A logging identification method for Fracture cavity carbonate reservoirs based on curve reconstruction and identification research: A case study of the N oil field in the South Tur-gai Basin

Abstract Fracture cavity carbonate reservoirs are developed in the Paleozoic of N Oilfield in South Turgay Basin. The reservoir types are complex and diverse, and the heterogeneity is strong. How to accurately identify such reservoirs has become a difficult problem in exploration and development. Using a single conventional logging method to identify such reservoirs has always been a difficult point in logging interpretation. At the same time, well sections lacking core and imaging logging data also need to be accurately identified. Combined with core, thin section and imaging logging data, it is determined that there are four reservoir types and one non-reservoir type in this area. Several conventional logging curves closely related to pores and fractures are used to reconstruct the curves, and the optimized logging parameters are extracted by factor analysis to extract the main factors, which are interpreted as pore factor, fracture factor and density factor respectively. Finally, the factor score is calculated, and various reservoir and non-reservoir types are identified according to the factor score crossplot. This method is used to identify the reservoir in the fracture-cavity development section of XX well. The identification results are in good agreement with the core and imaging logging data, which provides a new method for logging identification of fracture-cavity carbonate reservoir with conventional logging data.