摘要
针对页岩缝网储层应力敏感性研究中实验压力偏低导致难以真实反映储层条件的问题,本研究采用从低压至真实储层应力的全程模拟实验方法,系统开展了页岩缝网储层应力敏感性评价,并通过理论分析量化了其对裂缝渗流的影响。页岩缝网应力敏感性曲线呈现四段式特征,渗透率越低,该特征越显著;总体渗透率保持率随裂缝岩心渗透率增加而上升,最高达25.46%;页岩缝网岩心受压依次经历塑性形变、拟塑性形变、弹性形变和刚性4个应力响应阶段,裂缝岩心渗透率大幅下降主要发生于第一阶段,最大降幅为73.63%;裂缝岩心存在应力滞后效应,渗透率越高者可压性越大,进入同一应力阶段所需起始净应力也越大。在实际储层应力条件下,岩心多处于弹性形变阶段,部分裂缝储层在开发后期进入刚性阶段。实际储层应力敏感性曲线可分为“L”型与类直线型两类,实际储层条件下页岩裂缝岩心渗透率损失普遍低于25%,属弱应力敏感。在实际生产中,低压差条件下应力敏感对流量影响小于5%,可忽略不计;但在大压差生产时,其影响程度超过10%,最高达17.59%。若在页岩缝网储层产能评价中忽略应力敏感性,将导致结果显著偏高。本研究可为非常规油气资源的高效开发提供技术依据。
To address the issues of low experimental pressure and the difficulty in accurately reflecting reservoir conditions in studies on the stress sensitivity of shale fracture network reservoirs,this study employed a whole-process simulation experiment method from low pressure to actual reservoir stress to systematically evaluate the stress sensitivity of shale fracture network reservoirs and quantify its impact on fracture seepage through theoretical analysis.The stress sensitivity curve of shale fracture networks exhibited four-stage characteristics,which became more pronounced as permeability decreased.The overall permeability retention rate increased with the increase of fracture core permeability,reaching a maximum of 25.46%.Shale fracture network cores under compression underwent four stress response stages successively:plastic deformation,pseudo-plastic deformation,elastic deformation,and rigid deformation.The most significant reduction in fracture core permeability occurred in the first stage,with a maximum decrease of 73.63%.The fracture cores exhibited a stress hysteresis effect.Cores with higher fracture permeability demonstrated greater compressibility and required higher initial net stress to enter the same stress stage.Under actual reservoir stress conditions,most cores were in the elastic deformation stage,while a small portion entered the rigid deformation stage during later development phases.The actual reser-voir stress sensitivity curves could be divided into two types:“L”-shaped type and quasi-linear type.Under actual reservoir conditions,the permeability loss of shale fracture cores was generally less than 25%,indicating weak stress sensitivity.In actual production,under low pressure difference conditions,the impact of stress sensitivity on flow rate was less than 5%and could be considered negligible.However,under high pressure difference production,its degree of impact exceeded 10%,with a peak of 17.59%.If stress sensitivity was neglected in the productivity evaluation of shale fracture network reservoirs,the results would be significantly overestimated.These findings provide a technical basis for the efficient development of unconventional oil and gas resources.
作者
李中超
田巍
张航
管臻
LI Zhongchao;TIAN Wei;ZHANG Hang;GUAN Zhen(State Key Laboratory of Shale Oil&Gas Enrichment Mechanisms and Effective Development,Beijing 102206,China;Zhongyuan Oilfield Company,SINOPEC,Puyang,Henan 457001,China;Zhongyuan Laboratory,Puyang,Henan 457001,China;Shashi Steel Pipe Branch,SINOPEC Petroleum Machinery Co.,Ltd.,Jingzhou,Hubei 434001,China)
出处
《石油实验地质》
北大核心
2026年第1期1-9,共9页
Petroleum Geology & Experiment
基金
国家重点基础研究发展计划(2013CB228002)
中国石化科技攻关项目(P25138)
河南省博士后基金(2018120)联合资助。
关键词
页岩缝网
应力敏感性
四段式特征
渗透率伤害率
体积流量
渗流
shale fracture network
stress sensitivity
four-stage characteristics
permeability damage rate
volu-metric flow rate
seepage
