Title: A novel semi-analytical model for oil-water two-phase flow of a fractured vertical well in triple media carbonate reservoir

Authors: Yong Wang; Xin Ma; Wenqing Wu; Zonghong Feng

Addresses: School of Sciences, Southwest Petroleum University, Chengdu, Sichuan 610500, China ' School of Science, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China ' School of Science, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China ' School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China

Abstract: Carbonate reservoir is one of the important reservoir in the world. Because of the characteristics of carbonate reservoir, vertical well and acid fracturing has become a key technology for efficiently developing carbonate reservoir. Establishing corresponding mathematical models and analysing transient pressure behaviours of this type of well-reservoir configuration can provide a better understanding of fluid flow patterns in formation as well as estimations of important parameters. A mathematical model for a oil-water two-phase flow fractured vertical well in triple media carbonate reservoir by conceptualising vugs as spherical shapes is presented in this article. A semi-analytical solution is obtained in the Laplace domain by using source function theory, Laplace transformation and superposition principle. Analysis of transient pressure responses indicates that several characteristic flow periods of fractured vertical wells in triple media carbonate reservoir can be identified. Parametric analysis shows that water saturation of matrix, vug and fracture system and half-length can significantly influence the transient pressure responses of fractured vertical wells in triple media carbonate reservoir. The model presented in this article can be applied to obtain important parameters pertinent to reservoir or fracture by type curve matching, and it can also provide useful information for optimising fracture parameters. [Received: May 18, 2019; Accepted: May 6, 2021]

Keywords: acid fracture; oil-water two-phase flow; fractured vertical well; transient pressure analysis; triple media carbonate reservoir.

DOI: 10.1504/IJOGCT.2022.122071

International Journal of Oil, Gas and Coal Technology, 2022 Vol.30 No.1, pp.18 - 45

Accepted: 06 May 2021
Published online: 08 Apr 2022 *

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