The development of a numerical model applicable to dual porosity hydrocarbon reservoirs with complex well structures.

摘要

Multilateral drilling and completion technology has been developed and widely applied in hydrocarbon reservoirs. Other than traditional wellbore design which focuses on wellbore length and placement, several new factors need to be considered and optimized for complex well architectures such as number of branches, dip angles, and lateral spacing. A numerical simulator specifically designed for complex well configuration is necessary to effectively simulate and understand the production performance of such systems.;In the study, a 3-dimensional, multi-phase numerical model was developed for dual porosity hydrocarbon reservoir which accommodates various well architectures. Horizontal wellbore, multi-lateral wells, and slanted or tilted branches from the stem well are considered. Dual porosity model is embedded in the numerical model to simulate reservoir with highly developed natural fracture system. The convection-dominant flow in highly permeable fracture is governed by Darcy's Law, while the less permeable matrix serves as a source to feed into the fracture. As the traditional wellbore models are not suitable to accurately represent complicated well configuration, accordingly, the simulator adapts a Local Grid Refinement (LGR) technique to improve the accuracy. Validated by both analytical solution and commercial simulator, the numerical model is proved to generate a more accurate production decline behavior.