Method For Obtaining Permeability Of Tight Rock And Logging Prediction Of Reservoir Productivity

In recent years,with the development and improvement of geophysical exploration technology,the development cost of tight reservoirs has been greatly reduced,however,the resource reserves of conventional reservoirs have been decreasing.Therefore,the development and utilization of tight reservoirs have been paid much attention,and have achieved some achievements,which has become a new research hotspot.The buried depth of tight sandstone is large,the maturity of the composition and structure is low,and the physical property is poor.Because of the low porosity and low permeability of tight rock,it is difficult to measure its permeability in the laboratory,the measurement period is long and the cost is expensive.But it is relatively easy to measure the velocity and resistivity data of the core evaporation in the laboratory,permeability mainly depends on the pore structure of the rock,including pore size and sorting.Therefore,using pore structure as a bridge,analyzing and studying the relationship between evaporation rate and permeability,and starting from the relationship between resistivity and relative permeability,it is of certain significance to calculate relative permeability from rock and electricity parameters.Absolute permeability and relative permeability are important parameters for productivity prediction,and accurate prediction of reservoir productivity will help to guide the rational development of tight sandstone oil and gas fields.This paper first introduces the basic geological characteristics and reservoir space characteristics of tight rock reservoir,expounds the characteristics of pore space and the basic characteristics of relative permeability curve of tight sandstone.The evaporation process of 14 rock samples was measured in the laboratory,and the T2 spectrum of 6 rock samples saturated and centrifuged were measured by nuclear magnetic resonance.On the basis of this analysis the relationship between the rock evaporation rate,T2 logarithmic average value,permeability,porosity,and we found that the overall rate of evaporation of core sample is proportional to the saturated T2 logarithmic mean value,the movable water T2 logarithmic mean value,porosity and permeability;The permeability is positively correlated with the mean pore throat radius;then set up the functional relationship between evaporation rate and permeability.From the resistivity data in calculating relative permeability curve model,put forward the improvement methods,improve the calculation accuracy of the relative permeability of oil,and on this basis,from rock electrical data of different coring direction(horizontal and vertical)from shale plunger samples to calculate the relative permeability curve of horizontal and vertical piston core samples,It is found that the water relative permeability and oil relative permeability of the core in the horizontal direction are slightly higher than those in the vertical direction.The method of obtaining anisotropy of permeability is also described in this paper.Finally,the above method is applied to the actual well,the reservoir parameters are calculated,the productivity prediction is carried out,and the prediction results are compared with the test results of the test gas,and the prediction results are still available.The innovation of this paper is mainly to analyze and discuss the relationship between permeability and core evaporation rate,and discuss the anisotropy of permeability of tight rock.