考虑应力敏感的致密气藏动态产能方程及应用  

Establishment and application of tight gas dynamic productivity equation considering stress sensitivity

作　　者：赫文昊 魏虎 和向楠 王凯 李涛 HE Wenhao;WEI Hu;HE Xiangnan;WANG Kai;LI Tao(Research Institute of Shaanxi Yanchang Petroleum(Group) Company Ltd.,Xi’an 710075,China)

机构地区：[1]陕西延长石油(集团)有限责任公司研究院,西安710075

出　　处：《非常规油气》2021年第4期55-61,共7页Unconventional Oil & Gas

基　　金：陕西省青年科技新星基金项目“陆相页岩微纳米孔喉结构非均质性及对页岩气赋存状态的控制机理”(2019KJXX-054)。

摘　　要：致密气藏生产过程中储层应力敏感性强,地层压力下降快,流体物性差异大,是目前致密气井产能分析和稳产预测的关键。基于高速非达西渗流Forchheimier二项式方程,引入了储层应力敏感性和生产压降导致气体高压物性变化2个因素,形成了气井生产任意时间点产能方程建立的方法。利用该方法获得气井稳产期末产能方程及地层压力,再通过物质平衡法得到气井稳产期。研究结果表明井区储层应力敏感性中等偏强,幂指数关系式可准确表达储层应力敏感性,在气井产能方程建立时应力敏感系数不可忽略。通过迭代求解,仅利用产能试井资料即可快速获得拟稳态时期产能方程,无需拟合生产动态即可进行稳产期预测。以Y40井为例,与实际稳产期对比,考虑应力敏感的动态产能方程计算的稳产期误差为2.39%;其他多个模拟产量的计算结果误差均小于5%。与数值模型拟合预测方法相比,考虑应力敏感的动态产能方程法所需生产动态数据少、计算快速准确。When producing tight gas reservoir,the reservoir stress sensitivity is strong,the formation pressure drops quickly,and the fluid physical properties vary greatly.These are the keys to productivity analysis and stable production prediction of tight gas wells.Based on the Forchheimier binomial equation of high-speed non-Darcy seepage flow,this paper introduces the two factors of reservoir stress sensitivity and changes in gas properties at high pressure caused by production pressure drop,forming a method to establish the productivity equation at any point in gas well production.This method is used to obtain the productivity equation and formation pressure at the end of the stable production period of the gas well,and then obtain the stable production period of the gas well by the material balance method.The study research show that the stress sensitivity of the area is between medium and strong,the power exponential relationship can accurately express the stress sensitivity,and the stress sensitivity coefficient cannot be ignored when establishing gas well productivity equation.Through iterative solution,the productivity equation of the pseudo-steady state period can be quickly obtained by using only the productivity test data,and the stable production period can be predicted without simulating the production data.Taking well Y40 as an example,compared with the actual stable production period,the error of the stable production period calculated by considering the stress-sensitive dynamic productivity equation is 2.39%;the error of the calculation results of other simulation production is less than 5%.Compared with the method of predicting by numerical simulation,the method of dynamic productivity equation considering stress sensitivity requires less production data,and the calculation is fast and accurate.

关 键 词：致密气 应力敏感 产能方程 拟稳态 合理配产 

分 类 号：TE37[石油与天然气工程—油气田开发工程]