Numerical Simulation of the Non-Darcy Flow Based on Random Fractal Micronetwork Model for Low Permeability Sandstone Gas Reservoirs

Abstract

Darcy’s law is not suit for describing high velocity flow in the near wellbore region of gas reservoirs. The non-Darcy coefficient β of the Forchheimer’s equation is a main parameter for the evaluation of seepage capacity in gas reservoirs. The paper presented a new method to calculate β by performing gas and con-water flow simulations with random 3D micropore network model. Firstly, a network model is established by random fractal method. Secondly, based on the network simulation method of non-Darcy flow in the literature of Thauvin and Mohanty, a modified model is developed to describe gas non-Darcy flow with irreducible water in the porous medium. The model was verified by our experimental measurements. Then, we investigated the influence of different factors on the non-Darcy coefficient, including micropore structure (pore radius and fractal dimension), irreducible water saturation ( S wi ), tortuosity, and other reservoir characteristics. The simulation results showed that the value of the non-Darcy coefficient decreases with the increase in all: the average pore radius, fractal dimension, irreducible water saturation, and tortuosity. The non-Darcy coefficients obtained by the fractal method of microparameters are estimated more precisely than the conventional methods. The method provides theoretical support for the productivity prediction of non-Darcy flow in gas reservoirs.

Influence of fluid viscosity and flow transition over non-linear filtration through porous media

“…Flow-through porous packing can be characterized by two primary parameters, i.e., the pressure drop driving the Cow and the volumetric Cux resulting due to that pressure drop or vice versa. The accurate estimation of pressure drop and Cow rate in porous media Cow extends a great amount of significance in several natural and industrial aspects including modelling of groundwater hydrology (Ma et al 2020), oil and gas exploration (Li and Chen 2020), design of tunnel drainage system (Zhang et al 2020), single or multiphase Cows through packed column (Kundu et al 2019), etc. Darcy's linear model is the most widely used approach for the modelling of Cow through porous packing.…”

Investigation on the Fracturing Permeability Characteristics of Cracked Specimens and the Formation Mechanism of Inrush Channel from Floor

“…According to Pei-Sen et al, the confining pressure had a significant effect on seepage inhibition, and the variation trend of permeability decreased with the increasing confining pressure [16]. Researchers have also investigated the failure characteristics and fracture modes of cracked rocks and some related problems [4,[17][18][19][20][21][22][23][24][25][26][27][28][29]. However, these studies still have not systematically analyzed the fracturing and permeability characteristics of cracked rock masses under different loading conditions.…”

Analytical Solution of Unsteady-state Forchheimer Flow Problem in an Infinite Reservoir: The Boltzmann Transform Approach

“…Lucas et al (2007), presented that quadratic deviation in Forchheimer law appear as a result of non-periodicity in porous media and fractures [6]. Several other authors have modelled the Forchheimer flow in porous media by employing the numerical method [7][8][9][10][11][12][13], and semi-analytical approach [14][15][16][17][18][19][20][21][22][23][24][25].…”