The Pore Structure Characteristics of the Chang 2 Formation in the Dongxigou Production Area of Qingpingchuan Oil Production Plant

Through detailed observation and experimental analysis of core samples from the Chang 2 reservoir in the Dongxigou mining area of Qingpingchuan Oil Production Plant, the pore types, pore structure characteristics, and reservoir physical properties, among other key parameters, have been revealed. The study found that the reservoir in this area has diverse pore types, mainly intergranular pores and dissolution pores, with uneven pore size distribution but predominantly small to medium pores. The pore connectivity is good, which is beneficial for the seepage and extraction of oil and gas. The reservoir physical properties are dually controlled by sedimentation and diagenesis, with intergranular pores being dominant, poor pore connectivity, and low permeability. Reservoir classification evaluation indicates that Type I reservoirs are mainly distributed in the Chang 211, Chang 221, and Chang 223 sublayers, while Type II and Type III reservoirs are widely distributed. Diagenesis has a significant impact on reservoir physical properties, with compaction and cementation leading to deteriorated reservoir performance, and dissolution improving reservoir storage capacity to some extent. A thorough analysis of the pore structure characteristics of the Chang 2 reservoir helps optimize development plans, improve oil and gas recovery rates, and is of great significance for promoting the sustainable development of Qingpingchuan Oil Production Plant.