RESEARCH & DISCUSSION
FANG Xixian
Based on the introduction of the common mud logging techniques and their functions in shale oil exploration and development in China, analysis is focused on the problems of using TOC as the most important parameter to evaluate oil-containing conditions of shale oil in shale oil reservoir evaluation. It is concluded that TOC parameter composition, rock pyrolysis analysis mechanism and practical data have proved that the liquid hydrocarbon content of shale oil reservoirs and the production of shale oil horizontal wells are not correlated with TOC, so it is misleading to take TOC as the necessary parameter to evaluate the oil-containing conditions of shale oil reservoirs. A new idea is proposed to evaluate the oil-containing conditions of shale oil reservoirs by replacing TOC with S1 which directly reflects the liquid hydrocarbon content of shale oil reservoirs in rock pyrolysis logging. Combined with the characteristics of shale oil accumulation and the functions of different mud logging techniques, it is concluded that: Shale oil oiliness can be judged by using rock pyrolysis parameter Tmax and regression analysis of rock pyrolysis logging data to predict crude oil density. Formation fluid pressure can be judged by gas logging net added value, aftereffect, "single peak", drilling fluid parameters and trough surface observation. The porosity obtained from multi-dimensional NMR data and gas logging regression data can be used to judge the physical properties of shale oil reservoirs. Lithofacies and fractures can be judged by core and related analysis data. Using XRD, XRF and lithology can judge the formation fracability. Based on the analyses of evaluation parameters, combined with the evaluation parameters of domestic shale oil breakthrough blocks and the analyses of related data, the evaluation parameter system of shale oil reservoirs was established.