Geomechanical modelling of cold heavy oil production with sand

Abstract

The contribution of geomechanics to provide a rigorous quantification of porosity changes and associated permeability changes is often neglected when considering hydrocarbon production. However, it often has significant effects on production rates and ultimate recovery. For the cold heavy oil production with sand (CHOPS) technique, geomechanics is the key for reservoir simulations and promoting successful operations. In fact, the technique employed in CHOPS significantly affects the stress state within the reservoir by inducing “on-purpose” formation damage. It is not only vital to comprehend the behaviour of the reservoir during production, but it is crucial to identify how to harness that behaviour to improve productivity. In order to simulate the mechanical behaviour of unconsolidated sand material, an elastoplastic damage model was formulated. Fluid-flow-geomechanical modelling was then performed for predicting individual well behaviour and overall field performance. The combined effect of fluid-flow and geomechanics improved predictions with respect to oil, water, and gas production rates at key wells. Fluid rates matched satisfactorily most of the wells. In addition, the onset and propagation of equivalent wormhole networks were quantified throughout the production history. This enabled quantification of the volume of produced sand at individual wells. The comparisons between the measured and simulated sand volume rate at well locations showed reasonable agreement. Such calibrated models can then be used for the placement of new wells to optimize production.

Keywords

CHOPS / Numerical simulation / Sanding / Geomechanics

Declaration of competing interests

No conflicts of interest associated with this publication. As corresponding author, I confirm that the manuscript had been read and approved for submission by the authors.

Acknowledgments

The authors thank Repsol and Schlumberger for permission to publish this paper.

References

[1] M. Uddin, 2005. Numerical studies of gas exsolution in a live heavy oil reservoir, in: Proc., SPE International Thermal Operations and Heavy Oil Symposium, January 1, 2005, p. 11, https://doi.org/10.2118/97739-MS.SPE-97739-MS.

[2] N. Sultan, V. De Gennaro, A. Puech, Mechanical behaviour of gas-charged marine plastic sediments, Geotechnique 62 (9) (2012) 751-766, https://doi.org/10.1680/geot.12.OG.002.

[3] J. Ivory, J. Chang, R. Coates, K. Forshner, 2009. Investigation of cyclic solvent injection process for heavy oil recovery, in: Proc., Canadian International Petroleum Conference, January 1, 2009, p. 17, https://doi.org/10.2118/2009-161.PETSOC-2009-161.

[4] J.F. Shao, P. Marchina, 2002. A damage mechanics approach for the modelling of sand production in heavy oil reservoirs, in: Proc., SPE/ISRM Rock Mechanics Conference, January 1, 2002, p. 8, https://doi.org/10.2118/78167-MS.SPE-78167-MS.

[5] Mohamad-Hussein, Ni Assef, Qinglai, Numerical modeling of onset and rate of sand production in perforated wells (in en), J. Pet.Explor. Prod.Technol. (2018), https://doi.org/10.1007/s13202-018-0443-6.

[6] Jean Lemaitre,A Course on Damage Mechanics, Springer-Verlag, Berlin Heidelberg, 1992.

[7] W.F. Chen, A.F. Saleeb, Constitutive Equations for Engineering Materials: Vol. 1-Elasticity and Modeling, John Wiley, New York, 1982.

[8] Johan Clausen, Lars Andersen, Lars Damkilde, 2010. On the differences between the drucker-prager criterion and exact implementation of the mohrcoulomb criterion in FEM calculations, in: Proc., the European Conference on Numerical Methods in Geotechnical Engineering, 2010, pp. 101-106. Numerical Methods in Geotechnical Engineering: proceedings of the seventh european conference on numerical methods in geotechnical engineeering, Trondheim, Norway, 2-4 june 2010.

[9] G. Duveau, W.Z. Chen, J.F. Shao, O. Ozanam, 2003. Numerical modeling of EDZ in unsaturated argillite: influence of constitutive laws and hydromechanical parameters,in:Proc., European Commission CLUSTER Confer-Ence and Workshop on EDZ in Radioactive Waste Geological Repositories, November 2003.

[10] Keith Michael Kosar, 1989. Geotechnical Properties of Oil Sands and Related Strata, University of Alberta, 1989.

[11] Bernard Tremblay, George Sedgwick, Don Vu, CT imaging of wormhole growth under solution-gas drive, SPE Reservoir Eval. Eng. 2 (1999) 37-45, https://doi.org/10.2118/54658-PA, 01.

[12] J.S. Bell, P.J. McLellan, In-situ stress in the western Canada sedimentary basin (in en-US), in: Geological Atlas of the Western Canada Sedimentary Basin, vol. 1, 1994, pp. 439-446.

[13] Osman Hamid, In-situ Stress Analysis of Southwest SaskatchewanMSc Thesios, University of Saskatchewan, Canada, 2008, 2008.