Mechanical response of kerogen at high strain rates

Abstract

As the main organic component of shale, the kerogen has a direct impact on the shale reservoirs. A molecular aggregate is used to study mechanical behaviour of kerogen, of which the molecular weight distribution is rational conforming to the Gaussian distribution. The mechanical response of kerogen is obtained with different strain rates by using molecular dynamics simulations. The results show that kerogen shows material hardening and fracture strain decrease with the strain rate. In the plastic range, we analyse the causes of stress oscillation at the microscopic level, and obtain the relationship between the stress oscillation and hydrogen bond. A compressible hyper-viscoelastic constitutive model of kerogen is established, which describes the mechanical behaviour of kerogen with different strain rates. Our research provides a valuable insight in the kerogen properties, and helps to understand the mechanical behaviour of shale reservoirs from a micro-perspective.