致密油储层岩石孔喉比与渗透率、孔隙度的关系

Relationship of pore-throat ratio vs.permeability and porosity of tight oil reservoir rock

李伟峰 刘云 于小龙 魏浩光

LI Weifeng LIU Yun YU Xiaolong WEI Haoguang

延长油田股份有限公司勘探开发研究中心 西北大学地质系 延长石油集团研究院钻采所 中国石化石油工程技术研究院

Exploration and Development Research Center, Yanchang Oil Field Co., Ltd., Yan'an716000, Shaanxi, China Department of Geology, Northwest University, Xi'an710069, Shaanxi, China Drilling and Production Department of Research Institute, Shaanxi Yanchang Petroleum(Group)Co., Ltd., Xi'an710075, Shaanxi, China Research Institute of Petroleum Engineering, SINOPEC, Beijing100101, China

孔喉比是致密油储层岩石最重要的微观物性之一，对储层的剩余油分布与驱替压力影响很大。利用复合毛细管模型，考虑储层岩石的孔喉比、配位数、孔隙半径和喉道半径等孔隙结构参数，建立了致密油储层岩石的微观物性与宏观物性孔隙度、渗透率之间的理论关系式。并用44组板桥地区长6油层组致密油储层岩心的恒速压汞实验数据进行拟合。结果表明：致密油储层岩石孔隙度φ主要受孔隙半径影响，喉道半径控制岩石的渗透率k，孔喉比与φ^0.5/k^0.25间具有确定的函数关系。利用2组渗透率接近、孔隙度差异较大的岩心驱油实验，证实φ^0.5/k^0.25值大的致密砂岩，水驱油阻力大。

Pore-throat ratio is one of the most important microscopic physical properties of tight oil reservoir rocks and it has great effect on the remaining oil distribution and displacement pressure of reservoirs.After pore structure parameters of reservoir rocks were analyzed, such as pore-throat ratio, coordinate number, pore radius and throat radius, the theoretical relation between microscopic physical properties and macroscopic physical properties (porosity and permeability) of tight oil reservoir rocks was established by using the composite capillary model.Then, constant-rate mercury injection experiment data of 44 suites of cores taken from Chang 6 oil formation in Banqiao area were used for fitting.It is indicated that the porosity () and permeability () of tight oil reservoir rocks are controlled by pore radius and throat radius, respectively.There is a good mathematical relationship between pore-throat ratio and /.Oil displacement experiment was performed on two suites of cores whose permeabilities are close and porosities are more different.It is verified that the water displacing oil resistance in tight sandstones with higher / is higher.

10.13639/j.odpt.2017.02.001