Research And Application Of Adaptive Pore Fluid Pressure Prediction Method

In the process of exploration and development of oil and gas resources,accurate pore fluid pressure prediction can provide important support for sweet spot prediction and the formulation of drilling construction plans.The study of high-precision pore fluid pressure prediction methods is a hotspot.However,most of the current pore fluid pressure prediction methods based on logging data and seismic data use empirical formulas and experimental parameters,and have high prediction accuracy only in a small-scale local space or a small amount of stratum.The limitations of the application are obvious.In particular,their calculation parameters adopt empirical constants,and they cannot be adaptively optimized and adjusted according to changes in reservoir burial depth,thickness,lithology,porosity,permeability,fractures and other geological characteristics,and it is impossible to obtain high prediction accuracy in areas without core mechanics testing and drilling testing,so that the application of the pore fluid pressure is limited.Therefore,adjusting the pore fluid pressure calculation formula in different geological environmental conditions,optimizing the key parameters of the algorithm,and improving the calculation accuracy of pore fluid pressure are still important research directions.Eaton method is one of the popular pore fluid pressure prediction methods.This method is practical and has a good effect on the prediction of under-compacted shale.Eaton method is a typical empirical model method.The accuracy of its prediction results highly depends on empirical parameters.The empirical parameters are affected by factors such as depth and lithology.The empirical parameters of different locations are generally different.However,in conventional seismic data Eaton method pore fluid pressure prediction,a set of empirical parameters is often shared in an area,which is not good for accurate prediction of pore fluid pressure.To improve the prediction accuracy of Eaton method,adaptive control theory is introduced,and an adaptive pore fluid pressure prediction method is proposed.This method can calculate the empirical parameters corresponding to each seismic trace and use it to accurately predict pore fluid pressure,realizing the improvement of Eaton method.Based on the study of traditional pore fluid pressure prediction theories,firstly improve the shortcomings of Eaton's method,and an innovative method for pore fluid pressure prediction based on adaptive control is proposed;Secondly,complete the program compilation on C++ and parameter optimization of the algorithm,using logging data and seismic data to test the algorithm,verifying the effectiveness and applicability of the method,and forming a set of adaptive pore fluid pressure prediction methods;Finally,the adaptive pore fluid pressure prediction method is applied to the pore fluid pressure prediction of the Weiyuan shale gas target reservoir,and comprehensively evaluate the pore fluid pressure of the target reservoir in this area,and good application results have been achieved,providing a basis for the description of shale gas reservoir and analysis of oil and gas characteristics.