Abstract
In this study, a 3D multicomponent multiphase simulator with a new fracture characterization technique is developed to simulate the enhanced recovery of coalbed methane. In this new model, the diffusion source from the matrix is calculated using the traditional dual-continuum approach, while in the Darcy flow scale, the Discrete Fracture Model (DFM) is introduced to explicitly represent the flow interaction between cleats and large-scale fractures. For this purpose, a general formulation is proposed to model the multicomponent multiphase flow through the fractured coal media. The S&D model and a revised P&M model are incorporated to represent the geomechanical effects. Then a finite volume based discretization and solution strategies are constructed to solve the general ECBM equations. The prismatic meshing algorism is used to construct the grids for 3D reservoirs with complex fracture geometry. The simulator is validated with a benchmark case in which the results show close agreement with GEM. Finally, simulation of a synthetic heterogeneous 3D coal reservoir modified from a published literature is performed to evaluate the production performance and the effects of injected gas composition, well pattern and gas buoyancy.
Highlights
In a coalbed methane (CBM) reservoir, the gas sorption effect makes the coal seam act as the source and reservoir rock, containing a significant amount of methane with higher purity than conventional gas reservoirs [1]
We develop a 3D, multicomponent multiphase simulator with explicit fracture characterization to simulate the recovery of coalbed methane
The finite difference (FD), the Galerkin finite element (FE), and the finite volume (FV) methods have been studied by previous researchers [37,38,39]
Summary
In a coalbed methane (CBM) reservoir, the gas sorption effect makes the coal seam act as the source and reservoir rock, containing a significant amount of methane with higher purity than conventional gas reservoirs [1]. Pan et al [10] implemented the 2D EOS model into the established coal seam methane simulator SIMED II and compared its results with ELM and IAS They concluded that 2D EOS provided higher accuracy in representing the sorption behavior which significantly improved the production forecast of ECBM over a wide pressure range. The later developed COMET3 [31] enables the triple-porosity dual-permeability option to model the cleat and large-scale fracture system All these simulators are in the context of a highly-conceptualized equivalent-continuum approach, which assumes fractures are evenly distributed and interconnected and can be represented by structured blocks. We develop a 3D, multicomponent multiphase simulator with explicit fracture characterization to simulate the recovery of coalbed methane In this new model, the methane flow from the matrix by diffusion is calculated using the conventional dual-continuum approach. We conclude this paper and provide suggestions for future research direction
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
