Structural-Casing/Soil Interaction Effects on Wellhead Motion
- Udaya B. Sathuvalli (Blade Energy Partners) | P. V. (Suri) Suryanarayana (Blade Energy Partners)
- Document ID
- Society of Petroleum Engineers
- SPE Drilling & Completion
- Publication Date
- December 2016
- Document Type
- Journal Paper
- 273 - 285
- 2016.Society of Petroleum Engineers
- Soil friction, Wellhead growth, Wellhead Motion, API 2GEO, Formation effects, ratcheting
- 4 in the last 30 days
- 377 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
During production in prolific high-temperature wells, the forces exerted by the inner strings can cause noticeable wellhead motion (WHM). The thermal forces created by the inner strings are balanced by the structural casing and by the friction between the structural casing and the formation. Depending on the shear-stress profile at the structural-casing/soil interface, the point of fixity (POF) of the structural casing may lie below the mudline, and gross motion in the subterranean section of the structural casing may occur. When the shut-in well cools back to the undisturbed state, the thermal forces disappear. Because of the anisotropic nature of the frictional forces, the wellhead does not always return to its original position, and a fraction of the overall wellhead displacement is locked in at the mudline. This phenomenon recurs during subsequent production and shut-in cycles, and it can lead to ratcheting. Ratcheting becomes a critical issue when the net thermal force on the wellhead is an appreciable fraction of (or exceeds) the pullout capacity of the structural casing.
Current models to assess WHM regard the inner casings as elastic springs that are attached between the wellhead and the POF. The conductor/soil or the casing/cement interactions below the POF are traditionally addressed by finite-element analyses (FEAs). In this paper, we discuss the importance of the anchoring shear stress at the conductor/soil interface and provide methods to assess its orders of magnitude. We present solutions to frequently encountered problems in operational and design situations where sections of casing below the assumed top of cement (TOC) come loose or when the subterranean motion of the conductor is appreciable. These solutions can be used instead of FEA. By coupling the results of this model with the t–z response of pile-driven conductors (API RP 2GEO 2011), we present semianalytical models that are applicable in a variety of wellhead-loading situations.
|File Size||1 MB||Number of Pages||13|
Aasen J. A. and Aadnoy, B. S. 2004. Multistring Analysis of Well Growth. Presented at the IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition, Kuala Lumpur, 13–15 September. SPE-88024-MS. http://dx.doi.org/10.2118/88024-MS.
API RP 2GEO, Geotechnical and Foundation Design Considerations. 2011. Washington, DC: API.
API RP 90, Annular Casing Pressure Management for Offshore Wells, first edition. 2006. Washington, DC: API.
Beer, F. P. and Johnston, E. R. 1988. Vector Mechanics for Engineers. Statics and Dynamics, fifth edition. New York City: McGraw-Hill.
Carnahan, B., Luther, H. A., and Wilkes, J. O. 1969. Applied Numerical Methods. Hoboken, New Jersey: Wiley.
Dawson, A. P. and Murray, M. V. 1987. Magnus Subsea Wells: Design, Installation, and Early Operational Experience. SPE Res Eng 2 (4): 305–312. SPE-12973-PA. http://dx.doi.org/10.2118/12973-PA.
Fort, J. and Sénéquier, P. H. 2003. Two Year Production of 14.2×106 SM3/D of Gas and 24 000 M3/D of Condensates at 150×105 Pa and 190°C. Oral presentation given at the 22nd World Gas Conference, Tokyo, Japan, 1–5 June.
Halal, A. S., Mitchell, R. F., and Wagner, R. R. 1997. Multi-String Casing Design with Wellhead Movement. Presented at the SPE Production Operations Symposium, Oklahoma City, Oklahoma, 9–11 March. SPE-37443-MS. http://dx.doi.org/10.2118/37443-MS.
Hardiman, L. A. 2006. Elgin/Fraklin: 5 Years On. Oral presentation given at the 23rd World Gas Conference, Amsterdam, 5–9 June.
Kocian, E. M., Mefford, R. N., Hilbert, L. B. et al. 1990. Compressive Loading Casing Design. Presented at the IADC/SPE Drilling Conference, Houston, 27 February–2 March. SPE-19923-MS. http://dx.doi.org/10.2118/19923-MS.
Lacasse, S., Nadim, F., Andersen, K. H. et al. 2013a. Reliability of API, NGI, ICP and Fugro Axial Pile Capacity Calculation Methods. Presented at the Offshore Technology Conference, Houston, 6–9 May. OTC-24063-MS. http://dx.doi.org/10.4043/24063-MS.
Lacasse, S., Nadim, F., Langford, T. et al. 2013b. Model Uncertainty in Axial Pile Capacity Design Methods. Presented at the Offshore Technology Conference, Houston, 6–9 May. OTC-24066-MS. http://dx.doi.org/10.4043/24066-MS.
Lambe, T. W. and Whitman, R. V. 2000. Soil Mechanics, SI Version. New York City: John Wiley and Sons.
Lewis, D. and Miller, R. A. 2009. Casing Design. In Advanced Drilling and Well Technology, ed. B. Aadnoy, I. Cooper, S. Miska et al., Chap. 2, 17–52. Richardson, Texas: Society of Petroleum Engineers.
Liang, Q. J. 2012. Casing Thermal Stress and Wellhead Growth Behavior Analysis. Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, Perth, Australia, 22–24 October. SPE-157977-MS. http://dx.doi.org/10.2118/157977-MS.
Lubinski, A., Althouse, W. S., and Logan, J. L. 1962. Helical Buckling of Tubing Sealed in Packers. J Pet Technol 14 (6): 655–670. SPE-178-PA. http://dx.doi.org/10.2118/178-PA.
McCabe, A. C. 1989. Well Vertical Movement on Platform Wells. Presented at Offshore Europe, Aberdeen, 5–8 September. SPE-19241-MS. http://dx.doi.org/10.2118/SPE-19241-MS.
Mitchell, R. F. 1986. Simple Frictional Analysis of Helical Buckling of Tubing. SPE Drill Eng 1 (6): 457–465. SPE-13064-PA. http://dx.doi.org/10.2118/13064-PA.
Mitchell, R. F. 1996. Comprehensive Analysis of Buckling with Friction. SPE Drill & Compl 11 (3): 178–184. SPE-29457-PA. http://dx.doi.org/10.2118/29457-PA.
Parcevaux, P. A. and Salt, P. H. 1984. Cement Shrinkage and Elasticity: A New Approach for a Good Zonal Isolation. Presented at the SPE Annual Technical Conference and Exhibition. Houston, 16–19 September. SPE-13176-MS. http://dx.doi.org/10.2118/13176-MS.
Pilisi, N. and Lewis, D. 2012. Hydrodynamic Loads, Soil and Structure Interaction in Conductor Design for Offshore Platforms and Jack-Up Rigs. Presented at the IADC/SPE Drilling Conference and Exhibition, San Diego, California, 6–8 March. SPE-151403-MS. http://dx.doi.org/10.2118/151403-MS.
Terzaghi, K. and Peck, R. B. 1948. Soil Mechanics in Engineering Practice. New York City: John Wiley and Sons.
Timoshenko, S. P. and Goodier, J. N. 1970. Theory of Elasticity. New York City: McGraw-Hill.