Log Evaluation And Method Research Of Water Flooded Reservoir

After a long term flood development, many oil fields have entered the high water cut stage, the production tail of flood development. Because the Complicated geology conditions of the majority of oil-field in our country, the porcess of waterflood is very complex. So there is still high exploitable oil at the high water cut stage with high exploitation value. This needs more research of the water-flooded mechanism. It is particularly importance to figure out the changement of various parameters in the process of water floods. With the clear water-flooded mechanism, we can accurate calculate reservoir parameters, such as remainder oil saturation, irreducible water saturation, irreducible oil saturation. And accurate evaluate the water flooded layer.Because of the affection of injection water, pore structure, fluid property and oil-water distribution will change during the process of water flood. Water saturation degree aggrandizement after flooding, and complex change of the property of formation water, those changments cause variety of the formation resistivity. Because of the flushing of injection water and reservoir heterogeneity, the variety of pore structure and fluid property give great difficulty to well logging interpretation of water flooded layers.With analysis of waterflood experimental data and theory emulation research, we particularly analyzed the variety regulation of formation resistivity with the increase of water saturation, and built up calculation model of the water saturation on the formation resistivity inflection point, analyzed and evaluated impact factors of the variety regulation of formation resistivity. These works have important meaning to the research of well logging interpretation of water flooded layers.In the paper, in view of characteristics of the water flooded reservoir of Upper Ng Group in Chengdao oilfield and Nanyang oilfield, built up the interpretation models of reservoir parameters, analyzed impact factors of water cut, and built up the statistical interpretation models of water cut. Significantly improve the precision of log interpretation. The paper also emphasizes the methods of the depth correction of the core analysis data and high resolution processing of Logging curves. And we developed the corresponding software.According to the water flooding features of Chengdao oilfield and Nanyang oilfield, water flooded reservoir handling programs are exploited. From handling the real logging data, a good effect of geological application with high precision is obtained.