Field Testing of an Automated Well Tester in a Heavy Oil Application

Rafael Bastardo, WeatherfordRafael Bastardo, WeatherfordJosJoséé Scoglio, PetrozuataScoglio, PetrozuataAsherAsher ImamImam, Weatherford, Weatherford

Outline•• Project ProfileProject Profile

–– The MPM (Multiphase Flow Metering) evaluation programThe MPM (Multiphase Flow Metering) evaluation program

–– Description of test unitDescription of test unit

•• Process and InstrumentationProcess and Instrumentation–– GasGas--liquid cylindrical cyclone technologyliquid cylindrical cyclone technology

–– Metering challengesMetering challenges

•• Test ResultsTest Results–– Impact of diluentImpact of diluent

•• DiscussionsDiscussions–– WaterWater--cut resultscut results

–– Liquid volume resultsLiquid volume results

•• ConclusionConclusion

Field Operations•• Current Well Testing Equipment:Current Well Testing Equipment:

–– Could not measure water cut in realCould not measure water cut in real--time.time.

–– High maintenance issues (moving parts with High maintenance issues (moving parts with heavy crude)heavy crude)

•• Objective:Objective:–– Test a partial separation MPM to see if it could Test a partial separation MPM to see if it could

meter the wells productionsmeter the wells productions

–– Accuracy:Accuracy:

•• ±± 10% Accuracy of total liquid volume10% Accuracy of total liquid volume

•• ±± 5% Accuracy of water cut5% Accuracy of water cut

•• ±± 2% Repeatability2% Repeatability

DIL

UEN

TD

ILU

ENT TANK 1

TANK 2

TANK 3

REMMSREMMS

WELL 4

WELL 5

WELL 2

WELL 3

WELL 6

WELL 1

PRODUCTION LINE

TEST LINE

DILUENT LINE

MULTIPORT VALVE

CHOKE VALVE

Test UnitTest Unit

Proving TanksProving Tanks

Well Pad Layout

ParameterParameter UnitsUnits MinMin MaxMax

Liquid Flow RateLiquid Flow Rate BPDBPD 314314 3,7743,774

Gas Flow Rate Gas Flow Rate (Leg A)(Leg A) MSCFDMSCFD 100100 1,0601,060

Gas Flow Rate Gas Flow Rate (Leg B)(Leg B) MSCFDMSCFD 77 100100

Average Water Average Water CutCut %% 00 100100

Operating Operating PressurePressure PSIGPSIG 2929 200200

Operating Operating TemperatureTemperature DEG FDEG F 100100 250250

ViscosityViscosity CpCp 1010

Partial Separation System (PSS)

Test unit was not designed Test unit was not designed specifically for Petrozuata testspecifically for Petrozuata test

Centrifugal Centrifugal ForceForce

Gas-Liquid Cylindrical Cyclone Technology

•• Separates gas from liquidSeparates gas from liquid

•• Proprietary control algorithmProprietary control algorithm

•• Conventional gas and liquidConventional gas and liquidmetering equipmentmetering equipment

Metering Challenges•• The separator cannot get all of the gas The separator cannot get all of the gas

out of the highly viscous liquid.out of the highly viscous liquid.

•• Key to success: Ability to meter the Key to success: Ability to meter the viscous oil/water with entrained gas.viscous oil/water with entrained gas.–– The Coriolis meter can measure the liquid mass The Coriolis meter can measure the liquid mass

rate accurately with some entrained gas. rate accurately with some entrained gas.

–– Red Eye 2G waterRed Eye 2G water--cut meter can measure the cut meter can measure the water cut accurately with some entrained gas.water cut accurately with some entrained gas.

calculated

legLiqvol

ratemasscutwaterOilNet

ρ__

)_1(_ ×−=

OilOHcalculated cutwatercutwater ρρρ ×−+×= )_1(_2

Calculation of Liquid Volumes

calculated

legLiqvol

ratemasscutwaterWaterNet

ρ__

)_(_ ×=

gasentrainedliquidlegliq ratemassratemassratemass __ ___ +=~0

11

22

33

44

Liquid Measurement•• References used:References used:

–– FracFrac tank used for total liquid volumestank used for total liquid volumes

–– Hand samples for water cut measurementsHand samples for water cut measurements

•• Liquid Metering Challenges:Liquid Metering Challenges:–– Impact of diluent on crude properties.Impact of diluent on crude properties.

–– Error due to assuming fixed oil density. Error due to assuming fixed oil density.

+

0

100

200

300

400

500

Instantaneous Liquid Mass Rate lb/min

0

20

40

60

80

100

Liquid Valve Position %

Zero Mass Flow

Liquid Valve Closed

Liqu

id M

ass

Flow

[lb/

min

]Li

quid

Con

trol

Va

lve

[%]

Test Results - Impact of Diluent•• Normal Field Operating ConditionsNormal Field Operating Conditions

–– 15 to 25% diluent injection15 to 25% diluent injection

Liqu

id C

ontr

ol

Valv

e [%

]

Instantaneous Liquid Mass Rate lb/min

0

20

40

60

80

100

Liquid Valve Position %

Liquid Valve Closed

Liqu

id M

ass

Flow

[lb/

min

]

0

50

100

150

200

250

300

Mass Flow

Test Results - Impact of Diluent•• Small Percentages of DiluentSmall Percentages of Diluent

–– Below the minimum 15%Below the minimum 15%–– Total liquid volume overestimationTotal liquid volume overestimation

Test Results - Impact of Diluent

•• Large Percentages of DiluentLarge Percentages of Diluent–– Above the maximum 25%Above the maximum 25%

–– Large amounts of diluent decreases oil density Large amounts of diluent decreases oil density significantlysignificantly

–– Total liquid volume underestimation due to fixed Total liquid volume underestimation due to fixed oil densityoil density

-15.00%

-10.00%

-5.00%

0.00%

5.00%

10.00%

15.00%

20.00%

25.00%

0 5 10 15 20 25 30 35 40 45

TEST NUMBER

WA

TER

-CU

T %

DIF

FER

ENC

E

REMMS Water-cut Difference

No. Wells: 16API: 11-19Temperature: 98-110 FPressure: 100-170 psig

Calibrated Red EyeWell Pad A

Generic CalibrationsWell Pad B & C

Water-Cut Results•• Well Pad AWell Pad A

–– Red EyeRed Eye 2G meter calibrated with well specific calibrations2G meter calibrated with well specific calibrations

•• Well Pad B & CWell Pad B & C–– Red EyeRed Eye 2G meter calibrated with global calibrations2G meter calibrated with global calibrations

Liquid Volume Results

-30.00%

-25.00%

-20.00%

-15.00%

-10.00%

-5.00%

0.00%

5.00%

10.00%

15.00%

0 5 10 15 20 25 30 35 40 45

TEST NUMBER

TOTA

L LI

Q. P

RO

DU

CTI

ON

% D

IFFE

REN

CE

REMMS Total Volume Difference

No. Wells: 16API: 11-19Temperature: 98-110 FPressure: 100-170 psig

Conclusion•• Partial Separation system is an option for Partial Separation system is an option for

measuring heavy crude production.measuring heavy crude production.

•• The amount of Injected Diluent had a Large The amount of Injected Diluent had a Large Impact on properties of the Petrozuata oil Impact on properties of the Petrozuata oil and the equipment performanceand the equipment performance

•• Weatherford PSS Qualified as SuccessfulWeatherford PSS Qualified as Successful–– Total liquid volume accuracy of Total liquid volume accuracy of ±±10% with 10% with

confidence factor of 90% and confidence factor of 90% and ±±2% repeatability2% repeatability

–– With well specific calibrations, With well specific calibrations, Red EyeRed Eye 2G water 2G water cut accuracy was within cut accuracy was within ±±5%5%

Keys to Success•• Successful Collaboration of PSS Successful Collaboration of PSS

ComponentsComponents–– GLCC technology GLCC technology –– able to separate flow able to separate flow

sufficiently to effectively meter.sufficiently to effectively meter.

–– Level control logic Level control logic –– key to operating partial key to operating partial separation system.separation system.

–– CoriolisCoriolis--Red EyeRed Eye 2G meter combination 2G meter combination ––accurately measure flow rates and wateraccurately measure flow rates and water--cut cut with some entrained gas.with some entrained gas.

–– The open architecture, flow metering technology, The open architecture, flow metering technology, flexibility, easy operation /diagnostics show PSS flexibility, easy operation /diagnostics show PSS units is an excellent solution for heavy oil units is an excellent solution for heavy oil applications.applications.