Mixed sedimentary patterns of Sha1 and Sha2 members in A oilfield of Bohai bay basin

Starting from the petrological characteristics and combining with the analysis of paleogeomorphology and sedimentary dynamics, the mixed sedimentary patterns of Sha1 and Sha2 members in A oilfield in Bohai bay basin were analyzed. The results show that the fan delta deposits are mainly developed in Sha1 and Sha2 members of oilfield A, and oolitic shoal, bioclastic shoal, clastic shoal and mixed shoals are also developed. Many sedimentary facies types existed at the same time are the environmental conditions for the formation of mixed deposition. According to the characteristics of lithologic association and spatial distribution, the mixed sedimentary patterns in the study area are divided into four types, namely, facies mutation mixed deposition, facies transition zone mixed deposition, mixed deposition dominated by clastic facies and mixed deposition dominated by carbonate facies, among which the mixed deposition dominated by clastic facies and the mixed deposition dominated by carbonate facies are the main mixed sedimentary types in the study area.