ESP with Gas Lift the solution for well integrity and...
Transcript of ESP with Gas Lift the solution for well integrity and...
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