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.
分类： 力学 >> 流体力学 分类： 矿山工程技术 >> 油气田井开发工程 提交时间： 2022-05-12
摘要： 真实油气藏几乎都有突变界面，建立相应的渗流数学模型，其关键是突变界面处的连接条件。已有的渗流理论已确定根据质量守恒定律，在突变界面处各相渗流速度和压力都连续（CPVCM）。但通过调研文献发现：①根据CPVCM推断的突变界面两侧的流体饱和度分布存在实际的反例；②在驱替前缘，CPVCM与Rankine-Hugoniot跃变条件矛盾；③由它推导出的数值计算格式被油藏数值模拟证明会出现非物理结果而被弃用。继而回溯了文献根据质量守恒方程推导CPVCM的过程，发现这些推导过程最终都出现指代错位，即用界面上同一质点的流速代表了界面两侧不同质点的流速，实质上预置了渗流速度连续，属于自证。接着以不可压缩流体为例，同样根据质量守恒定律和两相流达西公式推导出各相流速和压力都不连续的界面条件（JPVCM），从而建议不可压缩两相渗流应将上游权函数和总流速相等作为突变界面处的连接条件。
分类： 矿山工程技术 >> 油气田井开发工程 分类： 力学 >> 流体力学 提交时间： 2021-01-06
摘要： 多孔介质间突变界面在油气藏开发中广泛存在。传统的渗流理论认为压力和达西速度在非连续界面处是连续的，我们在以往的研究对其进行了证伪。多孔介质物性突变界面为固定界面，本文在前期不可压缩流体的基础上，以气-水两相为例，考虑流体的压缩性，建立了这类突变界面处流体压力和渗流速度的连接条件。研究结果表明，在多孔介质固定的物性突变界面：（1）总体压力必然连续，但各相流体压力可以不连续；（2）总渗流速度相等，但各相流体的渗流速度可以不连续；（3）固定突变界面与移动突变界面的连接条件不同，不能用Rankine–Hugoniot条件描述；（4）根据突变界面的连接条件以及两相达西公式根据界面两端压力以及流体分布可计算出跨物性突变界面的各相流体的流速，跨物性的突变界面的流量应取上游值
分类： 矿山工程技术 >> 油气田井开发工程 分类： 力学 >> 流体力学 提交时间： 2020-12-25
摘要： 气-液两相驱替在油气藏开发中广泛存在。传统的渗流理论认为压力和达西速度在非连续界面处是连续的，我们在以往的研究对其进行了证伪。本文在前期不可压缩流体的基础上，以气-水两相驱替为例，研究了多孔介质中移动的气-水突变界面处的压力和渗流速度的连接条件。研究结果表明，在气-水两相驱替界面处：（1）总体压连续，但流体压力可以不连续；（2）总体流速的分布可以不连续，但满足特定的函数关系；（3）流体各相渗流速度不连续。
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