Abstract
Laboratory investigations of the deformation characterstics of chalks and weakly cemented sandstones from a number of North Sea reservoirs, and from outcrops, demonstrate that these materials are elastic under initial loading, but exhibit strongly non-linear deformation behaviour at higher stresses. This behaviour can be described by a characteristic failure surface in stress/pore volume coordinates. This paper presents a description of this behaviour. When reservoir rocks of this type are loaded, maintaining a uniaxial strain condition, the material, undergoes ductile yield at relatively low stress followed by significant porosity decrease at almost constant stress (pore collapse). The onset of pore collapse depends on the rock type, its pre-deformational porosity and the extent and nature of the cementing material. Eventually a hardening occurs that is a response to the increasing compaction and porosity decline in the sample. Reservoir rocks will mobilize maximum compaction drive if they yield in this manner, but may also suffer a permeability loss due to the decrease in porosity. Other detrimental aspects of reservoir compaction (well casing collapse and surface subsidence) may also occur. When subject to large shear stresses in the presence of high pore pressures, the materials investigated are observed to deform readily in shear. They may approach a liquefact stat. This aspect of the mechanical behaviour is interpreted as a possible mechanism for the rapid transfer of substantial volumes of reservoir solids in a well. This phenomenon has been reported to occur in a number of fields, generally, following rapid drawdown of previously “shut-in” well.
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References
Addis, M.A. (1987). Mechanisms of sediment compaction responsible for oil field subsidence. Unpublished Ph.D Thesis, University of London.
Aam, K. (1988). Ekofisk subsidence: The problem, the solution, and the future. In: Proceedings of the International Conference on Behaviour of Offshore Structures, Trondheim, Norway, June 1988, p. 19–40.
Atkinson, J. H. and Bransby, P.L. (1978). The Mechanics of Soils: An Introduction to Critical State Soil Mechanics, McGraw-Hill, London.
Barton, N., Makurat, A., Harvik, L., Vik, G., Bandis, S., Christianson, M. and Addis A. (1988). The discontinuum approach to compaction and subsidence modelling as applied to Ekofisk. In: Proceeding of the International Conference on Behaviour of Offshore Structures, Trondheim, Norway, June 1988, pp. 129–142.
Bishop, A.W. and Henkel, D.J. (1962). The Measurement of Soil Properties in the Triaxial Test. Edward Arnold, London.
Bratli. R.K. and Risnes, R. (1981) Stability and failure of sand arches. Soc. Petroleum Eng. (April), 236–248.
Farmer, I (1983) Engineering Behaviour of Rocks, 2nd ed. Chapman and Hall, London.
Goldsmith, A.S. (1989). Permeability decline and compressibility in sandstone reservoir rocks. In: V. Maury and D. Fourmain-traux (eds.), Rock at Great Depth, (Vol. 2), Balkema, Rotterdam, pp. 923–928.
Janbu, N. (1985). Soil models in offshore engineering. 1985 Rankine Lecture. Geotechnique, 35 (3), 241–281.
Johnson, J.P. and Rhett, D.W. (1987). Compaction behaviour of Ekofisk Chalk as a function of stress. SPE paper 15872, SPE European Petroleum Conference, London, 20–22 October, 1986.
Johnson, J.P., Rhett, D.W. and Seimers, W.T. (1988) Rock mechanics of the Ekofisk Reservoir in the evaluation of subsidence. Offshore Technology Conference, Houston, Texas, OTC5621, pp. 39–50.
Jones, M.E. (1988) Determination of the Mechanical Properties of Reservoir Rocks using the Triaxial Test: Experimental Guidelines. Norwegian Petroleum Directorate, YA-524, Stavanger.
Jones, M.E. and Leddra, M.J. (1987). Ground motions and seismicity due to fluid production from subsurface reservoirs. Mem. Geol. Soc. China, N.9. (December), 465–494.
Jones, M.E., Leddra, M.J. and Addis, M.A. (1987). Reservoir Compaction and Sea floor Subsidence Due to Hydrocarbon Extraction. Offshore Technology Report, OTH 87 276. HMSO, London.
Jones, M.E., Leddra, M.J. and Potts, D. (1989). Ground motions due to hydrocarbon production from the chalk. International Chalk Symposium, September. Preprint No. 59, Thomas Telford, London, pp. 341–347.
Lambe, T.W. and Whitman, R.V. (1979). Soil Mechanics, S.I. Version, 2nd edn. Wiley, New York.
Leddra, M.J. and Jones, M.E. (1989). Steady-state flow during undrained loading of the Chalk. International Chalk Symposium. Preprint No. 18, Thomas Telford, London, pp. 117–124.
Leddra, M.J., Pederstad, K., Lønøy, A. and Jones, M.E. (1989). The influence of increasing effective stress on the permeability of chalks under hydrocarbon reservoir conditions. International Chalk Symposium, September. Preprint No. 19, Thomas Telford, London, pp. 125–131.
Patillo, P.D. and Smith, M.B. (1982). The effect of formation flow on the integrity of perforated casing. SPE 11123, presented at the SPE Fall Meeting, New Orleans, September, 1982.
Potts, D.M., Jones, M.E. and Berget, O.P. (1988) Subsidence above the Ekofisk Oil reservoirs. Proceedings of the International Conference on Behaviour of Offshore Structures, Trondheim, Norway, June 1988, p. 113–128.
Risnes, R., Bratli, R.K. and Horsrud, P. (1982a). Sand stresses around a wellbore. Soc. Petroleum Eng. J. (December), 883–898.
Risnes, R., Bratli, R.K. and Horsrud, P., (1982b). Sand arching — a case study. European Petroleum Conference, London October, 1982. Paper EUR 310.
Ruddy, I., Anderson, M.A., Pattillo, P.O., Bishlawi, M. and Foged, N. (1988) Rock compressibility, compaction, and subsidence in a high-porosity chalk reservoir: A case study of Valhall Field. SPE paper 18278, SPE 63rd Annual Technical Conference, Houston, October, 1988, pp. 179–186.
Smits, R.M.M., De Waal, A., and Van Kooten, J.F.C. (1986). Prediction of abrupt reservoir compaction and surface subsidence due to pore collapse in carbonates. SPE paper 15642, SPE 61st Annual Technical Conference, New Orleans, October, 1986, pp. 1-11.
Teeuw, D., (1971). Prediction of formation compaction from labora tory compressibility data. Soc. Petroleum Eng. J. (Sept.), 263–271.
Terzarghi, K. (1936). The shearing resistance of saturated soils and the angle between the planes of shear. International Conference on Soil Mechanics and Foundation Engineering 1, Cambridge, Massachusetts, Proceedings, Vol. 1, pp. 54–56.
Terzarghi, K., (1943). Theoretical Soil Mechanics. Wiley, New York.
Uriel, S. and Serrano, A.A. (1973) Geotechnical properties of two collapsible volcanic soils of low bulk density at the site of two dams on the Canary Islands Proceedings of the 8th International Conference on Soil Mechanics and Foundation Engineering, Moscow, 1973, pp. 251–264.
Vaughan, P.R. (1985). Mechanical and hydraulic properties of in situ residual soils. 1st International Conference in Geomechanics of Tropical and Saprolitic Soils, Brazilia, February, 1985.
Yassir, N. (1989). Mud volcanoes and the behaviour of over-pressured clays and silts. Unpublished PhD Thesis, Universty of London.
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© 1990 Norwegian Institute of Technology
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Jones, M.E., Leddra, M.J., Goldsmith, A., Berget, O.P., Tappel, I. (1990). The Geotechnical Characteristics of Weak North Sea Reservoir Rocks. In: Buller, A.T., Berg, E., Hjelmeland, O., Kleppe, J., Torsæter, O., Aasen, J.O. (eds) North Sea Oil and Gas Reservoirs—II. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-0791-1_16
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DOI: https://doi.org/10.1007/978-94-009-0791-1_16
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