Thermal in Situ Water Summary Report

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Thermal In Situ Water Conservation Study

A Summary Report

May 2012

Rich HillJacobs Consultancy


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Executive SummaryAlberta Innovates Energy and Environment Solutions (AI-EES) is part of Alberta Innovates, acollective system built on a strong legacy and proven success. As the lead agency for energyand environmental research in Alberta, AI-EES brings together decision makers fromgovernment and industry as well as research and technology organizations, to develop solutionsfor the biggest challenges facing Albertas energy and environment sector.

Further to its ground breaking studies on life cycle assessment of bitumen derived fuels andSAGD energy efficiency study, AI-EES commissioned a new study on thermal in situ waterconservation (the Study). The objectives of the Study were to:

Assess the impact of increasing water recycle and moving toward Zero Liquid Discharge(ZLD) on energy usage, greenhouse gas (GHG) emissions, and waste generation inthermal in situ production of bitumen.

Identify promising new water treatment technologies that best balance environmentaltradeoffs and economic returns.

Nine thermal in situ producers and three government agencies/departments participated in, andprovided technical guidance to, the Study. In total, over 100 simulations were completed toevaluate nine different water treating configurations in terms of water use, water recycle, energyconsumption, GHG emissions, and waste generation.

Overall, the Study found that Warm Lime Softening (WLS) and, similarly, Hot Lime Softeninghad the lowest GHG emissions. The produced water recycle rate (PWRR) was limited to 87%with fresh make-up water, but the PWRR quickly deteriorated when the make-up water TotalDissolved Solids (TDS) exceeded about 7,000 ppm. In contrast, Produced Water Evaporationwas estimated to have PWRR in excess of 90% even with TDS levels in excess of 24,000 ppmin the makeup water. However, GHG emissions with Produced Water Evaporation werebetween seven and eight percent (7-8%) higher than from WLS.

The best overall balance of PWRR and GHG emission may be achieved by using WLS of theproduced and make up water and by using evaporation treatment of the boiler blowdown(Blowdown Evaporation). Blowdown Evaporation had GHG emissions only three percent (3%)higher than WLS and had PWRR on par with Produced Water Evaporation.

With regard to the above objectives, the Study identified the following high-level conclusions:

Trade-offs exist between water use, GHG emissions, and waste generation.


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PWRR can exceed 90% with currently available technology.

Technologies that minimize water use, such as evaporation and ZLD, will increase GHGemissions between 3% and 10% on an overall SAGD plant. At a Steam to Oil Ratio

(SOR) of 3, this represents a 30-100% increase in GHG emissions not directlyattributable to steam generation.

ZLD increases the PWRR by 1-3%, but increases GHG emissions between 2% and 6%over Produced Water Evaporation. Because all the salts are disposed of in solid form,solid waste increases between 12 and 29 times over Evaporation. However, perhapsmore importantly for the operators, ZLD increases capital costs and operationalcomplexity and may decrease facility reliability.

New technology options examined in the Study offer the potential to better balance thetrade-off between GHG emissions and water recycle, However, the changes are

evolutionary and incremental rather than revolutionary or a step-change over the bestcommercial technologies available. Improved reliability and operability could bepotentially larger drivers for water treating technology selection than reductions in GHGemissions and water use, especially producers using ZLD.

IntroductionThis public report summarizes important aspects of the Thermal In situ Water ConservationStudy conducted by Jacobs Consultancy for Alberta Innovates Energy and Environment

Solutions (AI-EES) and a consortium consisting of the following Industry and Governmentorganizations:

AI-EES (Sponsor and Steering Committee Chair)

Alberta Environment and Water (AEW)

Energy Resources Conservation Board (ERCB)

BP Canada

Canadian Natural Resources Limited (CNRL)

Cenovus Energy

Conoco-Phillips (COP)

Nexen Inc.

PennWest Exploration


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Statoil Canada

Suncor Energy (Suncor)

Total E&P Canada Ltd.

This report is organized as follows:

Purpose of the Study

Water Use in the Oil Sands

Methodology and Design Basis

Results

A place for New Technology

Key Findings

Purpose of the StudyAlberta Innovates Energy and Environment Solutions (AI-EES) is part of Alberta Innovates, acollective system built on a strong legacy and proven success. As the lead agency for energyand environmental research in Alberta, AI-EES brings together decision makers fromgovernment and industry as well as research and technology organizations, to develop solutionsfor the biggest challenges facing Albertas energy and environment sector.

In the context of sustainable development of oil sands in Alberta, AI-EES previouslycommissioned a number of ground breaking studies including:

Life Cycle Assessment Comparison of North American and Imported Crudes(http://extranet.aet.alberta.ca/SIIS.public/EIPA/Download.aspx?DocumentElementId=66435 ) which established green house gas (GHG) intensity of bitumen derived fuels inrelation to those of North America and imported crudes in a scientific manner.

Steam Assisted Gravity Drainage (SAGD) Energy Efficiency Study ( http://ai-ees.ca/media/22039/sagd-energy-efficiency-study-final-report.pdf ) which identifiedenergy efficiency improvement opportunities in SAGD operations.

It becomes very evident from these studies that water use and water treatment are closelylinked to the energy efficiency and carbon intensity of thermal in situ bitumen recoveryprocesses.

As water has become an issue of concern within the industry, AI-EES initiated an Industry andgovernment sponsored study to understand the trade-offs between water recycle, GHG


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emissions, and waste generation for various water treating technologies. This Study startedwith a public forum in September of 2010, the formation of a consortium later in 2010 and thecommissioning of the Study in March of 2011; the study lasted 10 months.

Water Use within the Oil SandsBitumen in the Alberta Oil Sands is currently extracted using surface mining and in situ recoveryprocesses. The dominant in situ recovery processes are steam gravity drainage (SAGD) andcyclic steam stimulation (CSS). Both processes use steam to extract bitumen from oil sandsformations in place. To do this, a number of wells are drilled into the reservoir. In SAGD, thesewells are drilled horizontally in pairs. For each pair, one well is for injection and the other is forbitumen production. Steam produced on the surface is forced down the injection well at highpressure. In the reservoir the steam condenses and heats the earth enough for the bitumen tobecome mobile. The bitumen and water mix in the reservoir and flow to the production well.The oil-water mix is either pressured to the surface or preferably, pumped to the surface forseparation of the water and bitumen. The injection of steam is substantial and depending onthe reservoir, the condensed water can be between two and four times the volume of oilrecovered. Therefore, operators attempt to reuse (recycle) as much water as possible. Waterrecycling has the potential to reduce the actual water consumption (make-up water) to less thanhalf of the volume of oil recovered. However, the treatment of water for reuse not only requiresspecialized equipment, it consumes energy and generates waste. The tradeoff between waterand GHG emissions and waste generation is the focus of this Study (Figure 1).

Figure 1. The Trade-off

+ Waste


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Water Treatment

As steam is forced into the reservoir and condenses, the hot water is in intimate contact with theformation and reservoir fluids. While making its way through the reservoir, the water picks upsalts and is mixed with oil to form a water-oil emulsion. At the surface, the oil and water areseparated and the de-oiled water is further treated for use in steam generation.

The produced water is dark or dark brown in color and contains salts, fines (clays and sands),dissolved organics, and residual oil. Even after de-oiling, the produced water can look like themiddle two samples in Figure 2. It is the treatment of this water that is of critical importance forthe recycle of water in the bitumen production from oil sands.

Before the water can be recycled (re-injected into reservoirs), it must be turned into steam, andnot just steam but high pressure steam. Within industry, the maxim is that as the pressure ofthe steam increases, so must the quality of the water. In controlled and closed loopenvironments this is readily achieved. Unfortunately, in the production of bitumen, water isneither in a controlled environment nor in a closed loop. Therefore, at in situ facilities, watertreatment becomes almost as important as the production of oil.

Figure 2. In situ water samples (from left to right, WLS overflow sample 1, de-oiled produced watersample 1, de-oil produced water sample 2, and WLS flow sample 2)

.


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Water Pathways

The water recycle in thermal in situ recovery is illustrated in Figure 3. Of the steam injected,water is retained in the reservoir, recycled, or disposed. Make-up water is required to offset thewater lost in the reservoir and/or disposed. While the water lost to the reservoir cannot becontrolled or manipulated, the amount disposed depends on the water quality, the type oftechnology used, and the operability at the Central Processing Facility (CPF) of the thermal insitu production plant. Water efficiency can be defined in many ways some of which are asfollows:

Water Intensity = Make-up water/oil produced

Produced Water Recycled = Steam Make-up Water

Produced Water Recycle Rate (PWRR) = (Steam- Make-up Water)/Produced Water

(expressed as a percentage)For the purposes of this Study, we will focus on PWRR as an indicator of the extent of waterrecycle.

Figure 3. The Water Balance

CPF

Reservoir

MakeupWater

(MU)

DisposalWater

(DW)

Steam(STM)

Reservoir Retention(RR)

ProducedWater(PW)

As indicated above, one of the variables dictating the amount of make-up water required is thequality of the water. Both the qualities of the produced water and make-up water are important.The produced water quality is a function of the reservoir. However, because water has become


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a more critical resource, in situ bitumen producers have moved towards using more brackishsources of make-up water where available. The choice and availability of water impacts:

Disposal water volumes

Make-up water volumes Technology selection

GHG emissions

Solid waste generation

For the purposes of this study, two representative produced water qualities were selected aswell as four make-up water qualities, making a total of eight different possible water qualitycombinations. Total Dissolved Solids (TDS) is a simple metric that is used to describe thequality of the water. Salts and silica are the primary contributors to TDS. As TDS increases the

quality of the water decreases. Dissolved organics are also present in the produced water andhave a profound impact on the technologies that can be used to treat in-situ water. A summaryof the water qualities used in the Study is shown in Table 1.

Table 1. Representative Water Samples

Methodology and Design BasisTo determine the trade-offs among water use, GHG emissions, and waste generation, arigorous, simulation based study was conducted using Jacobs Consultancys proprietary ionicwater model. The Study consists of four key tasks:

1. Define various commercial options and configurations for water treatment

2. Identify two representative produced water and four make-up water samples


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3. Simulate each configuration and water use in a proprietary ionic water model to estimateenergy input, water usage, GHG emission, and waste generation (liquid and solidwastes)

4. Analyze the data and determine the trade-offs for energy, water use and wastegeneration.

To assess the trade-offs for water in a consistent manner, estimates of GHG emissions andwaste generation were simulated for a thermal in situ bitumen production facility with thefollowing key characteristics:

33,000 Barrels per Day (BPD) bitumen production

Steam to Oil Ratio (SOR) of 3.0

Gas to Oil Ratio (GOR) of 5.0

High level of heat integration Mechanical lift of produced fluids

Flue gas/air preheat exchange

Reservoir water retention rate of 10%

For the most part, the majority of the Study was focused on SAGD. However, for comparisonpurposes a few CCS cases were also evaluated. In addition, a number of cases were alsoincluded for negative water retention, where the amount of produced water exceeds the amountof injected steam. Altogether, more than 100 simulations were conducted, accounting for four

make-up waters, two produced waters, and nine configurations of water treatment systems.

Results Warm lime softening (WLS) and Evaporation are two commercially proven methods to treatproduced water from thermal in situ production facilities. The technology options for watertreatment for in situ bitumen production are limited for a number of reasons related to thecharacteristics of the produced water, including contaminants such as:

organics including micro-colloidal droplets and dissolved organic acids

silica

carbonates


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Warm Lime Softening and Evaporation

A typical WLS configuration is represented in Figure 4. In this configuration, the emulsion isrouted to the Central Processing Facility (CPF) for oil/water separation. The produced water isde-oiled, but still contains some organic compounds as indicted in Table 1. The make-up wateris pre-treated and heated to 85 C and combined with produced water for the first step of thetreatment process, which is WLS. In this step, the water is chemically treated to reduce thehardness (Ca + Mg) and silica. Total TDS, however, is virtually unchanged, because, for themost part, the ions in the water are replaced, but not removed. The softened water from theWLS then is routed through an ion exchange step to further remove hardness prior topressurization, pre-heating and steam generation. In the steam generation section, Once-Through Steam Generators (OTSGs) produce a wet steam that consists of about 77% steamand 23% water. The water is separated from the steam and is known as blowdown water,which is recycled back to the limits of the boiler or disposed of to remove contaminants from thesystem. The Study focused on WLS, but Hot Lime Softening (HLS) can also be used, wherethe temperature of the softening operation is increased. HLS performs similarly to WLS withregards to the configuration, water chemistry, water recycle and GHG emissions.

Figure 4. Warm Lime Softening Diagram

A typical Evaporator configuration is represented in Figure 5. In this configuration, the producedand make-up waters follow the same processing as in the WLS case, but after mixing, thecombined water stream is treated with evaporators. In this case, the water is essentially distilledto produce low TDS water. The distilled water from the evaporator is still treated with ion


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exchange to remove trace hardness, but then is pressurized, pre-heated and routed through theOTSG. In this case, almost all the blowdown from the boiler can be recycled. Contaminantsthat come in with the produced and make-up water are disposed from the evaporatorconcentrate.

Figure 5. Produced Water Evaporation Diagram

In fact, with water produced from an evaporator, a different, type of boiler (drum boiler) can be

used for steam generation. However, within the context of the water recycle and GHGemissions evaluation of this Study the results are similar. As a result, this report focuses on theOTSG configuration.

Each of the configurations was simulated using all eight possible representative watercombinations shown in Table 1. The simulations were completed to calculate the following keyparameters, depending on the system and technology constraints:

Disposal water volume

Make-up water volume

Energy use

GHG emissions

Type of waste and waste volume


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As mentioned above, PWRR is a common method for measuring the reuse of water. Theimpact of WLS and evaporation is shown in Figure 6 below, which plots PWRR versus TDS inthe make-up water for the two water treatment technologies The solid and dashed lines inFigure 6 refer to PW1 and PW2, respectively, while the four makeup water qualities are shown

along the horizontal axis (FW, BW1, BW2, and BW3). We find that Produced Water Evaporationoperated at maximum recycle offers higher PWRR than WLS, especially when the quality of thewater deteriorates.

Figure 6. PWRR%WLS vs. Evaporation

60%

65%

70%

75%

80%

85%

90%

95%

100%

0 5,000 10,000 15,000 20,000 25,000 30,000

P W R R

( % )

MU Water TDS to Treating (PPM)

PWRR%

WLS- No Flash (BC2)

Evap + OTSG (2A)

FW BW1 BW2 BW3

PW1PW2

Produced Water Evaporator configurations can achieve a much higher PWRR than WLS and,depending on the water quality, can reduce the makeup water requirements between 1500 m 3 /d(40%) and 3800 m 3 /d (57%). With fresh make-up water and produced water having low levelsof organics and TDS, it may be possible to achieve recycle rates above 90% with ProducedWater Evaporators without decreasing the intervals between OTSG fouling to unacceptable

levels.

However, the ability of Produced Water Evaporators to achieve high water recycle comes at theprice of additional GHG emissions (efficiency). Figure 7 shows the additional GHG emissionsproduced from treating water by the two water treating methods at the TDS levels shown inFigure 6. In this figure, the GHG emissions are shown as a percentage of emissions over the

ExceedsBoiler TDSlimit

1500 m3/d

3800 m3/d


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minimum GHG emissions, which are defined as the amount of GHG emissions from generatingthe steam needed for bitumen production without the emissions from water treatment.

Figure 7. GHG EmissionsWLS vs. Evaporation

0%

5%

10%

15%

20%

25%

30%

0 5,000 10,000 15,000 20,000 25,000 30,000

G H G E m i s s i o n s o v e r M i n i m u m

( % )


Water Treating GHG Emissions

WLS- No Flash (BC2)

Produced Water Evap (2A)

FW BW1 BW2 BW3

PW1PW2

As shown in Figure 7, the GHG emissions from treating the water for Produced WaterEvaporators are between 7% and 8% higher than for treating water for WLS, depending on thewater quality. The increase in GHG emissions from Produced Water Evaporators is a result ofthe additional imported power needed to operate the evaporators. Despite the fact that theevaporators are very efficient in terms of distillation, they still consume energy not required forWLS and do not take full use of the dissolved solids tolerances of the OTSG, which is thepredominant technology used commercially to generate steam for SAGD and CSS plants.

Blowdown Evaporation

Another option to take advantage of the robustness of an OTSG and still allow for higher PWRRis to use blowdown evaporation as shown in Figure 8. In this case, the bulk water treatment isdone via WLS, but an evaporator used on the boiler water blowdown can significantly decreasethe amount of water treated in the evaporators and thereby reduce energy and GHG emissions.

7% 8%


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Figure 8. Blowdown Evaporation

Figure 9. PWRR%- WLS, Produced Water Evaporation, Blowdown Evaporation

60%

65%

70%

75%

80%

85%

90%

95%

100%

0 5,000 10,000 15,000 20,000 25,000 30,000

P W R R

( % )


PWRR %

WLS- No Flash (BC2)

Evap + OTSG (2A)

Blowdown Evaporation (1B)

PW1PW2

FW BW1 BW2 BW3


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Figures 9 and 10 show the performance of this configuration, which is termed BlowdownEvaporator. As shown, the Blowdown Evaporator case has about the same PWRR performanceas the Produced Water Evaporation case, but generates only about half the additional GHGemissions. Furthermore, the GHG emissions do not increase as the water quality deteriorates,

for the following reasons: first, the blowdown volume is constant; second, the steam volumerequired is always the same; and third, the steam/liquid ratio from the boiler is the same.Therefore only the TDS level changes. Even with the TDS increase from very brackish water,the TDS in the boiler feed water is still well below the maximum capabilities of the OTSG.

Figure 10. GHG EmissionsWLS, Blowdown Evaporation, and Produced Water Evaporation

0%

5%

10%

15%

20%

25%

30%

0 5,000 10,000 15,000 20,000 25,000 30,000


( % )


Water Treating GHG EmissionsWLS- No Flash (BC2)Produced Water Evap (2A)


PW1PW2

FW BW1 BW2 BW3

Zero Liquid Discharge

Although blowdown evaporation can achieve high recycle rates, it still generates liquid wasteand requires a disposal well. Zero Liquid Discharge (ZLD) is required for those operatorswithout access to a disposal well. On a commercial scale, additional equipment beyondevaporation is required for ZLD, including the following:


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An additional stage of evaporation to bring the solids content in the concentrate from~100,000 wtppm TDS to 200,000 wtppm

A crystallizer which takes the concentrated brine from the final stage of evaporation andconcentrates it further to about 65 wt% TDS. Traditionally the degree of concentration in

the crystallizer is limited by the amount of organics in the water from thermal in situproduction facilities.

A dryer removes most of the moisture from the crystallizer brine. The dryer uses naturalgas in a rotary dryer to dry the sludge to a concentration containing approximately tenweight percent moisture. Particulate and ash removal from the gas effluent from thedryer is usually necessary which is often accomplished by large bag-type filters.

Figure 11 is a conceptual flow diagram of Produced Water Evaporation with ZLD. The flowdiagram is similar to the Produced Water Evaporation scheme shown in Figure 5, and theequipment detailed above is included in the ZLD block.

Figure 11. Produced Water Evaporation plus ZLD

Due to the addition of the extra evaporator and crystallizer, more water is recovered, but this

step requires more energy and therefore results in more GHG emissions. Figure 12 13 reflectthe improvement in PWRR from ZLD, which is between 1% and 3% over Produced WaterEvaporation alone. However, as shown in Figure 13, the increase in GHG emissions from ZLDranges from 2% to 6%, over Produced Water Evaporation alone.


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Figure 12. PWRR%- WLS, Produced Water Evaporation and ZLD comparison

60%

65%

70%

75%

80%

85%

90%

95%

100%

0 5,000 10,000 15,000 20,000 25,000 30,000

P W R R

( % )


PWRR%

WLS- No Flash (BC2)


2A + ZLDFW BW1 BW2 BW3

PW1PW2

Figure 13. GHG Emissions- WLS, Produced Water Evaporation and ZLD comparison

0%

5%

10%

15%

20%

25%

30%

0 5,000 10,000 15,000 20,000 25,000 30,000


( %

)


Water Treating GHG Emissions

WLS- No Flash (BC2)


2A + ZLD

FW BW1 BW2 BW3

PW1

PW2


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Waste Generation from Water Treatment

From a waste generation standpoint, each of the configurations produces different types andvolumes of waste. The Produced Water Evaporation case mainly produces a liquid waste in theform of the evaporator condensate (disposal water). However, to improve the reliability of deepwell injection of this disposal water, it is often treated to remove silica, which generates a smallamount of solid that may impact the injection of liquid waste. On the other hand, both WLS andBlowdown Evaporation produce more solid waste, which in the case of WLS is in the form ofslurry that contains silica as well as magnesium and calcium salts. In addition, both WLS andBlowdown Evaporation produce liquid waste in the form of disposal water. The ZLD technologyproduces only solid waste. However, the amount of solid waste from ZLD is much higher thanfrom any other technology because all the contaminants in the water are, ultimately, removed asa solid. Solid waste volume from ZLD ranges from 50% to 300% more than WLS and 12 to 29times as much as from Blowdown Evaporation alone.

Figures 14, 15, and 16 reflect the amount of liquid and solid waste for each of theconfigurations. Figure 14 shows liquid waste from WLS, Produced Evaporation, and BlowdownEvaporation. Figure 15 shows solid waste from WLS, Produced Evaporation, and BlowdownEvaporation. Figure 16 shows solid waste from ZLD and from WLS and Produced WaterEvaporation

Figure 14. Liquid WasteWLS, Blowdown Evaporation, and Produced Water Evaporation

0

1,000

2,000

3,000

4,000

5,000

6,000

0 5,000 10,000 15,000 20,000 25,000 30,000

L i q u i

d W a s t e

( m 3 /

d )


Liquid Waste GenerationWLS- No Flash (BC2)


Blowdown Evaporation(1B)

PW1PW2

FW BW1 BW2 BW3


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Figure 15. Solid WasteWLS, Blowdown Evaporation, and Produced Water Evaporation

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

0 5,000 10,000 15,000 20,000 25,000 30,000

S o l i d W a s t e

( k g /

d )


Solid Waste Generation

WLS- No Flash (BC2)Produced Water Evap (2A)


PW1PW2

FW BW1 BW2 BW3

Figure 16. Solid WasteWLS, Produced Water Evaporation and ZLD

0

20,000

40,000

60,000

80,000

100,000

120,000

0 5,000 10,000 15,000 20,000 25,000 30,000

S o l i d w a s t e

( k g /

d )


Solid Waste Generation

WLS- No Flash (BC2)Produced Water Evap (2A)2A+ZLD

FW BW1 BW2 BW3

PW1PW2


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A Place for New TechnologyAs part of the Study, several new technology options were evaluated. The Study found thatchanges with regard to the trade-off between GHG emissions and water recycle are likely to beevolutionary and incremental as a result of new technology, but can still be significant. Newtechnology can also improve reliability, operability of water treatment and can reduce the capitalcost. Therefore, there are significant drivers for pursuing and investing in new water treatingtechnologies. One way to evaluate the three commercial technologies discussed above is on the basis of theamount of GHG emissions produced per unit of water recycled and compare their performanceover a range of TDS in the make-up water against a theoretical minimum. The theoreticalminimum is based on 100% PWRR with the same energy consumption as the WLSconfiguration (all the energy is for steam generation and the power is associated with the

various pumps). As shown in Figure 17, the gap between Blowdown Evaporation and thetheoretical minimum ranges from less than four kg of GHG emissions per m 3 of water recyclewhen fresh water is used as makeup to ten kg of GHG per m 3 of water recycle when the make-up water has very high TDS.

Figure 17. GHG Emissions Gap Between Commercial Water Treatment and Theoretical

100

120

140

160

180

200

220

240

0 5,000 10,000 15,000 20,000 25,000 30,000 G H G

e m i s s i o n s / W a t e r R e c y c l e d

( k g / m 3 )

MU Water TDS (PPM)

Performance GapWLS- No Flash (BC2)

Produced Water Evap (2A)Blowdown Evaporation (1B)

PW1PW2

FW BW1 BW2 BW3

WLS at 100% PWRR (Theoretical Best)

Trade-off Gap


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As indicated in Figure 17, new technology has the ability to reduce the trade-off between energyconsumption and water recycle by 8% with high TDS water. However, this is only one of thedrivers for new technology and is in addition to potential savings in capital cost, increasedreliability, improved reliability, and lower waste generation, especially for operations requiring

ZLD.

Key FindingsIn summary, the key findings of the Study are as follows:

Produced Water Recycle Rates (PWRR) can surpass 90% with the use of commerciallyavailable technologies.

A trade-off between water recycle, GHG emissions, and waste generation exists, whichbecomes more pronounced as the quality of the water deteriorates.

Technology options are impacted by the relative value of water, the amount of wastegenerated, and the value of GHG emissions.

At high level, Blowdown Evaporation had the best overall trade-offs among water use, wastegeneration and GHG emissions. However, the best technology depends on facility specificconditions (e.g. produced water and make-up water chemistry), power generation (powerfrom grid vs. natural gas cogen) and how GHG emission is valued.

Zero Liquid Discharge (ZLD) is a technology option that enables a producer to generate only

solid waste. This Study found that ZLD can increase the PWRR between 1% and 2%, butincreases GHG emissions between 2% and 8% over Blowdown Evaporation. Because allthe salts are disposed of in solid form with ZLD, solid waste generation increases between12 and 29 times more than from evaporation alone. However, perhaps more importantly forthe operators, ZLD increases capital costs and operational complexity and reducesreliability. Therefore, new technology may offer the greatest benefit in improving currentmethods for ZLD.

New technology can improve tradeoff between GHG emissions and water recycle up to 7% -8%, but can provide even more value by decreasing capital and operating costs andimproving reliability and operability.

In conclusion, water recycle is an important component of in situ bitumen production. There aretrade-offs between GHG emissions and water recycle which change with water quality andtreatment technology. The relative value of GHG emissions compared to water use and waterquality influences technology selection along with reliability, operability, and capital costs.Current technology that is commercially available provides relatively good performance between


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GHG emissions and water recycle and the performance gap from theoretical is relatively small.Among the current technologies available, Blowdown Evaporation has the best balance of waterrecycle and GHG emissions. Blowdown Evaporation produces GHG emissions that are only 3%higher than the GHG emissions from WLS, which has one of the lowest GHG emissions of

available commercial technologies. In addition, Blowdown Evaporation provides PWRR inexcess of 90% even with high TDS brackish water.

New technology can reduce the performance gap between GHG emissions and water recycle.However, new technology may ultimately provide more value in decreasing capital andoperating costs and improving reliability and operability. New technologies to improve ZLD mayhave the most benefit in terms of reducing GHG emissions relative to water recycle while at thesame time having the most benefit over existing technologies in terms of capital cost,operability, and reliability

AcknowledgementJacobs Consultancy would like to acknowledge following Steering Committee members for theirvaluable input to the Study:

John Zhou, AI-EES (Sponsor and Steering Committee Chair) Kudjo Fiakpui, Alberta Energy Resources Conservation Board (ERCB) Sarah Moody, Alberta Environment and Water

Marc Tremblay, BP Canada Subodh Peramanu, Canadian Natural Resources Limited Susan Sun, Cenovus Energy *George Yuan and Sudhir Parab, Conoco-Phillips Denis Westphalen, Nexen Inc. Colin MacLeod, PennWest Exploration Clyde Fulton and John Kus, Statoil Canada Jun Park, Suncor Energy

Craig McCulloch, Total E&P Canada Ltd.

*now with CNRL

Documents

Thermal in Situ Water Summary Report