Logging Evaluation of the Ordovician Carbonate Reservoir Beds in the Lungudong Region, Tarim Basin

Abstract:In recent years, great progress has been made constantly in oil and gas exploration in the Lungudong region of the Tarim Basin. However, progress has been slow in the evaluation of its main oil‐producing horizons — the Ordovician carbonate reservoir beds. Based on previous researches and on the various data such as drilling, geology and oil test, in combination with the interpretation of each single‐well imaging and conventional logging data, and through analysis and comparison, the identification methods in imaging and conventional logging for four types of carbonate reservoir beds in this region are summarized in this paper. Calculation formulas for four reservoir bed parameters, i. e. shale content, porosity, permeability and oil saturation in this region are proposed; and reservoir beds in this region are divided into three levels (I, II and III) by combining oil test data and logging data, The lower limits of the effective porosity of reservoir beds and the fracture porosity of effective reservoir beds are determined as 1.8% and 0.04%, respectively. The physical property parameters are calculated by conventional logging curves, and the most advantageous areas for reservoir development are predicted comprehensively. On the plane, the high‐value zones of reservoir bed parameters are mainly concentrated in the N‐S‐trending strike‐slip fault, the Sangtamu fault horst zone and near the LG38 well area; vertically, the reservoir bed parameters of the Yijianfang Formation are better than those of the Yingshan and Lianglitage formations.