Abstract:
China is rich in lacustrine shale oil resource which has become one of national strategic resource. As a typical representative of self-sourced petroleum resources, shale oil enrichment has the characteristic of in-situ generation and inner-sourced storage. The occurrence and production mechanism of shale oil and gas in micro/nano-scale pore-fracture system is complex. Laboratory-based device innovation and technological revolution are important driving force to promote the theoretical innovation, large-scale exploration, and effective production of lacustrine shale oil. Through summarizing the research progress and main understandings of several hotspots involving the geological evaluation of shale oil such as fine-grained sedimentation and organic matter enrichment, rock structure and mineral composition, micro/nano-scale pore-fracture system, fluid occurrence and movable fluid, and fracability and fracture propagation, it is proposed that the experimental method for geological evaluation of shale oil is changing from source rock to reservoir, from hydrocarbon generation capacity to hydrocarbon storage capacity, and from hydrocarbon expulsion capacity to hydrocarbon production capacity. At present, there are three challenges in the development of experimental techniques for shale oil evaluation. (1) It is difficult to accurately characterize the shale oil reservoirs of different scales due to fine-grained sedimentation and its complex mineral composition. (2) The mechanism of pore evolution and hydrocarbon occurrence is complex under the combined action of organic and inorganic materials so that it is very difficult to evaluate the hydrocarbon mobility. (3) It is difficult to completely reproduce the real geological conditions at the laboratory, and the accuracy of laboratory-based evaluation needs to be further improved. The future experimental method for the geological evaluation of shale oil should focus on strengthening the research of the in-situ, refined, multi-scale experimental devices and evaluation methods, the dynamic evaluation of key shale reservoir attributes, as well as the construction of field laboratory and integration of geological and engineering technology, so as to improve the accuracy of reservoir characterization and prediction based on experimental technology, as well as the application of field laboratory. The relevant research and understanding are expected to provide the technical support for the geological evaluation of lacustrine shale oil, and a reference for the research on both enrichment theory and technological innovation of mobility evaluation.