Simple Calculation of Compaction-Induced Casing Deformation Adjacent to Reservoir Boundaries
- Y. Guo (AWMS, BP America) | N. Last (BP Exploration) | M. Blanford (Geoscale, BP America)
- Document ID
- Society of Petroleum Engineers
- IADC/SPE Drilling Conference and Exhibition, 6-8 March, Fort Worth, Texas, USA
- Publication Date
- Document Type
- Conference Paper
- 2018. IADC/SPE Drilling Conference and Exhibition
- 1.2.3 Rock properties, 5.1 Reservoir Characterisation, 5 Reservoir Desciption & Dynamics, 5.3.4 Integration of geomechanics in models, 5.1.1 Exploration, Development, Structural Geology, 5.3 Reservoir Fluid Dynamics
- casing D/t ratio, compaction, casing grade, borehole orientation, casing strain
- 5 in the last 30 days
- 174 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 8.50|
|SPE Non-Member Price:||USD 25.00|
Compaction-induced casing damage, particularly adjacent to reservoir boundaries, has been observed in many fields. As part of mitigation planning for potential casing collapse due to reservoir compaction, expensive numerical models are often employed to quantitatively assess casing strain under simulated reservoir conditions. In order to simplify casing deformation analysis and reduce analysis time, the current study was initiated to quantify the effects of depletion magnitude, rock compressibility, borehole orientation, casing diameter-to-thickness ratio (D/t ratio) and grade on compaction-induced casing deformation using finite element modelling (FEM). The model results allowed an empirical equation to be derived to predict casing strain that is sufficiently accurate for engineering applications.
The objective of the study was achieved by building a series of 3D FEM models to systematically simulate the deformation of casings cemented perfectly within a horizontal reservoir that underwent up to 8.3% compaction due to depletion. To capture the pattern of casing strain variation adjacent to the reservoir boundaries, the simulations were run over a range of borehole deviations (0°, 22.5°, 50°,67.5° and 90°). For each borehole deviation, casing D/t ratios of 8.14, 19.17 and 32.67 and grades of 40 ksi, 90 ksi and 135 ksi were defined to evaluate their impact on casing strain variations.
The FEM models show that casing deformation adjacent to reservoir boundaries is accommodated by radial expansion and axial shortening in vertical wellbores, while the deformation is characterized by bending in deviated wellbores. The maximum strain adjacent to reservoir boundaries varies systematically, but nonlinearly with each variable evaluated. The maximum strain increases with reservoir compaction strain, i.e. increases with rock compressibility and depletion, but decreases with increasing hole deviation. Both casing D/t ratio and grade affect casing strain, but their effects are secondary. In general, the maximum strain is greater for casings with smaller D/t ratios and higher grades at any given borehole deviation and compaction strain. The variation of the maximum casing strain with compaction strain can be described by a power law. Both its constant and exponent are functions of borehole deviation, casing D/t ratio and grade.
Because of the complexity of borehole-reservoir geometry and casing plastic behavior, there is no analytical solution available to estimate compaction-induced casing strain adjacent to reservoir boundaries. Numerical models may be used to predict the casing strain, but the numerical analysis is time consuming and requires specialist knowledge. The equation proposed from this study is sufficiently accurate compared to numerical models in terms of casing strain prediction, but provides a much simpler and quicker analysis. In addition, the study provides insight on the variation of casing strain with the major controlling factors, leading to a more complete understanding of compaction-induced casing deformation.
|File Size||1 MB||Number of Pages||18|
Dusseault, M. B., Bruno, M. S., and Barrera, J. 2001. Casing Shear: Causes, Cases, Cures. Society of Petroleum Engineers. SPE Drilling &Completion 16(2): 98–107.doi:10.2118/72060-PA.
Fuh, G.-F., Morita, N., and Furui, K. 2009. Modeling Analysis of Sand-Screen Collapse Resistance Under Geotectonic Load. Paper SPE 124388 presented at the SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, 4-7 October. doi: 10.2118/124388-MS.
Furui, K., Fuh, G.-F., and Morita, N. 2012. Casing- and Screen-Failure Analysis in Highly Compacting Sandstone Fields. SPE Drilling & Completion 27 (2): 241–252. doi:10.2118/146231-PA.
Hilbert Jr., L.B., Gwinn, R.L., Moroney, T.A., and Deitrick, G.L. 1999. Field-Scale and Wellbore Modeling of Compaction-Induced Casing Failures. SPE Drilling & Completion 14(2): 92–101. SPE-56863-PA. http://dx.doi.org/10.2118/56863-PA.
Li, X., Mitchum, F. L., Bruno, M., Pattillo, P. D., and Willson, S. M. 2003. Compaction, Subsidence, and Associated Casing Damage and Well Failure Assessment for the Gulf of Mexico Shelf Matagorda Island 623 Field. Paper SPE84553 presented at the SPE Annual Technical Conference and Exhibition, 5-8 October, Denver, Colorado. doi:10.2118/84553-MS.
Morita, N., Kasahara, Y., Hikida, H., and Ito, Y. 2005. Collapse Resistance of Tubular Strings Under Geotectonic Load. Paper SPE 95691 presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, 9-12 October. doi: 10.2118/95691-MS.
Pattillo, P. D. and Kristiansen, T. G. 2002. Analysis of Horizontal Casing Integrity in the Valhall Field. Paper SPE78204presented at the SPE/ISRM Rock Mechanics Conference, 20-23 October, Irving, Texas. doi:10.2118/78204-MS
Yang, L. Q., Zhang, H., Liang, J. Y., and Wang, H. Y. 2009. Mechanisms of Casing Failure in the Extra Heavy Oil Reservoirs and Measures to Protect Deformation. Paper PETSOC2009-026 presented at the Canadian International Petroleum Conference, 16-18 June, Calgary, Alberta. doi:10.2118/2009-026.
Yudovich, A., Chin, L. Y., and Morgan, D. R. 1989. Casing Deformation in Ekofisk. Journal of Petroleum Technology 41(07): 729–734. doi:10.2118/17856-PA.
Da Silva, F. V., Debande, G. F., Pereira, C. A., and Plischke, B. 1990. Casing Collapse Analysis Associated With Reservoir Compaction and Overburden Subsidence. Paper SPE20953 presented at the European Petroleum Conference, 21-24 October, The Hague, Netherlands. doi:10.2118/20953-MS.
Abbassian, F. and Parfitt, S.H.L. 1998. A Simple Model for Collapse and Post-Collapse Behavior of Tubulars with Application to Perforated and Slotted Liners. SPE Drilling &Completion 13(3): 190–196. SPE-51188-PA. http://dx.doi.org/10.2118/51188-PA.
Furui, K., Fuh, G.-F., Abdelmalek, N., and Morita, N. 2010. A Comprehensive Modeling Analysis of Borehole Stability and Production-Liner Deformation for Inclined/Horizontal Wells Completed in a Highly Compacting Chalk Formation. SPE Drilling &Completion 25(4): 530–543. SPE-123651-PA. http://dx.doi.org/10.2118/123651-PA.