Abstract

In recent years there has been an increasing interest in the use of Advanced Production Data Analysis (APDA) methods for dynamic reservoir description. These methods analyze available daily production data, reducing Well Testing operations cost and avoiding production loss, with accuracy comparable to Pressure Transient Analysis (PTA). Different models have been proposed for homogeneous, coalbed methane and shale gas reservoirs. Unfortunately, carbonate reservoirs production are still being analyzed with homogeneous models.

This work presents the analytical derivation of two Advanced Production Data Analysis methods (Dynamic Material Balance and Blasingame Type Curves) based on the dual porosity model, to analyze daily production of Oil Carbonate reservoirs. Pseudosteady-state and transient (slabs and spheres) interporosity flow between matrix and fractures were considered.

The development was based on long-time approximate solutions of diffusivity equation in dual porosity system, for constant flow rate in a closed system with no-flow boundary. They were compared to exact solution in Laplace Space using Gaver-Stehfest algorithm. Then applying the appropriate dimensionless definition, both APDA methods were derived, including the generation of type curves. The validation was made using synthetic data generated by a numerical simulator for constant and variable flow rate.

Results confirm the applicability of current APDA methods basd on homogeneous reservoirs, for the cases of transient interporosity flow between matrix and fracture. Nevertheless, additional considerations must be taken into account in the case of pseudosteady-state interporosity flow.

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