A novel method for calculating the dynamic reserves of tight gas wells considering stress sensitivity  

作　　者：Chang-Hao Chen Jing Luo Jian Cao Jing Liang Xu-cheng Li Ting-kuan Cao Ya-hui Xu Lin-Feng Cai Peng Yu Tan-Yin Zhu 

机构地区：[1]Northwest sichuan oil field,Southwest Oil and Gas Field Branch of CNPC,Jiangyou,China [2]Institute of Exploration and Development,Southwest Oil and Gas Field Branch of CNPC,Chendu,China

出　　处：《Earth Energy Science》2025年第1期1-8,共8页地球能源科学(英文)

基　　金：supported by CNPC Southwest Oil and Gas Field Branch's 2023 Scientific Research Program Project(20230303-14).

摘　　要：The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir in the ZT block of northwestern Sichuan is densely packed and highly heterogeneous,featuring complex gas-water distribution,substantial variations in test production among gas wells,and a rapid decline rate.To precisely determine the dynamic reserves of these tight water-bearing gas wells,this study focuses on the water-tight gas reservoirs in the ZT block of northwestern Sichuan,conducting core X-ray diffraction,constant-rate mercury injection,and reservoir rock stress sensitivity experiments.Utilizing the experimental findings,the porosity and permeability of the rock samples under effective stress conditions are adjusted via binary linear regression.These adjusted parameters are then incorporated into the water-sealed gas material balance method,thereby establishing a novel approach for calculating dynamic reserves in water-tight gas reservoirs under stress sensitivity conditions.The results show that:(1)the rock porosity ranges from 6.08%to 10.22%,permeability ranges from 0.035 mD to 0.547 mD,clay mineral content ranges from 6.58%to 19.14%,pore radius distribution ranges from 90μm to 180μm,throat radius distribution ranges from 0.61μm to 3.41μm,with significant differences in throat distribution,indicating poor reservoir fluid flow capacity and strong tightness;(2)after aging experiments,rock samples exhibit plastic deformation,with porosity and permeability unable to fully recover after pressure relief.The stress sensitivity curve of rock samples shows a two-stage characteristic,with moderate to strong stress sensitivity;(3)porosity stress sensitivity is mainly influenced by pore radius and mineral composition-larger pore radius and higher clay content lead to stronger stress sensitivity,with porosity loss rates ranging from 8.26%to 23.69%.Permeability stress sensitivity is mainly influenced

关 键 词：Dynamic gas reserves Stress sensitivity Binary linear regression Tight gas reservoir Effective stress 

分 类 号：P61[天文地球—矿床学]