Compact digital rock core generation method considering particle size distribution and porosity

Abstract

The invention belongs to the fields of engineering thermophysics, chemistry, petroleum engineering and the like, and discloses a compact digital rock core generation method considering particle size distribution and porosity. The method comprises the following steps of: obtaining a spherical particle pile through a random growth expansion and contraction strategy according to the physical property parameters of a pore structure of an actual rock; achieving the simulation of the growth expansion and movement process of spherical particles, wherein the radius of the particles is continuously increased in the simulation expansion process, and if the particles are covered, the covering phenomenon is eliminated by moving the particles. When the inter-particle coverage cannot be eliminated by moving the particle position, the particle radius is contracted. According to the method, a simpler method is provided for generating the pore structure representing the compact rock core, convenience is provided for modeling of simulating the multi-phase multi-component flow migration pore structure in the porous medium, a basis is provided for deepening understanding of the pore structure and fluid flow coupling, and development of research revealing the micro-pore flow law is promoted.

Description

technical field [0001] The invention belongs to the fields of engineering thermophysics, chemistry, petroleum engineering, etc., and in particular relates to a digital core generation system based on the pore structure of porous media to realize pore-scale numerical simulations such as microscopic multi-phase multi-component flow and fluid-solid coupling. method. Background technique [0002] In the fields of engineering thermophysics, chemistry, and petroleum engineering, random spherical particle-filled sandstone cores or microscopic models composed of round particles are used as a research tool in the research of microscopic multiphase multicomponent flow, fluid-solid coupling, etc. has a very important role. Among them, the porosity of the filled core, the filling coordination number and the size distribution of the filling particles are the three main characterization parameters of the random filling of the particles. Porosity is the proportion of the total volume occ...

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Problems solved by technology

Particle position rearrangement, for example by allowing the particles to move around their initial positions, and / or by causing them to shrink or expand, can produce a denser pack core, but also cannot precisely control the size distribution in the final pack, and if rearrangement, which can also be time-consuming

There are also dynamic simulation models (such as discrete element methods), which, in addition to potentially facing the same mathematical and implementation difficulties as other traditional filling algorithms, tend to be more computationally demanding than dedicated filling algorithms because they must also Properly simulating the dynamics of the filling process, not just the final result, requires long computation times, which also slows down the simulation as particle complexity increases

[0004] In principle, the above methods cannot be satisfied at the same time: it has the characteristics of preferential filling of large particles, and can move, shrink and expand the particle size, so that it can generate denser porous media; it can control the size distribution of filling particles under the premise of satisfying compactness ; lower computation time

In terms of implementation methods, the swelling sphere algorithm adopted by the predecessors only considered the particle size distribution as an input parameter, and did not consider the limitation of porosity. However, for denser porous media, limiting the porosity of the filled core is a non-negligible control dense factor

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