富油煤作为一种公认的特殊煤炭资源，储量巨大，是我国重要的战略能源。富油煤原位热解是一种摒弃传统煤炭开采，直接在地下热解提油的新技术。前人对原位注气加热研究主要集中在油页岩开采利用。地块热解后的残余热量具有重要经济效益，然而鲜见其余热利用过程研究。通过构建富油煤半焦层降温冷却的二维大尺度模型，研究了冷却介质种类、入口流速及温度、半焦层初始温度、布井方式、水平裂缝数目、加热时长和加热介质入口流速对余热利用过程的影响规律。结果表明，冷却介质流速对半焦层冷却效果提升有限；加热介质流速对平均温度上升的贡献有限。相较N2和水蒸气，CO2作为冷却介质能加快半焦层冷却。增加注气井数量有助于改善半焦层温度的均匀性、提高冷却效率，但半焦层冷却效果几乎不受注气井位置影响。双水平裂缝布置能满足有效冷却的要求。通过对半焦层冷却初始状态各参数优化，有助于了解冷却过程的温度变化规律，提高余热利用效率，为富油煤原位热注入开采全过程研究提供理论依据。

Tar-rich coal, as a recognized distinctive type of coal resource, is a crucial strategic energy in China with enormous reserves. In-situ pyrolysis of tar-rich coal is a new technology that abandons traditional coal mining and directly extracts oil from underground pyrolysis.Previous studies on in-situ gas injection heating mainly focused on the exploitation and utilization of oil shale. Although the residual heat from block pyrolysis has significant economic benefits, the process of utilizing waste heat has received little attention.A two-dimensional large-scale model of the semi-coking area cooling of tar-rich coal was built in order to analyze the influence rules of cooling medium type, inlet velocity and temperature of cooling medium, initial temperature of semi-coke area, well layout, number of horizontal cracks, heating duration and inlet velocity of heating medium on the waste heat utilization process. The results demonstrate that the flow velocity of the cooling medium has a limited effect on the cooling effect of the semi-coking area. The contribution of the heating medium velocity to the average temperature rise is limited.CO2 as the cooling medium is favorable for the cooling of semi-coking area when compared to N2 and water vapor. The temperature uniformity of the semi-coke layer and the cooling efficiency can be improved by increasing the number of gas injection wells, but the location of gas injection wells has essentially little impact on semi-coking area cooling.The double horizontal fracture arrangement is sufficient to meet the requirements of effective cooling. By optimizing the parameters of the initial state of semi-coking area cooling, it is helpful to understand the temperature variation law of the cooling process, improve the utilization efficiency of waste heat, and provide a theoretical foundation for the entire process of in-situ thermal injection mining of tar-rich coal.

0 引言

1 模型和方法

   1.1 几何模型

   1.2 网格划分和无关性验证

   1.3 模型选取和边界条件

   1.4 研究参数设置

2 结果与讨论

   2.1 半焦层余热利用过程数值模拟

   2.2 煤层原位热解及半焦层余热利用过程耦合数值模拟

3 结论