Geomechanics considerations in enhanced oil recovery

Geomechanics plays significant role in decisions regarding all phases of exploration and production of oil and gas. Specifically, geomechanics influences prospect appraisal, field development, and primary, secondary, and tertiary production activities. Injection of enhanced oil recovery (EOR) fluids such as polymer, steam and gas/ CO₂ affect reservoir stress re-distribution and re-orientation in the field. Hence geomechanics studies need to be conducted in every step of the EOR processes, from EOR screening to abandonment. This paper reviews geomechanical issues related to polymer, steam and hydrocarbon gas/ CO₂ continuous and water-alternating-gas flooding both in sandstone and carbonate formations. A number of published laboratory and field case studies will be presented and discussed in regard to geomechanics issues. The geomechanical effects pertinent to waterflooding and EOR processes in unconventional reservoirs such as shale reservoirs and oil sands will also be discussed. Finally, reservoir properties affected by stress changes and how to incorporate it in reservoir modeling will be discussed.