致密油储层边界层影响因素及渗透率下限实验  

EXPERIMENTS ON THE INFLUENCING FACTORS OF THE BOUNDARY LAYER AND PERMEABILITY LIMIT FOR THE TIGHT OIL RESERVOIR

作　　者：马铨峥[1] 杨胜来[1] 孟展[1] 王璐[1] 钱坤[1] 韩伟[1] MA Quanzheng;YANG Shenglai;MENG Zhan;WANG Lu;QIAN Kun;HAN Wei(MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China)

机构地区：[1]中国石油大学石油工程教育部重点实验室,北京102249

出　　处：《大庆石油地质与开发》2018年第1期159-164,共6页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家重点基础研究发展计划(973)项目"提高致密油储层采收率机理与方法研究"(2015CB250904);国家自然科学基金项目"致密油储层基质渗吸规律及原油动用机理研究"(51574257)

摘　　要：致密油储层渗透率极低,孔喉结构复杂,半径较小,边界层的存在都会进一步增大渗流阻力,对储层渗流影响较大。为了研究致密储层边界层的影响因素,首次采用N2驱替的实验方法,分析了压力梯度、孔喉半径和渗透率与边界层的关系。研究结果表明:随着压力梯度和渗透率的增大,边界层厚度和边界层厚度占用率均呈幂率递减,对储层渗流影响也逐渐减弱;随着孔喉半径的减小,边界层厚度先增后减,存在一个极大值,但随着边界层厚度占用率逐渐增大,对储层渗流影响也逐渐增强;通过拟合,得到不同压力梯度下的渗透率下限值及经验公式,压力梯度越大,渗透率下限值越低。通过该研究,加深了对致密性储层边界层影响因素和渗透率下限的认识,为改善边界层对致密储层渗流影响、确定合理的生产压差提供了理论依据。The permeability of the tight oil reservoir is extremely low,the structures of the pore and throat are complex and moreover their radii are rather small,and further more the existence of the boundary layer will further increase the seepage resistance and have a great influence on the reservoir seepage. In order to study the influencing factors of the boundary layer of the tight reservoirs,the testing method with the help of N2 flooding,the relationships between the pressure gradient,the pore and throat radii and the permeability and the boundary layer were by analyzed. The study achievements show that with the increases of the pressure gradient and the permeability,the thickness of the boundary layer and its occupancy rate decline in the form of the power law,the influence on the reservoir seepage weakens gradually. With the decrease of the pore and throat radii,the thickness of the boundary layer increases first and then decreases,and furthermore there is the maximum value of the thickness,however when the thickness occupancy rate of the boundary layer is gradually increased,the influence on the reservoir seepage is also enhanced gradually; the permeability lower limit and the empirical formula were obtained by the fittingunder different pressure gradients,the greater the pressure gradient is,the lower the permeability lower limit will be. Based on the above researches,for the tight reservoir,the deep understandings have been achieved for the influencing factors of the boundary layer and the permeability lower limit,which have provided the theoretical basis for improving the influence of the boundary layer on the tight reservoir seepage and determining the reasonable production pressure differential.

关 键 词：致密油储层 边界层 压力梯度 孔喉半径 渗透率下限 

分 类 号：TE122.1[石油与天然气工程—油气勘探]