CD-CN地区风化壳岩溶储层测井识别与流体性质判别

Reservoir and Fluid Properties Identification of Weathering Crust in CD-CN Area

摘要: CD-CN地区中二叠统茅口组属于早成岩期风化壳岩溶储层，勘探开发潜力大。风化壳岩溶储层的岩性、孔隙结构、测井响应特征等极为复杂，导致储层测井识别及流体性质判别难度较大。首先在岩性识别和储集空间分析的基础上，基于电成像测井和常规测井，提出了裂缝型、裂缝–溶洞型和溶洞型三大类储层的测井识别方法；然后在储层产能数据的标定下，将三大类储层进一步划分为I类、II类、III类储层；最后根据油气测试和生产数据，建立了储层流体性质识别方法。研究结果表明，本文在储层识别与级别划分基础上建立的储层级别–RT交会图版的流体性质识别效果较好，该方法划分出的I类、II类、III类储层的气水电阻率界限分别为100Ω∙m、200 Ω∙m和300 Ω∙m，有效的解决了不同储层类型、不同储层级别和不同流体性质导致的储层电阻率重叠现象，提高了风化壳岩溶储层的流体性质判别符合率。

Abstract: Maokou Formation of middle Permian in CD-CN area belongs to the weathering crust karst reservoir in the early diagenesis stage. It has great potential for gas exploration and development. The lithology, pore structure and logging response characteristics of the weathering crust karst reservoir are very complex, which makes it difficult to identify the reservoir and fluid properties. Firstly, on the basis of lithology identification and reservoir space analysis, and based on electrical imaging logging and conventional logging, the methods of identification of fracture type, fracture-cavern type and karst cavern type reservoirs are proposed. Then, based on the calibration of production data, the three levels of reservoirs are further divided into type I, type II and type III reservoirs. Finally, based on the oil and gas testing and production data, a method for identifying reservoir fluid properties is established. The results show that the fluid identification effect of the reservoir level versus RT plot is better. The gas water resistivity reservoir boundaries of type I, II, III are 100 Ω∙m, 200 Ω∙m and 300 Ω∙m respectively. This method effectively solves the overlap phenomenon of the resistivity caused by the mixture of different reservoir types and different reservoir levels and the different fluid properties, and improves the identification rate of the weathering crust karst reservoir fluid property.