Field Case Study of Geomechanical Impact of Pressure Depletion in the Low-Permeability Cupiagua Gas-Condensate Reservoir

摘要

In-situ stress depletion is one of the primary causes ofrnproductivity reduction in low permeability reservoirs. Naturalrnfractures not only enhanced the overall porosity andrnpermeability of these reservoirs, but also increase the stresssensitivity.rnCharacterization of both pressure and stress fields,rncombined with well response analysis, is the first step in orderrnto understand the behavior of such reservoirs.rnThis paper presents the study of stress-sensitivernpermeability in the near critical Cupiagua gas condensaternreservoir in Colombia. The unusual tectonic stress regime sHrn> sV > sh combined with the evidence of natural fractures andrnthe earthquake activity in the area make this an interestingrncase in looking for potential geomechanical impact onrnreservoir performance. A critical analysis of well tests coupledrnwith the interpretation of core analysis, and numericalrnsimulation is presented. Some practical recommendationsrntrying to optimize reservoir management and final recoveryrnare established.rnResults suggest that permeability reduction not only is duernto near well gas condensante effects but also associated withrnturbulent flow and in-situ stress depletion. Opening/closure ofrnnatural fractures is one potential mechanism to explain thernstress sensitivity of productivity.