Fine Structural Interpretation & Reservoir Prediction On B Layer In A Area

The area of interest is located in southern D depression of C basin. Even though it undergoes years of exploration and development, study level in terms of structure analysis and reservoir recognition is still relatively low. The overlapping and interaction between delta front sand bodies and nearly NS trending faults, nosing structure faults or grabens consequently result in the occurrence of various traps, which can be defined as structural trap, lithologic- structural trap and fault- lithologic trap. Some exploratory wells are drilled in lower structure and commercial oil is found from B layer. It is proved that B layer in A block is a potential developing area. On the basis of new 3D seismic acquisition in 20 xx, surrounding the production demand, a great number of faults and related structural traps have been found in the study area of this paper due to fine structural interpretation and reservoir identification. It lays a solid foundation for the next step appraisal and well placement.A set of reasonable and reliable stratigraphical classification system was established after the stratigraphic subdivision and correlation, which was based on the accumulation of a great deal of basic data, including drilling data, cored data, logging data, doghouse dope,production performance data and the achievement that made by previous workers..Fine well-seismic calibration and structural interpretation are carried out, through which the characteristic that overall regional structure is clear and the obvious zonations for structural framework were found, manifested as a southeast-dipping monocline dominated by NE-SW trending faults in the west field area, and a southwest dipping monocline controlled by NE-SW oriented faults in the east area, as well as nosing structure controlled by the middle fracture belt. Several seismic attributes sensitive to reservoir variation were optimized and seismic attributes analysis was conducted. Based on the analysis of sand body and seismic attributes, the seismic inversion method reflecting the actual geological settings of the study area was selected and the optimum parameters related to reservoir sensitivity was determined. Quantitative reservoir inversion was implemented. Accurate description of channel sand body was made. In combination with oil accumulation analysis, we realized that rock property is mainly responsible for the scale of reservoir, while the oil trapping is influenced by structure and faults. Finally, the suggestion of favorable area and well placement was made, which pointed out where to place the well and provided a basis of reserves assessment.