Trans-scale Numerical Study Of Two-phase Flow Characteristics In Shale Gas Reservoir

With the growth of the economic,the increasing demand of energy and the difficulties of the conventional oil and gas exploitation,the work centrality of domestic natural gas turns to the unconventional from the conventional oil and gas exploitation.Unlike the conventional structure,the prediction of the inner flow in the shale is difficult because of the tight structure and the low permeability of the shale.To explore the flow from the fracture to the pore,this paper simulated the hydraulic fracturing of multi-scale process using Fluent and COMSOL Multiphysics.This paper studied the effects of different inlet,different proppant density and different solid volume fraction for proppant deposition and found that improper inlet location may cause unsupported area.Then we compared Darcy-Stokes model and Brinkman-Stokes model when doing free/porous coupled flow and found out that Brinkman-Stokes model is better.This paper studied the permeability properties using the Brinkman-Stokes method in mesoscale and found that equivalent permeability increased with the increase of the fracture width and porosity while the percentage of fracture part of the total flow decreased with the increase of the fracture width.This paper conducted the direct numerical simulation on single phase and gas-water two phase flow in micro scale.In the single phase simulation we found that the velocity at the interface of the porous zone is faster compared with the free flow and the less the porosity,the faster the velocity is.During the process of gas-water displacement in porous media,water-water interface,water-gas interface,gas-gas interface can be found coexist at the free/porous interface.Staggered arrangement and aligned arrangement are both studied in the paper,which can find the effect of different porous media form.