ESP with Gas Lift: A solution for Well Integrity and Sustained Production in High GOR Wells

Panit Jedsadawaranon, Suwitcha Ratanatanyong, Thanudcha Khunmek

And Donald Nicolson - Mubadala Petroleum

Derek Kongsawat, Bo Zhu – GE WPS Thailand

INNOVATION FEATURE

One of the main challenges of Electric

Submersible Pumps (ESPs), or a centrifugal

pump in general, is that they cannot handle

significant amounts of gas. As a consequence,

the ESP performance is affected by the GVF

(Gas Volume Fraction) present at the pump

intake. A higher GVF means an increase of

compressible fluids in the system to be

handled by the ESP; in this situation, once the

pump is not able to deliver the well fluid to

surface, the pump “gas locks”.

Well Design Issues

When an ESP is designed for a given well, it is

important to consider which of the three

options to overcome free gas will be

implemented: avoid it, separate it or handle

it.

The conventional practice implemented in

Mubadala Petroleum’s Jasmine oilfield in the

past has been to complete oil production

wells with a gas separator to prevent the gas

from getting into the ESP. A production packer

with a Gas Vent Valve (GVV) would have also

been installed to allow the separated free gas

to pass through the packer, and finally to

surface through the tubing and production

casing annulus. This however, exposed the

annulus to potentially corrosive high CO2 gas

present in the Jasmine field. As the

production casing is normally not designed

for corrosive service, casing corrosion has

been seen in some wells, leading to well

integrity problems.

Well Design Options

There were a number of solutions originally

reviewed by the Mubadala Petroleum and GE

teams, as shown below:

1. ESP with Gas Handler.

2. ESP with Gas Lift Valve.

3. ESP with secondary conduits above

packer for gas release.

4. Dual Completion with ESP.

All of the above options were analyzed and

compared with each other in terms of

reliability, cost, equipment lead time,

simplicity, worldwide deployment and

operation experience. Following the analysis,

the option of deploying the ESP with a Gas Lift

Valve (GLV) was selected.

The design involves having a Gas Lift Mandrel

(GLM) under the production packer, with a

GLV installed. This allows separated gas from

the ESP to flow back into the tubing above the

ESP. This solution does not require any gas

vent feature at the production packer and

preserves the completion fluid in the annulus,

hence the well integrity.

Concept Challenges

Some of the challenges encountered include:

• Estimating the liquid level between the

ESP and the packer to ensure adequate

placement of the Gas Lift Valve (GLV)

• Achieving the desired GLV opening and

closing pressures to ensure smooth

operation of the GLV

• Determining GLV design and Side Pocket

Mandrel (SPM) size ranges given a

potentially wide range in gas rates

All these challenges were overcome by careful

engineering design which cannot be fully

elaborated in this paper. Designs were mostly

well specific and had to in some cases

accommodate situations where there were

wide swings in well conditions.

IMPACT AND VALUES

As mentioned above, wells producing from

high GOR reservoirs have traditionally

required gas separators with the ESP

completions, which allowed for the separated

gas to be vented into the tubing- casing

annulus. Given the high CO2 content of the

gas, the resulting well integrity issues resulted

in wells being shut-in, or the execution of

costly workovers to fix the resulting well

integrity problems. As a preventive step,

other wells which didn’t have integrity issues

but which were known to produce from high

GOR reservoirs may also be shut-in.

The implementation of an innovative well

completion approach of running ESP with Gas

Lift helped address these issues and hence

has the following benefits;

• Ensures wells remain integral while

producing from high GOR reservoirs.

Eliminates the need for costly workovers.

• Eliminates the need for higher grade

production casing supposing the old

completion were deployed.

• Ensures continued oil production from

high GOR reservoirs.

• Allows for optimization (GLV change outs)

with inexpensive through tubing

intervention.

WHY SHOULD THIS PROJECT WIN THE

AWARD

• First time implementation of “ESP with

Gas Lift” completion in the region.

• Utilizes simple proven technology in an

innovative way.

• Improved safe operation of the wells;

maintains and complies with well

integrity standards.

• Maximizes production and allows for

wells to be produced at expected

drawdown pressures.

• Cost effective; easy to assembly, deploy,

and repair.

APPENDIX I – THE EXAMPLE OF ESP WITH GAS LIFT WELL SCHEMATIC

APPENDIX II – DESIGN METHODOLOGY

ESP with Gas lift design utilizes both ESP and gas lift design. The process starts with the

conventional ESP design based on reservoir description, production history and production

constraints.

Gas lift valve will then be designed subject to these parameters to ensure that Gas lift valve

would open to release any trapped gas below the ESP production packer and avoid the gas locks.

See Data Tables and Calculations for well A and well B below for the reference.

Data Tables and Calculations

TABLE 1 – Well A – Production Test Summary (Test Results on 12-Aug)

Variable Value Units

Oil 346 BPD

Water 11 BPD

Fluid 357 BPDWater Cut 3 %

Gas Rate 3670000 scf/dayGOR 10,607 scf/STBGLR 10280 scf/STB

Frequency 45 Hz

API 35.2 ºIntake Pressure 1087 psiDischarge Pressure 984 psi

Intake Temp 207 ºF

Mtr. Oil Temp 2130 ºF

Free Gas at Intake 94 %

Free Gas Into Pump 15.5 %

Pump 68 Stg TE2700

Intake TR5 MAGS-3

Motor TR5 120 HP

TABLE 2–Well B– Production Test Summary (Test Results on 9-Aug)

Variable Value Units

Oil 366 BPDWater 550 BPD

Fluid 916 BPD

Water Cut 60 %Gas Rate 310,000 scf/dayGOR 847 scf/STB

GLR 338 scf/STBFrequency 35 Hz

API 31.9 ºIntake Pressure 1863 psiDischarge Pressure 2379 psi

Intake Temp 189 ºF

Mtr. Oil Temp 195 ºF

Free Gas at Intake 18 %

Free Gas Into Pump 0.13 %

Pump 68 Stg TE2700

Intake TR5 MAGS-3

Motor TR5 120 HP