Gas Well Dewatering PetromRomania –Member of …€¦ · requires no batch treating or shut-in...

Gas Well Dewatering Petrom Romania – Member of OMV Group

August 2009Vasile Stanculescu, Nicolae

Gheorghe

2 Gas wells Dewatering|

Presentation contents

� Background

� Selection criteria

� Lifting methods

� History

� Application results

� Operational challenges

� Summary of results

� Conclusions


Background – As Related to Gas Well Dewatering

� Petrom is the Largest Producer of Oil and Gas in South Easter Europe

� In 2004 a 51% Acquisition of shares by OMV occurred

� In February 2007 a Service Company was approached by Petrom to discuss

Dewatering Options for approximately 100 gas wells

� April 2007 Initial Data was captured indicating that there was a solid

opportunity for Gas Well Dewatering

� In June 2007 a Test Contract was signed

� During the 4th Quarter of 2007 Designs were completed and first

installations occurred


Initial Well Evaluations

► Signs of liquid loading:

►high differential casing-tubing pressure between 9 -20 bars

►decreasing liquid production

►decreasing gas rate

►not constant/rather fluctuating gas and liquid production

► Evaluation

► Initial evaluations were completed to determine optimal lift type and uplift potential

►The optimal lift type was chose based on economical and technical (pressure, rate, tubulars, perforated interval, water cut…) criteria


Lift Methods Evaluated

Most Common Dewatering Methods► Velocity Strings► Foamer Application

► Batch► Continuous

- Capillary injection- Injection in annulus

► Soap Sticks► Plunger Lift► Compression

Less common however still applied with larger volumes► Gas Lift ► Rod-Pump

Other Forms of Lift also used for Dewatering in specific cases► Hydraulic Lift► Progressive Cavity Pump► Electric Submersible Pump


Continuous Foam Injection

Annulus Injection► Advantages:

► really cheap method► easy to install ► requires no batch treating or shut-in time

► Disadvantages: ► Not applicable in wells with packer► Results can be influenced by the tubing

Capillary Injection► Advantages:

► Applicable in Packer completions and in deep application► Simple to operate

► Disadvantages: ► Costly compared to Annular injection► Potential Operational Issues

- Limits Wellbore Access- Emergency Shut down options


Plunger Lift System

Advantages:► Requires no outside energy source; uses well’s energy to lift► Rig not required for installation► Easy maintenance ► Keeps well clean of paraffin deposits► Low-cost artificial lift method► Handles gassy wells► Good in deviated wells

Disadvantages:► Specific GLRs to drive system:

►400 Scf/bbl/1000feet no Packer►1000 Scf/bbl/1000feet with Packer

► Low-volume potential (<200 BPD)► Solids► Requires surveillance to be optimized► Requires ID tubular to be constant

Lubricator

Catcher

Solar Panel

Controller

Dual “T” Pad

Plunger

Bumper

Spring


History

► In 4th Q of 2007 and 1st Q of 2008, 6 wells in one of the Petromfields, were analyzed and installed with dewatering methods:

► 4 continuous foam injection in the annulus

► 1 capillary injection banded

► 1 plunger lift


Pilot Test - Results

► In 4th Q of 2007, 3 wells were equipped with foam injection method resulting in a gas rate of 33000 Sm3/day.

► At the 1st Q of 2008 after installing the other 3 wells Petromobtained a total increase of 49000 Sm3/day; an average of 8300 Sm3/day/well equipped Pilot Test Contract

100000

110000

120000

130000

140000

150000

160000

170000

180000

190000

200000

1-Oct-07

21-Oct-07

10-Nov-07

30-Nov-07

20-Dec-07

9-Jan-08

29-Jan-08

18-Feb-08

9-Mar-08

29-Mar-08

Gas R

ate

[Sm

3/d

ay]

Gas Rate Before Installation Gas Rate After Installation


Q2 –Q3 of 2008

► In 2nd and 3rd Q of 2008 the main focus was:

►maintaining the increase obtained for the wells in the pilot test

►gathering information for the new wells and analyzing them for future installation

►preparing the new Dewatering Contract between Petrom and Service Company

► In the last part of 3rd Quarter the first 5 wells from the Dewatering contract, have been installed (continuous foam injection into annulus)


End of Q3 2008

Wells installed at end of 3rd Q 2008

60000

65000

70000

75000

80000

85000

90000

1-Apr-08

1-May-08

1-Jun-08

1-Jul-08

1-Aug-08

31-Aug-08

1-Oct-08

31-Oct-08

Gas R

ate

[S

m3/d

ay]


� The total increase of gas production for these 5 foam injection

methods was 18300 Sm3/day; an average of 3700

Sm3/day/well


Q3 of 2008 – Detailed Results

W1-Field 3 – Results► Well description:

► This well was a Gas Lift well which was receiving 12000 Sm3/day of injection gas per day to lift. Gas Production from formation was 3000 Sm3/day with 0.2 m3/day of oil and 0.5 m3/day of water

► Objective:► reducing costs with gas injection► reducing gas injection rate► obtaining a constant gas rate as high as possible

► Results:► well was equipped with continuous foam injection in the annulus► by the end of 4th Q of 2008 the gas injection rate was decreased from 12000-15000 Sm3/day to 6000 Sm3/day

► the reservoir gas rate increased from an average of 3000 Sm3/day to a constant gas rate of 4000 Sm3/day

► in April 2009 it was decided to stop gas injection and to produce the well only with foamer injection. The gas rate remained at the same value of 4000 Sm3/day surveillance

► well is under close surveillance


Well W1-Field 3 –- Gas Lift Well/Converted to flowing Gas

Well

W1 Real Results

0

5000

10000

15000

20000

25000

30000

11-Mar-08 30-Apr-08 19-Jun-08 8-Aug-08 27-Sep-08 16-Nov-08 5-Jan-09 24-Feb-09 15-Apr-09 4-Jun-09

Gas R

ate

[S

m3/d

ay]

0

5

10

15

20

25

Liq

uid

rate

[m

3/d

ay]

Reservoir Gas Rate Injection Gas Rate Liquid Rate

Installation of

continuous

foam injection in

the annulus

Injection rate

was dropped to

6000 Sm3/dayInjection rate

was dropped to

0 Sm3/day


� In 4th Q of 2008, 26 wells were installed, resulting in an increase of gas production of

105000 Sm3/day, an average of 4300 Sm3/day/well installed

Q4 of 2008

Wells Installed in 4th Q 2008

300000

320000

340000

360000

380000

400000

420000

440000

460000

480000

500000

1-Jul-08

21-Jul-08

10-Aug-08

30-Aug-08

19-Sep

-08

9-Oct-08

29-Oct-08

18-Nov-08

Gas R

ate

[Sm

3/d

ay]

Gas Rate After Installation Gas Rate Before Installation


Q4 of 2008 - Detailed Results

W2 Field 2 – Results► Well description:

► During the previous year the wells production decreased from 50000 Sm3/day to 18-23000 Sm3/day.

► casing-tubing differential pressure, increased from 10 bars to 23 bars

► liquid production decreased from 30 m3/day to 15 m3/day ► Objective:

►maintaining gas rate to a value of 28000 Sm3/day and avoiding well from stopping production

►unloading the well► Results

►well was equipped with continuous foam injection in the annulus► first month after installation the gas rate increased from 18000 Sm3/day to 46000 Sm3/day

►water rate increased from 18 m3/day to 30 m3/day►well is under close surveillance


W2 Field 2 – Real Results

W2 Real Results

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

3-Mar-08 22-Apr-08 11-Jun-08 31-Jul-08 19-Sep-08 8-Nov-08 28-Dec-08

Gas R

ate

[S

m3/d

ay]

-4

6

16

26

36

46

56

Tu

bin

g P

ressu

re, C

asin

g P

ressu

re [

bars

]; L

iqu

id R

ate

[m

3/d

ay]

Gas Rate Tubing Pressure Casing Pressure Liquid Rate

The well started to load up

Installing of

continuous

foamer

injection


Q4 of 2008 - Detailed Results

W3 Field 2 – Result ► Well description:

► Well has an fluctuating production with gas fluctuations between 17000 Sm3/dy and 27000 Sm3/day

► 4-5months before installation soap sticks have been used as treatment but even with this method well continued to have:

- High differential casing-tubing pressure of 15-18 bars- Fluctuating gas rates between 17000-27000 Sm3/day - Fluctuating liquid production

► Objective:►maintaining gas rate to a constant value of 27000 Sm3/day ►unloading the well

► Results:► well was equipped with continuous foam injection in the annulus

► first month after installation the gas production was increasedto 37000 Sm3/day


W3 Field 2 – Real Result

W3 Real Result

0

10000

20000

30000

40000

29-Feb-08 19-Apr-08 8-Jun-08 28-Jul-08 16-Sep-08 5-Nov-08 25-Dec-08

Ga

s R

ate

[S

m3

/da

y]

0

5

10

15

20

25

30

35

40

45

50

Tu

bin

g P

res

su

re, C

as

ing

Pre

ss

ure

[b

ars

]; W

ate

r R

ate

[m

3/d

ay

]

Gas Rate Tubing Pressure Casing Pressure Liquid Rate

Performed soap

stick treatment

Installing of

continuous

foamer

injection


Challenges During Operations

► Condensate Production – Production figures provided were not always accurate due to inconsistent measurements. In some cases this made optimization difficult

► Holes in Tubing – Initially major issues were found with un-diagnosed holes in the tubing. Solution was to require Echometer tests as part of evaluation process

► Flow Line Pressure – Significant difference in flow line pressure during Summer and Winter changed the impact of the lift method applied

► Choke Size Limitations – Wellhead chokes sizes if not properly modeled, may only result in higher flowing tubing pressure with minimal increase in production


Overall View - Dewatering Project in 2008

► At the end of 2008 have been installed 35 wells►1 plunger technology►1 capillary banded technology►4 continuous foam injection through capillary technology►29 continuous foam injection in the annulus technology

► Total increase of production obtained was 125000 Sm3/day, an average of 3500 Sm3/day/well installed

► Other benefits :►Corrosion Problem

- applying chemicals reduced corrosion problems significantly► Paraffin Problems

- applying plunger reduced the paraffin and scale problems


Overall view regarding Dewatering in 2008

Overall View - 2008

500000

550000

600000

650000

700000

750000

1-Oct-07

15-Dec-07

28-Feb-08

13-May-08

27-Jul-08

10-Oct-08

24-Dec-08

Gas r

ate

[Sm

3/d

ay]



Conclusions

� The results of the application of modern dewatering methods, increased the

average gas production of equipped wells by 22%.

� The success is based on a good cooperation between Petrom and Service

Company.

� Petrom will continue and expand the application of gas dewatering methods

in it’s operations.

Thank you!

Gas Well Dewatering PetromRomania –Member of …€¦ · requires no batch treating or shut-in...

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Transcript of Gas Well Dewatering PetromRomania –Member of …€¦ · requires no batch treating or shut-in...