Study on the Main Control Factors of Mesozoic Volcanic Reservoir in Well Block 4 of K Oilfield in Laizhou Bay Depression, Bohai Bay Basin

In recent years, with the continuous discovery of Mesozoic buried hill oil and gas reservoirs in the Bohai Sea area, oil and gas discoveries have been found, but there are significant differences in production capacity. However, research on the influencing factors of volcanic rock oil and gas production capacity differences in the study area has not yet been carried out. The K oilfield in Laizhou Bay Depression is one of the buried hill oil and gas reservoirs. In order to further clarify the reservoir characteristics of the oil reservoir and provide a basis for the formulation of oilfield development plans, a systematic study was conducted on the volcanic rock facies types, physical properties, reservoir space, and main control factors of the oil reservoir using data such as rock cores, sidewall cores, and scanning electron microscopy. The results show that the Mesozoic reservoir in this area mainly develops 11 kinds of rocks, including volcanic clastic rock, pyroclastic lava, lava and sedimentary volcanic clastic rock, as well as three kinds of lithofacies, including explosive facies, volcanic sedimentary facies and effusive facies. The fourth well area is dominated by explosive facies heat wave and pyroclastic flow, and effusive facies simple lava flow; Its storage space includes pores and fractures, with pores including intergranular dissolution pores, devitrification pores, clay intergranular pores, and mold dissolution pores. The four well areas are mainly composed of intergranular dissolution pores; Cracks mainly include structural cracks and weathering cracks; The Mesozoic reservoirs in this area are mainly controlled by three factors: lithology, lithofacies, dissolution, and geological models. Based on comprehensive analysis, it is believed that the thermal wave near source facies and thermal debris flow near source facies are relatively advantageous reservoirs in the study area, laying the foundation for predicting favorable reservoirs.