Logging Identification and Evaluation of Dominant Seepage Intervals
How to effectively identify the dominant seepage channels formed by long-term waterflooding in sandstone reservoirs is one of the difficult problems to be solved urgently at present.The identification methods of the dominant seepage channels in the existing resear-ches are mostly based on the dynamic monitoring between wells or between well groups,or the combination of dynamic and static data to evaluate and predict through complex algorithm models.In view of the strong heterogeneity of the target sand body and the reconstruction of long-term waterflood development,the permeability of the reservoir is poorly correlated with the porosity,which is mainly controlled by the characteristics of the pore structure of the reservoir.By analyzing the microscopic mechanism and leading factors of the formation of the dominant seepage intervals,the change of the microscopic pore structure and the degree of macroscopic heterogeneity of the reservoir are taken as the two major assessment factors.The comprehensive evaluation index of the dominant seepage interval was established,and then the logging characterization method of the two factors was established,and the identifi-cation and evaluation of the dominant seepage interval based on NMR and conventional log-ging data was gradually realized.Through the comparison with the actual wells,it is found that the Sd index of sand body parts with strong erosion and high flooding degree is above 20,so Sd≥ 20 is determined as the dominant seepage interval.The identification accuracy of this index for regional dominant seepage interval can reach 73％.
the preferential flowing sectionthe microscopic pore structuremacroscopic het-erogeneityconventional loggingnuclear magnetic logging
NETL
NSTL
万方数据
