Evaluation of carbonate reservoir fracture on Shun Nan district in the northern slope of the central Tarim area

Accurate evaluation of reservoir fractures is a key factor to implement the effective development of oil and gas productivity prediction and volume fracturing. The formation of Shun Nan district in the northern slope of the central Tarim area is mainly due to carbonate rocks, controlled by strike slip fault and present stress, and therefore, fracture distribution is extremely complex. Combining with geology, core, well logging, and other materials, the paper analyzes features of geological structure, crustal stress, and reservoir natural fracture, and gets the qualitative relationship among geological structural trend, crustal stress direction, and attitude of reservoir natural fracture. In addition, based on the multiple regression theory, the fitting model of crustal stress size and natural fracture parameters is established. This study reveals that the reservoir of Shun Nan district in the northern slope of the central Tarim area is a microfracture development formation with a mass of high angle fracture. The direction of the insitu stress in this area approximately parallels the fault (tectonic) tendency of NEE. The fracture of this formation is affected by the early geological formation movement. The present in-situ stress presents the characteristics of complex fracture distribution. In general, fracture occurrence is more affected by current stress than the early geological formation movement, correlation between crack width and in-situ stress is the biggest, and the width, length, and porosity of fracture reflect a negative contribution to the value of the in-situ stress, but the fracture density reflects a positive contribution to the value of the in-situ stress.