applied well testing

8/18/2019 Applied Well Testing

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Applied Well TestingApplied Well TestingDieter Becker Dieter Becker

Echometer CompanyEchometer Company


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Well Test ObjectivesWell Test Objectives

•• Reservoir PressureReservoir Pressure

•• PermeabilityPermeability

•• Skin Factor Skin Factor


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Types of Well TestsTypes of Well Tests

•• DrillstemDrillstem TestTest

•• Drawdown TestDrawdown Test•• Buildup TestBuildup Test

••

Injection TestInjection Test•• Falloff TestFalloff Test


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Test ToolsTest Tools

•• DrillstemDrillstem toolstools

•• Wireline Conveyed Pressure GaugeWireline Conveyed Pressure Gauge

•• Permanently Installed Pressure GaugePermanently Installed Pressure Gauge

•• Capillary TubeCapillary Tube

•• Surface Pressure GaugeSurface Pressure Gauge•• Acoustic DeviceAcoustic Device


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Advantages of AcousticAdvantages of Acoustic

Pressure MeasurementsPressure Measurements

•• No need to pull rods & pump No need to pull rods & pump

•• Less costLess cost

•• Better early time dataBetter early time data•• Data viewed in real timeData viewed in real time

•• Ensures test objectives metEnsures test objectives met

•• Well returned to production ASAPWell returned to production ASAP

•• No downhole tools No downhole tools•• Able to test highly deviated wellsAble to test highly deviated wells

•• No potential fishing No potential fishing


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Load &AccelerationSignals

Motor Current and Power SignalsPressure SignalAcoustic

Signal

Pump

Flowline

Microphone

Fluid Level

Flowing BHP

Reservoir Pressure

PolishedRodSensor

Casing Head Pressure

Computer and A/D Transducer

12 Voltbattery

G a s S u p p l y

ValveControl

Gas

Gaseous Liquid

Liquid

WELL ANALYZER SYSTEMWELL ANALYZER SYSTEM


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Well Analyzer Well Analyzer


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Wellhead AttachmentWellhead Attachment


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Test SetupTest Setup


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Measurement ScheduleMeasurement Schedule


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Liquid LevelLiquid Level


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Depth DeterminationDepth Determination


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Test DataTest Data


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Data PlotsData Plots


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BHP vs. TimeBHP vs. Time


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Liquid AfterflowLiquid Afterflow


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LogLog--Log PlotLog Plot


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MDH PlotMDH Plot


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Horner PlotHorner Plot


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What is Skin Effect?What is Skin Effect?


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Skin DamageSkin Damage


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Negative Skin factor Negative Skin factor


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Skin Factor Skin Factor

•• Skin factor used to quantify skin effectSkin factor used to quantify skin effect

•• Run pressure transient test (buildup) toRun pressure transient test (buildup) todetermine skin effect.determine skin effect.

•• Skin factor used to see if productionSkin factor used to see if production

increase is possible with stimulationincrease is possible with stimulation•• Determine economics of stimulationDetermine economics of stimulation


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Flow EfficiencyFlow Efficiency

khS qB Ps /2.141 ???

Jideal Jactual ency FlowEffici /?

)/()(/ pwf p ps pwf p Jideal Jactual ?????


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Analysis ToolsAnalysis Tools

•• LogLog--Log Plot w/DerivativeLog Plot w/Derivative

•• Horner PlotHorner Plot•• MDH PlotMDH Plot

•• Type CurvesType Curves


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LogLog--Log PlotLog Plot


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Horner PlotHorner Plot


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MDH PlotMDH Plot


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Type Curve MatchingType Curve Matching


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Case StudyCase Study

ProductionProduction

AfterAfter

TreatmentTreatment

(MCFGPD)(MCFGPD)

TreatmentTreatmentProductionProduction

BeforeBefore

TreatmentTreatment

(MCFGPD)(MCFGPD)

Skin Factor Skin Factor

--3.043.04

2702702000 gal acid2000 gal acid1701701.61.6

2502501500 gal acid1500 gal acid43437.087.08


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SummarySummary

•• Run Pressure Transient TestRun Pressure Transient Test

•• Determine Skin EffectDetermine Skin Effect

•• Determine if Production IncreaseDetermine if Production IncreasePossiblePossible

••

Determine Economics ofDetermine Economics ofStimulationStimulation


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Horizontal Well TestingHorizontal Well Testing

??Differ from Vertical Well Tests as follows:Differ from Vertical Well Tests as follows:

– – Flow geometry is 3 dimensional instead of 1Flow geometry is 3 dimensional instead of 1

dimensional. Analysis more difficult.dimensional. Analysis more difficult.

– – Open interval to flow much larger and not wellOpen interval to flow much larger and not well

known.known.

– – Vertical permeability plays important role.Vertical permeability plays important role.

– – Many possible flow regimesMany possible flow regimes


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Early Time FlowEarly Time Flow

Ky and Kz

Ky

Kz


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Late Time FlowLate Time Flow

Boundary


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Pressure ResponsePressure Response

Pressure

Derivative


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SummarySummary

??Data acquisition uses conventionalData acquisition uses conventionalmethods.methods.

??Analysis more complicated than verticalAnalysis more complicated than vertical

well.well.

??Requires more information about reservoirRequires more information about reservoirrock properties.rock properties.

??Best analysis from use of computerBest analysis from use of computersimulation to match pressure andsimulation to match pressure andderivative.derivative.

applied well testing

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