摘要
页岩吸附气和应力敏感现象是影响气井产能的重要因素,目前页岩气藏水平井二项式产能方程未完全考虑二者影响,导致产能评价不准。结合多级压裂水平井特征和页岩吸附气特性,将应力敏感系数引入Forchheimer渗流方程,推导了考虑吸附气和应力敏感的页岩气水平井二项式产能方程。同时,基于考虑压裂液含量的页岩气物质平衡,建立了地层压力与累产气水量等参数的关系式。以某页岩气藏一口水平井生产资料为基础,结合地层压力表达式和改进遗传算法,采用计算机编程求解产能公式系数,井底流压拟合值与实测值平均误差仅2.01%;进一步预测生产,井底流压预测值与实测值平均误差仅2.02%,相比已有方法更加准确;同时计算出该井初始无阻流量为23.74×10^4 m^3/d,最终技术可采储量1.54×108 m^3。结果表明,考虑吸附气和应力敏感的页岩气藏多级压裂水平井二项式产能方程可靠性较高。该研究成果为页岩气动态产能评价提供了一种新的理论方法。
The adsorbed gas and stress sensitivity phenomena are important factors affecting the deliverability of shale gas well.However,their impact to the current binomial deliverability equations for horizontal wells in shale gas reservoirs have not fully been considered,which results in inaccurate deliverability evaluation.Combining the characteristics of multistage fractured horizontal wells and the adsorbed gas in shale,the stress sensitivity coefficient was introduced into the Forchheimer flow equation to derive the horizontal well deliverability equation.Simultaneously,according to the material balance theory of shale gas when considering the fracturing fluid content,the formation pressure equation that related to production data was derived after strict deduction.Based on the production data of a horizontal well of a certain gas reservoir,the formula of deliverability coefficient was obtained through computer programming with the combination of formation pressure equation and improved genetic algorithm.The average error between fitting result and the measured value of sand face pressure is 2.01%.After further prediction of production,the prediction average error of the sand face pressure is 2.02%of measured value,which is more accurate than the existing methods.Besides,the open flow potential calculated of this well is 23.74×10^4 m^3/d,and the technical recoverable reserve is 1.54×108 m^3.The calculation results show that this new binomial deliverability equation is highly reliable.The research results provide a new theoretical method for shale gas deliverability evaluation.
作者
刘建仪
何汶亭
廖鑫怡
LIU Jian-yi;HE Wen-ting;LIAO Xin-yi(College of Petroleum and Natural Gas Engineering,Southwest Petroleum University,Chengdu 610500,China)
出处
《科学技术与工程》
北大核心
2020年第7期2652-2658,共7页
Science Technology and Engineering
关键词
页岩气
应力敏感
压裂液
二项式产能方程
改进遗传算法
shale gas
stress sensitivity
fracturing fluid
binomial deliverability equation
improved genetic algorithm
