Re-recognition of the sedimentary environment of the GI oil layer in the large area with dense well patterns sedimentary environment recognition in Gao I of Gaotaizi Reservoir in SaZhong development region

The sedimentary environment determines the development characteristics of reservoirs, and the understanding of the sedimentary environment is a necessary prerequisite for reservoir description work. It was originally believed that the GⅠ10-20 Oil Layer was deposited in the outer front subfacies of the delta, mainly with sheet sand and no underwater distributary channels developed. However, with the densification of the well pattern, the logging curves of the GⅠ10-16 in multiple wells show typical channel characteristics and are continuously distributed in narrow strips on the plane. Through detailed analysis of coring data and fine dissection of the dense well pattern, multiple underwater distributary channel sand have been identified in the GⅠ10-GⅠ16. It is analyzed that they should be deposited in the inner front subfacies of the delta. The distribution characteristics of the sand have been characterized, and the connectivity relationship between injection and production wells has been clarified, laying a geological foundation for tapping the potential of remaining oil such as perforation and fracturing of the channel sand.