TY - JOUR
T1 - ANALYTICAL STUDY ON A ONE-DIMENSIONAL MODEL COUPLING BOTH DARCY FLOW AND LOW-VELOCITY NON-DARCY FLOW WITH THRESHOLD PRESSURE GRADIENT IN HETEROGENEOUS COMPOSITE RESERVOIRS
AU - Liu, Wenchao
AU - Duan, Yaoyao
AU - Zhang, Qitao
AU - Chen, Zhangxin
AU - Yan, Xuemei
AU - Sun, Hedong
AU - Taleghani, Arash Dahi
N1 - Publisher Copyright:
© 2022 by Begell House, Inc.
PY - 2022
Y1 - 2022
N2 - In the exploitation process of unconventional tight oil reservoirs in modern times, the involved heterogeneous composite reservoirs are common; in such reservoirs, different rock compartments indicate different permeability properties. In ultra-low-permeability compartments, non-Darcy flow with a threshold pressure gradient (TPG) happens, but in relatively high-permeability compartments, Darcy flow happens. The existence of TPG introduces a nonlinear motion boundary problem, which makes a composite reservoir model coupling both Darcy flow and non-Darcy flow much more challenging. Here, a new model of one-dimensional flow in a heterogeneous composite reservoir with TPG is presented in consideration of a boundary motion process. Relying on a previous exact analytic solution for such a motion boundary problem in a homogeneous reservoir, semi-analytic solutions for the heterogeneous composite reservoir model are obtained by adopting the Laplace transformation method and mathematical arguments. Significantly, applications of Duhamel's principle in compartments with Darcy flow serve as a key procedure to analytically solve the model. And their semi-analytic versions are also validated. Finally, by relying on these solutions, the necessity of incorporating the motion boundary process is demonstrated in the mathematical modeling, and the deviation degree of the transient pressure type curves is also analyzed when the boundary motion process is neglected.
AB - In the exploitation process of unconventional tight oil reservoirs in modern times, the involved heterogeneous composite reservoirs are common; in such reservoirs, different rock compartments indicate different permeability properties. In ultra-low-permeability compartments, non-Darcy flow with a threshold pressure gradient (TPG) happens, but in relatively high-permeability compartments, Darcy flow happens. The existence of TPG introduces a nonlinear motion boundary problem, which makes a composite reservoir model coupling both Darcy flow and non-Darcy flow much more challenging. Here, a new model of one-dimensional flow in a heterogeneous composite reservoir with TPG is presented in consideration of a boundary motion process. Relying on a previous exact analytic solution for such a motion boundary problem in a homogeneous reservoir, semi-analytic solutions for the heterogeneous composite reservoir model are obtained by adopting the Laplace transformation method and mathematical arguments. Significantly, applications of Duhamel's principle in compartments with Darcy flow serve as a key procedure to analytically solve the model. And their semi-analytic versions are also validated. Finally, by relying on these solutions, the necessity of incorporating the motion boundary process is demonstrated in the mathematical modeling, and the deviation degree of the transient pressure type curves is also analyzed when the boundary motion process is neglected.
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U2 - 10.1615/JPorMedia.2022039869
DO - 10.1615/JPorMedia.2022039869
M3 - Article
AN - SCOPUS:85135964925
SN - 1091-028X
VL - 25
SP - 47
EP - 76
JO - Journal of Porous Media
JF - Journal of Porous Media
IS - 9
ER -