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Why a Multiphase Flowmeter can significantly reduce the Why a Multiphase Flowmeter can significantly reduce the Rejection Rate of Well Test versus SeparatorRejection Rate of Well Test versus Separator

Bruno PINGUET & Samia BIFOUTMay 2013

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Contents

Why Well Testing? History & Vx Technology Data Principle How to set a multiphase flow meter (Vx technology) New Model Development for faster and better measurement in Periodic Testing Conclusion Surface mapping of production data: the 4-D model for large field.

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Why Well Testing & Who Needs Measurement Data?

Allocation• Hydrocarbon Accounting• Reservoir Management• Regulatory Reporting

Reservoir Management• Model verification• Drive Management

• EOR

Production Management• Lift & Injection Optimization

• Decline curves• PI monitoring

Facilities Management• De-bottlenecking

• Water management• Flow assurance

Production Measurements• Rate Measurements

• Trending• Sampling

Everyone

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Some Indication of Performance Indicators (KPI) & Schlumberger

Allocation factors– oil volume 0.80 to 0.90– water volume 0.70 to 0.90– gas volume 0.60 to 0.90

Rejection rate ~ 15- 40% Reproducibility - Repeatability Data delivery time, including QA and

“validation”

Well Testing Operations > 80 years Culture of Excellence in Training 24/7 Support Helpdesk Pride in Technology & Service Quality Dedicated Engineering, Reservoir and

Production Engineers QHSE Culture and performance

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Conventional Test Separators

Gas meteringDaniel differential orifice meter

Liquid metering Low flow rate High flow rate‘Floco’ positive displacement ‘Rotron’ Vortex

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Vision of Schlumberger for Periodic Well testing

Back to the beginning of the 1990’s; Schlumberger had a vision of being much more time and cost effective by developing of a multiphase flowmeter for Periodic Well Testing

Accurate flow rate measurements

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Vx Technology Description

Data AcquisitionFlow ComputerGamma Ray

Detector

Barium-133

Differential pressureTransmiter

PressureTransmitter

Bernoulli Equation

or ISO 5167

Fraction Meter based on the

attenuation of -ray and

composition dependent

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Introduced in 1998 Continuous rate measurements No stabilization required No phase separation, No moving parts No Emulsion, No foaming dependency No Sensor in direct contact with the fluid No tuning factor, No flow calibration High Pressure Solution > 5,000 psia Compact Solution: 1.6x1.7x1.8 m3

Lightweight: 1,500 kg Different sizes: 29, 52, 88 (100 – 150,000 bpd) Lowest Total Pressure Lost

PhaseTester*:Periodic Testing (service/rental)

145

Cumulative Years of experience with Vx

Technology:

TOP SIDE: > 5000 years

SUBSEA: > 1500 years

PERIODIC WELL TESTING: > 1000 years

Vx Technology Overview

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Fraction Measurement & “Full” Gamma Ray Spectrum

0

2,500

5,000

7,500

10,000

12,500

15,000

17,500

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241 251 261

Channel #

AA

EXS80A

DWA

5%WA

10%WA

15%WA

Photo-electric effectf (composition, density)

Compton interaction f (density, composition)

Energy Level

GasOilFresh Water 5% Salinity10% Salinity15% Salinity

Compton interaction f (density)

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Photo-electric effectf (composition, density)

Compton interaction f (density, composition)

Low Energy Linear attenuation

High Energy Linear attenuation

0

w

g

o

Gas

OilWater

Coun

ts R

atio

at h

igh

ener

gy

Counts Ratio at low energy

Gamma Ray Spectrum & Solution Triangle

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Gas

OilWater

o

w

g

Line

ar A

ttenu

atio

n at

hig

h en

ergy

Linear Attenuation at low energy

WLR = 0.63

GVF = 0.24

Coun

ts R

atio

at h

igh

ener

gy

Counts Ratio at low energy

Accurate Measurement means proper setting of the meter

It is a reference measurement made at the Venturi throat giving the fluid mass attenuations.

It reflects the ability of each phase to absorb gamma rays or scatters gamma rays

Every fluid has its own specific mass attenuation (a kind of finger print).

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In-Situ Reference Mass Attenuations

Gamma rays countsMass Attenuations

Density of given fluid Accurate flow rates

In-situ Reference: Pouring oil sample into the Venturi

30-45 minutes

for each fluid

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How to be more efficient?

How to improve Quality Measurement?

Truck mounted PhaseTester Unit

The Wish to Reduce Time

& Improve Quality

is always a challenge

Production Testing with PhaseTester

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Let’s see the Water Mass Attenuation Modeling: H2O +NaCl

Quality check and/or Replacement of Water InSitu Reference

1- Mix volumes dilution water + saturated formation water

2- Create a range of salinities

3- Made water insitu reference for all samples

4- Study resulting model Water Mass Attenuation

Correlation was a success

i

Eii

E

i : mass fraction of components i

iE : mass attenuation for

component i and energy E

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How modeling the Oil Mass Attenuations?

Challenges of oil mass attenuation Different compositions are expected Different fraction of elemental components Composition may change with age of the well

Source : National Institute of Standards and Technology

Green is less than 1% change

Yellow is less than 2% change

Components 32 81 356

(cm2/g) (cm2/g) (cm2/g)

H2S 1.7627 0.2584 0.1092CO2 0.3216 0.1651 0.1019

C1 0.2731 0.1980 0.1270C2 0.2670 0.1901 0.1220C3 0.2650 0.1871 0.1200C4 0.2643 0.1861 0.1190C5 0.2638 0.1851 0.1182C6 0.2629 0.1850 0.1180C7 0.2628 0.1841 0.1179C8 0.2628 0.1841 0.1179C9 0.2628 0.1841 0.1172C10 0.2627 0.1831 0.1172C11 0.2622 0.1831 0.1170C12+ 0.2618 0.1831 0.1170

i

Eii

E

i : mass fraction of components i

iE : mass attenuation for component i and energy E

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One first field: Complete Analysis with > 1,600 well tests

Validation

Execution

Study

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Isolation principle of high deviant points

Average(A)

Model (B)

23-Feb-09 (C )

A/B [%]

A/C [%]

LE(32keV) 0.02525 0.02545 0.02665 0.77 5.24HE(81keV) 0.01705 0.01687 0.01794 1.10 4.95XE(356keV) 0.01182 0.01184 0.01240 0.11 4.63

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Linear model created 3 levels of energy

Building Correlations for Oil Linear Attenuations

Model simulation

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Study possible effects on accuracy of Mass Attenuation of the model versus field measurement

Field Test & Mass Attenuation Model Validation

Errors study for all energy levels (32keV, 81keV, and 356keV)

Deviation [%]

LE (32 keV)

HE (81 keV)

XE(356 keV)

<0.5 49.7% 41.9% 44.7%<1.0 76.1% 72.7% 78.6%<1.5 86.7% 88.6% 94.4%<2.0 94.3% 96.7% 98.4%<2.5 98.8% 98.7% 99.3%<3.0 99.9% 99.9% 99.9%

2/3 of the data set

used for modeling

1/3 data to validate &

200 well tests laterLE Input (32 keV)

HE Input (88keV)

XE Input (356kev)

Oil Rate Output

Gas Rate Output

GVF Output

Real Case 0.49% 0.42% 0.39% 0.53% 0.12 % 0.08%Worst Case 3% 3% 3% 1.57% 0.77% 0.34%

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Conclusion (#1)

Vx Technology is based on fluid properties measurement directly no combined factor to build following the fluid, or fuzzy logic used in the interpretation.

The PhaseTester setting requires only the inputs of density measurement and mass attenuation for each phase (with several ways to get it) – No Combined Factor like on a separator

On large field, and high activity it is demonstrated that using an in-situ modeling leads to uncertainty – < 0.5% on oil flow rate – < 0.1% on the gas flow rate (Oil well).

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Conclusion (#2)

Either, it is possible to skip the in-situ reference now for the entire field and then be able to set the meter and start to flow immediately, saving time at the well site by up to 2:00

Or doing a real-time quality control at the well site and then guarantee that the field data measurement are immediately correct.

Overall one solution or another will lead to reduce drastically the rejection rate of the Periodic Well Testing <1% for comparison in some fields with local well test operators > 40%

Rejection rate is dollars not used in optimum way for oil companies and leads to poor reservoir management in the best case! (Middle East and One Watery Well)

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Any question?Any question?Bruno Pinguet

Marketing & Technical ManagerOneSubsea & Schlumberger Testing

pinguet1@email.com

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A way beyond – The 4 D Production Data Mapping

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Production Data Mapping: Gas Density

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Low SG

High SG

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Production Data Mapping: GOR

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Low SG & High GOR

High SG & Low GOR

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Any question?Any question?Bruno Pinguet

Marketing & Technical ManagerOneSubsea & Schlumberger Testing

pinguet1@email.com