Pore Pressure Modelling and Stress-Faulting-Regime Determination of the Montney Shale in the Western Canada Sedimentary Basin
- Oscar Contreras (University of Calgary) | Geir Hareland (University of Calgary) | Roberto Aguilera (University of Calgary)
- Document ID
- Society of Petroleum Engineers
- Journal of Canadian Petroleum Technology
- Publication Date
- August 2013
- Document Type
- Journal Paper
- 349 - 359
- 2013. Society of Petroleum Engineers
- 5.6.1 Open hole/cased hole log analysis, 5.3.4 Integration of geomechanics in models, 3.2.3 Hydraulic Fracturing Design, Implementation and Optimisation, 5.8.2 Shale Gas
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This work establishes an effective approach to predict pore pressure in theoverpressured Montney shale and overburden from sonic logs by implementingnormal-trend and explicit methods. The cause of the overpressure condition inthe Montney is also addressed. These two methods were selected on the basis ofthe study carried out by Contreras et al. (2012) that worked successfully forpore pressure prediction under subpressured conditions in parts of the westernCanada sedimentary basin (WCSB). As a second objective, the stress-faultingregime was determined in the study area by use of stress polygons and data fromdiagnostic fracture-injection-test analysis as a quantification of the minimumhorizontal stress. This is of paramount importance because there is not ageneric theory explaining the stress-faulting regime for most of the westernregion of the WCSB. The Eaton method from sonic logs (Eaton 1975) and theBowers method (Bowers 1995) were implemented in two vertical wells drilledthrough the Montney shale. The first part of the analysis considered two normalcompaction trends, but unreasonable pressure profiles were obtained andrequired a revision on the depositional environment. It was found that for thestudy area, three normal compaction trends have to be considered. The Bowersmethod was initially implemented using both loading and unloading conditions inorder to establish a safe range of pore pressure to allow successful wellplans. It is concluded that undercompaction could be masked as the onlyoverpressure mechanism in the Montney shale in the study area. The formationexperiences an inverse faulting regime that will lead to the creation ofhorizontal hydraulic fractures. The Eaton method using three normal compactiontrends and an exponent equal to 0.9 works successfully in the study area. TheBowers method uses the loading and the unloading conditions, and the specificcorrelation parameters were found to be suitable for the study area and can beextrapolated to adjacent future production and exploratory wells.
|File Size||1 MB||Number of Pages||11|
Anderson, E.M. 1951. The Dynamics of Faulting and Dyke Formation WithApplications to Britain, second edition. Edinburgh, UK: Oliver andBoyd.
Bowers, G.L. 1995. Pore Pressure Estimation From Velocity Data: Accountingfor Overpressure Mechanisms Besides Undercompaction. SPE Drill &Compl 10 (2): 89-95. SPE-27488-PA. http://dx.doi.org/10.2118/27488-PA.
Contreras, O., Hareland, G., and Aguilera, R. 2012. An InnovativeApproach for Pore Pressure Prediction and Drilling Optimization in anAbnormally Subpressured Basin. SPE Drill & Compl 27(4): 531-545. SPE-148947-PA. http://dx.doi.org/10.2118/148947-PA.
Eaton, B.A. 1975. The Equation for Geopressure Prediction from Well Logs.Presented at the Fall Meeting of the Society of Petroleum Engineers of AIME,Dallas, 28 September-1 October. SPE-5544-MS. http://dx.doi.org/10.2118/5544-MS.
Jaeger, J.C. and Cook, N.G.W. 1979. Fundamentals of Rock Mechanics,third edition, 28-30. London: Chapman and Hall.
Keneti, A. and Wong, R.C.K. 2010. Investigation of Anisotropic Behavior ofMontney Shale Under Indirect Tensile Strength Test. Presented at the CanadianUnconventional Resources and International Petroleum Conference, Calgary, 19-21October. SPE-138104-MS. http://dx.doi.org/10.2118/138104-MS.
Law, B.E. 2002. Basin-Centered Gas Systems. AAPG Bull. 86 (11): 1891-1919. http://dx.doi.org/10.1306/61EEDDB4-173E-11D7-8645000102C1865D.
Song, L. 2011. Logging Derived Minimum Horizontal Stress. IAC ProgressReport, Department of Chemical and Petroleum Engineering, University ofCalgary, Calgary, Alberta.
Zoback, M.D. 2007. Reservoir Geomechanics. Cambridge, UK: CambridgeUniversity Press.