碳酸盐岩油藏储层测井挖掘效应的综合分析

H油田碳酸盐岩油藏由于构造变化大，岩性复杂，在流体识别及流体界面的划分中出现了很多矛盾。对于气体识别，采用补偿中子测井挖掘效应在有些区块有效，而有些区块是无效的，因此，需要对挖掘效应的影响因素进行分析。首先，分析了H油田碳酸盐岩油藏岩性和孔隙结构特征；然后，分析了其中的KA、KB储层孔渗等物性特征；并通过多口井的测井曲线，总结了中子测井和密度测井在气层所形成的挖掘效应响应特征，分析了形成真假挖掘效应的原因；从理论上阐述了密度测井与中子测井的相互关联性，推导了两种测井响应的关联方程，从井眼扩径、孔隙结构、孔渗物性及饱和度等多个角度分析了挖掘效应的因素影响的机理，最后，给出了综合利用挖掘效应判断气层的分析方法，提出了判断真假挖掘效应的几条依据。根据这一方法，较好地完成了H油田K油藏流体识别，可为后续H油田以及类似的碳酸盐岩复杂油气藏准确识别流体类型提供借鉴。

Comprehensive Analysis of Logging and Excavation Effects in Carbonate Reservoirs

Due to the large structural changes and complex lithology, there are many contradictions in fluid identification and fluid interface division of carbonate reservoir in H Oilfield. For gas identification, compensated neutron logging mining effect is effective in some blocks, but not in others. Therefore, it is necessary to analyze the influencing factors of mining effect. Firstly, the lithology and pore structure characteristics of carbonate reservoir in H Oilfield are analyzed. Then the physical characteristics of Layer KA and KB such as pore permeability are analyzed. The response characteristics of mining effects formed by neutron logging and density logging in gas reservoirs are summarized by those curves of several Wells, and the reasons of forming true and false mining effects are analyzed. The density log and neutron log correlation was expounded in theory, and two kinds of logging response correlation equation were deduced. The factors affecting the mechanism of the excavation effect were analyzed from the borehole diameter expanding permeability, pore structure, physical property and saturation. Finally, the comprehensive utilization of mining effect judgment analysis method of gas was suggested and the excavation effect of judge true and false of a few basis was put forward. The fluid identification of K Reservoir in H Oilfield is well completed with this method. Therefore, this method can provide reference for the accurate identification of fluid types in H Oilfield and similar complex carbonate reservoirs.