/1994 2471.0 85.6 1.4 1.0 8836 31.8 0.03 Tuihu-1, 1A 25/09/2003 4845.0 153.4 2.6 0.3 2276 8.2 0.01 Tupapakurua-1 1/06/1971 1150.0 47.3 0.8 0.6 4835 17.4 0.02 Uruti-1 7/10/1943 356.0 25.5 0.4 0.3 2675 9.6 0.01 Uruti-2 10/01/1944 1553.0 60.9 1.0 0.7 6259 22.5 0.02 Victoria 157.0 20.2 0.3 0.2 2062 7.4 0.01 Vogeltown Bore 1909 422.0 29.1 0.5 0.3 2994 10.8 0.01 Waihapa-1, 1A 7/07/1985 4942.0 144.4 2.4 0.2 2125 7.6 0.01 Waihapa-3 27/11/1988 2706.0 85.9 1.4 1.0 8836 31.8 0.03 Waihapa-6 18/11/1989 3245.0 100.0 1.7 1.2 10284 37.0 0.04 Whanga Road Bore 195.0 20.4 0.3 0.2 2062 7.4 0.01 Wharehuia-1 15/02/1985 3595.0 114.3 1.9 1.3 11732 42.2 0.04 Windsor-2 20/09/2000 1469.4 64.0 1.1 0.8 6578 23.7 0.02 Windsor-3 8/10/2000 1555.6 63.1 1.1 0.7 6480 23.3 0.02 Wingrove-1 1600.0 59.2 1.0 0.7 6063 21.8 0.02 WANGANUI Ararimu-1 26/03/1970 1057.6 50.3 0.8 0.6 5130 18.5 0.02 Kaitieke-1 4/02/1966 394.0 28.7 0.5 0.3 2994 10.8 0.01 Manutahi-1 19/05/1984 1391.0 46.1 0.8 0.5 4737 17.1 0.02 Ohaupo-1 1/01/1983 1207.0 57.0 1.0 0.7 5866 21.1 0.02 Ohura-1 1/01/1964 635.0 36.2 0.6 0.4 3706 13.3 0.01 Parikino-1 17/08/1964 2316.5 70.2 1.2 0.8 7192 25.9 0.03 Puniwhakau-1 25/01/1965 2146.0 75.3 1.3 0.9 7683 27.7 0.03 Santoft-1 13/03/1964 312.0 21.7 0.4 0.3 2258 8.1 0.01 Stantiall-1 5/11/1942 2096.0 59.9 1.0 0.7 6161 22.2 0.02 Tatu-1 28/10/1964 860.0 43.7 0.7 0.5 4516 16.3 0.02 Waikaka-1 12/03/1970 978.7 47.6 0.8 0.6 4934 17.8 0.02 Whakamaro-1 28/04/1969 916.0 45.5 0.8 0.5 4737 17.1 0.02 Whangaehu-1 20/02/1996 3495.0 89.9 1.5 1.1 9253 33.3 0.03 Whitianga-1 19/01/1964 295.0 24.1 0.4 0.3 2479 8.9 0.01 Young-1 4/11/1942 1035.0 37.2 0.6 0.4 3804 13.7 0.01 SOUTH ISLANDCANTERBURY Arcadia-1 24/11/2000 1479.0 20.9 0.9 0.6 5547 20.0 0.02 Chertsey Bore 16/09/1921 661.0 17.6 0.5 0.3 2994 10.8 0.01 Ealing-1 5/11/2000 1696.0 18.9 0.8 0.6 4934 17.8 0.02 J.D. George-1 5/10/1969 1649.9 24.8 1.2 0.8 7192 25.9 0.03 Kowai-1 23/03/1978 1410.0 20.7 0.9 0.6 5351 19.3 0.02 Leeston-1 26/08/1969 1158.5 18.6 0.7 0.5 4124 14.8 0.01 Oamaru-1 1954 908.0 21.3 0.8 0.5 4614 16.6 0.02 Oamaru-2 1961 665.0 22.9 0.7 0.5 4541 16.3 0.02 WEST COAST A1 1908? 122.0 19.4 0.3 0.2 1964 7.1 0.01 Ahaura-2 11/02/1978 1069.0 50.6 0.9 0.6 5253 18.9 0.02 Arahura-1 30/05/1964 1736.0 72.9 1.2 0.9 7511 27.0 0.03 Aratika-2 14/12/1977 1149.0 55.5 0.9 0.7 5743 20.7 0.02 Aratika-3 19/01/1978 1729.0 76.8 1.3 0.9 7903 28.5 0.03 Arnold River-1 18/01/1985 710.0 40.0 0.7 0.5 4124 14.8 0.01 B1 22.0 15.8 0.3 0.2 1645 5.9 0.01 B2 34.0 16.2 0.3 0.2 1645 5.9 0.01 B4 24.0 15.9 0.3 0.2 1645 5.9 0.01 Bore 251 123.0 18.5 0.3 0.2 1865 6.7 0.01 Bore 252 459.0 28.1 0.5 0.3 2872 10.3 0.01 Bounty-1 29/10/1970 3131.0 134.3 2.3 0.2 1974 7.1 0.01 Card Creek-1 15/02/1986 1342.0 53.3 0.9 0.6 5449 19.6 0.02 Corehole-10 1/01/1943 445.0 30.7 0.5 0.4 3191 11.5 0.01 Corehole-11 1/01/1942 423.0 27.1 0.5 0.3 2774 10.0 0.01 Corehole-8 7/10/1942 100.0 17.9 0.3 0.2 1865 6.7 0.01 Corehole-9 1/01/1942 215.2 22.7 0.4 0.3 2381 8.6 0.01

GNS Science Report 2007/23 36

Well Name DateCompleted

Total Depth

(m)BHT(oC) MW MWt

(CF=0.7) MWe

(CF=0.1) MWh TJ PJ

SOUTH ISLANDWEST COAST Glenn Creek-1 29/09/1985 739.0 41.0 0.7 0.5 4222 15.2 0.02 Harihari-1 8/03/1971 2527.4 81.2 1.4 0.9 8321 30.0 0.03 Hohonu-1 28/06/1986 1039.0 51.6 0.9 0.6 5228 18.8 0.02 Kaimata Bore 4/01/1918 407.0 29.3 0.5 0.3 2994 10.8 0.01 Kawhaka-1 6/06/1943 852.0 43.4 0.7 0.5 4418 15.9 0.02 Kokatahi-1 28/10/1987 1914.0 69.7 1.2 0.8 7192 25.9 0.03 Kokiri-1 16/07/1980 3233.0 122.8 2.1 0.2 1813 6.5 0.01 Kumara-2 19/07/1985 1756.0 65.2 1.1 0.8 6676 24.0 0.02 Kumara-2A 10/09/1985 1697.0 63.5 1.1 0.8 6578 23.7 0.02 Limestone Test Bore 148.0 20.3 0.3 0.2 2062 7.4 0.01 Matiri-1 29/12/1985 1467.0 70.9 1.2 0.8 7290 26.2 0.03 Mawhera-1 18/02/1985 697.0 39.9 0.7 0.5 4124 14.8 0.01 Murchison-1 1245.0 62.4 1.0 0.7 6357 22.9 0.02 Niagara-2 5/06/1986 952.0 48.5 0.8 0.6 5032 18.1 0.02 No1 Kotuku Consolidated 51.0 16.8 0.3 0.2 1743 6.3 0.01 No1 Kotuku Oilfields 290.0 25.4 0.4 0.3 2577 9.3 0.01 No1 Kotuku Petroleum 293.0 25.5 0.4 0.3 2577 9.3 0.01 No1 Lake Brunner 32.0 16.1 0.3 0.2 1645 5.9 0.01 No1 Maoriland 14/07/1936 44.0 16.6 0.3 0.2 1645 5.9 0.01 No2 Kotuku Oilfields 247.0 23.8 0.4 0.3 2479 8.9 0.01 No2 Kotuku Petroleum 187.0 21.7 0.4 0.3 2258 8.1 0.01 No2 Lake Brunner 229.0 23.2 0.4 0.3 2356 8.5 0.01 No2 Maoriland 22/07/1936 19.0 15.7 0.3 0.2 1645 5.9 0.01 No3 Bore 147.0 19.2 0.3 0.2 1964 7.1 0.01 No3 Kotuku Oilfields 183.0 21.5 0.4 0.3 2258 8.1 0.01 No3 Kotuku Petroleum 375.0 28.4 0.5 0.3 2872 10.3 0.01 No3 Lake Brunner 147.0 20.3 0.3 0.2 2062 7.4 0.01 No3 Maoriland 28/07/1936 40.0 16.4 0.3 0.2 1645 5.9 0.01 No4 Lake Brunner 32.0 16.1 0.3 0.2 1645 5.9 0.01 No4 Maoriland 15/08/1936 40.0 16.4 0.3 0.2 1645 5.9 0.01 No5 Lake Brunner 133.0 19.8 0.3 0.2 2062 7.4 0.01 No5 Maoriland 26/08/1936 41.0 16.5 0.3 0.2 1645 5.9 0.01 No6 Lake Brunner 98.0 18.5 0.3 0.2 1865 6.7 0.01 No7 Lake Brunner 38.0 16.4 0.3 0.2 1645 5.9 0.01 No8 Lake Brunner 137.0 19.9 0.3 0.2 2062 7.4 0.01 No9 Lake Brunner 265.0 24.5 0.4 0.3 2577 9.3 0.01 Notown-1 30/09/1944 2116.0 90.6 1.5 1.1 9352 33.7 0.03 Paddy Gully-1 294.0 25.5 0.4 0.3 2675 9.6 0.01 Petroleum Creek-1 13/11/1985 64.0 17.3 0.3 0.2 1743 6.3 0.01 Petroleum Creek-2 15/11/1985 59.0 17.1 0.3 0.2 1743 6.3 0.01 Petroleum Creek-5 20/11/1985 17.3 15.6 0.3 0.2 1645 5.9 0.01 RSE-1 22/04/2004 263.1 24.3 0.4 0.3 2479 8.9 0.01 RSE-2 3/05/2004 179.3 21.3 0.4 0.2 2160 7.8 0.01 Ruby Bay-1 1966 281.0 23.0 0.4 0.3 2356 8.5 0.01 SFL-1 10/12/1942 1663.0 62.5 1.1 0.7 6480 23.3 0.02 SFL-2 18/03/1943 908.0 40.9 0.7 0.5 4222 15.2 0.02 Shaft 25.0 15.9 0.3 0.2 1645 5.9 0.01 Taipo Creek-1 31/01/1985 679.0 39.3 0.7 0.5 4001 14.4 0.01 Tapawera-1 7/05/1988 1180.0 48.7 0.8 0.6 5032 18.1 0.02 Taramakau-1 14/02/1964 2129.0 75.8 1.3 0.9 7805 28.1 0.03 Waiho-1 16/07/1972 3749.4 113.2 1.9 1.3 11634 41.9 0.04 Westgas-1 1/02/1996 346.6 26.6 0.5 0.3 2774 10.0 0.01 Westgas-3 3/10/1997 310.6 25.4 0.4 0.3 2577 9.3 0.01 WEST SOUTHLAND - SOLANDER Alton 61.0 16.9 0.3 0.2 1743 6.3 0.01 Happy Valley-1 12/01/1988 1623.0 62.1 1.0 0.7 6357 22.9 0.02 Happy Valley-1A 6/02/1988 1600.0 61.5 1.0 0.7 6357 22.9 0.02 Happy Valley-1C 28/02/1987 3131.4 106.0 1.8 1.2 10898 39.2 0.04 Merryvale-1 239.0 21.8 0.4 0.3 2258 8.1 0.01 Papatotara-1 261.0 22.5 0.4 0.3 2258 8.1 0.01 Tuatapere-1 306.0 23.9 0.4 0.3 2479 8.9 0.01 Upukerora-1 15/12/1987 2009.0 72.4 1.2 0.8 7388 26.6 0.03 NOT IN BASIN SOUTH ISLAND Centre Bush-1 498.0 29.2 0.5 0.3 2994 10.8 0.01 J.T. Benny-1 6/01/1965 1013.0 46.4 0.8 0.5 4737 17.1 0.02 J.W. Laughton-1 5/04/1965 2135.0 81.1 1.4 0.9 8321 30.0 0.03 Kauana-1 179.0 20.5 0.4 0.2 2160 7.8 0.01 Pukerau-1 15/03/1970 73.0 17.4 0.3 0.2 1743 6.3 0.01 Pukerau-2 13/05/1972 118.0 18.9 0.3 0.2 1964 7.1 0.01 Pukerau-3 17/04/1971 165.0 20.5 0.4 0.2 2160 7.8 0.01 Waikaia-1 1/01/1974 197.0 20.6 0.4 0.2 2160 7.8 0.01 Waikaia-2 1/01/1975 121.0 18.5 0.3 0.2 1964 7.1 0.01 TOTAL ENERGY 317.5 190.6 4.8 1696547 6108 6.1

1 Fairway Drive

Avalon

PO Box 30368

Lower Hutt

New Zealand

T +64-4-570 1444

F +64-4-570 4600

Dunedin Research Centre

764 Cumberland Street

Private Bag 1930

Dunedin

New Zealand

T +64-3-477 4050

F +64-3-477 5232

Wairakei Research Centre

114 Karetoto Road

Wairakei

Private Bag 2000, Taupo

New Zealand

T +64-7-374 8211

F +64-7-374 8199

National Isotope Centre

30 Gracefield Road

PO Box 31312

Lower Hutt

New Zealand

T +64-4-570 1444

F +64-4-570 4657

Principal Location

www.gns.cri.nz

Other Locations