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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。
The thermal expansion coefficient and thermal conductivity of vertical stratification and parallel stratification of oil shale in Fushun were measured by means of dilatometer and thermal conductivity analyzer. According to the test results, the thermal rupture value of oil shale under orthogonal anisotropy and physical field unidirectional coupling test. The results show that there is anisotropy in thermal expansion and thermal conductivity in the orthogonal direction of oil shale. At 25 ℃, the vertical coefficient of thermal expansion is 1.69 times that of parallel bedding, while the thermal coefficient of parallel bedding is 1.83 times of vertical bedding. With the increase of temperature, the thermal expansion coefficient fluctuates, and the thermal conductivity decreases linearly. When fractured along different bedding inclination angles, the KI values of stress intensity factor at crack tip are different, and the KI value is the largest along horizontal bedding fracturing. The concept of local effect of thermal conductivity is put forward. Higher heating rate can be obtained in the direction of lower heat conductivity coefficient and wider area of overheating than in the direction of high thermal conductivity and overheated area, The temperature changes have an impact. The research results have certain significance for the development of oil shale in situ pyrolysis mining technology.