基于烷烃气体碳同位素分馏机制的近临界水法油页岩原位开采温度-时间-转化率预测模型

烷烃气体碳同位素在能源开发动态监测中应用广泛。含水条件下有机质和水反应会引起碳同位素热力学分馏效应，因此，目前基于纯动力学分馏机制建立的碳同位素分馏模型，不适宜直接用来刻画近临界水、高温蒸汽等油页岩原位含水开采过程的烷烃气体碳同位素特征，这进一步制约了油气转化率模型的建立。本项目拟以桦甸地区陆相油页岩为研究对象，充分运用地球化学、有机质成烃动力学、数值分析等领域的理论与方法，开展多重条件下近临界水萃取油页岩实验研究，明确油气转化率随萃取温度和时间变化规律及优质油气分布范围，在揭示烷烃气体碳同位素分馏机制的基础上，构建基于含水条件下烷烃气体碳同位素分馏模型的温度-时间-转化率预测模型，实现近临界水法油页岩原位开采状态可监测。研究成果可为油页岩原位开采过程中油气转化率的动态监测提供理论依据，有利于根据转化率变化实时调整加热温度、时间等萃取方案，优化产物结构，提高采收率，降低开采成本。

Carbon isotopes of alkanes are widely used in dynamic monitoring of energy mining process. The reaction of organic matter and water will cause a thermodynamic fractionation effect of carbon isotopes. Therefore, the current carbon isotope fractionation model based on pure kinetic fractionation mechanism is not suitable for directly describing the characteristics of carbon isotope of alkanes gas from near-critical water, high temperature steam and other in-situ water extraction processes of oil shale, which further restricts the establishment of prediction model. This project intends to take the terrestrial oil shale in Huadian area as the research object, and make full use of theories and methods in geochemistry, organic matter hydrocarbon generation kinetics, numerical analysis and other fields to carry out experimental studies on near-critical water extraction of oil shale under multiple conditions. The law of change of oil and gas conversion rate with extraction temperature and time was clarified, and the high quality oil and gas distribution range. Based on revealing the carbon isotope fractionation mechanism of alkane gas, a prediction model of oil and gas conversion rate was constructed, which based on the kinetic model of carbon isotope of alkane gas under water-containing conditions. Then, the in-situ mining process can be monitored. The research results can provide a theoretical basis for the dynamic monitoring of oil and gas conversion rate during the in-situ extraction of oil shale, which is conducive to real-time adjustment of extraction schemes such as heating temperature and time according to changes in conversion rate, optimize product structure, improve recovery factor, and reduce extraction costs.