Formation Pressure Prediction Based On Core Data And Seismic Data

Formation pressure as a control factor of rich shale, provides the reference for the comprehensive evaluation of shale gas distribution, migration and accumulation. In the process of exploration, based on the formation pressure prediction map, we can infer the direction of hydrocarbon migration and route to guide the prospecting work. In oil and gas development phase, the formation pressure prediction provide a basis for the comprehensive evaluation of oil and gas, and provide a basis for “sweet pot” discrimination, and provided the basis for well placement. Formation pressure prediction can also help the selection of drilling parameters and drilling construction scheme, to ensure safe drilling quickly.As terms used in formation pressure is confused, we will first classify some important concepts and accurately define some confused concepts. Then, based on the burial process of rocks, we summarize and analyze on the abnormal-pressure mechanism. Then from the aspect of geological to analysis and illustrate the role of abnormal pressure in oil and gas reservoirs, and for the oil and gas migration. Finally, we analyzed the effect of abnormal high pressure for speed.Based on the studying of existing formation pressure prediction methods, the author thinks that the formation pressure prediction methods at present commonly used for the application lack of rock physic theory. Their theoretical basic are not strong enough, and those methods over-simplify the relationship between formation pressure and speed, and the understanding of effective pressure coefficient is inadequate. Therefore, this article embarks from the basic theory of rock physics, based on the laboratory core data to establish the dragon stream group of shale rock-physical model, using laboratory core data to analyze appropriate effective pressure and rock modulus relation, accurately defining the effective pressure coefficient of rock. These theories are the basis of formation pressure prediction. Integrated using of these theories, based on laboratory core data, logging data and seismic data, we can build formation pressure prediction model.Using the theory of rock physics depth trend rate, combined with litho-logy classification, we can achieve accurate formation pressure prediction based on logging data.Within the area D, the established formation pressure prediction model is used. Combine shale rock-physics model with formation data and well data to calculate theoretical formation modulus. Based on the laboratory data, we can establish the relationship between effective pressure and rock modulus, including the linear and the nonlinear relationship. We use the actual formation pressure testing data, logging data and laboratory testing data to calibrate parameter to make the model suitable for target formation. We can use the formation velocity analysis method to extract the target layer velocity spectrum. Then, we combine shale rock-physic mole with the layer velocity spectrum to predict formation pressure in area D.