Determination of elastic constants of anisotropic heavy petroleum product using molecular dynamics simulation

Abstract

For the purpose of experimental verification of the assumption that the elastic properties of heavy petroleum can be characterized by a matrix of elasticity for a transversely isotropic medium, molecular dynamics simulation studies were performed. It is shown that the main structural elements of heavy petroleum are some saturated hydrocarbons, resin-solvated asphaltenes and self-associated asphaltenes. The obtained numerical results of the Young's modulus, shear modulus and Poisson's ratio in a wide temperature range for these compounds suggest that their elastic properties are closer in nature to the properties of solids, rather than amorphous entities. The method presented for determining the elasticity of a complex material in this paper can be found convenient and sufficiently accurate. This is so, since by analyzing the molecular composition of a complex compound and defining the main structural elements of it, properties of each of them can be estimated separately, in a first place, and then a general result can be derived for a substance as a whole. Numerical results obtained in this research may be useful for those who are interested in heavy petroleum fractions rheology, and those who perform numerical studies in petroleum hydrodynamics and acoustics.