汪清、农安和桦甸油页岩物理力学性质及裂缝起裂压力对比分析研究

Comparative analysis of physical and mechanical properties and fractureinitiation pressure of oil shale in Wangqing, Nong’an and Huadian

摘要:

本文主要探究了吉林省汪清、农安和桦甸地区油页岩物理力学性质的关键参数和裂缝起裂压力的取值范围及其分布特点。首先对汪清、农安、桦甸三地油页岩的抗压强度、抗拉强度、弹性模量、泊松比参数取值范围进行了对比分析，发现三地油页岩的抗压强度、抗拉强度、弹性模量、泊松比范围是相近的，由此得到吉林省油页岩抗压强度的范围是9～30 MPa，均值是15.35 MPa；抗拉强度的范围是0.3～3 MPa，均值是0.95 MPa；弹性模量的范围是0.22～9.9 GPa,均值是3.1 GPa；泊松比的范围是0.2～0.5，均值是0.33。随后，计算了三地油页岩在不同埋藏深度下的裂缝起裂压力，发现在相同埋藏深度下，汪清、农安、桦甸三地油页岩裂缝起裂压力是依次减小的；并且随埋藏深度的增加，裂缝起裂压力近似线性增大。最后，得到吉林省油页岩在不同埋藏深度下的裂缝起裂压力：当埋藏深度d=200 m时，起裂压力范围是0.5～2.3 MPa；当d=400 m时，起裂压力范围是1.0～4.5 MPa；当d=600 m时，起裂压力范围是1.6～6.8 MPa；当d=800 m时，起裂压力范围是2.1～9.0 MPa；因此，对吉林省油页岩进行水力压裂开采时，建议压力范围控制在0.5～9 MPa。

Abstract:

This paper mainly explores the key physical and mechanical parameters, and fracture initiation pressure range and distribution characteristics of oil shale in the Wangqing, Nong’an and Huadian areas of Jilin Province. Comparison and analysis of compressive strength, tensile strength, elastic modulus and Poisson’s ratio of oil shale in Wangqing, Nong’an and Huadian lead to the finding that the ranges of compressive strength, tensile strength, elastic modulus and Poisson’s ratio of oil shale are similar in Wangqing, Nong’an and Huadian of Jilin Province. The results show that the range of compressive strength of Jilin oil shale is 9 to 30MPa, and the average value is 15.35MPa; the range of tensile strength is 0.3 to 3MPa, and the average value is 0.95MPa; the range of elastic modulus is 0.22 to 9.9GPa, and the average value is 3.1GPa; the range of Poisson’s ratio is 0.2 to 0.5, and the average value is 0.33. Calculation of the fracture initiation pressure of oil shale at different burial depth indicates that the fracture initiation pressures of Wangqing, Nong’an and Huadian oil shale decrease in turn at the same burial depth. With the increase of burial depth, the fracture initiation pressure almost increases linearly. At last, the fracture initiation pressure of Jilin oil shale under different burial depth is found as: when d=200m, the range of the fracture initiation pressure is 0.5 to 2.3MPa; when d=400m, the range of the fracture initiation pressure is 1.0 to 4.5MPa; when d=600m, the range of the fracture initiation pressure is 1.6 to 6.8MPa; and when d=800m, the range of the fracture initiation pressure is 2.1 to 9.0MPa. Therefore, it is recommended that the pressure range should be controlled at 0.5 to 9MPa for the fracture initiation pressure of Jilin oil shale.