天然气工业2026，Vol.46Issue(5)：64-75,12.DOI:10.3787/j.issn.1000-0976.2026.05.006
致密砂岩气藏变启动压力梯度实验及表征模型研究
Experiment and characterization model of variable threshold pressure gradient in tight sandstone gas reservoirs
摘要
Abstract
Tight sandstone gas reservoirs have the typical characteristics of low porosity,low permeability and complex pore throat structure,and exhibit obvious nonlinear flow patterns in the middle and late development stages.The threshold pressure gradient(TPG),as a key parameter of nonlinear flow in tight sandstone gas reservoirs,is of important theoretical significance and engineering value for the productivity evaluation and development plan optimization of gas reservoirs,but its dynamic evolution patterns and controlling factors are lack of systematic research.Taking a certain block in the Sulige Gas Field as an example,this paper selects typical core samples to conduct TPG experiments under varying pore pressures,simulating its evolution patterns during the depletion development of gas reservoirs.In addition,a mathematical characterization model of variable TPG incorporating pore-throat structure,capillary pressure and boundary layer effect is established on the basis of fractal theory,Hertz contact theory,and boundary layer theory.The following results are obtained.First,water saturation and interfacial tension are directly proportional to TPG,while porosity,Young's modulus and wetting angle are inversely proportional to TPG.Second,porosity and water saturation have greater impact on TPG.In comparison with the initial stage of development,these factors exert a more substantial influence during the middle and late stages.Third,a variable threshold pressure gradient effect is present within the gas reservoir.TPG is smaller in the initial stage of development than in the middle and late stages,and its variation range is larger in the middle and late stages.In conclusion,the variable threshold pressure gradient and productivity model established in this paper can accurately characterize flow characteristics,and lay a methodological foundation for improving the prediction accuracy of gas reservoir productivity.关键词
致密砂岩气藏/启动压力梯度/开发中后期/数学表征/物模实验Key words
Tight sandstone gas reservoir/Threshold pressure gradient(TPG)/Middle and late development stages/Mathematical characterization/Physical simulation experiment分类
能源科技引用本文复制引用
田冷,朱远,李进步,姬鹏程,柴晓龙,刘莉莉,郑荣臣..致密砂岩气藏变启动压力梯度实验及表征模型研究[J].天然气工业,2026,46(5):64-75,12.基金项目
国家科技重大专项项目"致密气藏采收率标定方法"(编号:2025ZD140430204)、"井网加密优化提高采收率技术研究"(编号:2025ZD1405503),中国石化实验室专项项目"低渗致密气藏开发中后期渗流阻力变化规律研究"(编号:KLP25018). （编号:2025ZD140430204）
