Production Analysis PA and Application of Rate Transient Analysis RTA in Carbonate Oil Reservoirs for Reservoir Characterization and Connectivity

Abstract

Abstract Analytical approaches are primary reservoir engineering techniques for understatingreservoir/well performance and reservoir characterization which creates additional value on top of comprehensive geological models. Different techniques such as Pressure Transient Analysis (PTA), Rate Transient Analysis (RTA), and analytical models provide good understating on reservoir extension and properties, reservoir connectivity and well interference signatures. For complex carbonate reservoir models, relying solely on petrophysical properties from core and LOG and calibrated is not enough. Several case studies are published where the static model is guided by seismic driven Acoustic Impedance(AI) which matched the porosity at the wellbore. These methods significantly enhance the reservoir property distribution if a reliable seismic data is available. Nevertheless, the permeability map and reservoir connectivity analysis still require detail investigation of well performances and production data. This paper discusses the application of production data analysis to characterize the reservoir in larger scale and reveal the reservoir connectivity and flow barriers in the prevailing heterogeneity. Authors addressed the integrated production data analysis including RTA/PTA, 2D numerical simulation and deconvolution technique in gas cases (Ataei et al 2017). The basic equations of RTA which requires single phase condition are still applicable in the current case study which involve oil above bubble point pressure. Simple 2D numerical simulation were used to address the challenges and the provides a solution to have better understanding of reservoir continuity, a reliable permeability map for upscaling core data and incorporating in the model into large (field scale). The calculated KH from PTA data was also integrated with that of estimated from RTA and evaluated by 2D model before integrating in into full field reservoir simulation model for future forecasting.