• 应用研究 •

### 致密油储层毛细管力自发渗吸模型分析 1)

1. *中国矿业大学(北京)深部岩土力学与地下工程国家重点实验室，北京 100083;
中国科学院力学研究所流固耦合系统力学重点实验室，北京 100190;
**新疆油田公司勘探开发研究院开发所，新疆克拉玛依 834000;
††塔里木油田公司油气工程研究院，新疆库尔勒 841000
• 发布日期:2019-08-26
• 作者简介:2) 杨柳，讲师，主要从事岩石与流体相互作用方面的研究工作。E-mail：shidayangliu@cumtb.edu.cn
• 基金资助:
1) 国家自然科学青年基金资助项目(11702296)。

### SPONTANEOUS CAPILLARY IMBIBITION MODEL IN TIGHT OIL RESERVOIRS 1)

YANG Liu*,†,2), ZHAO Yiqing**, JIANG Rongmin††, ZHANG Xuhui, LU Xiaobing

1. *State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China;
Key Laboratory for Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China;
**Exploration and Development Research Institute of Xinjiang Oilfield Company, Karamay 834000, Xinjiang, China;
††Oil and Gas Engineering Research Institute of Tarim Oilfield Company, Korla 841000, Xinjiang, China
• Published:2019-08-26

Abstract: The fracturing construction shows that the lower flowback efficiency is often accompanied with a high production in tight oil reservoirs, which may be due to the spontaneous imbibition of the fracturing fluid. However, the tight oil reservoir has poor physical properties with a complex permeable mechanism. A spontaneous imbibition model for tight oil reservoirs is desirable. Based on the oil-water flow theory, a mathematical model of the spontaneous imbibition is established. The numerical difference method is used to solve the equations and analyze the influencing factors. The results show that the imbibition volume and the imbibition front position of the tight oil reservoir are linear functions of the square root of time, as is consistent with the prediction of the classical Handy imbibition model. It indicates that the imbibition model is reliable. The numerical results show that the phase diffusion coefficient is the main control parameter of the imbibition rate and has a positive correlation with the imbibition rate. The phase diffusion coefficient increases first and then decreases with the water saturation; it increases with the increase of the irreducible water saturation, and the relative endpoint permeability of the oil and the water; it decreases with the increase of the permeability characteristic index, the oil-water viscosity ratio and the residual oil saturation. The results of this paper can help to understand the fracturing fluid imbibition mechanism in the tight oil reservoirs, and can be used for optimizing the flowback regime and improving the production of the tight oil.