Integrated Predrill Pore-Pressure and Borehole-Stability Prediction for Prelude Development
- Kirk S. Hansen (Shell International Exploration and Production) | Gary Wang (Shell International Exploration and Production) | Olayinka Adeleye (Shell International Exploration and Production) | Katja V. McNeil (Shell Development Australia) | Brent A. Couzens-Schultz (Shell International Exploration and Production) | Kostia Azbel (Shell International Exploration and Production) | Manoj D. Sarfare (Shell International Exploration and Production) | Uday Tare (Shell International Exploration and Production)
- Document ID
- Society of Petroleum Engineers
- SPE Drilling & Completion
- Publication Date
- December 2014
- Document Type
- Journal Paper
- 418 - 430
- 2014.Society of Petroleum Engineers
- Browse basin, fault reactivation, pore pressure, fracture gradient, borehole stability
- 1 in the last 30 days
- 585 since 2007
- Show more detail
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|SPE Non-Member Price:||USD 35.00|
Pore-pressure (PP) and fracture-gradient (FG) predictions were prepared for Prelude development wells in the Browse basin in offshore northwest Australia. The PP forecasts were based on resistivity- and sonic-based models calibrated with pressure measurements and drilling events, such as kicks from existing wells. FGs were based on leakoff tests and loss events from offset wells and were not necessarily equal to either the minimum compressive principal stress (often considered a lower bound to FG) or the formation-breakdown pressure (often considered an upper bound to FG that includes effects of formation tensile strength and nearwellbore hoop stress). The minimum compressive horizontal stress was calculated from lithology-dependent effective-stress ratios. Maximum horizontal stress was inferred from observed breakouts. PP and stresses were combined with formation properties from well logs and laboratory rock-mechanics tests to provide input for elastoplastic (shales) and poroelastic (sands) boreholestability (BHS) models. These techniques are applicable to exploration, appraisal, or early-development wells that have potential for encountering geopressured formations in high-angle well sections requiring good predrill estimates to adequately plan the casing and drilling programs and determine BHS. The predrill studies can be extended to provide integrated real-time PP and BHS while drilling, and the models can be recalibrated after each well to provide updated predictions for subsequent wells. There are only minor deviations in the predicted PP and FG among the different well locations considered. Common features include potential loss zones in the shallow overburden, pressure ramp within the Jamieson, pressure regression below the Aptian, and near-hydrostatic pressure within the Upper Swan and below. The BHS models indicate that minimum-required mud weight in deviated sections could be up to 20% higher than that required to balance formation PP. In one well that would cross a suspected fault, the risk of fault reopening or reactivation is low.
|File Size||1 MB||Number of Pages||13|
Athy, L.F. 1930. Density, Porosity, and Compaction of Sedimentary Rocks. AAPG Bull. 14: 1–24. http://dx.doi.org/10.1306/3D93289E-16B1-11D7-8645000102C1865D.
Bell, J.S. and Gough, D.I. 1979. Northeast-Southwest Compressive Stress in Alberta: Evidence from Oil Wells. Earth Planet. Sc. Lett. 45 (2): 475–482. http://dx.doi.org/10.1016/0012-821X(79)90146-8.
Berg, S. 2012. 2d Vertical Effective Stress Modeling of the Tor Area. MSc thesis, Norwegian University of Science and Technology,
Trondheim, Norway (May 2012). Bowers, G.L. 1995. Pore Pressure Estimation from Velocity Data: Accounting for Overpressure Mechanisms Besides Undercompaction. SPE Drill & Compl. 10 (2): 89–95. SPE-27488-PA. http://dx.doi.org/10.2118/27488-PA.
Bradley, W.B. 1979. Failure of Inclined Boreholes. J. Energ. Resour.-ASME 101 (4): 232–239. http://dx.doi.org/10.1115/1.3446925.
Couzens-Schultz, B.A. and Chan, A.W. 2010. Stress Determination in Active Thrust Belts: An Alternative Leak-Off Pressure Interpretation. J. Struct. Geol. 32 (8): 1061–1069. http://dx.doi.org/10.1016/j.jsg.2010.06.013.
Halliburton 2009. DrillworksVR Software Suites Drillworks Expert, Pro and Standard, http://www.halliburton.com/public/landmark/contents/Data_Sheets/web/H06498.pdf (accessed 23 November 2014).
Hansen, K.S. 1991. Comparison between Field Observations and Theory for Stress-Induced Borehole Ellipticity. Presented at the 32nd U.S. Symposium on Rock Mechanics (USRMS), Norman, Oklahoma, 10–12 July. ARMA-91-995.
Heidbach, O., Barth, A., Connolly, P., et al. 2004. Stress Maps in a Minute: The 2004 World Stress Map Release. Eos Trans. Am. Geophys. Union 85 (49): 521–529. http://dx.doi.org/10.1029/2004EO490001.
Kenter, C.J. 1997 Overview of Diana Applications in Petroleum Engineering. In Finite Elements in Engineering and Science. Proc., Second International DIANA Conference. Amsterdam, 4–6 June.
Lockner, D.A. and Beeler, N.M. 2002. Rock Failure and Earthquakes. In International Handbook of Earthquake and Engineering Seismology, Part A, eds. W.H.K. Lee, H. Kanamori, P.C. Jennings, and C. Kisslinger. Vol. 81A, Chap. 32, 505–537. Amsterdam, The Netherlands: Academic Press.
McLellan, P. and Hawkes, C. 2001. Borehole Stability Analysis for Underbalanced Drilling. J Can Pet Technol 40 (5): 31—38–38. PETSOC-01-05-01. http://dx.doi.org/10.2118/01-05-01.
Morales, R.H., Abou-Sayed, A., and Jones, A.H. 1989. Field Investigation of Wellbore Breakouts as an Indicator on In-Situ Stress Orientation. Presented at the 30th U.S. Symposium on Rock Mechanics (USRMS), Morgantown, West Virginia, 19–22 June. ARMA-89-0877.
Nelson, E., Hillis, R., and Mildren, S. 2006. Stress Partitioning and Wellbore Failure in the West Tuna Area, Gippsland Basin. Explor. Geophys. 37 (3): 215–221. http://dx.doi.org/10.1071/EG06215.
Osborne, M.J. and Swarbrick, R.E. 1997. Mechanisms for Generating Overpressure in Sedimentary Basins: A Re-evaluation. AAPG Bull. 81 (6): 1023–1041.
Shen, X., Bai, M., and Smith, R. 2011. Numerical Scheme for Calculation of Shear Failure Gradient of Wellbore and its Applications. In Drilling and Completion in Petroleum Engineering – Theory and Numerical Applications, ed. W. Standifird. Vol. 3, Chapt. 4, 57–80. London, UK: CRC Press.
Swarbrick, R.E., Osborne, M.J., and Yardley, G.S. 2002. Comparison of Overpressure Magnitude Resulting from the Main Generating Mechanisms. Chapter 1 in Pressure Regimes in Sedimentary Basins and Their Prediction, eds A.R.Huffman and G.L.Bowers. AAPG Memoir 76, 1—12. Tulsa, OK: AAPG.
Weatherford 2011. Integrated Subsurface Engineering Services, http://www.weatherford.com/dn/WFT164209 (accessed 23 November 2014).
Zoback, M.D. 2007. Reservoir Geomechanics. Cambridge, UK: Cambridge University Press.