The Seismic Imaging Technology And Its Application In Geological Interpretation Of LF 13-1 Oil Field

Pearl River Mouth Basin is the largest Meso-cenozoic sedimentary basin in Northern South China Sea, and it is also an important offshore oil and gas resource base in China. The Zhu I Depression in the north has rich hydrocarbon resource, and high quality source rock with high abundance, good types of organic matter. The exploration of Zhu I Depression has started nearly 30 years, the oil and gas reserves has been proven almost 8.7x108m3 under the guidance of the theoretical results obtained at different stages by the end of 2012. Currently, it has been the most rich region of oil and gas reserves discovered in Pearl River Mouth Basin. As exploration progresses, the depression has some problems at present:First, oilfield development has come to the middle and late period and production has declined, so new discoveries are needed urgent as a production substitute. Second, the exploration target and reservoirs all concentrated in marine deposit tectonic province, most are anticline reservoirs, other types of trap have yet to be found. Third, depression’s exploration degree and proven rate is low. Forth, lack of exploration experience in new fields and some unavoidable technical problems also exist. To solve these problems, we need to integrate correlative data and combine the knowledge, technology, means in interdisciplinary fields.The main research area of this paper is Lufeng 13-1 oil field. Lufeng 13-1 oil field located in Huilu low bulge that lies on the sourth of Lufeng Sag in Zhu I Depression, and it is a anticline structure that developed on the basement uplift. Its westward is Huizhou Sag and eastward is Haifeng Sag. Structural configuration of the region is complicated. The main oil-producing formation is the Enping Formation,Zhuhai Formation and the sandstone of under section of Zhujiang Formation in Neogene.This paper makes comprehensive use of seismic processing, seismic structure interpretation and combines the logging data with lithological data to establish stratigraphic sequence in the research area in order to explain the underground geological problems effectively.Because the bad original imaging of seismic data processing, it can not accurately reflect the underground geological conditions and can’t effectively explain the actual problem, this paper rehandles with the original seismic data processing at the beginning to solve the problem of seismic profile imaging before the research of Lufeng 13-1 oil field. The key of seismic section image is the problem of signal-to-noise ratio and resolution, whether the information contained in earthquake frequency is rich, whether the characteristic of wave group is obvious and whether it can effectively reflect the actual geological conditions. This seismic data reprocessing based on the new technology, a variety of technology combination on the premise of improving the signal-to-noise ratio at the same time to improve the resolution of the profile as much as possible. They are:(1) LIFT thought for the removal and repression of prestack noise to retain the signal effectively and improve the signal-to-noise ratio at the same time; (2) by means of many combinations to remove various types of multiple wave, which mainly are underwater multiple wave, multiple wave between the layers and multiple wave of different offset in seismic trace sets to make deep-imaging quality has been greatly improved and suppress multiple wave effectively; (3) the use of asymmetric walking curved rays prestack time migration and anisotropic pre-stack depth migration, adequately solve the actual problem of stratum heterogeneity to deal with data in face unit. After the achievement of reprocessing, this paper uses the new seismic processing section to analyze the main structure interpretation and research the beneficial effect on new profile for the tectonic interpretation. Then, combined with the well data, this paper makes a structure interpretation on the new seismic profile and makes a clear ahout the corresponding time-depth on the seismic section of the reflection horizon. Using a variety of methods and combining with seismic attribution technology, this paper makes a comprehensive interpretation about horizon and the main fault structures. Similarly, studying new seismic processing section to the geophysical response changes,this paper focuses on the beneficial effect on identification and establishment of sequence. Combining with seismic data, seismic profile, well data and lithological data, this paper establishes the stratigraphic sequence of the research area and preliminary divides into secondary-order sequence and third-order sequence of the main research area and briefly analyzes division basis. Through the research, I have a new understanding of earth physics knowledge, especially the seismic processing technology and I can accurately recognize the geological meaning of the different response on seismic profile. Combined with geological thought, my various aspects understanding which is good for the future work has been improved at the same time.