well testing management
DESCRIPTION
RFT interpretationTRANSCRIPT
SPE DISTINGUISHED LECTURER SERIESis funded principally
through a grant of the
SPE FOUNDATIONThe Society gratefully acknowledges
those companies that support the programby allowing their professionals
to participate as Lecturers.
And special thanks to The American Institute of Mining, Metallurgical,and Petroleum Engineers (AIME) for their contribution to the program.
Giovanni Da Prat, Ph.D.
Da Prat Consulting
Well Testing ManagementImpact on Reservoir Evaluation
and Well Productivity
Presentation Outline
Objectives and Concerns
Environment and Risk Factors
Testing Management
Conclusions
Field Cases of Application
Well Testing Alternatives
Well Test Objectives
Temporary well completion to acquire well andreservoir data under controlled conditions
Testing management approach is a key driverto achieve evaluation objectives
Data interpretation providesvaluable reservoir managementinformation
Industry Concerns and Remarks
Used to minimize uncertainties and increase profit
Avoided investment in attractive prospect
It may be mandatory to proof fieldcommerciality
Operationally successful job however objectiveswere not obtained
Multilayer Testing Environment
Layer B
Layer A
Selective Layer Testing
8 1/2” 7” @ 17690’
12 1/4”
17 1/2”
9 5/8” @ 15500’
26”
Layer B
Layer A
20 ft @ 500’
Basic Evaluation Program
Testing Time and ProgramSampling Procedures
Perforation
Well Testing
Completion orAbandonment
Well Test Design
FlowNo
Yes
InformationObjectivesCostsGeologySeismicPetrophysicsOpen hole testsWireline Testers
Testing Risk Factors
Layers communication due to poor cement bond
High pressure and temperatures (over 350°F)
Pressure and fluid loss through packers
Annulus-tubing fluid communication
Layers crossflow
Water coning or sanding
Testing Management Key Issues
Test Design
Testing Time
InformationValue
FluidSampling
AvailableTechnology
Expertise
Risk Factors
Cost - Effective
Testing Field Cases
The following field cases are intended to illustrate testingapplications and successful achievement of evaluation objectives
Well Production Increase (Ref. SPE ATW Workshop, London)
Reservoir and Well Evaluation (Ref. SPE 81065)
Reservoir and Well Evaluation
0 1Km.
Interpreted Seismic Section
well
Confirm seismic and geologyexpectations
Obtain reservoir parametersand well potential
Evaluate dynamic conditions forsand flow
Obtain fluid samples for PVT analysis
Temporary Completion
Well completion for testing
TCP-DST Equipment
Reservoir is isolatedafter testing
Tested Reservoirs
Testing History
Build up data analysis
K = 375 mDS = 21 P = 4200 psia4050
[psi
a]
40 60 80 100 120
45000
[Msc
f/D
]
Production Period
Build up period
Pressure, psia
rates
Sanding ControlTest
Testing time, hrs
[Msc
f/D]
45000
4050
[psi
a]
40 60 80 100 120
Well Productivity
AOFP = 344 MMscf/dCGR = 24.5 STB/MMscf/d
Tested gas and condensate rates can be increased to 125 MMscf/D and 3100 BPD
2.5E+5
IPR plot3500
50000
1500
1.5E+5 3.5E+52.5E+5
Testing time
28%Reservoir Testing
10%DST pulling out
12%Well Control
9%Reservoir isolation
41%
DST string settingand running todepth
Reservoir model consistent with seismic interpretation
Testing Evaluation
Testing program changes based on team decisions
Tested gas and condensate rates are sustainable
Considerable well skin effect
Development Well
Tested Reservoirs
Complete using 7 inch production tubing
Perforation-Completionand Testing Strategy
Use high shot density guns
Flow after flow and isochronal type of tests
Testing evaluation to be obtained in 2.5 days
Well Completion
Layer B
Layer A9 5/8 in. SHOE
No-Go Nipple Profile
7 in. Production Tubing
9 5/8 in.Permanent PackerNo-Go Nipple
Profile
7 in. SHOE
Testing History
2500
3000
5 15 25 35 45 55
Production period
Build-up period
Pressure, psia
Rates
155 25 35 45 55
Testing time, hrs
[MM
scf /D
][p
sia ]
3000
2500 E -3 0 .0 1 0 .1 1 1 0 1 0
1 E + 7
1 E + 8
1 E + 9
Log-Log plot: dm(p) and dm(p)' [psi2/cp] vs dt [hr]
Build up data analysis
Conclusions
Increased and optimized tested production rates
Obtained testing results are in agreement with test design
No evidence of fault or aquifer
Water production due to poor cement bond
Well Testing Alternatives
Information
Sampling
HeterogeneitiesBoundariesConnectivity
Permeability andskin
Pressure
Scale of Measurement(large)
Static data
Quality depends on fluid type and contamination
degree
Scale of Measurement( Up scaling Uncertainties)
Initial Reservoir Pressure
Comments
Wireline FormationTesters(WFT)
Geology andGeophysics, WFT
GeochemistryCross well seismic
WFT, Cores and Logs
WFT
Method
Testing data acquisition and interpretation methodology has advanceddramatically during the last ten years, still there are manycases were evaluation objectives are not obtainedat all or questioned. There are no alternativesto well testing and appropriate testingmanagement is the solution formost of the cases
Conclusions