A new method for identifying and evaluating bitumen-bearing reservoirs based on conventional logging curves

Abstract

<p>Bitumen is a kind of hydrocarbon with high density and poor mobility, with similar conventional logging response characteristics to oil and gas. The identification of bitumen from logging curves has always been a difficult issue in the oil and gas industry. A series of methods have been applied to identify and evaluate bitumen-bearing reservoirs, relying on either high-cost logging projects such as nuclear magnetic resonance, or special petrophysical experiments. In most actual cases, however, these approaches are not feasible. Therefore, it is necessary to innovatively investigate the logging evaluation technology of bitumen-bearing reservoirs from conventional logging data. Combining the response mechanism of conventional neutron and density logging curves, this research constructed a bitumen identification index called N_Bitumen to qualitatively identify bitumen-bearing reservoirs. The identification coincidence rate is 93.7%. A bituminous multimineral log response volume model is established to quantitatively calculate the amount of bitumen in the reservoir. The interpretation accuracy of single well porosity logging is improved by 19.1%. Conclusively, a set of widely applied and highly accurate calculation methods for bitumen identification in reservoirs is obtained, overcoming the high cost and low feasibility of existing technologies. The purpose of effective identification and evaluation of bitumen-bearing reservoirs can be realized without major economic cost by the processing and interpretation of conventional logging data. This study is significant to the interpretation of reservoir physical properties from logging curves, reservoir effectiveness evaluation, and the optimization of field development plans.</p>