| Huajing area is located in the south of the Tianhuan depression in the Ordos basin,it is one of the main oil production area.In recent years,a series of major breakthroughs in the construction of tight oil and gas exploration have taken place in this area and many new oil and gas desserts were found,Huajing area has become oil and gas exploration hot spots in the Ordos Basin,but with the deepening of the exploration,the Chang6 tight reservoir with the characteristics of low porosity,low permeability and complex oil-water relationship makes the well logging low compliance rate and poor effect.In this paper,the logging curves with obvious response to the tight oil are firstly selected,the study of the correction methods of the mud invasion effect correction of the resistivity curve is carried out,then we used logging data and core experimental data to conduct the"four-features relationship" and established the reservoir parameter interpretation model and obtained the lower limit of the reservoir property.Based on the logging curves with obvious response to tight oil,we carried out the study of the identification method of the fluid content of the tight oil,finally we developed a set of fine interpretation software suitable for the Chang6 tight oil in the work area.Specific understandings are as follows:(1)According to the characteristics of the Chang6 tight oil well logging response,we found that natural gamma curve,density curve,acoustic time-difference curve,compensated neutron curve and array induction resistivity curve are obvious response to the tight oil.(2)The array induction resistivity curves of the Chang6 have a significant amplitude difference,indicating that the mud intrusion is obvious,so it is necessary to carry out mud invasion correction for the array induction resistivity.In this paper,a resistivity mud invasion correction method based on array geometric factor is adopted to match the mud intrusion and low intrusion characteristics of tight reservoirs,which is in accordance with the results of Schlumberger corrosion resistivity correction.(3)Based on "four-features relationship",the response characteristics of Chang6 tight oil well logging are determined,and then the different calculation methods of mud content and porosity are compared and analyzed,we found that the use of natural gamma value to calculate the mud content is feasible and so is the use of density to calculate porosity.The correlation between porosity and permeability is determined by analyzing the core experimental data and used to calculate the permeability of the work area.Then,using the experimental data of rock mass in the work area,the a,b,m and n values are established,and the interpretation model of high-precision reservoir parameters is established.Finally,the lower limit of reservoir property of Chang6 is established by the method of hole saturation,productivity analysis and empirical statistical analysis.The porosity is 6.4%,the permeability 0.035mD(4)According to the well logging curve which is sensitive to tight oil,a new parameter ODI is proposed to identify the fluid properties of the reservoir.Compered with the other methods,the results show that the ODI method is the best for the identification of the fluid content of the tight oil.(5)In order to integrate methods,we used Fortran programming language to form a software(Logtofi)which is suitable to the Chang6 tight oil in Huaqing area.The software is stable and the result is reliable,which satisfies the requirements of the evaluation of the logging of tight oil. |
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