Geomechanics Approach to Quantify Subsurface Uncertainties and Risks of Water Injection in Marginal Deepwater Development

Summary Developing marginal deepwater offshore Sabah remains an insurmountable challenge for major operators due to its regional geology formed along fold thrust belt that are heavily deformed by many thrusts faults and folds. Thin interbedded reservoirs prove to be challenging for deepwater development program due to the volume and therefore, water injection has been selected as the most effective Improved Oil Recovery (IOR) method to sweep the recoverable oil in place for the Field Development Plan (FDP) monetization. To increase the propensity of water injection operation to succeed, quantifying subsurface uncertainties and risks analysis pertaining to geoscience interpretation is the key. There aren’t any branches that is more relevant to address this challenge other than Geomechanics, the study of rocks mechanical behaviors in response to Earth’s pressure and stresses. Understanding the criticality of Geomechanical inputs into water injection design (matrix injection) and its operation is crucial since the opposite comes at the cost of risking the caprock seal breach and well integrity. The question this paper is trying to address is to quantify the uncertainties of water injection from Geomechanics perspective by establishing safe pressure threshold of injection.