G898井沙三段低电阻率油层录井综合解释评价

Comprehensive mud logging interpretation and evaluation for low-resistivity pay zones

G898井沙三段油气显示层的高分辨率感应电阻率为1．2～1．8Ω·m，与其相邻水层的电阻率非常接近，且明显低于其上下相邻泥岩层的电阻率，为典型的低电阻率特征，仅依据测井资料难以正确解释。利用气测及岩石热解、定量荧光、罐顶气轻烃色谱、热解色谱、核磁共振等录井资料，从含油丰度、储集层流体性质等方面进行深入分析后认为，该层为中孔、低渗储集层，具有一定的含油丰度，束缚流体含量较高，基本不含可动水，综合解释为油层，且原油性质为中质油。综合解释结论与试油结果一致，展示了录井资料在该类油气层的发现及评价方面的优势。

The high resolution induction resistivities for oil and gas show layers for the third interval of Shahejie group from well 898 are 1.2 to 1.8 Ω·m, it is close to the resistivities of the adjacent water layers, and obviously lower than the resistivities of the adjacent upper and lower mud stone layers, showing the typical low resistivity characteristics, so it is not easy to interpret oil and gas show layers for the third interval of Shahejie group correctly only according to wireline logging data. Making use of mud logging data, such as gas logging, rock pyrolysis, quantitative fluorescence, tank top gas lighter hydrocarbon chromatography, pyrolytic chromatography, nuclear magnetic resonance and so on, after analyzing deeply the aspects of oil-bearing richness, reservoir fluid property etc., the authors considered oil-gas show layers for the third interval of Shahejie group were middle porosity and low permeability reservoirs with a certain oil-bearing richness, irreducible fluid content are higher, and they basically didn't contain moveable water. They were oil layers through comprehensive interpretation, and the crude properties were neutral oil. The comprehensive interpretation conclusions were identical with oil testing results, which revealed mud logging superiorities in this kind of oil-gas layer discovery and evaluation.