Fracturing reformation techniques of reservoirs with abnormal breakdown pressure in Gaojiapu area of Jizhong sag

The reservoir in Gaojiapu area features in abnormal breakdown pressure, narrow fracture, hard sand, and sand plug. Combined with the dip log data, triaxial rock mechanical test parameters, and lab Kaiser geostress testing data, optimal design of perforation aimed at reducing breakdown pressure is conducted by using such parameters as hole diameter, density, depth, phase angle, and penetration. According to the optimized perforation plan, by employing the multistage slug fracturing technology, the combined ceramsite technology with the small and medium grain size 20~40 meshes and 30~50 meshes, and the technology of increasing the bottom hole injection pressure, the breakdown pressure is reduced successfully, the average proppant concentration and sand size of the area are enhanced greatly.