Numerical Simulation of the Impact of Natural Fracture on Fluid Composition Variation Through a Porous Medium

This paper investigates heat and mass transport around a cylinder featuring non-isothermal homogenous and heterogeneous chemical reactions in a surrounding porous medium. The system is subject to an impinging flow, while local thermal non-equilibrium, non-linear thermal radiation within the porous region, and the temperature dependency of the reaction rates are considered. Further, non-equilibrium thermodynamics, including Soret and Dufour effects are taken into account. The governing equations are numerically solved using a finite-difference method after reducing them to a system of non-linear ordinary differential equations. Since the current problem contains a large number of parameters with complex interconnections, low-cost models such as those based on artificial intelligence are desirable for the conduction of extensive parametric studies. Therefore, the simulations are used to train an artificial neural network. Comparing various algorithms of the artificial neural network, the radial basic function network is selected. The results show that variations in radiative heat transfer as well as those in Soret and Dufour effects can significantly change the heat and mass transfer responses. Within the investigated parametric range, it is found that the diffusion mechanism is dominantly responsible for heat and mass transfer. Importantly, it is noted that the developed predictor algorithm offers a considerable saving of the computational burden.

Section: Resultssupporting

confidence: 78%

Application of Machine Learning to Investigation of Heat and Mass Transfer Over a Cylinder Surrounded by Porous Media—The Radial Basic Function Network

Alizadeh

Abad

Fattahi

et al. 2020

Feasibility Analysis and Optimal Design of Acidizing of Coalbed Methane Wells

Guo

Chen²,

Yao

et al. 2019

Plugging is a prominent reason for production reduction in coalbed methane (CBM) wells. In order to solve this problem, authors conducted the feasibility analysis and optimal design of acidizing of CBM wells to remove the plugging in Hancheng block (H block) China. First, X-ray diffraction analysis shows that the plugging contains acid-soluble minerals and the field case indicates that acidizing effect is positively correlated with the content of acid-soluble minerals. Inspired by this, authors analyze determining factors of the content of acid-soluble minerals. Well logging parameters (DEN, AC, GR) are selected to establish a neural network model to predict the content of acid-soluble minerals. Furthermore, a feasibility criterion of acidizing of CBM wells is proposed. Then, a forward model and an inversion algorithm are proposed to diagnose the plugging. The multisolution problem of parameters inversion is solved by the Gauss–Marquardt (G-M) algorithm based on the stochastic initial value and maximum probability. Combining this method with the current numerical model of acidizing, authors present an optimal design in order to optimize the volume and injection rate of the acid. Meanwhile, by experimental study, authors propose a new acid formulation. Finally, results have been applied in the field to confirm the feasibility of the acidizing. It turns out that acidizing is an effective stimulation technology for some specific CBM wells, and the feasibility analysis and the optimal design can improve the effect of acidizing of CBM wells.

A New Method for Ultra-Low Permeability Reservoir Characterization After Water Flooding Development

Zhen-yu

Qin

et al. 2020

In order to reveal the pattern of oil–water movement during water flooding development in ultra-low permeability reservoir, flow units division and multiple methods such as rate-controlled mercury injection, nuclear magnetic resonance, water flooding in real sandstone model, permeability test are used to perform quantitative characterization of ultra-low permeability reservoir from two aspects, geological property and coupling micro-mechanism. Radius size and number-percentage of mainstream throats and moveable fluid saturation for different clusters of flow units have been characterized. Displacement types for different clusters of flow units and remaining oil distribution types have been specified. This provides a geological evidence to develop and adjust the water injection development plan. In this paper, the number-percentage of mainstream throats has been first proposed, which is a critical parameter to evaluate the difficulty of the predominant channel development process during water injection development. The quantitative characterization of the dominant seepage channel is realized.