Abstract
Reservoir simulation is a powerful technique to predict the amount of produced hydrocarbon. After a solid representation of the natural fracture geometry, an accurate simulation model and a physical reservoir model that account for different flow regimes should be developed. Many models based on dual-continuum approaches presented in the literature rely on the Pseudo-Steady-State (PSS) assumption to model the inter-porosity flow. Due to the low permeability in such reservoirs, the transient period could reach several years. Thus, the PSS assumption becomes unjustified. The numerical solution adopted by the Multiple INteracting Continua (MINC) method was able to simulate the transient effects previously overlooked by dual-continuum approaches. However, its accuracy drops with increasing fracture network complexity. A special treatment of the MINC method, i.e., the MINC Proximity Function (MINC–PF) was introduced to address the latter problem. And yet, the MINC–PF suffers a limitation that arises from the existence of several grid-blocks within a studied cell. In this work, this limitation is discussed and two possible solutions (transmissibility recalculation/adjusting the Proximity Function by accounting for nearby fractures) are put forward. Both proposed methods have demonstrated their applicability and effectiveness once compared to a reference solution.
Highlights
Oil and gas production from unconventional resources is, for the most part, uneconomical due to the low-permeability and high-heterogeneity reservoirs
The MINC6–PF can predict the gas production once compared to the explicit discretized model set as a reference solution
MINC6–PF and MINC8–PF overestimate the gas production comparing to the reference solution
Summary
Oil and gas production from unconventional resources (shale gas, tight oil) is, for the most part, uneconomical due to the low-permeability and high-heterogeneity reservoirs. These are characterized by high fracture irregularity which renders flow simulation to be very challenging. To overcome this problem, fluid flow simulation can be simplified by sacrificing fracture network complexity. Fluid flow simulation can be simplified by sacrificing fracture network complexity Another challenge is the very low permeability in the tight matrix as compared to fractures which makes the main flow mechanisms (excluding gravity) primarily diffusive – from matrix to fracture and vice versa. Most of the studies conducted on unconventional reservoirs used in-house reservoir simulators that were initially developed for conventional
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