微裂缝各向异性相对渗透率实验

Anisotropy experiment of microfracture relative permeability

郑文宽 刘月田 刘逸盛 王一茗 马嘉雨

中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249

State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China

微裂缝会导致储层渗透率出现各向异性，但目前人们的认识仅局限于微裂缝对储层绝对渗透率的影响上。为研究微裂缝对油水两相渗流的影响，利用人造微裂缝岩心进行油水两相相对渗透率对比实验。研究结果表明，微裂缝对相对渗透率曲线形态影响很大。造缝后平行裂缝面方向岩心油、水相对渗透率分别下降和上升较快，等渗点水相饱和度减小，对应的相对渗透率增大，残余油饱和度明显增大，两相渗流区变窄，最终驱替效率降低；垂直裂缝面方向的相对渗透率受微裂缝影响较小，与基质相渗曲线形态更为接近，即微裂缝会导致基质的相对渗透率具有各向异性特征；闭合微裂缝也会对相对渗透率曲线形态产生影响，主要体现在闭合微裂缝主方向水相相对渗透率上升较快，两相总导流能力较大。

The microfractures developed in the reservoir result in the anisotropic permeability of the reservoir, but the study of anisotropy at the present stage is limited to absolute permeability. In order to study the influence of microfractures on oil-water two-phase flow, experiments using artificial microfracture cores were conducted to compare the oil-water relative permeability curves. The experiment results show that microfracture has a great influence on the morphology of the relative permeability curve. After the fracturing process, the oil-water relative permeability curve rises or drops dramatically, the relative permeability at the isopotal point gets better, the saturation of remaining oil gets bigger, two-phase flow area of the cores becomes narrower, and the final displacement recovery efficiency decreases. The relative permeability curve in the direction perpendicular to the fracture surface is less affected by the microfracture and more similar to the relative permeability curve of matrix. That is the microfractures result in anisotropy in the relative permeability of the matrix. The microfracture with permeability close to the matrix also affect the morphology of the relative permeability curve, which is mainly reflected in the rapid rise of the relative permeability of the water phase in the direction of the microfracture and the better two-phase total conductivity.

10.6056/dkyqt201903020