Seismic Tectonic Interpretation And Reservoir Comprehensive Evaluation In Biyang Depression

The interpretation of seismic data is a very important step in the work of geophysics as well as an important process to transform the seismic data into geological language. It relates to whether the seismic data could perform itself effectively. Nowadays, the interpretation of seismic data is not only confined to routine structure interpretation, but more depends on seismic information, using advanced interpretation technologies, developing further research on the comprehensive analysis of layer’s characteristics, oil and gas’s distributing rules, and so on. The interpret of datum is the last stage of earthquake reconnaissance, it has very important meaning for achieving well geological effect.The key of expediting reconnaissance exploitation is how to distill geological information from earthquake datum quickly. The earthquake interpret system is a tool which apply geological datum to earthquake interpret effectively, it can shorten interpret cycle, offer a resort for scanning the shape of conformation, it also offer reconnoiter personnel a resort to distill geological information from earthquake datum quickly.Reservoir prediction is the core of oil and gas exploration,the techniques of reservoir seismic prediction are a comprehensive and intercross technology series, which include many methods. Seismic reservoir prediction obtains the more and more extended application along with the seismic survey technology progress. Good benefit in exploration has been achieved. The principle and the physical significance of seismic inversion for reservoir prediction also rapidly developed and demonstrated good prospects.Biyang depression locates in the south part of Henan province, It’s a Mesozoic and Cenozoic terrestrial facies lake fault depression which grows on Qinling folded zone, it is about1000km2and famous for "small and abundant". South steep slope belt and deep area of Biyang sag, which was discovered in thirty years ago, has a OIIP of1.5*108tons(1,095MMBO) and remaining recoverable reserves over OIIP of8.7*107tons(635MMBO), representing big potential and the good exploration prospect, especially in nontectonic lithology. Therefore prediction research is performed in eastern part of Biyang sag area to seek new drilling target for increased reserves. The work had obvious economic efficiency and the social efficiency.The paper discussed the local geology, the structure and the reservoir characteristic in detail.Biyang Depression is one of the lower Tertiary faulted basins. In the center and south part of the Biyang Depression, the reservoirs locate in fanned delta and braided stream delta environments, which leads to fast changes of facies and seismic velocity as well as diagenetic inhomogeneity. The reservoirs consist of thin inter beds of sandstone and mudstone. The types of traps include fault-nose, faulted block and structural lithological pattern. According to the structure characters of deep stratums, reservoir characters and variability of velocity, we use horizon calibration, integrated interpretation, fine fault interpretation and variable velocity mapping to accomplish fine interpretation of structures, and adopt log constrained inversion and seismic attributes to predict the thin interbeded reservoirs of sandstone and mudstone. After thirty years of petroleum and gas exploration, the exploration in Biyang depression enters high mature exploration period, difficulty of exploration becomes more serious, the exploration targets become more complex. To continue the exploration deeply, we have to resolve the choke points, and the unfavorable quality of seismic data having been collected is one of the choke points which affects continuing the exploration in Biyang depression deeply, By analyzing it is considered that high accuracy3D seismic ex.Taking Biyang Depression as an example, this work has done the comprehensive seismic interpretation and reservoir evaluation for the area. First of all, the detailed3D structure interpretation has been done in the study area, then three-dimensional velocity field has been established by acoustic logging data, and finally we have gotten the result maps such as To contour map, structural map and isopach map for the work area. Secondly, based on the structure interpretation, this work has extracted seismic attributes for the target layer, and then the reservoir parameters and distribution has been predicted by seismic attributes using Neural network for the mainly three oil formations in east-central Biyang Depression, the reservoir parameters include porosity, sand thickness, oil and gas distribution. Finally, according to the reservoir prediction results of the study area, the comprehensive reservoir evaluation has been completed, and four favorable target zones have been selected out.