Characterization of gas production from a shale-gas reservoir:
1. Having known the fact that the proppants retained in the open natural fractures in the stimulated reservoir volume try to relieve the loss of fracture permeability by the effective stress, how exactly the exponential-decay-reduction in fracture-conductivity (or fracture–effective-permeability) takes place as a function of an effective-closure-stress? Whether such reduction predominantly results from fracture attributes (distribution of fracture length, fracture aperture thickness, fracture spacing, fluid velocity within the fracture, fracture-dip, fracture-surface-roughness and fracture porosity at the fracture-network-scale) or the matrix attributes (matrix grain size distribution, matrix porosity, matrix tortuosity and matrix effective diffusion coefficient)?
2. Can we apply the relatively simple conventional power-law relationship in order to deduce the fracture-permeability as a function of fracture-porosity in the region of stimulated-reservoir-volume (SRV) associated with a shale-gas-reservoir?
3. Will it not be more simplified, if we deduce the porosity of fracture and matrix as a function of only the effective stress – leaving aside the other critical fracture and matrix attributes associated with the stimulated-reservoir-volume (SRV) region?
4. Having known the fact that the apparent-permeability of the shale-matrix varies as a function of “time-dependent” effective stress along with Surface/Knudsen/Free-molecular diffusion and Adsorption/Desorption, how exactly the determination of permeability of the shale-matrix by the conventional pulse-decay method or using the concept of methane-adsorption-capacity will be justified, where the pore-size distribution varies by several orders of magnitude (and in turn, displaying Surface diffusion and Knudsen diffusion as well in addition to Fickian diffusion)? A simple coupling of Poiseullie flow with the Knudsen flow will suffice? Whether all the different diffusive processes; as well as “Adsorption and Desorption” will remain significant throughout the simulation processes; and even, if so, will they remain dominant throughout the simulation period?
5. In a real field scenario, whether the fractures in the SRV region will really be ‘less-stress-dependent’ as assumed in a typical single-stage-fractured horizontal well, where only the fractures outside the SRV region is considered to be more-stress-dependent?
6. What should be the favorable ‘minimum BHP’ and ‘fracture-density’ that will possibly lead to a faster shale-gas production? What will happen to the forecast, if the cumulative-gas-production quickly reaches the plateau?
7. Will it be feasible to deduce a correlation between shale-gas production and pore-compaction as a function of ‘distance-from-the-wellbore-region’ and the ’BHP’?
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