Interpretation of Immiscible WAG Repeat Pressure-Falloff Tests
- Bruno A. Stenger (Oryx Petroleum Services) | Salem A. Al Kendi (ADCO) | Abdulla B. Al Katheeri (ADCO) | Ammar F. Al Ameri (ADCO)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- December 2011
- Document Type
- Journal Paper
- 687 - 701
- 2011. Society of Petroleum Engineers
- 5.6.4 Drillstem/Well Testing, 2.2.2 Perforating, 5.8.7 Carbonate Reservoir, 5.1.1 Exploration, Development, Structural Geology, 5.4 Enhanced Recovery, 6.5.2 Water use, produced water discharge and disposal
- Immiscible WAG
- 9 in the last 30 days
- 743 since 2007
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This paper reviewed the interpretation of repeat pressure-falloff (PFO) tests acquired in two vertical pattern injectors operating in a carbonate reservoir undergoing full-field development. Enhanced vertical-sweep conformance through phase mobility control in the presence of strong reservoir heterogeneity was the major expected benefit from an immiscible water-alternating-gas (WAG) displacement mechanism.
PFO tests were carried out during the monophasic injection phase to determine well injectivity and reservoir properties, and were subsequently acquired at the end of each 3-month injection cycle. Analytical falloff-test interpretation relied on the use of the two zone radial composite model. Multiple falloff-test interpretations indicated that the two pattern vertical injectors behaved differently even though both had been fractured. The difference in behavior was linked to different perforated intervals and reservoir properties. Gas- and water-injection rates were showing differences between both pattern injectors as a consequence. Injected gas banks had a small inner radius and were almost undetectable at the end of the subsequent water cycle. Changes in the pressure-derivative slope at the end of the subsequent water-injection cycle indicated most likely the creation of an effective mixing zone of injected gas and water in the reservoir.
Numerical finite-volume simulation was required to account for potential injected-fluid segregation and the heterogeneous multilayered nature of the reservoir. Repeat saturation logs acquired in observation wells monitored the saturation distribution away from the injection wells. Fluid saturations derived from the simulation model were showing a good agreement with the analytical results in general, although the need to account for gas trapping was confirmed. Eight planned development WAG injectors were repositioned as a consequence of WAG 1 and WAG 2 pattern performance.
|File Size||3 MB||Number of Pages||15|
Ambastha, Anil Kumar. 1988. Pressure Transient Analysis for CompositeSystems. Research Report SGP-TR-117, DOE Contract No. DE-ACO3-81SF11564,Stanford Geothermal Program Contract No. DE AS-07-84ID12529, Department ofPetroleum Engineering, Stanford, University, Stanford, California, USA (October1988), 42-43.
Awan, A.R., Teigland, R., and Kleppe, J. 2008. A Survey of North SeaEnhanced-Oil-Recovery Projects Initiated During the Years 1975 to 2005. SPERes Eval & Eng 11 (3): 497-512. SPE-99546-PA. http://dx.doi.org/10.2118/99546-PA.
Balbinski, E. and Goodyear, S. 1999. Fazed by three-phase relperms? SPEReview (March 1999).
Bourdet, D., Ayoub, J.A., and Pirard, Y.M. 1989. Use of Pressure Derivativein Well Test Interpretation. SPE Form Eval 4 (2): 293-302.SPE-12777-PA. http://dx.doi.org/10.2118/12777-PA.
Caudle, B.H., and Dyes, A.B. 1958. Improving Miscible Displacement byGas-Water Injection. In Transactions of the American Institute of Mining,Metallurgical, and Petroleum Engineers, ed. Vol. 213, 281-284. Dallas:Society of Petroleum Engineers.
Christensen, J.R., Stenby, E.H., and Skauge, A. 2001. Review of WAG FieldExperience. SPE Res Eval & Eng 4 (2): 97-106.SPE-71203-PA. http://dx.doi.org/10.2118/71203-PA.
Earlougher, R.C. Jr. 1977. Advances in Well Test Analysis, Vol. 5,82-85. Richardson, Texas, USA: SPE. ISBN 0-89520-204-265127-MS.
Egermann, P., Vizika, O., Dallet, L., Requin, C., and Sonier, F. 2000.Hysteresis in Three-Phase Flow: Experiments, Modeling and ReservoirSimulations. Paper SPE 65127 presented at the SPE European PetroleumConference, Paris, 24-25 October. http://dx.doi.org/10.2118/65127-MS.
Haajizadeh, M., Hafez, H.H., Chaliha, P.R., and Al-Katheeri, A.B. 2007.Sub-miscible Gas-WAG Injection Piloting and Compositional Modeling in aCarbonate Reservoir. Paper SPE 11731 presented at the International PetroleumTechnology Conference, Dubai, 4-6 December. http://dx.doi.org/10.2523/11731-MS.
Mattax, C.C. and Dalton, R.L. 1990. Reservoir Simulation, Vol. 13,125. Richardson, Texas, USA: Monograph Series, SPE.
Melville, P., Al Jeelani, O., Al Menhali, S., and Grötsch, J. 2004.Three-Dimensional Seismic Analysis in the Characterization of a Giant CarbonateField, Onshore Abu Dhabi, United Arab Emirates. In AAPG Memoir 81: SeismicImaging of Carbonate Reservoirs and Systems, ed. G.P. Eberli, J.L.Masaferro, and J.F. Sarg, 123-148. Tulsa: AAPG.
Merrill, L.S., Kazemi, H., and Gogarty, W.B. 1974. Pressure Falloff Analysisin Reservoirs With Fluid Banks. J Pet Technol 26 (7):809-818. SPE-4528-PA. http://dx.doi.org/10.2118/4528-PA.
Oak, M.J. 1990. Three-Phase Relative Permeability of Water-Wet Berea. PaperSPE 20183 presented at the SPE/DOE Enhanced Oil Recovery Symposium, Tulsa,22-25 April. http://dx.doi.org/10.2118/20183-MS.
Skauge, A. and Dale, E.I. 2007. Progress in Immiscible WAG Modelling. PaperSPE 111435 presented at the SPE/EAGE Reservoir Characterization and SimulationConference, Abu Dhabi, UAE, 28-31 October. http://dx.doi.org/10.2118/111435-MS.
Spiteri, E.J. and Juanes, R. 2006. Impact of relative permeabilityhysteresis on the numerical simulation of WAG injection. J. Pet. Sci.Eng. 50 (2): 115-139. http://dx.doi.org/10.1016/j.petrol.2005.09.004.
Stenger, B.A., Al-Katheeri, A.B., Hafez, H.H., and Al-Kendi, S.H. 2009.Short-Term and Long-Term Aspects of a Water Injection Strategy. SPE Res Eval& Eng 12 (6): 841-852. SPE-116989-PA. http://dx.doi.org/10.2118/116989-PA.
Svendsen, A.P., Wright, M.S., Clifford, P.J., and Berry, P.J. 1991.Thermally Induced Fracturing of Ula Water Injectors. SPE Prod & Oper 6 (4): 384-390. SPE-20898-PA. http://dx.doi.org/10.2118/20898-PA.