Calibration Method of Petroleum Underground Horizon Based on High Precision Gravity and Magnetic Exploration

Because the high-precision calibration results of the petroleum underground layer are of great significance for oil production efficiency, research on the calibration method of the petroleum underground layer based on high precision gravity and magnetic exploration is researched. The gravity magnetic model is used to retrieve the bedrock depth, and the results of the basement structure and sedimentary rock distribution of the gravity and magnetic geology in the petroleum underground horizon of the Tongbai basin are obtained. On this basis, the geological data, logging data, seismic data, and VSP data are comprehensively used, and the layered calibration method is used to calibrate the petroleum underground layer of the Tongbai basin. Considering the seismic datum and the core elevation in the area, the rock formation is divided by various logging curves. The average time difference and density of the divided rock layers are interpolated at equal depth intervals to obtain velocity sequences and density sequences at equal time intervals and finally realize time-depth conversion. When the drilling geological horizon is unified, the synthetic record of the seismic reflection layer is compared with the geological horizon to realize the horizon calibration of the seismic reflection layer. When the local stratification is not uniform, the seismic reflection layer is calibrated by tracking the seismic reflection layer, high-precision velocity analysis, and various synthetic records to verify the reliability of the geological horizon. The results show that the proposed method can accurately survey the geological conditions of the Tongbai basin. It detected 14 basement faults, and the NW-trending and NE-trending faults controlled the basin, while the north-south faults controlled the later evolution of the basin. The method can be used for the horizon calibration of inclined wells, which is suitable not only for anisotropic media but also for formations with a less lateral variation of local formation lithology. Moreover, its usage is flexible, and it can be corrected by multiple speed data.