油页岩热物理特性试验与高温热破裂数值模拟研究

 利用热膨胀仪和导热分析仪测试抚顺油页岩垂直层理和平行层理热膨胀系数和导热系数，利用试验结果，在正交各向异性、物理场单向耦合条件下进行油页岩热破裂数值试验。研究结果表明：油页岩正交方向热膨胀性能及导热性能存在各向异性。25 ℃时，垂直层理热膨胀系数为平行层理的1.69倍，而平行层理导热系数为垂直层理的1.83倍。随着温度升高，热膨胀系数起伏变化，导热系数呈线性规律降低。沿不同层理倾角压裂时，裂纹尖端应力强度因子KI值不同，沿水平层理压裂时KI值最大。提出导热局部效应概念，在油页岩导热系数较低但过热面积开阔的方向上可以获得比在导热系数高而过热面积狭小的方向上更高的升温速率，这一效应对裂缝面附近各点的温度变化规律有影响。研究结果对发展油页岩原位热解开采技术具有一定意义。

THERMOPHYSICAL EXPERIMENT AND NUMERICAL SIMULATION ON THERMAL CRACKING OF OIL SHALE AT HIGH TEMPERATURE

Thermal expansion and thermal conductivity instruments were used to measure the coefficients of thermal expansion(CTE) and thermal conductivity(TC) of Fushun oil shale in directions vertical and parallel to bedding. Experimental results were adopted in the simulation of thermal cracking based on the orthotropic assumption and one-way physical coupling. The CTE vertical to bedding was 1.69 times as much as that parallel to bedding，while the TC parallel to bedding was 1.83 times larger than that vertical to bedding direction. With the temperature increasing，the TC descended linearly while CTE fluctuated. KI varied when hydraulic fracturing dip changed，and KI reached the maximum when the dip was zero. The concept called the local effect during the thermal conducting was put forward to reflect the temperature distribution near the fractured area.