Reserve Estimation and Production Facilities: A Case · PDF fileReserve Estimation and Production Facilities: A Case ... study will focus on the reserve estimation and production facilities

25 | P a g e

International Journal of Petroleum and Geoscience Engineering

Volume 03, Issue 01, Pages 25-40, 2015 ISSN: 2289-4713

Reserve Estimation and Production Facilities: A Case Study on Titas Gas

Field, Bangladesh

Farzana Yeasmin Nipa a, Md. Minhaj Uddin Monir a,*

a Department of Petroleum and Mining Engineering, Jessore University of Science and Technology, Jessore-7408, Bangladesh

*Corresponding author: Tel.: +88 0421 62020 Ext. 240;

E-mail address: [email protected]

A b s t r a c t

Keywords:

Titas Gas Field,

Reserve estimation,

Production facilities,

Volumetric Method,

Material Balance Method.

Titas gas field is one of the largest gas field and most significant commercial energy resource of

Bangladesh. Therefore, future development of the country largely depends on the judicial use of

this valuable resource. The field was discovered in 1963 and put into production in April 28,

1968. Totally, sixteen wells have been drilled in Titas gas field since 2009. Estimation of gas in

place (GIP) and gas reserves are very crucial for the energy planning and natural gas production

facilities. In this study, gas in place values of the Titas gas field has been estimated using

volumetric and material balance method. Geophysical data, fluid properties data and production

data have been analyzed using volumetric analysis as well as material balance to verify initial

gas in place and reserve estimates for the Titas gas field. In volumetric and material balance

analysis, gas initially in place is 7169 Bcf and 7800 Bcf respectively at Titas gas field since

March, 2009. The daily gas production of Titas gas field is about 394.98 mmscfd with 431.94

bpd of condensate and 1801.7 bpd of water. This study estimates gas in place and daily

production of Titas gas field.

Accepted:23 March2015 © Academic Research Online Publisher. All rights reserved.

1. Introduction

The Titas gas field is located 100 Km away to the

direction of northern-east from the capital city of

Bangladesh, Dhaka (Fig.-1) [10]. It lies in the south

central part of the Surma Basin, and on the western

margin of the Tripura high. It is also located at

24014´N 91022ˊE and 24028´N 91010ˊE respectively

[9]. This field accounts for 43% of country’s gas

production. Estimation of gas in place and gas reserve

are very important for the sale of natural gas. The

reservoir sequence in Titas comprises 12 identifiable

sands that for convenience have been divided into

three groups – “A”, “B” and “C” (Fig.-2). The most

prolific of the sands are those of group A which

constitute the main producing horizon in Titas [9].

Quantitative and qualitative data are mainly used in

this study. The production and pressure data (March

and April) are used to calculate gas in place by

reserve estimation methods. Qualitative data was

collected from the secondary sources like books,

journals, articles, websites and reports [11]. The

major part of the qualitative data is used in this study

for showing the relation between volumetric and

material analysis as well as production performance

in the Titas gas field.

The specific objectives of this research are estimated

the gas reserve of Titas reservoir by volumetric and

F. Y. Nipa et al. / International Journal of Petroleum and Geoscience Engineering (IJPGE) 3 (1): 25-40, 2015

26 | P a g e

material balance method and studied the production

facilities of the Titas gas field. This study estimates

gas in place, recoverable reserves and daily

production of Titas gas field. Maximizing productivity

can be found in future by applying these two methods

for all the gas fields in Bangladesh.

Fig. 1: Location map of Titas Gas Field (modified after Titas geological report 2009 by Petrobangla).

Fig. 2: Sub-surface location of Titas field and gas bearing sands (Source: Petrel software, Petrobangla).


27 | P a g e

2. Methodology

A well-arranged methodology is extremely needed for

good accomplishment of any research work. This

study will focus on the reserve estimation and

production facilities of Titas gas field by using reserve

estimation methods.

2.1. Reserve Estimation

Reserve estimation is an essential study in the field of

petroleum engineering. Various methods are used to

estimate the reserves of discovered reservoirs

depending on the availability of data and development

stage of the reservoir. The methods that are used

predominantly are: Volumetric, Material Balance,

Decline Curve, and Reservoir Simulation. Generally,

the range of uncertainty associated with an estimate

decreases and confidence level increases as more

information becomes available and when the estimate

is supported by more than one estimation method.

2.1.1. Reserve Estimation by Volumetric Method

In volumetric method estimated rock volume of the

reservoir is multiplied with porosity and gas saturation

to calculate the gas in place. The volumetric method is

the most commonly used approach to estimating

reserves in the early stages of production from an oil

or gas field. As more data become available mainly no

production data, the estimate may be refined,

sometimes through the use of other reserves

estimation methods. The volumetric method is used

by employing the standard reserves equation with the

appropriate choice of parameters.

General Information:

1. Early stage of reservoir development and

after discovery.

2. Geology, Geophysical, Rock and fluid

properties data.

3. Recovery Factor assigned arbitrarily.

4. No time dependency.

5. No production data.

The equation for calculating gas in place is:

G =Ahϕ(1 − Swi)

Bgi× 𝑅𝐹

Where, A = Productive area: Hydrocarbon bearing

area of the reservoir; acres.

h = Net pay thickness: It is the vertical extent

thickness of the productive portion of a reservoir. It is

the thickness of those intervals in which porosity and

permeability are known or supposed to be high

enough for the interval to be able to produce oil or

gas; ft.

ϕ = Porosity: The ratio of pore volume to bulk volume

of a reservoir rock; fraction.

Swi = Initial Water Saturation: The ratio of volume of

water and pore volume at initial conditions; fraction.

Bgi = Initial Gas Formation Volume Factor: The ratio

of gas volume at reservoir conditions and gas volume

at standard conditions; ft3/SCF.

G = Gas in Place: The total natural gas estimated to

have originally existed in the earth’s crust in naturally

occurring accumulations including both discovered

and undiscovered resources; BCF.

RF = Recovery Factor: It is based on analysis of

production behavior from the reservoir, by analogy

with other producing reservoirs and/or by engineering

analysis.

2.1.2. Reserve Estimation by Material Balance

Method

The material balance method is employed to estimate

the volume of hydrocarbons in place in a reservoir

when appropriate geologic, production and laboratory

data are available. The material balance method is the

most commonly used approach to estimating reserves

in the later stages of production from an oil or gas

field. It is generally accepted that methods based on


28 | P a g e

production performance data [7] are more accurate

than those based strictly on inference from geological

and engineering data. Some more theoretical

background on following material balance method

about Gas Field is being performed [1] that may affect

the accuracy of the results. When economic

producibility limits are coupled with the material

balance, reserves are determined.

General Information:

1. Later stage of reservoir development.

2. Geophysical, Rock and fluid properties data,

Production data.

3. Recovery Factor is calculated.

4. Time dependent.

The equation for calculating gas in place is:

Z

P=

RFG

GP

Zi

Pi

1

Where, P = Shut in Reservoir Pressure: The

equilibrated reservoir pressure measured when the

entire gas or oil outflow has been shut off; Psi.

Z = Gas Compressibility factor: It is defined as the

ratio of the gas volume at a given temperature and

pressure to the volume the gas would occupy if it

were an ideal gas at the same temperature and

pressure; Dimensionless.

Pi = Initial Shut-in Reservoir Pressure: The

equilibrated reservoir pressure measured when the

entire gas or oil outflow has been shut off at initial

conditions; Psi.

Zi = Initial Gas Compressibility factor: It which is the

change in volume per unit volume per unit change in

pressure at initial conditions; Dimensionless.

GP = Cummutative Production: The total amount of

oil and gas recovered from a reservoir as of a

particular time in the life of the field until a specific

date; SCF.

2.2. Production Facilities

Titas gas field production history dates back to 1962

with the drilling of Titas well no.1 by Shell Oil Co.

(Pak.). The stacked reservoir of Titas was further

penetrated by four additional wells during the period

1962 to 1969. Petrobangla later on completed Titas

well no. 5 to Titas well no. 7. BGFCL drilled Titas

well no. 8, 9, and 10 during 1985. Under Gas Field

Appraisal Project, Titas well no. 11 was drilled during

the year 1990. During the period 2000 to 2006, five

more wells tagged as Titas well no. 12, 13, 14, 15 and

16 were completed and brought on-stream. Last year

(2007) Titas well no. 03 was killed due to wellhead

vicinity seepage and during the same year Titas well

no. 14 had also to be closed because of severe water

loading. First process operation of Titas field occurred

during 1986 via LTX facility based on Titas well no.

8. Titas well no. 9 joined the commercial production

on 1989, and Titas well no.10 during 1990. For the

latter two wells TEG and LTS unit were installed.

3. Results

3.1. Reserve estimation of Titas Gas Field

Estimation of gas in place (GIP) and gas reserves are

very crucial for the energy planning and natural gas

utilization scheme. Estimation of gas in place and gas

reserves is also very important for the sale of natural

gas.

3.1.1. Reserve Estimation by Volumetric Method

The gas reserves are determined by Volumetric

Method on putting the raw data from using equation

no. 1. The Gas Reserves in their calculation which is

shown in Table 1.


29 | P a g e

Table 1: Sand Wise Gas Reserve by Volumetric Method in Titas Gas Field (As on March 2009).

Sands GIIP Bcf (Volumetric Calculation)

A1 1151

A2 3376

A2b 768

A3 1089

A4 Upper (A4U) 172

A4 Lower (A4L) 75

A Sand Total 6631

B1 23

B2 0.0

B3a 127

B3b 147

B Sand Total 297

C1 143

C2 98

C Sand Total 241

B and C Sand Total 538

Total 7169

3.1.2. Reserve Estimation by Material Balance

The gas reserves are determined by Material Balance

on putting the raw data from using equation no. 2. The

Gas Reserves in their calculation which is shown in

Table 2.

Table 2: Sand Wise Gas Reserve by Material Balance in Titas Gas Field (As on March 2009).

Sands GIIP Bcf ( Material Balance )

A Sand Total 6650

B Sand Total 635

C Sand Total 515

B and C Sand Total 1150

Total 7800

3.2. Production Facilities of Titas Gas Field

The daily production of Titas gas field is given below

incorporating different types of wells and sand

formation (1st April, 2009) which is shown in Table

3.


30 | P a g e

Table 3: Daily Production of Titas Gas field (1st April, 2009) (Source: Titas Production Facilities Engineering Report, 2009).

Wells Formation Production Period Average Daily Production Average Wellhead

Pressure (psig) Gas (mmscfd) Cond. (bpd) Water

(bpd)

Titas 1 A Sand April 68 - Mar 09 31.27 32.62 26.59 1885

Titas 2 A Sand May 68 - Mar 09 33.06 34.49 28.12 1900

Titas 3 A Sand July 85 - Jan 08 0.0 0.0 0.0 0

Titas 4 A Sand Oct. 69 - Jan 08 32.33 33.73 27.50 1860

Titas 5 A Sand Jan 81 - Mar 09 33.38 34.82 28.39 1850

Titas 6 A Sand Feb 84 - Mar 09 35.00 36.48 29.77 1830

Titas 7 A Sand Jul 85 - Mar 09 32.99 34.43 28.07 1910

Titas 8 B and C Sand April 68 - Mar 09 22.13 23.09 18.81 1550

Titas 9 B and C Sand March 89 - Mar 09 31.37 33.16 26.68 1600

Titas 10 B and C Sand Sept 90 - Mar 09 14.84 15.49 12.58 1460

Titas 11 A Sand Jun 91 - Mar 09 25.93 27.06 22.06 2015

Titas 12 A Sand Jul 02 - Mar 09 21.37 31.79 1286.44 1725

Titas 13 A Sand Jun 00 - Mar 09 21.36 32.22 215.70 2100

Titas 14 A Sand Jun 00 - Nov 06 0.0 0.0 0.0 0

Titas 15 A Sand May 06 - Mar 09 29.99 31.30 25.51 1966

Titas 16 A Sand Dec 05 - Mar 09 29.96 31.26 25.48 1968

Total 394.98 431.94 1801.7

4. Discussions

4.1 Reserve Estimation of Titas Gas Field

The reservoir sands in the Titas field are composed of

stacked sands that are divided into three main layers:

‘A’, ‘B’ and ‘C’ Sands. The A Sand has a further six

sand members, A1, A2, A2B, A3, A4U and A4L.

Similarly, B and C Sands have another six gas bearing

sands: B1, B2, B3a, B3b, C1 and C2. The most

prolific are those of the Group ‘A’ Sands, which

constitute the main producing reservoirs in the Titas

gas field. Almost 85 percent of initial gas in place

(GIIP) is in the A sand which is similar in case of

petro-physical analysis of shaly sand reservoir of

Bengal Basin, Bangladesh [4-6]. From Titas Well

(‘‘A’’ Gas Sand), Gas initially in place is 6631 Bcf (as

on March, 2009) of the volumetric analysis. Where,

Gas initially in place at A1 is 1151 Bcf, A2 is 3376

Bcf, A2b is 768 Bcf, A3 is 1089 Bcf, A4 Upper

(A4U) is 172 Bcf and A4 Lower (A4L) is 75 Bcf. And

from Titas Well (‘‘B’’ & ‘‘C’’ Gas Sand), Gas

initially in place is 538 Bcf of the volumetric analysis

which is nearly comprehensive last Rashidpur gas

field reserve estimation [3]. In ‘‘B’’ Sand, Gas

initially in place is 297 Bcf of the volumetric analysis.

Where, Gas initially in place at B1 is 23 Bcf, B3a is

127 Bcf and B3b is 147 Bcf. And from “C’’ Sand,

Gas initially in place is 241 Bcf of the volumetric

analysis. Where, Gas initially in place at C1 is 143

Bcf and C2 is 98 Bcf. The sand wise gas reserve by

volumetric method in their calculation which is shown

in Figure 3 and Figure 4.


31 | P a g e

Fig. 3: Sand layers wise gas reserve by Volumetric Method in Titas Gas Field since on 2009.

Fig. 4: Sand groups-wise gas reserve by Volumetric Method in Titas Gas Field since on 2009.

From Titas Well (‘‘A’’ Gas Sand), Gas initially in

place is 6650 Bcf (as on March, 2009) of the material

balance analysis and it has shown that there is no

aquifer support in the sand A [2]. And from Titas

Well (‘‘B’’ & ‘‘C’’ Gas Sand), in the material balance

analysis, Gas initially in place is 1150 Bcf. Where,

Gas initially in place at ‘‘B’’ Gas Sand is 635 Bcf and

at ‘‘C’’ Gas Sand is 515 Bcf The sand wise gas

reserve by material balance method in their

calculation which is shown in Figure 5.

Fig. 5: Sand wise gas reserve by Material Balance Method in Titas Gas Field since on 2009.

1151

3376

7681089

172 75 23 0 127 147 143 98

0

1000

2000

3000

4000

A1 A2 A2b A3 A4U A4L B1 B2 B3a B3b C1 C2

Ga

s R

eser

ve

(Bcf

)

Sand Layers

Sand Layers Wise Gas Reserve by Volumetric

Method A1A2A2bA3A4UA4LB1B2B3aB3bC1C2

6631 Bcf

297 Bcf 241 Bcf

Sand Groups Wise Gas Reserve by Volumetric

Method

A Sand

B Sand

C Sand

6650 Bcf

635 Bcf515 Bcf

Sand Groups Wise Gas Reserve by Material

Balance Method

A Sand

B Sand

C Sand


32 | P a g e

Here, the reality is that the field has not been fully

appraised. These are the limitations in the volumetric

estimation. A2 sand is more dominant sand than any

other sands in volumetric calculation and B2 sand is

contains less GIIP Bcf in volumetric calculation than

other sands. The estimation of sand wise gas reserve

in Titas gas field by volumetric and material balance

methods are nearly close. They differ from each other

in their calculation which is shown in Figure 6.

Fig. 6: Gas reserves various by volumetric and material balance method in Titas Gas Field since on 2009.

The material balance method is simple, but effective

means for estimating not only original gas in place but

also gas reserves at different stages of reservoir

depletion. Material balance methods also provide a

check for the gas in place estimates of the volumetric

method.

4.2 Production Facilities of Titas Gas Field

The field was discovered in 1963 and was put into

production in 1968. Current daily gas production of

Titas field is about 394.98 mmscfd with 431.94 bpd of

condensate and 1801.7 bpd of water since on 2009.

The Titas gas field production which is shown in Fig.

7.

Fig. 7: Total production of Titas Gas Field since on 2009.

The Titas No. 1 Well (“A” Sand) was drilled as a

vertical well in 1962 to 13,235 ft MD. Earliest

reported production was in April, 1968 at 4.7 mmscfd

at 3,300 psig wellhead pressure with no reported

water and a condensate gas ratio of 2.27 bpd.

Reported production in March of 2009 is 31.27

6631

538

6650

1150

0

1000

2000

3000

4000

5000

6000

7000

A Sand B & C Sand

Ga

s R

eser

ve

(Bcf

)

Sand Groups

Gas Reserve Varioous by Volumetric & Material

Balance Method

Volumetric

Calculation

Material

Balance

394.98

mmscfd

431.94 bpd

1801.7 bpd

Total Production of Titas Gas Field Since on 2009

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)


33 | P a g e

mmscfd of gas with 32.62 bpd of condensate and

26.59 bpd of water at a wellhead operating pressure of

1885 psig. The Titas No. 1 well gas production is

shown in Figure 8.

Fig. 8: Titas Well 1 Gas production history since on 2009.

The Titas No. 2 Well (“A” Sand) was spud in

February, 1963 and was drilled as a vertical well to a

depth of 10,573.5 ft. The well was placed on

production in May, 1968. Early rates averaged 4

mmscfd with 2.18 bpd of condensate. Production rates

from the “A” Sand reported on March, 2009 were

33.06 mmscfd with 34.49 bpd of condensate and

28.12 bpd of water at a wellhead operating pressure of


shown in Figure 9.


In our study, the Titas No. 3 Well (“A” Sand) was

spud as a deviated well on August 3, 1969. The well

was completed in the “A” Sands and was placed on

production in July, 1985. Production from the well

continued until January, 2008. The well was

abandoned in February, 2008. Titas No. 3 well

suffered from vicinity seepage and uncontrollable

casing leakage which made its operation impossible.

The Titas No. 4 Well (“A” Sand) was spud as a

vertical well 1969 and was drilled to a depth of 9,350

ft. The “A” Gas sand was first put on production in

October, 1969 at 12.45 mmscfd. In March, 2009

reported flows from Titas 4 was 32.33 mmscfd with

27.50 bpd of water and 33.73 bpd of condensate at a

flowing tubing pressure of 1860 psig. The Titas No. 4

well gas production is shown in Figure 10.

4.7

31.27

2.27

32.62

0

26.59

0

5

10

15

20

25

30

35

Jan-6

8

Jan-7

1

Jan-7

4

Jan-7

7

Jan-8

0

Jan-8

3

Jan-8

6

Jan-8

9

Jan-9

2

Jan-9

5

Jan-9

8

Jan-0

1

Jan-0

4

Jan-0

7

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date

Titas Well 1 Gas Production

Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

4

33.06

2.18

34.49

0

28.12

05

10152025303540

Jan-6

8

Jan-7

1

Jan-7

4

Jan-7

7

Jan-8

0

Jan-8

3

Jan-8

6

Jan-8

9

Jan-9

2

Jan-9

5

Jan-9

8

Jan-0

1

Jan-0

4

Jan-0

7

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


34 | P a g e


The Titas No. 5 well (“A’’ Sand) was spud as a

deviated well on October 5, 1980 to a depth of 10,802

ft (9,780 ft TVD). The “A” Gas sand was first put on

production in January 1981 at 23 mmscfd with 9.57

bpd of water and 21.8 bpd of condensate. At March,

2009 reported production from the “A” Sand is 33.38

mmscfd of gas, 34.82 bpd of condensate and 28.39

bpd of water production at wellhead operating

pressure of 1850 psig. The Titas No. 5 well gas

production is shown in Figure 11.


In study, the Titas No. 6 Well (“A” Sand) was spud as

a vertical well on May 7th, 1983 to a total depth of

10,072 ft. The well was placed on production in

February, 1984 at 28.6 mmscfd of gas, 38.01 bpd of

condensate and 16.98 bpd of water at 3,086 psig.

March 2009 reported production from the “A” Gas

Sand is 35.00 mmscfd of gas at the wellhead

operating pressure of 1830 psig with 36.48 bpd of

condensate and 29.77 bpd of water production. The

Titas No. 6 well gas production is shown in Figure 12.

12.45

32.33

0

33.73

0

27.5

05

10152025303540

Jan-6

9

Jan-7

2

Jan-7

5

Jan-7

8

Jan-8

1

Jan-8

4

Jan-8

7

Jan-9

0

Jan-9

3

Jan-9

6

Jan-9

9

Jan-0

2

Jan-0

5

Jan-0

8

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

23

33.38

21.8

34.82

9.57

28.39

05

10152025303540

Jan-8

1

Jan-8

3

Jan-8

5

Jan-8

7

Jan-8

9

Jan-9

1

Jan-9

3

Jan-9

5

Jan-9

7

Jan-9

9

Jan-0

1

Jan-0

3

Jan-0

5

Jan-0

7

Jan-0

9

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


35 | P a g e


Titas No. 7 Well (“A” Sand) was spud as a deviated

well on December 1, 1984 and was drilled to a total

depth of 11,006 ft (9,491 ft). The well was placed on

production in July, 1985 at 19.7 mmscfd of gas, 4.5

bpd of condensate, and 2.26 bpd of water at 3,008

psig. March 2009 reported production from the “A”

Gas Sand was 32.99 mmscfd of gas, 34.43 bpd of

condensate and 28.07 bpd of water at the wellhead

operating pressure of 1910 psig. The Titas No. 7 well

gas production is shown in Figure 13.


The Titas No. 8 Well (“B” and “C” Sands) was spud

as a deviated well on May 25, 1985 to a total depth of

11,760 ft. The well was placed on production in April

1968 at 1.12 mmscfd with 0.63 bpd of water and 1.9

bpd of condensate. At March, 2009 reported

production from the “B” and “C” Gas Sands is 22.13


bpd of water production at the wellhead operating



28.6

3538.0136.48

16.98

29.77

05

10152025303540

Jan-8

4

Jan-8

6

Jan-8

8

Jan-9

0

Jan-9

2

Jan-9

4

Jan-9

6

Jan-9

8

Jan-0

0

Jan-0

2

Jan-0

4

Jan-0

6

Jan-0

8

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

19.7

32.99

4.5

34.43

2.26

28.07

0

5

10

15

20

25

30

35

40

Jan-8

5

Jan-8

7

Jan-8

9

Jan-9

1

Jan-9

3

Jan-9

5

Jan-9

7

Jan-9

9

Jan-0

1

Jan-0

3

Jan-0

5

Jan-0

7

Jan-0

9

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


36 | P a g e


In the study, Titas No. 9 Well (“B” and “C” Sands)

was spud as a deviated well on September 11, 1987 to

a total depth of 11,893 ft (10,403 ft). The well was

placed on production in March of 1989 at 25.5

mmscfd of gas, 25.59 bpd of condensate, and 13.36

bpd of water, at 2,990 psig. In March, 2009

production from the “B” and “C” Gas Sand is 31.37






The Titas No. 10 Well (“B” and “C” Sands) was spud

as a deviated well on February 14, 1988 and was

drilled to a total depth of 12,139 ft. The well was

placed on production in September of 1990 at initial

rates of 6.745 mmscfd of gas, 0.44 bpd of condensate,

and 0.14 bpd of water at 3,275 psig. In March, 2009

reported production from the “B” and “C” Gas Sand is

14.84 mmscfd of gas, 15.49 bpd of condensate and

12.58 bpd of water production at the wellhead



1.12

22.13

1.9

23.09

0.63

18.81

0

5

10

15

20

25

Jan

-68

Jan

-72

Jan

-76

Jan

-80

Jan

-84

Jan

-88

Jan

-92

Jan

-96

Jan

-00

Jan

-04

Jan

-08

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

25.5

31.37

25.59

33.16

13.36

26.68

0

5

10

15

20

25

30

35

Jan

-89

Jan

-91

Jan

-93

Jan

-95

Jan

-97

Jan

-99

Jan

-01

Jan

-03

Jan

-05

Jan

-07

Jan

-09

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


37 | P a g e


Titas No. 11 Well (“A” Sand) was spud as a deviated

well on February 10, 1990 and was drilled to a total

depth of 10,462. The well was placed on production in

June of 1991 at 10.896 mmscfd of gas, 0.54 bpd of

condensate and 0.22 bpd of water at 3,000 psig.

March 2009 reported production from the “A” Gas

Sand is 25.93 mmscfd of gas, 27.06 bpd of condensate

and 22.06 bpd of water production at the wellhead





deviated well on June 17, 1999 to a total depth of

9,875 ft (9,543.7 ft). The well was placed on

production in July of 2002 at 14.53 mmscfd of gas,

4.86 bpd of condensate and 951 bpd of water at 2,225

psig. In March, 2009 reported production from the

“A” Gas Sand is 21.37 mmscfd of gas, 31.79 bpd of

condensate and 1286.44 bpd of water production at

the wellhead operating pressure of 1725 psig. The

Titas No. 12 well gas production is shown in Figure

18.

6.745

14.84

0.44

15.49

0.14

12.58

0

5

10

15

20

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

10.896

25.93

0.54

27.06

0.22

22.06

0

5

10

15

20

25

30

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


38 | P a g e


The Titas No. 13 Well (“A” Gas Sand) was spud as a

deviated well on August 27, 1999 and was drilled to a

total depth of 11,489.5 ft. The well was placed on

production in June 2000 at 7 mmscfd of gas with no

reported liquids at 2,700 psig. In March, 2009

production from the “A” Gas Sand was reported to be

21.36 mmscfd of gas, 32.22 bpd of condensate and

215.70 bpd of water production at the wellhead




In the study, Titas No. 14 Well (“A” Sand) was spud

as a deviated well on July 12, 1999 and was drilled to

a total depth of 11,007 ft (10,554.5 ft TVD). The well

was placed on production in June 2000 at 2.7 mmscfd

of gas, 3.9 bpd of condensate, and no reported water

at 2,669 psig FWHP. The reported production ended

in November, 2006 at reported rates of 15.8 mmscfd

at 1,775 psig with 21.78 bpd of condensate and 14.92


pressure of 1,775 psig. Titas No. 14 well was

abandoned during the year 2007 due to heavy loading

of encroached water.


vertical well on February 3, 2006 and was drilled to a

total depth of 10,446.2. The well was placed on

production in May 2006 at 25.0 mmscfd of gas, 13.65

bpd of condensate, and 10.49 bpd of water at 2,185

psig. In March, 2009 reported production from the

“A” Gas Sand is 29.99 mmscfd of gas, 31.30 bpd of

condensate and 25.51bpd of water production at the

wellhead operating pressure of 1966 psig that relevant

14.53 21.374.8631.79

951

1286.44

0

200

400

600

800

1000

1200

1400

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

7 21.36

32.22

0

215.7

0

50

100

150

200

250

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


39 | P a g e

to evaluate the reservoir sand of Titas-15 well,

Bangladesh [8]. The Titas No. 15 well gas production

is shown in Figure 20.


The Titas No. 16 Well (“A” Gas Sand) was spud as a

deviated well on August 5, 2005 and was drilled to a

total depth of 11,673.2 ft (10,218.7 ft). The well was

placed on production in December, 2005 at 17

mmscfd of gas, 7.55 bpd of condensate, and 5.98 bpd

of water at 2,040 psig. In March, 2009 reported

production from the “A” Gas Sand was 29.96 mmscfd

of gas, 31.26 bpd of condensate and 25.48 bpd of

water production at the wellhead operating pressure of


shown in Figure 21.


5. Conclusions

Titas gas field is the largest gas producer in

Bangladesh. On the overall study, we have found

three main layers reservoir sands such as A, B and C

Sand. Among the sands the most prolific group of

sand is A which constitute the main producing

reservoirs in the Titas gas field. At the beginning of

the reservoir production, reserves are estimated based

on geological and engineering data but at later stages,

production data and additional well information from

appraisal/development drilling are given more

emphasis in estimating the reserves. The daily current

gas production of Titas field is about 394.98 MMcfd

with 431.94 bpd of condensate and 1801.7 bpd of

25

29.99

13.65

31.3

10.49

25.51

0

5

10

15

20

25

30

35

Jan-06 Jan-07 Jan-08 Jan-09

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)

17

29.96

7.55

31.26

5.98

25.48

0

5

10

15

20

25

30

35

Jan-05 Jan-06 Jan-07 Jan-08 Jan-09

Gas Rate (mmscfd)

Condensate Rate

(bpd)

Water Rate (bpd)

Date


Gas Production

(mmscfd)

Condensate

Production (bpd)

Water Production

(bpd)


40 | P a g e

water since on 2009. Among sixteen wells of Titas

gas field, the no. 6, 12 and 13 wells show the best

performance in their production facilities but the no. 3

and 14 wells show the lowest performance in gas

production. This method seems to be applicable to

most of the gas reservoirs of Bangladesh.

Nomenclatures

Bcf billion(s) of standard Cubic Feet

BGFCL Bangladesh Gas Fields Company Ltd.

Bpd barrels per day

Condensate liquid hydrocarbons which are sometimes

produced with natural gas and liquids

derived from natural gas

ft feet

ft3/Scf cubic feet per standard cubic feet

GIP gas in place

GIIP gas initially in place

Mmscfd millions of standard cubic feet per day

Psi pounds per square inch

Psig pounds per square inch gauge

Scf standard cubic feet

mD permeability in millidarcies

TVD true vertical depth

Acknowledgement

The authors would like to thanks to the authority of

BGFCL for the permission of field work and

department of Petroleum and Mining Engineering

(PME), Jessore University of Science and Technology

(JUST), Bangladesh for providing logistical support.

References

[1] Choudhury Z, Gomes E. Material Balance Study

of Gas Reservoirs by Flowing Well Method: A Case

Study of Bakhrabad Gas Field; SPE 64456, paper

presented at the Asia Pacific Oil and Gas Conference

and Exhibition, Brisbane, Australia, October 16-18,

SPE, 2000.

[2] Haq MB. Reserve Estimate and Development

Study of Titas Gas Field. Department of Petroleum

and Mineral Resources Engineering, BUET, Dhaka,

Bangladesh. M.Sc. Thesis, 2001.

[3] Intercomp-Kanata Management Ltd. (IKM), Gas

Field Appraisal Project, Reservoir Engineering report,

Rashidpur Gas Field, Bangladesh; Canadian

International Development Agency (CIDA) and

Bangladesh Oil, Gas and Minerals Corporation

(BOGMC) report, 1990.

[4] Islam MA, Islam MS, Latif MH, Mondal D,

Mahbub MA. Petrophysical analysis of shaly-sand gas

reservoir of Titas Gas Field using well logs. Journal

of Geology, Bangladesh, 2006; 25: 106-124.

[5] Islam MA, Islam MS, Mondal D. Log derived

shaly-sand analysis of Shahbazpur Gas Field, Bhola,

Bangladesh. Journal of Bangladesh Geoscience,

2007; 13: 63-77.

[6] Islam MA, Islam MS, Talukder S, Haque KE,

Rahman MA, Ahmed F. Petrophysical evaluation of

neogene shaly-sand gas reservoir: A case study of

Kailas Tila gas field, Bengal Basin, Bangladesh.

International Journal of Earth Science and

Engineering, 2009; 2: 499-511.

[7] Mattar L, McNeil R, Fekete Associates Inc. The

“Flowing” Gas Material Balance. The Journal of

Canadian Petroleum Technology, 1998.

[8] Rahman MM, Wobaidullah ASM, Imam B.

Evaluation of Reservoir Sands of Titas-15 Well by

Wireline log interpretation. Journal of Bangladesh

Geoscience, 2009; 15: 67-75.

[9] Reservoir Management Project (RMP)-2, Titas

Geological Study. Petrobangla, Bangladesh, 2009; 7:

35-36.

[10] Titas Geological Study. Prepared for

Petrobangla, 2009; 7: 47-52.

[11] Titas Production Facilities Engineering Report.

Petrobangla, Bangladesh, 2009; 10-12.

Documents

Reserve Estimation and Production Facilities: A Case · PDF fileReserve Estimation and Production Facilities: A Case ... study will focus on the reserve estimation and production facilities