Alternating Thin Reservoir Seismic Prediction Of Third Member Of Shahejie Formation In Rongshengpu Depression

The dissertation is a research on predication and estimation of favorable reservoirs, in which the researched subject body is the Third Member of Shahejie Formation in Rongshengpu Depression. Based on large mounts of cores data, logging data, and seismic data, and having done the research on the region's depositional system, it is considered that alluvial fan, under-water fan, delta, fan delta are mainly developed in this area. It is multiple lithosomic bodies that make the reservoirs developed very well, but single formation inside is thinker, and there are alternating thin reservoir in vertical, the lithology changes greatly in lateral. In short, it is strong heterogeneous in this area.In order to apply the seismic data to go further into the estimation in this area, this dissertation has deeply expounded the seismic convolution, Also, based on the many geology characters, including thicker formation, multiply intercalcated reservoir, fast pinch out in lateral and so on, combined with the shale velocity and density, there are three kinds of geology models have been built up: 1.monolayer wedge model; 2.double wedge model; 3.multiple wedge model. We have done forward modelings using 30 Hz wavelet in the above 3 models individually. By analyzing the forward modeling results, It has analyzed in detailed the relationship on the seismic reflection features, including the amplitude total and the main frequency, versus the wedge model total thickness, having built up the estimating models for such thin formations. However the wedge total thickness changed, the two thicknesses have fine correlatability. Therefore, having done some crossplot analyses of the seismic reflection (total amplitude and main frequency) and reservoir thickness, and getting the fitting equations, building up the reservoir thickness estimating model, it is the whole process to do the thickness estimation.After the discussion on the reservoir thickness estimation, it is preciously analyzed various reversion methods, and whose individual advantages and whose application conditions. Also, we have finished the acoustic impedance inversion in the member 3 of the Shahejie Formation in the Rongshengpu Depression. Based on the relationship of logging density, velocity with the impedance, the porosity model transferred by impedance has been built up. The geostatistics methods have been used to calculate the constants applied in the reservoir porosity and impedance models. Then, based on such model, the impedance data survey could be transferred into porosity survey and such relationship is used to forecast the properties distribution in the target formations. This dissertation is based on the sufficient studies on the domestic and international seismic technology development, aiming at practicing the reservoir thickness forecast, property estimation, and the oil&gas formation laws so on, having expounded and analyzed the seismometric, the reversion, compaction correction theory as well as whose application conditions and so on. After building up the transfer models among which one is transferred from absolute amplitude total in the seismic reflection to reservoir thickness and the other is transferred between impedance and reservoir properties, it has gotten many achievements in this region, combing with the structures, sedimentation and the gas&oil formation laws, and many forecast areas have proved to be true reservoir.In conclusion, with the study on the reservoir thickness distribution estimated by the seismic parameters as well as the reservoir properties estimated by the impedance conversion, aiming at the thin and intercalcated formations in the Member 3 of Shahejie Formation, this dissertation has found a suit of effective methods and skills to estimate the reservoir parameters in the subtle traps, which improved the seismic estimation theory to a high level.