Well Logging Evaluation Of Es4 Reservoir In Wang146 Area Wangjiagang Oilfield

With a view to the difficulties of fluid identification due to thin oil layers, complex lithology and ultra- heavy oil reservoirs of Wang 146 area of Wangjiagang Oilfield, as well as the reality of horizontal wells being main development well and weakness of interpretation method in horizontal wells. The well logging interpretation and result validation were made in the horizontal wells based on the logging reservoir evaluation in ultra-heavy oil reservoirs with vertical wel s.As for logging interpretation, high resolution logging series and core scale logging were chosen to eliminate the influence of thin layers. Principal component analysis with the least error was used to identify lithology of research area, after being compared with contrastive analysis cross plots method and triangulation diagram method. Parameter interpretation models were made according to the lithological changes of different facies, the respectively relative errors of the calculated values of porosity and permeability and core analysis data were 4.5% and 19%. By analyzing four properties of ultra-heavy oil in research area, using electrical-physical and electrical-physical property cross plots method and applying to resistivity index to identify oil layer and water layer without the influence of lithology and water, effective fluid interpretation method was established. The accuracy of final interpretation to real productivity is 88.4%.Because of special wellbore trajectory in the horizontal wells, logging curves were under influence easily, which made it difficult to identify stratigraphic interfaces and interpret fluids. Through analyzing the effect of rock anisotropy, layer thickness/shoulder bed etc. on induction logging curves, the formula and standard plates were used to correct. According to different response features of common logging curves in interfaces, as well as the relation between horizontal well track and reservoirs, critical interfacial points were determined to solve the problems on the division of reservoirs interfaces in horizontal wells. On the basis of fluids interpretation standard in the vertical wells and the relation between horizontal well track and reservoirs, the accuracy of fluids interpretation is 82%.