分类： 矿山工程技术 >> 矿山工程技术其他学科 提交时间： 2024-07-08
摘要： Simulation of subsurface energy system involves multi-physical processes such as thermal, hydraulical, andmechanical (THM) processes, and requires a so-called THM coupled modeling approach. THM coupled modelingis commonly performed in geothermal energy production. However, for hydrocarbon extraction, we need toconsider multiphase flow additionally. In this paper, we describe a three-dimensional numerical model of non-isothermal two-phase flow in the deformable porous medium by integrating governing equations of two-phasemixture in the porous media flow in the reservoir. To account for inter-woven impacts in subsurface condi-tions, we introduced a temperature-dependent fluid viscosity and a fluid density along with a strain-dependentreservoir permeability. Subsequently, we performed numerical experiments of a ten-year water flooding pro-cess employing the open-source parallelized code, OpenGeoSys. We considered different well patterns with colderwater injection in realistic scenarios. Our results demonstrate that our model can simulate complex interactions oftemperature, pore pressure, subsurface stress and water saturation simultaneously to evaluate the recovery per-formance. High temperature can promote fluid flow while cold water injection under non-isothermal conditionscauses the normal stress reduction by significant thermal stress. Under different well patterns the displacementefficiency will be changed by the relative location between injection and production wells. This finding hasprovided the important reference for fluid flow and induced stress evolution during hydrocarbon exploitationunder the environment of large reservoir depth and high temperature.
分类： 矿山工程技术 >> 矿山工程技术其他学科 提交时间： 2024-07-08
摘要： Rockburst is a phenomenon where sudden, catastrophic failure of the rock mass occurs in underground deep regions or areas with high tectonic stress during the excavation process. Rockburst disasters endanger the safety of people’s lives and property, national energy security, and social interests, so it is very important to accurately predict rockburst. Traditional rockburst prediction has not been able to find an effective prediction method, and the study of the rockburst mechanism is facing a dilemma. With the development of artificial intelligence (AI) techniques in recent years, more and more experts and scholars have begun to introduce AI techniques into the study of the rockburst mechanism. In previous research, several scholars have attempted to summarize the application of AI techniques in rockburst prediction. However, these studies either are not specifically focused on reviews of the application of AI techniques in rockburst prediction, or they do not provide a comprehensive overview. Drawing on the advantages of extensive interdisciplinary research and a deep understanding of AI techniques, this paper conducts a comprehensive review of rockburst prediction methods leveraging AI techniques. Firstly, pertinent definitions of rockburst and its associated hazards are introduced. Subsequently, the applications of both traditional prediction methods and those rooted in AI techniques for rockburst prediction are summarized, with emphasis placed on the respective advantages and disadvantages of each approach. Finally, the strengths and weaknesses of prediction methods leveraging AI are summarized, alongside forecasting future research trends to address existing challenges, while simultaneously proposing directions for improvement to advance the field and meet emerging demands effectively.
分类： 矿山工程技术 >> 矿山工程技术其他学科 提交时间： 2024-07-08
Wenjie Xu
Yingtao Hu
Yunmin Chen
Liangtong Zhan
Ruiqi Chen
Jinlong Li
Duanyang Zhuang
Qingdong Li
Ke Li
摘要： Hyper-gravity experiment enable the acceleration of the long-term transport of contaminants through fractured geological barriers. However, the hyper-gravity effect of the solute transport in fractures are not well understood. In this study, the sealed control apparatus and the 3D printed fracture models were used to carry out 1 g and N g hyper-gravity experiments. The results show that the breakthrough curves for the 1 g and N g experiments were almost the same. The differences in the flow velocity and the fitted hydrodynamic dispersion coefficient were0.97-3.12% and 9.09-20.4%, indicating that the internal fractures of the 3D printed fracture models remained stable under hyper-gravity, and the differences in the flow and solute transport characteristics were acceptable. A method for evaluating the long-term barrier performance of low-permeability fractured rocks was proposed based on the hyper-gravity experiment. The solute transport processes in the 1 g prototype, 1 g scaled model, and N g scaled model were simulated by the OpenGeoSys (OGS) software. The results show that the N g scaled model can reproduce the flow and solute transport processes in the 1 g prototype without considering the micro-scale heterogeneity if the Reynolds number (Re) � critical Reynolds number (Recr) and the Peclet number (Pe) � the critical Peclet number (Pecr). This insight is valuable for carrying out hyper-gravity experiments to evaluate the long-term barrier performance of low-permeability fractured porous rock.
分类： 矿山工程技术 >> 矿山工程技术其他学科 提交时间： 2024-07-08
摘要： The key to achieving rockburst warning lies in the understanding of rockburst precursors. Considering the correlation characteristics of rockburst acoustic emission (AE) parameters, a self-organizing map neural network (SOMNN) based method for rockburst precursor inversion was proposed. The feature of this method lies in acyclic data segmentation iteration process based on the thinking of "interference signal screening", "key signal extraction", and "precursor signal inversion". The rationality of this method has been verified in three groups of rockburst experiments. The results revealed that rockburst AE precursor signals consist of a series of signals characterized by long duration, high energy, low average frequency, high energy amplitude, and low peak frequency. Subsequently, potential value in long term rockburst warning of the precursor obtained in this study was shown via the comparison of conventional precursors. Finally, a preliminary interpretation for rockburst precursor was proposed under the framework of AE parameters physical significance, and it is revealed that AE precursor signals are likely linked to the creation of large-scale tensile cracks before rockburst
分类： 矿山工程技术 >> 矿山工程技术其他学科 提交时间： 2024-07-08
摘要： Broken coal and rock (BCR) are an important component medium of the caving zone in the goaf (or gob), as well as the main filling material of fault fracture zone and collapse column. The compaction seepage characteristics of BCR directly affect the safe and efficient mining of coal mines. Thus, numerous laboratory studies have focused on the compaction seepage characteristics of BCR. This paper first outlines the engineering problems involved in the BCR during coal mining including the air leakage, the spontaneous combustion, the gas drainage, and the underground reservoirs in the goaf. Water inrush related to tectonics such as faults and collapse columns and surface subsidence related to coal gangue filling and mining also involve the compaction seepage characteristics of BCR. Based on the field problems of BCR, many attempts have been made to mimic field environments in laboratory tests. The experimental equipment (cavity size and shape, acoustic emission, CT, etc.) and experimental design for the BCR were firstly reviewed. The main objects of laboratory analysis can be divided into compression tests and seepage test. During the compaction test, the main research focuses on the bearing deformation characteristics (stress-strain curve), pore evolution characteristics, and re-crushing characteristics of BCR. The seepage test mainly uses gas or water as the main medium to study the evolution characteristics of permeability under different compaction stress conditions. In the laboratory tests, factors such as the type of coal and rock mass, particle size, particle shape, water pressure, temperature, and stress path are usually considered. The lateral compression test of BCR can be divided into three stages, including the self-adjustment stage, the broken stage, and the elastic stage or stable stage. At each stage, stress, deformation, porosity, energy, particle size and breakage rate all have their own characteristics. Seepage test regarding the water permeability experiment of BCR is actually belong to variable mass seepage. While the experimental test still focuses on the influence of stress on the pore structure of BCR in terms of gas permeability. Finally, future laboratory tests focus on the BCR related coal mining including scaling up, long term loading and water immersion, mining stress path matching were discussed.
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