Study On Logging Evaluation Of Tight Sandstone Reservoirs In Xujiahe Formation In Northeastern Sichuan

The Yuanba area of The Northeast Sichuan Basin is located in the combination of North Sichuan Depression and Low structure belt in Sichuan Basin,there are many exploration layers in the vertical,and the exploration field and prospect are very broad.With the deepening of exploration process,the complexity of lithology in continental tight sandstone and diversity of reservoir types are more and more prominent,well logging data has serious multi solution and uncertainty when reflecting reservoir space and fluid properties.On the basis of fully studying on the tight sandstone formation data of Xujiahe Formation in the Yuanba area,this paper explored and established logging evaluation technique for tight sandstone reservoir in research area by using a variety of methods.The main achievements are as follows:establishing standard method for logging data of tight sandstone based on trend surface method and the lithology of intersection plate method;The characteristics of tight sandstone reservoir and logging response characteristics of Xujiahe formation are determined,and the corresponding qualitative evaluation method is established,set up quantitative calculation method of porosity and permeability aimed at tight sandstone with different lithology and reservoir type in Xujiahe Formation based on a variety of well logging models such as single mineral,double mineral and mixed framework;set up quantitative calculation method of tight sandstone saturation based on rock electricity analysis experiment,a qualitative identification template for gas reservoir in Xujiahe formation is developed;the standard of reservoir classification and evaluation is established based on the research results of the lower limit of effective reservoir of tight sandstone reservoir.The application of the logging evaluation technology in this research institute has achieved remarkable results in the Yuanba area,oil and gas exploration in the tight sandstone reservoir of Xujiahe Formation in the study area is strongly supported,and providing reference for tight sandstone oil and gas exploration in other areas of Sichuan Basin at the same time.