A new method for fluid identification and saturation calculation of low contrast tight sandstone reservoir  

作　　者：Shuai Wang Ran-Hong Xie Guo-Wen Jin Jiang-Feng Guo Li-Zhi Xiao 

机构地区：[1]State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing,102249,China

出　　处：《Petroleum Science》2024年第5期3189-3201,共13页石油科学（英文版）

基　　金：funded by the National Natural Science Foundation of China (42174131)。

摘　　要：The resistivity difference between oil and gas layers and the water layers in low contrast tight sandstone reservoirs is subtle. Fluid identification and saturation calculation based on conventional logging methods are facing challenges in such reservoirs. In this paper, a new method is proposed for fluid identification and saturation calculation in low contrast tight sandstone reservoirs. First, a model for calculating apparent formation water resistivity is constructed, which takes into account the influence of shale on the resistivity calculation and avoids apparent formation water resistivity abnormal values.Based on the distribution of the apparent formation water resistivity obtained by the new model, the water spectrum is determined for fluid identification in low contrast tight sandstone reservoirs.Following this, according to the average, standard deviation, and endpoints of the water spectrum, a new four-parameter model for calculating reservoir oil and gas saturation is built. The methods proposed in this paper are applied to the low contrast tight sandstone reservoirs in the Q4 formation of the X53 block and X70 block in the south of Songliao Basin, China. The results show that the water spectrum method can effectively distinguish oil-water layers and water layers in the study area. The standard deviation of the water spectrum in the oil-water layer is generally greater than that in the water layer. The new four-parameter model yields more accurate oil and gas saturation. These findings verify the effectiveness of the proposed methods.

关 键 词：Low contrast reservoirs Fluid identification Saturation calculation Water spectrum method Conventional logging 

分 类 号：TE311[石油与天然气工程—油气田开发工程]