共查询到18条相似文献，搜索用时 109 毫秒
1.
利用自主研发的多场耦合煤层气开采物理模拟试验系统,开展受采动影响导致工作面前方不同应力分布条件下的顺层钻孔瓦斯抽采物理模拟试验,对抽采过程中卸压区、应力集中区和原始应力区的煤层瓦斯压力、钻孔抽采流量、应力敏感系数和无因次渗透率等参数演化规律进行分析。试验结果表明,(1)在瓦斯抽采过程中钻孔周围瓦斯压力下降速率先快后慢,越靠近钻孔的瓦斯压力等压线越为密集,瓦斯流速越大,钻孔周围瓦斯压力梯度先增大后减小;(2)随着采动应力集中系数增大,煤层渗透率降低,瓦斯抽采流量减小,其中采动应力水平最大的应力集中1区瓦斯抽采流量最小,而应力水平最小的卸压区抽采流量最大;(3)应力集中区的应力敏感系数高于卸压区和原始应力区,而该区域无因次渗透率下降速率最慢。 相似文献
2.
韩城矿区碎软煤层发育,煤层透气性差,本煤层钻孔钻进困难,瓦斯抽采效果差。顶板梳状孔水力压裂技术结合了水力压裂技术和定向钻进技术二者的优势,是解决碎软低渗煤层瓦斯抽采难题的有效技术途径。在韩城矿区王峰煤矿3号煤层顶板粉砂岩中施工长钻孔并向煤层开分支,采用套管+封隔器座封的整体压裂方式进行水力压裂工程试验。钻孔总长度344 m,有效压裂长度284 m,累计注水量874.79 m3,最大泵注压力9.4 MPa。试验结束后对钻孔瓦斯抽采相关参数连续监测86 d,钻孔瓦斯抽采体积分数27%~51%,平均42.11%,钻孔瓦斯抽采纯量8.25~21.41 m3/min,平均17.02 m3/min,钻孔累计抽采瓦斯量约210万m3。与常规的穿层钻孔水力冲孔技术相比,该技术百米钻孔瓦斯抽采量提高了11.48倍,初步证明了该技术在碎软煤层瓦斯强化抽采领域的适用性。 相似文献
3.
断层对煤与瓦斯突出危险性影响较大,准确探测断层位置对预防灾害具有重要作用。目前,煤矿进行采掘作业之前,施工大量瓦斯抽采钻孔,但是这些钻孔包含的地质信息未被充分重视,为此,提出了利用穿层、顺层瓦斯抽采钻孔群探测隐伏断层的技术方法。通过建立瓦斯抽采钻孔探测断层的数学模型,计算断层面、煤层底板的三维坐标,通过绘制煤层底板等高线图及其三维图,确定断层位置、落差、产状和断层性质等基础参数。基于Matlab软件的图形用户界面（GUI）工具,编写了瓦斯抽采钻孔探测断层的软件,实现了断层信息的可视化,为准确判识断层提供了技术平台。通过钻孔定位、模型计算、图像处理、断层识别等综合技术方法,成功实现了利用瓦斯抽采钻孔进行隐伏小断层探测。 相似文献
4.
《岩土力学》2017,(6):1647-1656
利用自主研发的多场耦合煤层瓦斯抽采物理模拟试验系统,开展了不同吸附性气体抽采的物理模拟试验,探讨了煤层瓦斯抽采过程中煤储层气压、温度及煤层变形等参数的时空演化规律。结果表明:(1)煤储层气压在抽采前期下降较快并形成以钻孔为中心的气压等值面,距离抽采钻孔越远的区域煤层瓦斯流速越小,气压下降速率越低;(2)气体吸附性越强,抽采过程中的煤储层气压下降速率越低且持续时间越长;(3)煤储层温度的时间演化规律与气压基本一致,在抽采前期有显著的降低,在抽采后期受吸附态气体解吸吸热及热交换作用的影响,煤层温度出现先下降后小幅上升;(4)距离钻孔越近的区域气压下降量越大,煤层温度下降越明显,煤层所受有效应力越大,煤层变形量也越大;(5)抽采气体的吸附性越大,抽采所导致的煤层变形量越大。 相似文献
5.
针对碎软煤层顺层钻孔成孔深度浅、成孔率低、存在抽采盲区等突出问题,基于贵州省青龙煤矿煤层及顶底板岩层赋存特征,提出利用底板梳状钻孔进行碎软煤层长距离、区域瓦斯抽采与治理。首先分析了底板梳状钻孔的施工工艺原理及技术优势所在,从布孔层位、分支点位和钻孔间距的选择等方面总结了底板梳状钻孔的设计原则。通过钻进装备的优选、钻进工艺参数和钻具组合的优化,成功穿越破碎煤岩层孔段,并实现了127 mm套管全程护孔下放,在21605底抽巷施工完成了多组底板梳状定向钻孔。瓦斯抽采效果表明：底板梳状定向钻孔瓦斯抽采流量大、浓度高、衰减速度慢,单孔瓦斯抽采浓度60%～85%、抽采纯量08～25 m3/min,实现了碎软煤层瓦斯高效抽采。为碎软煤层矿井区域瓦斯抽采与治理提供了重要的借鉴。 相似文献
6.
《岩土力学》2019,(12):4581-4589
基于自主研发的多场耦合煤层气开采物理模拟试验系统,开展了不同顺层钻孔布置间距条件下的瓦斯抽采物理模拟试验,对瓦斯抽采过程中煤层瓦斯压力及抽采流量的演化规律进行了探讨。研究结果表明:煤层内不同测点的气压随着与抽采管之间距离的减小,下降速率加快;当受抽采叠加效应影响时,在相同距离条件下抽采管之间区域的气压下降速率大于外侧,且在抽采开始后该气压差异迅速到达峰值后呈下降趋势,而距离抽采管越近的区域,或随钻孔布置间距增加,叠加效应均减弱;在煤层垂直于钻孔的断面上,气压梯度与抽采瞬时流量存在幂函数关系,随着钻孔布置间距减小,或数量增加,同一位置的气压下降速率增大,抽采瞬时流量下降速率加快,累计流量增加,煤层渗透性系数ɑ值增大,说明煤层瓦斯抽采效率更高。研究结果可为现场合理布置抽采钻孔提供一定的理论依据。 相似文献
7.
针对淮北矿区松软煤巷条带消突采用“底板巷—穿层钻孔”成本高且效率低现状,采用顺层气动定向钻进技术,按钻孔设计精准控制钻孔轨迹于预抽条带煤层中,通过钻孔抽采瓦斯实现煤巷条带消突。根据淮北矿区松软煤层特性,开展煤巷条带预抽瓦斯定向孔设计、气动定向钻进装备选型、软煤定向孔成孔与护孔工艺、抽采效果评价等研究。该技术成功应用于淮北某矿Ⅲ635工作面煤巷条带消突,试验7个孔深均大于300 m钻孔,且全程下筛管,创造两淮软煤矿区顺层钻孔372 m最深记录,成功保障煤巷掘进,减少底板巷和穿层钻孔,为软煤矿区煤巷条带瓦斯高效治理探索出新方法。 相似文献
8.
煤层隐伏小断层的精细探测和准确预测,对预防煤矿地质灾害性事故至关重要。基于煤矿现行施工的穿层瓦斯抽采钻孔资料,利用Matlab数值计算和图形处理功能,通过编程计算煤层(顶)底板控制点三维坐标,绘制高精度煤层等高线图、等厚线图和三维立体图,进而实现定量预测煤层隐伏小断层位置、产状和性质。煤矿实例模型计算验证了利用瓦斯抽采钻孔资料预测煤层隐伏小断层的有效性和可行性。 相似文献
9.
松软煤层钻孔在钻进及抽采瓦斯过程中,容易发生钻孔形变、缩径、坍塌甚至堵孔等工程问题,造成瓦斯钻孔成孔率低、密封性差、服务时间短及瓦斯抽采阻力大等抽采问题。针对上述技术难题,基于松软煤层的构造演化过程,分析了自重应力、构造应力、采动应力及瓦斯应力等因素对松软煤层瓦斯钻孔稳定性的影响,得出了松软煤层钻孔的多应力耦合作用失稳机制。同时,针对松软煤层瓦斯钻孔失稳规律,提出以护孔为基础,自适应动态密封为关键的"护-封"一体化松软煤层瓦斯钻孔密封技术。工程试验结果表明,该技术可使单孔瓦斯抽采体积分数增加至90%以上,单孔瓦斯体积分数提高2~3倍,且抽采浓度稳定。 相似文献
10.
研究抽采过程中瓦斯运移特性有助于了解抽采气体来源、不同位置对抽采效果的贡献及抽采降压规律,为合理确定抽采时间、设计抽采位置和钻孔长度等提供依据。利用自主研发的多场耦合煤层气开采物理模拟试验系统,开展了卸压区不同钻孔长度条件下瓦斯抽采的物理模拟试验,分析了抽采过程中煤层瓦斯运移相对速度和方向特征。研究结果表明：抽采前期和钻孔周围区域分别是抽采量主要贡献时期和区域,瓦斯压力梯度大,流动快。卸压区瓦斯流动相对速度最快,应力集中区使得瓦斯相对流动速度衰减加速,且对原始区的瓦斯流动形成一道屏障,使其相对流动速度趋于0。随着抽采时间的增加,瓦斯相对流动速度逐渐衰减,对于瓦斯运移方向而言,抽采一旦开始便在煤层中形成了较为固定的运移通道,但在抽采后期和钻孔深部区域,由于瓦斯压力梯度小,流动缓慢,运移方向的不稳定性增强。而随着钻孔长度增加,卸压区内瓦斯相对流动速度表现出增大的趋势,因此,适当增大卸压区钻孔长度将有利于现场瓦斯开采。 相似文献
11.
针对黄陇侏罗纪煤田中硬煤层渗透性差、瓦斯抽采浓度及流量衰减速度快等问题，利用自主研发的水力压裂成套工艺设备，提出煤层定向长钻孔水力压裂瓦斯高效抽采技术，并在黄陇煤田黄陵二号煤矿进行工程应用试验。现场共完成5个定向长钻孔钻探施工，单孔孔深240~285 m，总进尺1 320 m；采用整体压裂工艺对5个本煤层钻孔进行压裂施工，累计压裂液用量1 557.5 m3，单孔最大泵注压力19 MPa；压裂后单孔瓦斯抽采浓度及百米抽采纯量分别提升0.7~20.5倍、1.7~9.8倍；相比于普通钻孔，压裂孔瓦斯初始涌出强度提升2.1倍，钻孔瓦斯流量衰减系数降低39.6%。试验结果表明:采取水力压裂增透措施后，瓦斯抽采效果得到显著提升，煤层瓦斯可抽采性增加，为类似矿区低渗煤层瓦斯高效抽采提供了技术支撑。 相似文献
12.
Gas outburst disasters and the mining technology of key protective seam in coal seam group in the Huainan coalfield 总被引：2，自引：1，他引：1
Coal and gas outburst disasters in coal seams are becoming more serious as coal mines extend deeper underground in China. To aid gas control in high-gas outburst coal seam group, this study performed research based on the geological conditions of the Xinzhuangzi coal mine in the Huainan coalfield. The laws of gas occurrence, the strength of the coal outburst, and the regional partition were studied. Simultaneously, we introduced the key protective seam mining technology and confirmed the mining sequence of coal seam groups. The results indicate that (1) each seam absorbs gas well, and the currently measured gas content is up to 15.0 m3/t. (2) Although some differences about coal seams outburst intensity remain, the differences in the same group are very small. (3) The coal seam B10 was chosen as the key protective seam and was mined first; then adjacent seams were mined from bottom to top by layer within the roof of B10 and from top-to-bottom within the floor of B10 to guarantee each adjacent coal seam received the good effects of pressure-relief and increasing permeability. (4) The main methods of gas extraction in each protected seam are surface boreholes and net-like penetrating boreholes in the floor roadway, and related technical parameters were determined according to the degree of pressure-relief in coal seam. This in situ experiment indicates a method aiding the gas control problem and guaranteeing safe and highly efficient exploitation of high-gas outburst seams. 相似文献
13.
针对我国低透气性煤层普遍存在瓦斯抽采效果差的现状,提出了利用大直径长钻孔水力压裂对煤层进行增透的技术措施,探讨了长钻孔水力压裂增透机理,并进行了煤矿井下煤层水力压裂瓦斯抽采试验。在成功施工顺层长钻孔的基础上,研发了一套适合井下水力压裂施工的快速封孔工具组合,分析了压裂过程中参数变化规律,提出了水力压裂影响范围、压裂效果和瓦斯抽采效果评价方法,并进行了考察和评价。研究表明:该技术克服了传统井下水力压裂存在的封孔质量差、压裂影响范围小等问题,压裂后煤层透气性系数提高了2.67倍,压裂最大影响半径达到了58 m,压裂后连续抽采130 d累计抽采纯瓦斯量为31.39万m3,日最高抽采量2 668 m3,瓦斯体积分数平均70.05%,百米钻孔瓦斯抽采纯量达到0.55 m3/min。 相似文献
14.
低透煤层增透效果的定量描述和评价一直处于盲目状态,使得煤矿瓦斯治理中致裂措施、瓦斯抽采不能因地制宜。增透率可反映采动或人工增透措施对煤岩体渗透特性的改变,并可定量评价煤层增透效果,其分布和演化规律可精准圈定瓦斯富集区域,指导瓦斯抽采钻孔的合理布置。在简化钻孔和裂隙模型基础上,求解了采动条件下钻孔的体积应变,提出了针对单孔的增透率计算方法;依托同煤矿塔山矿8212采面,开展现场裂隙探测试验,研究了工作面前方采动裂隙网络发育演化及卸压增透变化规律,并分析了单孔增透率随回采面推进的演化特征。结果表明：裂隙网络呈现“从无到有、从短变长、从窄变宽、不断贯通”的趋势,煤岩体单孔增透率随回采面推进呈现先逐渐上升后保持平稳的趋势,该成果有望直接优化煤矿现场瓦斯抽采孔的布置设计。 相似文献
15.
Xiang Cheng Guangming Zhao Yingming Li Xiangrui Meng Chunliang Dong Zenghui Liu 《Arabian Journal of Geosciences》2018,11(12):326
In the absence of a suitable coal seam to serve as the protective seam in deep mining, an innovative solution of using the soft rock seam as the protective seam mining has been put forward. Taking the Luling Coal Mine as the engineering background, theoretical analysis and similar simulation experiment were conducted to study the key technologies used in soft rock protective seam (SRPS) mining. This included the characteristics of the pressure-relief gas source and accumulation zone, and the pressure-relief gas extraction of the protected seam. The results show that after mining the SRPS, the pressure-relief gas rushing out of nearby coal seams has become the major gas source in SRPS mining. An omni-directional stereo pressure-relief gas extraction system was developed, which consisted of techniques such as buried pipes in the goaf, ground extraction wells, intercepting boreholes, and seam-crossing boreholes. During the investigation, the total pressure-relief gas extraction flow amounted to 29.5 m3/min, and the gas pre-extraction rate reached 66.6% for the overlying protected seams (seams 8 and 9). The investigation into the protective effects in the cut hole showed that the maximal gas pressure and content were 0.35 MPa and 4.87 m3/t, respectively. This indicated that drilling extraction boreholes in the gas accumulation zone played a key role in obtaining an improved pressure-relief gas extraction effect. Further, these findings suggested that SRPS mining (in combination with omni-directional stereo pressure-relief gas extraction technology) could turn dangerous coal seams into ones with much less gas content, and hence free from gas outburst. 相似文献
16.
对江南井田位于贵州织纳煤田西部,为高阶无烟煤赋存区,煤层发育具有层数多、厚度薄、成群分布"的特点。采用气含量测试、注入/压降试井、钻孔煤层和煤体结构分析等方法,对煤储层含气性、渗透性、储层压力和地应力等进行了系统分析。采用体积法估算了对江南井田煤层气资源量,评价了煤层气可采性和资源潜力。结果表明:对江南井田煤层气保存条件好,气含量高,资源量大,资源丰度较高;构造作用虽然破坏了煤的原生结构,但可采煤层均以碎裂结构为主,煤储层仍然保留有较好的裂隙网络,储层增渗可改造性强,具有抽采潜力。 相似文献
17.
Different parameters obtained through geophysical borehole logging using self potential, resistivity, gamma–gamma, neutron, natural gamma, and acoustic tools, help in the identification of strata and estimation of the physical, electrical, and acoustical properties of the subsurface lithology. In the coal mining industry, currently, the main application for the logs is to determine coal seam depth, thickness together with coal seam quality, qualitatively. Gamma and resistivity logging in seven boreholes at the Phulbari Coal Basin show high resistivity value and low gamma count rate data in coal seams than the interbeds. An attempt has been made to identify and characterize Gondwana coal seams to a limited extent of seam depth, thickness, and quality in seven boreholes together with draw relationship between resistivity, gamma count rate, and ash content of coal at the Phulbari Coal Basin of Bangladesh. 相似文献
18.
Although it is a well-accepted belief in the petroleum industry that horizontal well productivity can be limited by the pressure drop within the wellbore, little has been reported regarding how this pressure drop affects gas extraction from a coal seam and its further effects on mitigating coal and gas outburst dangers in coal. One of the major reasons for this scarcity is that the pressure-drop distribution in horizontal drainage boreholes is difficult to obtain. In this study, measurements of pressure drops in 54 drainage boreholes were performed in the No. 21 coal seam, which is the primary mining layer of Jiulishan Mine and poses a strong danger of coal and gas outbursts. Next, a coupled governing finite-element model, which includes the pressure drop in the borehole, Darcy flow in fractures, gas diffusion in the matrix blocks, and the dynamic evolution of the permeability of coal, was developed and implemented using a finite-element method to quantify the pressure-drop effects. Field tests of the pressure drops indicate that the pressure increases in a parabolic form with the increasing depth of the borehole, and lower outer end pressure is associated with larger pressure increments. The numerical results indicate that the pressure drop does affect the coal seam gas extraction, the pressure around the borehole increases with increasing borehole depth, and the increment of the pressure becomes larger when the borehole’s drainage effect is enhanced. However, the impact is small and can be ignored in engineering. 相似文献