低渗透气藏应力敏感性分析及对开采的影响

Stress sensibility analysis of low permeability gas reservoir and its influence on exploitation

针对低渗透气藏压敏效应较强,随着储层压力的下降,有效应力不断变化,引起气藏产能逐渐降低的特点,通过固定围压,改变内压(四升四降内压)的方法来研究内压变化对储集层渗透率的影响,同时分析评价渗透率的应力敏感性。根据实验结果,采用数值模拟软件对苏里格气田的1口低渗气井进行研究,近似模拟考虑和不考虑应力敏感条件下生产指标的变化,以及间歇式开采和波动式开采对气井生产动态的影响,从而综合分析应力敏感现象在低渗透气藏开采过程中的影响程度,为低渗透气藏的合理开采提供参考。

Many researches indicate that stress sensibility appears frequently in low permeability gas reservoir.The fluid pressure and effective stress will change in the course of production,and it will induce productivity decreasing.In this paper,the method of fixing peripheral pressure and altering internal pressure is discussed to study the effect of internal pressure on permeability and to analyze the stress sensibility of permeability.Based on experiment result,a numerical simulation software is utilized to study a low permeability gas well in Sulige gas field,including simulating the change of production index with and without consideration of stress sensibility,and the influence of intermittent and surge production on gas well production performance,thus to analyze the influence of stress sensibility during recovery process of low permeability gas reservoir.This paper provides a reference for exploiting low permeability gas reservoir.