Open Access

ARTICLE

4D Evolution of In-Situ Stress and Fracturing Timing Optimization in Shale Gas Wells

Qi Deng¹, Qi Ruan², Bo Zeng¹, Qiang Liu³, Yi Song¹, Shen Cheng¹, Huiying Tang^2,*

1 Shale Gas Research Institute, PetroChina Southwest Oil and Gas field Company, Chengdu, 610051, China
2 State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, 610500, China
3 Engineering Technology Department, PetroChina Southwest Oil and Gas Field Company, Chengdu, 610056, China

* Corresponding Author: Huiying Tang. Email:

Fluid Dynamics & Materials Processing 2025, 21(5), 1201-1219. https://doi.org/10.32604/fdmp.2025.060311

Received 29 October 2024; Accepted 17 February 2025; Issue published 30 May 2025

Abstract

Over more than a decade of development, medium to deep shale gas reservoirs have faced rapid production declines, making sustained output challenging. To harness remaining reserves effectively, advanced fracturing techniques such as infill drilling are essential. This study develops a complex fracture network model for dual horizontal wells and a four-dimensional in-situ stress evolution model, grounded in elastic porous media theory. These models simulate and analyze the evolution of formation pore pressure and in-situ stress during production. The investigation focuses on the influence of infill well fracturing timing on fracture propagation patterns, individual well productivity, and the overall productivity of well clusters. The findings reveal that, at infill well locations, the maximum horizontal principal stress undergoes the most significant reduction, while changes in the minimum horizontal principal stress and vertical stress remain minimal. The horizontal stress surrounding the infill well may reorient, potentially transitioning the stress regime from strike-slip to normal faulting. Delays in infill well fracturing increase lateral fracture deflection and diminish fracture propagation between wells. Considering the stable production phase and cumulative gas output of the well group, the study identifies an optimal timing for infill fracturing. Notably, larger well spacing shifts the optimal timing to a later stage.

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Keywords

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