Inversion Of Two-phase Media Reservoir Parameters

The existing geophysical processing methods are mostly based on single-phase media.As the study progresses,a detailed description of the oil and gas reservoirs is becoming increasingly important.Oil and gas reservoirs are dominated by sandstone and carbonate rocks,which are generally composed of solid and stream phases.If the solid medium is analyzed only,the existing single-phase medium theory can meet the processing requirements.To analyze the skeleton,solid particles and fluid in the sandstone reservoir,the medium of study is changed from single-phase medium to double Phase media,the traditional theory of elastic wave in the treatment of this model is not established.Therefore,it is necessary to propose a two-phase dielectric theory to describe in detail the structure of the underground geological body,the nature of the fluid and the overall effect of the geological structure.As a result of the more accurate description of the reservoir,so to introduce more parameters to accurately describe the reservoir.Throughout the domestic and foreign,dual-phase media theory has become the forefront of geophysical research.This paper analyzes and summarizes the domestic and foreign research on the theory of biphase media,combined with the actual needs,studied the propagation law of seismic waves in biphasic medium,and established the basic geophysical model.Based on the Mou equation,the basic biphasic medium theory reflection and transmission equations are established.The Biot model and BISQ model are used to describe the reservoir parameters quantitatively,and the relationship between the physical parameters of the rock is established,which is the theoretical basis for the reservoir parameter inversion.Reservoir parameter inversion is an important geophysical problem in predicting oil and gas reservoirs.This problem can be regarded as a nonlinear multi-parameter optimization problem,in which the petrophysical model attributes include the velocity of P-wave and S-wave,and the reservoir parameters include porosity,water saturation,permeability and so on.Because of the complexity and non-linear relationship between the two-phase media reservoirs,the conventional linear inversion can not be effectively obtained inversion results,and the genetic algorithm and other random methods have global search ability,but there are shortcomings of local search ability weak and premature convergence.In order to solve this problem,a new adaptive selection operator and a hybrid crossover operator are used to achieve real global coding capability,which can prevent premature convergence.Numerical experiments show the validity of the search for real number coding genetic algorithm.Finally,the content of this paper is applied to the actual seismic data,and the actual effect is explained and analyzed,and the results are compared with the logging data.