低渗致密储层微纳米孔喉分布及其对渗流的影响  

Distribution of micro-nano pore throat and its influence on seepage in low permeability and tight oil reservoir

作　　者：刘红英[1] 李冀秋[1] LIU Hongying;LI Jiqiu(Sinopec Petroleum Exploration and Production Research Institute,Beijing 100083,China)

机构地区：[1]中国石化石油勘探开发研究院,北京100083

出　　处：《非常规油气》2023年第3期98-102,共5页Unconventional Oil & Gas

基　　金：中国石化科技攻关项目“试验区油藏工程方案优化设计”(P19031-2)。

摘　　要：低渗-致密储层微观孔喉分布有较大差异,导致其渗流特征亦有明显不同。将室内实验与油藏工程计算相结合,定量研究了低渗-致密储层微纳米孔喉分布特征及其对渗流的影响。结果表明:1)孔喉半径小于1μm的孔喉体积占总孔喉体积的主体;2)岩心渗流特征曲线呈非线性渗流规律,渗透率降低,启动压力梯度显著增大,附加渗流阻力占总渗流阻力的比例也增大,研究物性范围内,附加渗流阻力占比均大于50%,渗透率为0.4 mD时,附加渗流阻力占比可达84.8%;3)微纳米孔喉的存在使得油井泄油半径降低,渗透率为0.4 mD时,极限泄油半径仅28.5 m,制约了井间及压裂水平井段间原油的动用。该研究成果可为认识低渗-致密油藏流体渗流规律和制定合理开发方案提供指导。The microscopic pore throat distributions of low permeability and tight reservoirs are quite different,which leads to the obvious difference of seepage characteristics.The characteristics of micro-nano pore throat and its influence on seepage flow in low permeability and tight oil reservoir are systematically and quantitatively studied by means of laboratory experiments and reservoir engineering calculations.The results show that:1)The pore throat volume with radius less than 1μm accounts for the main part of the total pore throat volume.2)The seepage characteristic curve shows a nonlinear law.When permeability decreases,the threshold pressure gradient increases significantly,and the proportion of additional seepage resistance to the total seepage resistance also increases.Within the range of physical properties studied,the proportion of additional seepage resistance is more than 50%.When the permeability is 0.4 mD,the proportion of additional seepage resistance can reach 84.8%.3)The existence of micro-nano pore throat leads to the reduction of oil drainage radius of oil wells.When the permeability is 0.4 mD,the ultimate oil drainage radius is only 28.5 m,which restricts the production of crude oil between wells and between fracturing stages of horizontal wells.The research results can provide guidance for understanding of the fluid flow law in low permeability and tight oil reservoirs and formulating reasonable development plans.

关 键 词：低渗-致密储层 微纳米孔喉 启动压力梯度 附加渗流阻力 泄油半径 

分 类 号：TE312[石油与天然气工程—油气田开发工程]