克拉2异常高压气藏开采压力变化对储层物性的影响

为了研究克拉 2气藏是否可以采用衰竭式开采 ,以及储层岩石变形是否会对产能产生影响 ,开展了气藏开采压力变化对物性参数影响的实验模拟研究。研究表明 ,克拉 2异常高压气藏开采过程中渗透率、孔隙度、孔隙压缩系数等物性参数都随开采压力而变化 ,但是在开采压力变化范围内 ,孔隙度、渗透率变化不大 ,渗透率变化具有轻微的不可逆性。对于克拉 2气藏 ,储层岩石变形对产能影响不大 ,可以采用衰竭式开采 ,以充分发挥异常高压气藏弹性能量大的优势 ,提高开发经济效益。而孔隙压缩系数随有效压力的变化较为敏感 ,建议在进行气藏生产动态预测时把储层孔隙压缩系数考虑为压力的函数 。

煤矿深部工作面开采压力的影响因素与事故预防措施

本文分析了成家庄煤矿11301工作面开采压力的特征,探讨了影响工作面开采压力的主要因素,并结合11301工作面开采条件,开展了新型水力压裂技术防治工作。结果表明,11301工作面平均压力步距从20.6 m降至16.3 m,动载系数从1.37降至1.14,工作面顶板弱化效果显著。

分析大倾角煤层开采矿山压力显现及其控制

我国科技的不断提升,带动了各个行业的发展,各个行业在实际发展过程当中,对于资源的使用情况都非常关注与重视.众所周知,煤炭是我国最重要的能源之一,在能源结构当中扮演主要角色,占据了70%的比例,而且在未来的很长一段时间之内,煤炭作为主体能源,其地位是不会改变的.煤炭工业与经济之间有着紧密的联系和关系,我国煤炭工业发展速度较为强劲,并且取得了一定成就.因此,本篇文章主要对大倾角煤层开采矿山压力显现进行了认真分析,最后提出了控制的方法与策略,希望能够为采矿工作的高效进行奠定基础.

矿山地质环境承载力与压力定量评价

采用层次分析法进行矿山地质环境承载力与压力定量评价,分别选取地质地貌、盖层性质、水文地质、构造界面4个因素作为承载力准则层,选择土地压力、煤炭压力、水压力3个因素作为压力准则层,遴选准则层所涵盖的关键因素作为指标层建立评价指标体系。利用标准量化以及升半梯形分布函数进行指标层赋值,选用特征根法,经归一化处理计算指标层各权重值。运用承载指数与压力指数对目标层逐层进行加权计算出评价分值。以云驾岭矿为例,应用已建立的评价体系对矿山地质环境承载力与压力进行定量评价,结果表明其承载力为较高承载,压力为中压,矿山地质环境状况良好。

第一类水合物藏降压开采实验模拟

我国南海含下伏游离气的水合物储层具有实现下伏游离气和水合物分解气“两气合采”的地质条件,开采该类型水合物藏能够增加产气量,提高经济性。但目前该类型储层的开采模拟室内实验研究较少,开采规律认识不足。本文采用实验室自行搭建的三维水合物模拟装置,建立了一套含有游离气层的第一类水合物储层制备新方法,研究了水合物藏降压开采过程的产气产水特性。结果表明,采用甲烷水合物四相点以下的生产压力能有力地加快水合物分解进程,提高开采效率,当开采压力从2.95MPa降低到2.14MPa,快速产气阶段气体采收率增加10%,总开采时间缩短约38%,总采收率从73%提高到81%。当开采井井孔位于水合物层时,可能会在井孔附近出现水合物二次生成现象,从而导致开采产气速率显著降低,相比于开采井井孔位于气层,相同累积产气量的情况下生产时间延长30%左右。对比第一、三类水合物藏发现,第一类水合物藏的快速产气阶段持续20min以上,比第三类水合物藏延长一倍多,但总的气体采收率稍低。本文塑造的是气饱和的第一类水合物藏,对实际海洋水合物藏的模拟具有一定局限性,今后研究还需从实验装置尺度、分区控温方法、实验介质筛选、储层重塑稳定性等方面着手,解决储层重塑关键技术问题,为我国含下伏游离气的泥质粉砂型天然气水合物藏开采提供基础数据参考。

凝析气藏开采方式的选择

选择合适的凝析气藏开采方式是经济有效开发凝析气藏的关键。介绍了衰竭式开采和保持压力开采方式的选择条件。以YH2-3构造E+K凝析气藏为例,通过数值模拟和气藏工程分析对开采方式的合理选择作了论证。

论深矿井开采出现的问题及防治措施

在我国深矿井开采就是指埋藏在距地表一定深度的煤炭,一般大于800米。近年来我国煤矿资源随着开采深度的越来越大,给煤矿开采带来了一系列困难,例如地热高、矿山压力显现剧烈及冲击地压、煤与瓦斯突出等。本文就煤矿深部开采条件下,结合深部开采环境的特点,针对地质灾害问题,把深部开采出现的主要问题做了分析,并针对这些问题采取了相应的技术措施。

邯郸矿区矿山地质环境承载力评价

依据矿山地质环境承载力的涵义及特点,从地质环境抗扰动能力和煤炭开采压力两个方面,建立矿山地质环境承载力评价指标体系,利用层次分析法确定指标权重值.对邯郸矿区进行系统的矿山地质环境承载力评价研究,研究结果显示:不同矿井的矿山地质条件、开采方法、开采技术水平及对环境的保护力度有差异,矿山地质环境抗扰动能力和煤炭开采压力有差异.研究结果对矿业开发、地质环境保护与恢复治理具有实用价值.

“十三五”矿业工程发展战略研究

随着"十二五"规划目标的实现,从能源贡献、研究贡献等方面,对矿业工程"十二五"发展现状进行了总结。根据"十三五"规划制定的新要求与目标,分析了以矿井建设、矿山压力与开采沉陷为代表的矿业工程各领域发展规律、发展态势、发展目标及实现途径,讨论了矿业工程面临的关键问题及未来优先发展领域的研究方向。同时,从硬件措施、人才队伍建设、相关政策措施保障等方面提出了实现"十三五"矿业工程发展战略的保障措施。相信在相关政策的保障下,矿业工程定能够取得更长远的发展,矿业工程领域从业人员定能够取得更辉煌的成就。

FEM analyses of stress and deformation of a flexible inner pressure bolt

The flexible inner pressure bolt is a new kind and new structural bolt (anchor rod). A number of structural improvements and performance test have been carried out. The bolt has superior compatibility to the soft crag and the large distortion tunnel with its flexibility. In order to study its stress, deformation and interaction mechanism thoroughly, a number of large distortion calcula- tions and analyses have been carried out on the bolt by FEM (finite element method), especially with the ANSYS software, based on the updated Lagrangian law. The results show that the maximum stress of the inner wall of the bolt is consistent with an elastic analytic solution. The maximum stress on the body occurs in the vicinity of the enhancement material. The link enhancement of the body seems to be quite essential. The experimental results indicate that the maximum injection pressure in the bolt is 2.5 MPa without link enhancement and 8.3 MPa with the enhancement. This link enhancement effect is highly significant. These results provide some basis for the design, application and anchoring stress analysis of the bolt.

Computational fluid dynamics simulation on the longwall gob breathing

In longwall mines, atmospheric pressure fluctuations can disturb the pressure balance between the gob and the ventilated working area, resulting in a phenomenon known as ‘‘gob breathing". Gob breathing triggers gas flows across the gob and the working areas and may result in a condition where an oxygen deficient mixture or a methane accumulation in the gob flows into the face area. Computational Fluid Dynamics(CFDs) modeling was carried out to analyze this phenomenon and its impact on the development of an explosive mixture in a bleeder-ventilated panel scheme. Simulation results indicate that the outgassing and ingassing across the gob and the formation of Explosive Gas Zones(EGZs) are directly affected by atmospheric pressure changes. In the location where methane zones interface with mine air, EGZ fringes may form along the face and in the bleeder entries. These findings help assess the methane ignition and explosion risks associated with fluctuating atmospheric pressures.

Huge thick conglomerate movement induced by full thick longwall mining huge thick coal seam

A discrete elemental method was used to study the thickness of conglomerate layer in a full thick seam mining activities under the influence of the law, pointing out the thickness of the conglomerate at different seam mining, and during the destruction and instability of existing state of laws. At 21141 thick seam mining, the face toward the direction of separation between the thick layer of conglomerate rock and the next bit after reaching its maximum capacity due to pull from the bottom of the plastic zone, formed a stratified and hierarchical down collapse. The shape of caving area is a ''triangular block'', the length of the plastic zone and face advancement from the linear fit between the height of the plastic zone and the advancing face is a quadratic function of distance, while the top layer of thick gravel layer is the overall bending subsidence trend. Tilting the direction of the face, a thick gob of collapsed conglomerate layer is formed in the coal gob entity on both sides of the thick conglomerate at the top of the overall fracture morphology performance, thus forming a mutual extrusion of articulated block structure. The instability, separation and balance of the thick conglomerate layer in the hinged block stope stress leads to abnormal occurrence of rock burst induced by face as the major factor in the accident. This research reveals the form of stress distribution in the destroyed layer of the thick conglomerate rock, analyzes the stope law of coupling for the pressure burst behavior law for the mining work face, and the choice of preventive measures to provide a theoretical basis and implementation.

Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress coupling analysis

Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face.

Study on relation between tectonic stress and coal-mining subsidence with similar material simulation

Using a minitype and stress-type test device for similar material simulation of coal-mining subsidence, the relation between tectonic stress and coal-mining subsidence was successfully simulated, furthermore, the test period of similar material simulation was obviously shortened and the test process was more dexterous and convenient. To do simi-lar material simulation with the minitype and stress-type test device was feasible and high-efficient. Bringing two models with the same geological and mining conditions to bear lateral compressive stress and tensile stress respectively and simulating the process of underground mining, the test results indicate that: under the compressive stress, the col-lapse of the coal roof occurs belatedly and the damaged range in cover of coal seam is smaller, therefore the movement and deformation of the cover and its damage to the ground geological environment are not evident; whereas under tensile stress, the situation is contrary to which mentioned above. A conclusion was obtained from the test that the ground environment hazards in coal mining areas were controlled by the regional geo-logical tectonic stress field.

Control on mine pressure of thick and strong roof stratum movement in long wall thick coal caving face

The caving of thick and strong roof stratum causes tremendous rock pressure in mine.The results of the analysis on dynamic natures of actual measurements of some fields,of which the roof pressure can be caused by thick and strong stratum in long wall thick coal caving face,could present the relation between the collapse and movement of thick and strong roof strata and surrounding rock pressure.In order to control the roof pressure effectively,the thick and strong roof strata,can be fractured and softened previ- ously by hydraulic fracturing and low-high pressure water infusion,fracturing and softening method.The results of study can provide basis for strata control and safe management in long wall thick coal caving face.

The instability mechanics of surrounding rock-coal mass system in longwall face and the prevention of pressure bumps

According to the movement and change rules of mechanical structure of surrounding rock coal mass system during coal excavation, the mechanism of sudden instability and damage was found out. The criterions that distinguishing the occurring of the pressure bump were put forward. This criteria have been applied successfully in the comprehensive prevent of pressure bumps in Tangshan colliery.

Dynamic effects of high-pressure pulsed water jet in low-permeability coal seams

Mine gas extraction in China is difficult due to the characteristics such as micro-porosity,low-permeability and high adsorption of coal seams.The pulsed mechanismof a high-pressure pulsed water jet was studied through theoretical analysis,experimentand field measurement.The results show that high-pressure pulsed water jet has threedynamic properties.What's more,the three dynamic effects can be found in low-permeabilitycoal seams.A new pulsed water jet with 200-1 000 Hz oscillation frequency andpeak pressure 2.5 times than average pressure was introduced.During bubble collapsing,sound vibration and instantaneous high pressures over 100 MPa enhanced the cuttingability of the high-pressure jet.Through high-pressure pulsed water jet drilling and slotting,the exposure area of coal bodies was greatly enlarged and pressure of the coal seamsrapidly decreased.Therefore,the permeability of coal seams was improved and gas absorptionrate also decreased.Application results show that gas adsorption rate decreasedby 30%-40%and the penetrability coefficient increased 100 times.This proves that high-pressurepulsed water is more efficient than other conventional methods.

良庄煤矿-580m水平中央泵房保护煤柱的确定

该文主要介绍了良庄煤矿在51103W工作面开采期间应用论证分析、矿压观测等技术手段,确定-580m水平中央泵房保护煤柱尺寸的情况。并根据现场的情况,进行了技术经济效益的对比分析。

Study on gob-side entry retaining technique with roadside packing in longwall top-coal caving technology

Pointed out some technical difficulties of gob-side entry retaining with roadside packing in longwall top-coal caving technology (LTCT), and analyzed the function mecha-nism of roadside filling body. Theory analysis shows the mechanical properties of high water material fit for the feature of deformation of gob-side entry retaining in LTCT, and gob-side entry retaining in LTCT face is one of effective ways to increase the recovery ra-tio of mining district.

Trial of small gateroad pillar in top coal caving longwall mining of large mining height

Coal seams in Tashan Mine of Datong Coal Group in China average 15 m thick and have been mined by the top coal caving longwall mining method of large mining height. Mining height was 3.8 m and the top coal caving height was 11.2 m. The gateroad pillar between panels was 38 m. During retreat mining,serious bumps occurred in the gateroads on both sides of the pillar affecting safety production. Therefore,pillarless mining was experimented. Using numerical modeling and comparative study of cases of similar mining condition,it was decided to employ a 6 m wide pillar,rather than the previous 38 m wide pillar.Support system for the gateroads was designed and implemented. During gateroad development,pillar failure conditions and entry deformation were monitored. Hydraulic fracturing method was employed to cut off the K3 sandstone along the entry rib so as to reduce the abutment pressure induced during retreat mining. Support reinforcement method combining grouting and advanced reinforcement methods was proposed to insure stable gateroad ahead of mining. Methane drainage and nitrogen injection were implemented to eliminate hazards associated with mine fire and spontaneous combustion. Since the development of gateroad has just completed,and retreat mining has not begun,the effectiveness of the proposed methods is unknown at this point. However,monitoring will continue until after mining.The results will be published in a separate paper.