A Method for Identifying Low Resistivity Reservoirs in Dongying Formation of Bozhong Oilfield

Xu Sainan;Cui Yunjiang;Bie Xuwei;Han Zhilei;Zheng Yang;Tianjin Branch of CNOOC Ltd.;

Tianjin Branch of CNOOC Ltd.

low resistivity reservoir;;inverted rhythm;;genetic mechanism;;conventional logging;;Bozhong Oilfield

To correctly identify the low resistivity oil reservoirs was of great importance for enhancing the efficiency of exploration and development.In Dongying Formation of Bozhong Oilfield there developed several sets of inverted rhythmic reservoirs,on the bottom of the inverted rhythmic reservoir there existed fine lithology and poor physical property,and the resistivity was lower on the top reservoir,it was difficult to determine the fluid properties of such low resistivity layers by conventional logging methods.Based on the analysis of genetic mechanism of low resistivity reservoir,study showed that influenced by the sedimentary rhythm control,the fine lithology and high shale content were the main factors of low resistivity reservoir on the bottom of inverted rhythmic reservoir in target zone.This paper presents a new method to study fluid identification based on sedimentary facies and sedimentary rhythm analysis.The new method is use to discriminate low resistivity reservoirs in the target zone.The results show that the ability of identifying the low resistivity reservoir is obviously improved by the method,which displays a favorable application prospect.The application ability of conventional logging data in identifying low resistivity reservoir is fully exploited.