In this study, we propose a new workflow to perform a 2-D coal bed methane recovery simulation with discrete fracture model (DFM) in consideration of both structural fractures (large-scale fractures) and cleats (small-scale fractures).
Further, outgassing through large-scale fractures and faults in the edifice is also supported by detailed field studies (e.g. Varley and Taran 2003).
The dual porosity/permeability approach has a lot of limitations which include (1) the fluid distribution within the matrix blocks remains constant during the simulation period, (2) the model cannot be applied to disconnected and discrete fractured (oriented fractures) media and a small number of large scale fractures can be considered for flow simulation.
When in-situ stresses are disturbed around large scale fractures, typically faults, the direction of principal stresses can deviate from the regional trend to a completely new direction.
In addition, with the aid of parallel computation, large scale fracture closure and contact problems can be successfully simulated using our proposed dynamic fracture closure model (DFCM) with very modest computation times.
Locally dual porosity models are implemented to characterize the heterogeneity of small-scale natural fractures, and large-scale fractures are represented explicitly by discrete fracture models.
The EGS project at Soultz-sous-Forêts, France, has a system of interconnected faults and large-scale fractures (Baria et al. 1999; Breesee 2015).
In view of these problems, a series of studies were carried out specifically on the theoretical basis of cement sheath sealing mechanical parameters, oil-displacement preflush improving the interface cementation quality, toughness set cement satisfying large-scale fracturing requirements and cementing technology conducive to the wellbore integrity.
Reactivation, primarily through mechanical shear, of pervasive, large-scale fractures is shown capable of causing both hydraulic and thermal short circuiting.
The large-scale fractures are represented explicitly as the major fluid conduits and the flow is numerically modeled, also in Laplace domain.
The limitations of dual-porosity/permeability approach are as follow: (1) the fluid distribution within the matrix blocks remains constant during the simulation period, (2) the model cannot be applied to disconnected and discrete fratured (oriented fractures) media and (3) a small number of large-scale fractures can be considered for flow simulation.
