Processing Method Study Of Complex Structure And Application

In the past dozens of years, Biyang depression and Yanqi basin have entered into high mature stage of exploration. However, with the deep development of exploration, the difficulty in complex structure becomes greater and greater, while the key factor of successful exploration lies in the precise imaging of complex structures.In order to improve exploration efficiency and decrease exploration risks, the research in blocks of the complex structures have been carried out and the imaging distortion caused by conventional time migration has been analyzed theoretically. The results indicate the necessity of precise imaging in complex structures, and point out the research in velocity field should be strengthened, the precise subsurface geological model should be established and the imaging precision could be enhanced through migration imaging with the method of wave equation pre-stack depth migration.Because of fault development, big changes of formation lithology and great variety of stratum velocity in vertical and horizontal direction, the conventional exploration methods could not applied in complex structure. In accordance with its geological characteristics in Biyang depression and Yanqi basin, starting from the geologic forward modeling, geologic model of known complex structure should be established. With the technique of forward modeling, pre-stack depth migration, the precise imaging method of complex structure among different migration imaging methods, has been confirmed. After that, the key techniques in the processing of pre-stack depth migration such as de-noising, static correction, model building, accurate velocity and model optimization have been studied, and the accurate migration imaging results could be finally obtained when selecting the applicable treatment scheme applied with the seismic data in complex structures.By using the pre-stack depth migration technique, seismic data in Biyang depression and Yanqi basin have been processed and highly precise migration imaging results have been reached. Through interpretation on those processed results, new idea of the complex structure has been formed, which confirms two favorable prospects for drilling: XQ43 well in Xinzhuang area of Biyang depression and T301well in Bendong area of Yanqi basin. After exploratory drilling, 21m/5 and 84.4m/4 oil layers have been separately drilled in those two areas. The proven geologic reserve is proved to be 10million tons and good economic benefits has been received.