Study Of High-precision 3D Seismic Exploration Acquisition In Dongying City Area

Along with constantly going deep into of exploring in Shengli oilfield, the exploration of complicated oil-gas reservoir and deep layer oil-gas reservoir has become more and more important. The fine exploration aiming at Dongying center apophysis has been carried on for many years, but the facts that the earth surface of Dongying city is very complicated and the purpose layer is lain pretty deeply have restricted continuously the exploration progress of this area.In 2002, after full technology demonstration combined with digital map, the agile observation system was designed, and by mixed use of vibrator and explosive source, the high precision 3D exploration has accomplished to 120 square kilometers full-cover in this area.Dongying city area is about 80 square kilometers, and there are many buildings inside it, which make much environment noise, but there are also many wide streets in direction of NS and EW, which has provided the convenience for construction of vibrator. Many villages, reservoir and aquaculture area etc around the city also increase the construction difficulty. Besides, the underground construct of this area is also very complicated, and the rupture system in mid-shallow layer is developed owing to Dongying center apophysis. At last, the deep stratum is lain very deeply (general between 3000m-8000m), so the S/N of materials in the past was not good.In the aspect of designing observation system, aiming at the surface and geology condition of this area, the geology model was designed based on the seismic and logging data before and the suitable observation system parameters are chosen by using the technology of ray tracing. At the same time, the fully using of digital map helped to scientifically set the location of shots and detectors, and the quality control was carried on in the distribution promptly to check up the cover frequencies of underground bin, azimuth and offsets to make sure the completeness of seismic data in city area(Burg,J.B,1964;Brown,A.R,1992;Sherff.W.C,1990).During the constructing course, the quality of single shot data was promoted chiefly by way of controlling of burying quality of detectors and the well drilling to avoid the stronger environment noise and the utilization of on-site processing system to the analysis promptly to datum.The scientific method design and strict field construction make better exploration effects in 3D seismic data gathering of Dongying city area, and it is shown that the resolution of mid-shallow layer data and the S/N in mid-deep layer data have been greatly improved from the single shot records and first stack profile. This example of exploration of Dongying city area accumulated valuable construction experience for seismic exploration in city area and established a good foundation for further development of high precision 3D exploration in old oilfields.