Open Access

ARTICLE

Evaluation of Estimated Ultimate Recovery for Shale Gas Infill Wells Considering Inter-Well Crossflow Dynamics

Cuiping Yuan^1,2,*, Sicun Zhong^1,3,*, Yijia Wu^1,3, Man Chen⁴, Ying Wang^1,3, Yinping Cao⁵, Jia Chen^1,2

1 Geological Exploration and Development Research Institute, CNPC Chuanqing Drilling Engineering Company Limited, Chengdu, 610000, China
2 Sichuan Yuesheng Oil & Gas Field Technical Service Company Limited, Chengdu, 610000, China
3 Sichuan Hengyi Petroleum Technology Service Company Limited, Chengdu, 610000, China
4 Sichuan Changning Natural Gas Development Company Limited, Chengdu, 610000, China
5 CNPC Chuanqing Drilling Engineering Company Limited Sulige Project Management Department, Erdos, 017300, China

* Corresponding Authors: Cuiping Yuan. Email: ; Sicun Zhong. Email:

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

Fluid Dynamics & Materials Processing 2025, 21(7), 1689-1710. https://doi.org/10.32604/fdmp.2025.065151

Received 05 March 2025; Accepted 19 May 2025; Issue published 31 July 2025

Abstract

Field development practices in many shale gas regions (e.g., the Changning region) have revealed a persistent issue of suboptimal reserve utilization, particularly in areas where the effective drainage width of production wells is less than half the inter-well spacing (typically 400–500 m). To address this, infill drilling has become a widely adopted and effective strategy for enhancing reservoir contact and mobilizing previously untapped reserves. However, this approach has introduced significant inter-well interference, complicating production dynamics and performance evaluation. The two primary challenges hindering efficient deployment of infill wells are: (1) the quantitative assessment of hydraulic and pressure connectivity between infill wells and their associated parent wells, and (2) the accurate estimation of platform-scale Estimated Ultimate Recovery (EUR) following infill implementation. This study presents a novel framework to quantify inter-well connectivity by deriving a material balance equation tailored for shale gas infill well groups, explicitly incorporating gas adsorption and desorption mechanisms. The model simultaneously evaluates formation pressure evolution and crossflow behavior between wells, offering a robust analytical basis for performance prediction. For infill wells intersecting the drainage boundaries of parent wells, EUR is estimated using an analytical model developed for multi-stage hydraulically fractured horizontal wells. Meanwhile, the EUR of the parent wells is obtained by summing their pre-infill EUR with the final inter-well crossflow contribution.

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Keywords

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