TY - JOUR
T1 - Quantitative study in shale gas behaviors using a coupled triple-continuum and discrete fracture model
AU - Wei, Shiming
AU - Xia, Yang
AU - Jin, Yan
AU - Chen, Mian
AU - Chen, Kangping
N1 - Funding Information:
The authors are grateful to the supports provided by the National Natural Science Foundation of China (Grand No. 51490651 ), and the Ministry of Science and Technology of the People's Republic of China ( 2017ZX05037-004 ). Equally important, we are grateful to Dr. Wu Yonghui and Mr. Wang Yu for their help to verify the correctness of our model.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/3
Y1 - 2019/3
N2 - The shale has ultra-low permeability wherein multi-scale natural fractures are well-developed. The success of providing high diversion channels makes multi-stage fractured horizontal wells (MFHWs) become the powerful technique for economically producing gas from shale. This study presents a triple-continuum and discrete fracture model to describe a fractured shale reservoir embedded with a MFHW. The model incorporates non-equilibrium desorption/adsorption mechanism (NEDAM), viscous flow, Knudsen diffusion, and surface diffusion. The discrete fracture networks (DFNs) is quantitatively constructed according to the fracture density and stimulated reservoir area (SRA). This model is used to analyze the temporal/spatial evolution of the gas pressure and the net desorption rate. NEDAM is compared with the conventional equilibrium desorption mechanism (EDM) and it's found that NEDAM uncovers the delayed phenomenon during gas desorption, and the use of EDM overestimates the production contributed from the adsorbed gas. The maximum net desorption rate of adsorbed gas gradually spread from the SRA region to the non-SRA region. The complete flow stages are clearly interpreted in a semi-logarithmic curve of well testing, and the flow stage controlled by the hydraulic fractures is clearly presented. Finally, the instructions on hydraulic fracturing treatment are given based on the production analysis.
AB - The shale has ultra-low permeability wherein multi-scale natural fractures are well-developed. The success of providing high diversion channels makes multi-stage fractured horizontal wells (MFHWs) become the powerful technique for economically producing gas from shale. This study presents a triple-continuum and discrete fracture model to describe a fractured shale reservoir embedded with a MFHW. The model incorporates non-equilibrium desorption/adsorption mechanism (NEDAM), viscous flow, Knudsen diffusion, and surface diffusion. The discrete fracture networks (DFNs) is quantitatively constructed according to the fracture density and stimulated reservoir area (SRA). This model is used to analyze the temporal/spatial evolution of the gas pressure and the net desorption rate. NEDAM is compared with the conventional equilibrium desorption mechanism (EDM) and it's found that NEDAM uncovers the delayed phenomenon during gas desorption, and the use of EDM overestimates the production contributed from the adsorbed gas. The maximum net desorption rate of adsorbed gas gradually spread from the SRA region to the non-SRA region. The complete flow stages are clearly interpreted in a semi-logarithmic curve of well testing, and the flow stage controlled by the hydraulic fractures is clearly presented. Finally, the instructions on hydraulic fracturing treatment are given based on the production analysis.
KW - Gas behavior
KW - Hydraulic fracture network
KW - Non-equilibrium desorption/adsorption mechanism
KW - Shale gas
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U2 - 10.1016/j.petrol.2018.10.084
DO - 10.1016/j.petrol.2018.10.084
M3 - Article
AN - SCOPUS:85056240323
SN - 0920-4105
VL - 174
SP - 49
EP - 69
JO - Journal of Petroleum Science and Engineering
JF - Journal of Petroleum Science and Engineering
ER -