高邮凹陷吴堡断裂带上白垩统赤山组低阻油藏成因分析

Genetic Analysis of K_2c Low Resistivity Reservoirs in Wubao Fault Zones of Gaoyou Sag

近年来,在高邮凹陷吴堡断裂带上白垩统赤山组发现了一批低电阻率油藏。这些油藏的储层电阻率与纯水层接近,但经试油后证明为油层。目前国内对于低阻油藏成因存在很多观点和认识,可是针对该区低电阻油层成因还尚未定论。依据该区赤山组岩心薄片粒度、压汞、重矿物、X衍射、岩心核磁共振和岩电试验等化验分析资料,从吴堡断裂带上白垩统赤山组储层微观特征研究入手,结合目前国内外对低电阻率成因的最新认识,对该区低阻油藏成因进行了深入分析,综合认为该区储层岩性细、束缚水饱和度高及粘土附加导电性是造成吴堡断裂带赤山组油层电阻率低的主要原因。该研究成果为测井识别油水层提供了理论依据,在后续勘探开发应用中效果显著。

In recent years,a number of K2c low-resistivity reservoirs have been found in Wubao Fault Zones of Gaoyou Sag.The resistivity of reservoirs was close to the water reservoirs,but they were proved to be oil reservoirs formation test.Currently,there were many views and understanding for the genesis of the low-resistivity reservoirs in China,but for the reservoirs in this area,there was not any researched result on them.Based on the core analysis of Chishan Formation,including thin section analysis,mercury intrusion,heavy minerals,X diffraction,nuclear magnetic resonance and rock-electricity laboratory analysis,by studying the microscopic characteristics of K2c reservoir in Wubao Fault Zone and in combination with the latest understanding of the causes of low-resistivity at home and abroad,the causes of low-resistivity reservoirs in this area were deeply analyzed.Comprehensive study shows that thin reservoir lithology,high immobile water saturation and thin,additional clay conductivity are the main reasons of low resistivity reservoirs.The study results provides a theoretical basis for logging recognition of oil layer from water layer,and the application results are obvious in oil subsequent exploration and development.