Microscopic Characteristics of Water Flooding and the Affecting Factors of Low-Permeability Sandstone Reservoir in Zhidan Area, Ordos Basin, China
Microscopic Characteristics of Water Flooding and the Affecting Factors of Low-Permeability Sandstone Reservoir in Zhidan Area, Ordos Basin, China
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DOI：
10.1260/0144-5987.33.2.145
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发表时间：
2015-04
影响因子：
2.7
通讯作者：
Yao Ma;Wenhou Li;Chiyang Liu
中科院分区：
文献类型：
--
作者：
Yao Ma;Wenhou Li;Chiyang Liu
本文旨在分析鄂尔多斯盆地低渗透砂岩油藏注水开发过程中存在的问题，并提供相关理论支持。采用砂岩微观模型进行水驱实验的方法，模拟水驱过程，从微观角度分析低渗透砂岩储层水驱特征。此外，通过物性分析测试、铸体薄片观察、扫描电镜（SEM）和x射线衍射测试，探讨了影响低渗透砂岩储层驱油效率的因素。结果表明：五种实验模型的位移方法主要为均匀位移、手指位移和网格位移，多种位移方法在一个模型中组合也很常见。实验模型中观察到的剩余油分布模式包括迂回剩余油和切断剩余油。最高驱替效率可达55.19%，平均驱替效率为42.41%。驱替效率较高，具有良好的注水开发前景。从储层客观因素和人为可控因素两方面分析了影响低渗透砂岩储层驱油效率的可能因素，包括储层物性、孔隙结构非均质性、储层润湿性、注入水量和驱油压力等。结果表明，孔隙结构的非均质性是最关键的因素。孔隙结构的非均质性越大，越容易产生环状剩余油，从而降低驱替效率。
This paper is to analyze the issues arose during water-flooding exploitation of the low-permeability sandstone reservoir in Ordos Basin, China, and to provide relevant theoretical supports. The method of sandstone micro-model for water flooding experiment was used here to simulate water flooding process, in order to analyze the characteristics of water flooding in low permeability sandstone reservoir from the microscopic view. In addition, the study explored affecting factors to displacement efficiency of low-permeability sandstone reservoir, by analytical tests of physical properties, casting thin sections observation, scanning electron microscope (SEM) and x-ray diffractometer test. The results show that the main displacement methods are homogeneous displacement, finger displacement and mesh displacement in the five experimental models, and a combination of multiple displacement methods in one model is also common. Distribution patterns of residual oil observed in the experimental models include circuitous residual oil and cut-off residual oil. The highest displacement efficiency can reach up to 55.19%, while the average is 42.41%. The displacement efficiency is relatively high, suggesting a good prospect for water-flooding development of the reservoir. We analyzed the possible affecting factors for displacement efficiency of low-permeability sandstone reservoir, from both the objective factors of reservoir and human controllable factors, including physical properties of the reservoir, heterogeneity of pore structure, wettability of the reservoir, volume of injected water and displacement pressure, etc. It turns out that heterogeneity of pore structure is the most critical factor. The greater the heterogeneity of pore structure is, the more likely the circuitous residual oil would be and then the decrease of displacement efficiency.