The Study On The Porosity Inversion Method Based On Pore Structure Parameter Constraint

Compared to conventional sandstone reservoirs,the difficulty of geophysical exploration techniques for hydrocarbon reservoirs in carbonate reservoirs has increased.The fundamental reason is that the rock physical model of the carbonate reservoir has undergone tremendous changes.The petrophysical model of conventional sandstone reservoirs is mainly based on the study of elastic parameters related to porosity.For the carbonate physical model,the elastic parameters are not only related to the porosity of the rock,but also related to the pore structure characteristics Related.Therefore,the resulting exploration technology of carbonate reservoirs with complex pore structure features also needs to be studied for suitability.For carbonate reservoirs with complex pore structure types,the porosity parameter is a very important parameter in reservoir description.The prediction of the porosity of conventional sandstone reservoirs is calculated by the mapping relationship of other elastic parameters.At present,for carbonate reservoirs,it is difficult to directly establish a linear relationship between the elastic parameters obtained from seismic inversion and porosity.Because there is a complex nonlinear relationship between porosity and elastic parameters.Studies have shown that for carbonate reservoirs,different pore structure types have a great influence on rock elastic parameters under the same porosity.The thesis carried out research on the elastic parameter inversion method based on the constraints of pore structure parameters for carbonate oil and gas reservoirs.By studying the basic theory of carbonate rock physics,the rock pore structure parameters were established.The rock physics model as the main controlling factor.Explored and formed a porosity inversion method and technical process based on the constraints of pore structure parameters.At the same time,the thesis completed the study of the shear wave prediction method of the carbonate reservoir logging curve under the constraint of pore structure parameters,and carried out the study of the prediction method of pores constrained by the pore structure parameters using logging data.Finally,combined with the seismic pre-stack inversion method,a porosity parameter seismic inversion process using pore structure parameter constraints is established.Based on the research of method and technology,the seismic data and logging data of carbonate reservoirs in an actual work area are used.The thesis develops the application of actual data to test the effectiveness of methods and technical processes.The actual data application results show that:(1)The rock porosity and elastic parameters of carbonate reservoirs show strong nonlinear characteristics,which are mainly affected by the changes of the rock pore structure.(2)The shear wave prediction based on carbonate reservoirs needs to fully consider the influence of pore structure parameters.The inversion strategy based on rock physics modeling is the key to the shear wave prediction.(3)The method and technical process of seismic porosity inversion based on the constraints of pore structure parameters can be applied in actual data and have good applicability.