致密气藏分段压裂水平井的不稳定压力与产量综合分析方法  

Comprehensive analysis method for transient pressure and production of multistage fractured horizontal well in tight gas reservoirs

作　　者：欧阳伟平 OUYANG Weiping(Changqing Downhole Technology Company,CNPC Chuanqing Drilling Engineering Company Limited,Xi’an,Shaanxi 710018,China;National Engineering Laboratory for Exploration and Development of Low-Permeability Oil and Gas Fields,Xi’an,Shaanxi 710018,China)

机构地区：[1]中国石油集团川庆钻探工程有限公司,长庆井下技术作业公司,陕西西安710018 [2]低渗透油气田勘探开发国家工程实验室,陕西西安710018

出　　处：《油气井测试》2018年第1期14-21,共8页Well Testing

基　　金：中国石油川庆钻探公司项目“致密油气藏压裂优化设计及监测评价技术一体化平台开发”(CQ2017B-23-2-4)

摘　　要：基于达西线性渗流的常规试井解释模型及产量递减分析模型不再适用于具有非线性渗流特征的致密气藏,采用视渗透率的方法,建立了一种综合考虑储层应力敏感、启动压力梯度以及滑脱效应的压裂水平井3D非线性渗流数学模型。利用混合有限元方法对模型进行求解,获得了非线性渗流条件下压裂水平井的试井理论曲线及产量递减Blasingame曲线。研究结果表明,应力敏感及启动压力梯度会"抬升"试井理论曲线,"降低"产量递减曲线,减小压力扩散速度,延缓外边界响应的时间。滑脱效应会小幅度"降低"试井理论曲线,"抬升"产量递减曲线,但其影响程度比较小。利用所建立的非线性渗流模型对苏里格气田压裂水平井试井测试资料进行试井解释,对生产数据进行产量递减分析,将两者解释得到的储层参数及裂缝参数进行对比校正,并通过模型预测产量与实际产量的对比,证实新方法可靠实用,能降低解释的多解性,比常规方法更先进,可用于存在非线性渗流特征的致密气藏储层动态评价。The conventional well test analysis model and production decline analysis model based on Darcy linear seepage theory are no longer applicable to tight gas reservoirs with nonlinear seepage characteristics.A 3D nonlinear seepage mathematical model of fractured horizontal well is established considering stress sensitivity,starting pressure gradient and slippage effect by using apparent permeability method.Well test type curves and production decline Blasingame curves under different nonlinear seepage conditions are obtained using the mixed finite element method.Effects of different nonlinear seepage factors on well test type curves and production decline curves have been studied.The calculation results show that stress sensitivity and starting pressure gradient will increase the value of well test theoretical curve,decrease the value of production decline curve,reduce the pressure diffusion speed,and postpone the corresponding time of the external boundary.However,the slippage effect will reduce the value of well test theoretical curve and increase the value of production decline curve,but the degree of its influence is small.Base on the nonlinear seepage model established,the well test data of fractured horizontal wells in Sulige gas field were interpreted by using the well test interpretation method,and production data were analyzed by using the advanced production decline analysis method.The results of reservoir parameters and fracture parameters interpreted by the two methods are compared,and then the model established is verified to be reliable and practical by the comparison between the model prediction and the actual output.The new method can reduce the multiple solutions of the interpretation,which is more advanced than the conventional method,and thus it can be widely applied in tight gas wells with nonlinear seepage characteristics.

关 键 词：致密气 试井 水平井 应力敏感 启动压力梯度 滑脱效应 非线性渗流 产量递减 试井解释 

分 类 号：TE353[石油与天然气工程—油气田开发工程]