Log Interpretation Method for Water-flooded Layer with Obvious Heterogeneous Reservoir Character in K Oil Field, Central Asia
GUO Zhenhua;LIN Yaping;LI Xintong;WU Guohai;LUO Man;
Water flooded layers with sedimentary rhythm have typical log characters, except for complex rhythm. Koil field of Central Asia has several characteristics: sand grain is relatively fine, reservoirsheterogeneous character isobvious, oil viscosity is high and water flooding is serious.On the plane,reservoirs with strong heterogeneity are distributed in strips along the provenance. Vertically, as the A/S increases, the reservoir heterogeneity becomes stronger. The sandstone reservoir of K oil field is typical in Central Asia. Its pore structure is complex, and the correlation between porosity and permeability is low. As a result, it is difficult to obtain a relatively accurate permeability. Therefore, it is important to perform reasonable reservoir classification before evaluation of the flooded layer.In the resistivity-oilcolumn height cross plot of hundreds of original oil layers, the distribution characteristics of the reservoir can directly reflect the quality of the pore structure(porosity, permeability).Based on this, using the core andreconstructedcapillary pressure curve, K oilfield reservoirs can be classified into three grades on the crossplot. grade Ⅰ is mainly fine sandstone that deposits in distributary channel; grade Ⅲ is mainly argillaceous sandstone that deposits in mouth bar; grade Ⅱ is mainly silt that deposits in both distributary channel and mouth bar. On the crossplot, multivariate regressions are performed for each type of reservoir so that the disperse points are gathered into strips, thereby obtaining several key factors that determine the resistivity of the original reservoir.The performed resistivity-oil column chart can be used directly for the qualitative identification of flooded layers.Furthermore, the original resistivity of the water-flooded layer can be inverted, and Fw can be calculated by combining the relative permeability data to achieve a quantitative evaluation of the water-flooded layer.In addition, a simple method for reservoir classification is proposed only using conventional log data. After all, the applicationin 34 new wells showed that the coincidence rateof Fw is 85.3%.
【CateGory Index】： P631.81;TE34