致密储层复杂流体模型及其适用性分析  

Analysis of complex fluid model and its applicability in tight reservoirs

作　　者：孙卫涛 熊繁升 曹宏[3] 杨志芳[3] 卢明辉[3] SUN Weitao;XIONG Fansheng;CAO Hong;YANG Zhifang;LU Minghui(School of Aerospace Engineering,Tsinghua University,Beijing 100084,China;Zhou Pei-Yuan Center for Applied Mathematics,Tsinghua University,Beijing 100084;Research institute of Petroleum Exploration & Development,CNPC,Beijing 100083,China)

机构地区：[1]清华大学航天航空学院,北京100084 [2]清华大学周培源应用数学研究中心,北京100084 [3]中国石油天然气股份有限公司勘探开发研究院,北京100083

出　　处：《石油物探》2021年第1期136-148,共13页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金(41874137,42074144);国家重点研发计划(2018YFA0702501);中国石油天然气集团有限公司“十三五”基础研究项目(2018A-3306,2019A-3307)共同资助。

摘　　要：致密油气储层普遍面临油气流动性低、产量不稳定的问题,对低孔渗致密储层的渗透率预测是油气勘探开发中亟待解决的问题。致密储层流体流动的关键机理不清楚,传统孔隙介质流体模型难以为渗透率预测提供足够的理论支撑,这些问题均制约了渗透率预测的准确度。针对微纳米尺度的致密储层孔隙结构,详细分析了致密储层复杂流体模型的理论基础和适用范围。不同尺度孔隙空间流动参数的数值计算和对比分析结果表明,Knudsen模型适用于较低压力下微纳米孔隙中的气体流动,对于致密储层油、水等液体或稠密气体来说,Knudsen流动的影响可以忽略;Forchheimer模型适用于孔隙介质中流体速度较高的情况,当致密储层中流体流速较低时,对流动惯性项的修正基本可以忽略。流体模型理论及其适应性分析对于深入理解致密储层复杂流动现象至关重要,研究结果为致密储层渗透率技术的应用研究提供了理论基础。Low oil/gas mobility and unstable production are two major problems associated with tight oil/gas reservoirs.Therefore,it is crucial to predict the permeability of low porosity oil/gas reservoirs for exploration and production.However,the mechanism of fluid flow in reservoirs with tight pores is still unclear.Traditional fluid flow models entail difficulties in providing theoretical support for predicting reservoir permeability.The theory and application conditions of complex flow models for tight reservoirs were analyzed in detail in this study.Numerical computations and analysis with different fluid parameters and pore sizes showed that the Knudsen model is suitable for gas flow in micro/nano pores at low pressure.The influence of Knudsen flow could be neglected for liquids(such as oil and water)and condensed gas in tight reservoirs.The Forchheimer model was found to be suitable for high velocity fluid flow in porous media.The correction of inertia was small and therefore could be neglected for low velocity fluid flows in tight reservoirs.The analysis of flow models and corresponding applications are important to further understand phenomena associated with complex fluid flow in tight reservoirs.The results provide strong baseline knowledge of the underlying mechanisms that can be used in the application of technology for improving the permeability of tight reservoirs.

关 键 词：致密储层 微纳米孔隙 孔隙流体流动 Knudsen模型 Forchheimer模型 低孔渗 渗透率 

分 类 号：P631[天文地球—地质矿产勘探]