汪清油页岩物理力学性质及裂缝起裂压力的研究

Research on Wangqing Oil Shale Physical and Mechanical Properties and Hydraulic Fracturing Pressure

摘要:

本文主要探究了吉林省汪清地区油页岩的物理力学性质及裂缝起裂压力。首先用DNS300型电子万能试验机对油页岩进行了物理力学性质的实验研究，分析并得到了油页岩的各项基本物理力学性质参数的取值范围。其中在垂直层理方向：油页岩的抗压强度范围是21～30 MPa；抗拉强度范围是1.1～3 MPa；弹性模量范围是7.1～9.9 GPa；泊松比范围是0.21～0.27；剪切模量是3.4 GPa。在平行层理方向：抗压强度范围是13～17 MPa；抗拉强度范围是0.3～0.6 MPa；弹性模量范围是1.2～1.6 GPa；泊松比范围是0.31～0.36；剪切模量是0.5 GPa。依据实验结果，选取合适参数，理论计算了汪清油页岩的裂缝起裂压力，并通过真三轴水力压裂装置进行了油页岩水力压裂实验，表明汪清油页岩裂缝起裂压力为5.34 MPa。根据理论计算与实验结果，建议汪清油页岩现场水力压裂实验的起裂压力控制在4～6 MPa。

关键词:汪清油页岩;物理力学性质;水力压裂实验;裂缝起裂压力

Abstract:

This paper mainly studied the physical and mechanical properties and the breakdown pressure of oil shale in Wangqing of Jilin Province. Firstly, the physical and mechanical properties of oil shale were studied with DNS300 electronic universal testing machine and the range of these parameters was obtained by analysis. In the vertical bedding direction, the compressive strength of oil shale is 21～30MPa, the tensile strength is 1.1～3MPa, the elastic modulus is 7.1～9.9GPa, the Poisson’s ratio is 0.21～0.27 and the shear modulus is 3.4GPa. In the parallel bedding direction, the compressive strength is 13～17MPa, the tensile strength is 0.3～0.6MPa, the elastic modulus is 1.2～1.6GPa, the Poisson’s ratio is 0.31～0.36 and the shear modulus is 0.5GPa. According to the experiment results, the breakdown pressure of Wangqing oil shale was calculated theoretically by selecting the appropriate parameters. Then the hydraulic fracturing experiments of oil shale were carried out by using true tri-axial hydraulic fracturing device, the results show that the breakdown pressure of Wangqing oil shale is 5.34MPa. On the basis of the theoretical calculation and experiment results, it is suggested that the breakdown pressure of the hydraulic fracturing experiment in the site of Wangqing oil shale should be controlled in 4～6MPa.

Key words:Wangqing oil shale; physical and mechanical properties; hydraulic fracturing experiment; breakdown pressure of hydraulic fracturing