Research On Sedimentary Facies And Reservoir Heterogeneity Using Logging Data

In the middle and later stage of the exploration and development of the field, a lot of the gas and oil has been mined out, but there are still some gas and oil rested in the reservoir. In order to increase the productivity of the remaining oil and gas, the reservoir analysis is needed. The content in this paper includes the research of sedimentary facies and reservoir heterogeneity in the selected area. Most of the traditional methods about the research on sedimentary facies and reservoir heterogeneity almost stay in the geological front, but this paper analysed them by using the logging data.For the research of the sedimentary facies, the paper used a method that the curve was turned to the form of grid first, then the curve shape was identified using the self-organization neural network, in the end the sedimentary facies could be identified. The recognition capability of this method is very high, and it can remove some uncertain factors from log data. For the research of reservoir heterogeneity, firstly there was a simple comprehension on the microscopic heterogeneity using the mercury penetration curve of every well in the selected area. Secondly the areal heterogeneity was researched and analysed by using the areal distribution of porosity and permeability. Thirdly this paper illustrated the interformational heterogeneity quantitatively through calculating the interformational coefficient of heterogeneity degree. Finally, in this paper, the logging data was looked as the parameters directly, then they were used in the computation process of intraformational heterogeneous synthetic index, so the reservoir heterogeneity model could be built up.From above analysis, we conclude that:(1) According to the main mercury penetration curve of the"A"wells in a certain area of SongNan, it can demonstrate that there was intense microscopic heterogeneity in the reservoirs, and these reservoirs can be divided into three types.(2) The layers of the third interval of Qingshankou Formation of the western in a certain area of SongNan whose total facies belongs to delta front. And after the automatic identification of the self-organization neural network, the curve shape of the selected wells could be discerned. The campaniform, the mid-high infundibuliform,the mid infundibuliform,the mid-low infundibuliform and the linear shape could delegate the subaqueous branch channel, mouth bar, distal bar, sand sheet and subaqueous distributary channel.(3) According to the areal distribution of the porosity and permeability in the certain area of Song Nan, it could be known that in this area, the heterogeneity in the eastern is weak, the western is strong.(4) The interformational coefficients of heterogeneity degree of"A52","A65"and"A103"reduced ordinally. It could demonstrate that the homogeneity of the three wells is getting worse, and the heterogeneity is getting better.(5) The microfacies are very important to the intraformational heterogeneity. So it can be looked as a parameter when we calculated the intraformational heterogeneous synthetic index, and the microfacies are indentified by the curve shape. The SP, GR and AC which are provided directly by the log data are the other three parameters. They are the original well log information, and they are the origin of the porosity, permeability, interlayer distribution and shale content. So it can reflect the situation of the intraformational heterogeneity visually, and consecutively. After the calculation, this method could indentify the heterogeneity degree very well.(6) According to the reservoir heterogeneity model, the heterogeneity of the reservoirs which are on the equivalent time horizons of every well in the southwest of the western in a certain area of SongNan can be known. The heterogeneity of the sand 1 is very intensely., but the heterogeneity of the sand 2 is very weak.This approach in the paper that the sedimentary facies and reservoir heterogeneity could be analysed by using logging data have achieved good results in practical applications. It could combine the Geophysical logging and Geology into a unit.grately. Especially the heterogeneity can be characterized in quantification by using the logging data, it can reflect the situation of the reservoir heterogeneity more straightforwardly and more continuously.