Research On The Logging Evaluation Methods Of Compact Sandstone Gas-bearing Reservoir In Puguang Area

The layers' characteristic of Puguang area is compact,compared with other formations,the pore space is very small and the permeability is very poor.Affected by the source and sedimentary environment,it has the characteristics of complicated mineral constituent,complex pore structure and little difference among the different lithology on the logging responses in reservoir.It is difficult to indentify the gas zone.Take account of these problems,this paper mainly carried out studying on reservoir well-logging evaluation punctiliously targeted with the formation of Jurassic and Triassic strata,mesozoic erathem,using multiply informations of core,geology,logging,gas testing etc.Based on the actual situation of study area,the basic properties of lithology,physical property,gas-bearing,electrical characteristics pore structure features and their relationships are systematically analyzed,firstly;Then through the models of core calibration and the multimineral model,the porosity and permeanility are acquired in different layers.Based on the rock-electro parameters of the neighborhood,saturation modle was builded used Archie's formula.In addition,irreducible water saturation interpretation modle was builded by the NMR experiment irreducible water data.From the response mechanism of different reservoir space,studied the fracture identification methods and build the identification standard of different reservoir space;Based on the above research,studied the methods for gas bed identification and analyzed the applicability.At last,combining with analysis of testing data,determined the lower limit of effective reservoir porosity and the well logging evaluation standard of different reservoir space.The application shows that the new porosity model have provided more accurate porosity,the discriminant method is more effective and the fluid identify method is more accurate.The interpration coincidence rate is higher than former.The research supplies the exporation of compact sandstone in Puguang aera with the techonological support.