Open Access

ARTICLE

A Chart-Based Diagnostic Model for Tight Gas Reservoirs Based on Shut-in Pressure during Hydraulic Fracturing

Mingqiang Wei^1,*, Neng Yang¹, Han Zou², Anhao Li³, Yonggang Duan¹

1 Petroleum Engineering School, Southwest Petroleum University, Chengdu, 610500, China
2 Sinopec Northwest Oilfield Branch, Bayingolin Mongolian Autonomous Prefecture, 841600, China
3 Southwest Oil and Gas Field Company, Huayou Company, Chengdu, 610017, China

* Corresponding Author: Mingqiang Wei. Email:

(This article belongs to the Special Issue: Fluid and Thermal Dynamics in the Development of Unconventional Resources II)

Fluid Dynamics & Materials Processing 2025, 21(2), 309-324. https://doi.org/10.32604/fdmp.2024.058454

Received 12 September 2024; Accepted 22 November 2024; Issue published 06 March 2025

Abstract

A precise diagnosis of the complex post-fracturing characteristics and parameter variations in tight gas reservoirs is essential for optimizing fracturing technology, enhancing treatment effectiveness, and assessing post-fracturing production capacity. Tight gas reservoirs face challenges due to the interaction between natural fractures and induced fractures. To address these issues, a theoretical model for diagnosing fractures under varying leak-off mechanisms has been developed, incorporating the closure behavior of natural fractures. This model, grounded in material balance theory, also accounts for shut-in pressure. The study derived and plotted typical G-function charts, which capture fracture behavior during closure. By superimposing the G-function in the closure phase of natural fractures with pressure derivative curves, the study explored how fracture parameters—including leak-off coefficient, fracture area, closure pressure, and closure time—impact these diagnostic charts. Findings show that variations in natural fracture flexibility, fracture area, and controlling factors influence the superimposed G-function pressure derivative curve, resulting in distinctive “concave” or “convex” patterns. Field data from Well Y in a specific tight gas reservoir were used to validate the model, confirming both its reliability and practicality.

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Graphic Abstract

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Keywords

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