提高回采工作面瓦斯抽放率的途径

通过对已试抽工作面的瓦斯抽放效果分析,对抽放钻孔直径、钻孔间距、抽放负压、封孔深度等直接影响瓦斯抽放率的因素进行了研究改进.探寻了戊组煤层钻孔瓦斯涌出规律,并提出了适合戊组煤层的合理瓦斯抽放参数.     

提高回采工作面瓦斯抽放率的途径

通过对已试抽工作面的瓦斯抽放效果分析 ,对抽放钻孔直径、钻孔间距、抽放负压、封孔深度等直接影响瓦斯抽放率的因素进行了研究改进 .探寻了戊组煤层钻孔瓦斯涌出规律 ,并提出了适合戊组煤层的合理瓦斯抽放参数 .     

长平矿“立体式”瓦斯抽采模式的探索与实践

瓦斯抽放是防治煤矿瓦斯灾害事故的根本措施,长平矿经过几年的探索实践,逐步形成了煤层瓦斯抽放、地面钻井抽放及开掘底板岩巷穿层钻孔抽放等独具特色的立体式瓦斯抽放模式,多措并举,大大降低了煤层的瓦斯含量及矿井瓦斯涌出量,为进一步提高矿井瓦斯抽放率及瓦斯治理技术奠定了坚实基础．     

低透气性煤层的瓦斯抽采工艺研究

瓦斯抽放是解决矿井瓦斯涌出、防治瓦斯超限的有效方法,其效果的好坏主要由预抽钻孔参数及煤层透气性系数决定.以阳煤集团开元公司五矿为实验基地,确定了矿井采面瓦斯抽采合理的工艺参数和封孔技术.通过改变预抽钻孔参数克服了煤层透气性低产生的问题,同时对矿井的瓦斯抽放规律进行了研究.通过优化实验方案,使瓦斯抽采效果明显改善,确保了工作面的安全生产.     

超高压水力割缝强化抽采瓦斯技术研究

水力割缝是一种重要的强化瓦斯抽采增透技术,现已开始在低透气性突出煤层应用。为了进一步考察其实际效果,选取新集二矿1煤组220112工作面底抽巷实施了100 MPa超高压水力割缝试验。试验结果表明:割缝后,瓦斯抽采纯量平均0.77 m3/min,是未割缝钻孔的瓦斯抽采纯量(0.34 m~3/min)的2.26倍;1煤层组瓦斯抽采钻孔抽采30、60天的抽采有效半径为5 m、7.5 m,极限抽采半径为8 m,相比水力冲孔、未割缝钻孔抽采有效半径显著增加,超高压水力割缝强化抽采瓦斯技术具有广泛的应用前景。     

地面钻井抽放上覆远距离卸压煤层气试验研究

通过模拟及实测,对下保护层开采后其上覆远距离煤卸压效果进行了研究,并在淮北桃园矿开展了地面钻井抽放上覆远距离卸压煤层气试验。结果表明,下解放层开采后其上覆远距离煤层能充分卸压,将地面抽放钻井打到采动裂隙“Ｏ”形圈内,可将其卸压煤层气大面积抽放出来,为我国煤层气开采提供了一条新途径,具有推广应用前景。     

掘进工作面瓦斯合理预抽期研究

为解决掘进工作面瓦斯超前预抽时间短、抽放率低、掘进过程中预测指标超标率高等问题,通过研究超前预抽钻孔抽放量衰减规律,建立了掘进工作面瓦斯合理预抽期的评价模型,选取了合理参数,确定了成庄矿瓦斯超前预抽钻孔合理预抽期,并进行了掘进工作面瓦斯超前预抽实验,对瓦斯合理预抽期研究结果进行了检验.实验结果表明,当超前预抽时间在合理预抽期内,瓦斯抽放率提高,煤层残余瓦斯含量减小,突出预测超标率降低;合理预抽期评价模型可靠,超前预抽合理预抽期研究具有实际应用价值.     

钻孔数量对瓦斯抽采量及抽采时间的影响

基于自主研发的多场耦合煤层气开采物理模拟试验系统升级改造了顺层钻孔瓦斯抽采系统,开展了不同钻孔数量条件下顺层钻孔瓦斯抽采物理模拟试验,探讨了瓦斯抽采量(瞬时流量、累积流量)和抽采时间的演化规律.结果表明:当钻孔数量由1个增加到2,3和4个时,单钻孔累积流量约下降至原来的0.60,0.45和0.35倍.不同钻孔数量抽采时,瞬时流量曲线出现交叉现象,即抽采前期钻孔数量越多瞬时流量越大,中后期逐渐变化为钻孔数量越多瞬时流量越小.累积流量随钻孔数量的增加呈对数函数增加,钻孔数量越多,其增加效果越不明显.抽采时间随钻孔数量的增加呈幂函数降低,钻孔数量越多,其下降效果越不明显.     

综采工作面浅孔瓦斯抽放消突技术应用研究

针对平顶山煤业股份有限公司八矿己15突出煤层综采工作面一直存在抽放率低、排放钻孔消突效果差、瓦斯时常超限、制约安全生产等问题,试验利用工作面前方煤体透气性增加的动压区进行抽放的浅孔瓦斯抽放措施.根据防突安全要求、有关参数测定结果,并结合煤层赋存和施工技术条件,确定了合理的钻孔布置和抽放等关键技术参数.浅孔瓦斯抽放措施实施后,通过分析效果检验超标率、瓦斯体积分数和产量变化,考察了消突效果、抽放效果和生产效益.结果证明,浅孔瓦斯抽放措施技术可行,防突防瓦斯效果明显,是突出煤层采煤工作面解决瓦斯问题的有效途径之一.     

采空区开区移动瓦斯抽放的数值模拟

针对我国高瓦斯矿井采空区瓦斯抽放的现状，强调了在工作面后方“边采边抽”的开区移动瓦斯抽放方法，以提高资源回收减少大气污染与瓦斯治理的双重效益．建立了非均质采空区瓦斯渗流--扩散的数值模型，模拟了瓦斯在采空区中的涌出、分布及积聚的流体力学原理．模拟表明，抽放流量与采空区瓦斯涌出量和抽放瓦斯浓度均呈显的反比关系，且抽放的纯瓦斯量基本保持恒定，结论与采空区瓦斯持续稳定释放的客观性完全一致；抽放口位置越深入采空区，瓦斯绝对涌出量略有降低，抽放浓度越高．由此确定了抽放口的最佳位置和抽放流量．结合实例，利用联络巷进行瓦斯抽放，可获得高于40％浓度的瓦斯，理论抽放效率在70％以上，若配合以漏风导流，可彻底抑制瓦斯涌入工作面，并降低配风量。     

煤层气有限导流压裂井的压力动态分析

针对煤层气产出过程中的降压,解吸,扩散,渗流等特点,应用非稳态解吸模型;研究了煤层气在基质和割理中的单相流动;建立了新有有限导流压裂井评价模型;讨论了裂缝壁面表皮系数,吸附系数,裂缝储容系数和窜流系数对压力动态的影响;分析了煤层气压裂井的压降典型曲线特征和参数估计方法,从而为煤层气藏开发提供了可靠的数据。     

Directivity effect of unloading bedding coal induced fracture evolution and its application

In the coal mining process, the gas contained in the coalbed is one source of the most serious accident hazards. Stress releasing from the coal deposit is the main controlling factor that leads to such accidents.Based on the bedding of coal samples, the gas permeability well describes the evolution of fracture, so the paper carries out research on the permeability properties of coal under different unloading directions.The research obtains that when the stress unloading direction is perpendicular to bedding, more penetrating fractures and bedding fractures occur, and the permeability significantly increases. Although the axial stress reduced, the confining pressure makes the permeability of the bedding plane fracture exist under constant. The permeability obtained when the unloading direction was perpendicular to the bedding is 52 times larger than that when it is parallel to the bedding. The results show that the efficiency of gas drainage is impacted by the relative direction of gas drainage drilling in relation to the bedding orientations. The maximum amount of gas extraction when drilling is perpendicular to the bedding is 1.3 times than that when drilling is oblique to the bedding, and 1.75 times than that when drilling is parallel to the bedding.     

煤层注水促抽瓦斯及其影响因素的数值模拟

为有效预防煤矿瓦斯灾害,获取煤层注水促抽瓦斯的合理参数,以常村煤矿2103工作面为例,依据多相渗流理论,采用Fluent软件的VOF模型及多孔介质模型耦合求解,对煤层注水促抽瓦斯技术及其影响因素进行数值模拟,并将模拟结果应用于现场,对比分析数值模拟与现场实测数据,二者基本吻合.研究结果表明:煤层瓦斯含量以注水孔为中心径向逐步降低,以抽采孔为中心径向逐步升高;注水前抽采阶段,随着抽采时间的增加,抽采范围逐渐增大,抽采孔瓦斯流量先快速下降,后逐步缓慢降低;注水促抽阶段,随着注水时间的增加,注水范围逐渐增大,注水流量逐步降低,煤层瓦斯含量缓慢升高,抽采孔瓦斯流量逐渐增加;注水后抽采阶段,随着抽采时间的增加,压力水覆盖范围持续增大,煤层瓦斯含量逐渐降低,抽采孔瓦斯流量逐渐减小.注水时机、注水时间、注水压力、注水方式、布置方式及钻孔间距是影响煤层注水促抽瓦斯效果的6个主要因素.瓦斯正常抽采20 d后,按照一注一抽方式及5 m间距布置注抽钻孔,在8 MPa煤层注水压力下间歇注水10 d,煤层注水促抽瓦斯效果较好.     

Status of research on biogenic coalbed gas generation mechanisms

Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods of differentiating between biogenic gasses are discussed.The generation of biogenic coalbed methane is consistent with anaerobic fermentation theory.Commercial biogenic coalbed gas reservoirs are mainly generated by the process of CO2 reduction.The substrates used by the microbes living in the coal include organic compounds,CO2,H2 and acetate.The production ratio and quantity of biogenic coalbed methane depend on the exposed surface area,the solubility and permeability of the coal and the microbial concentration in the coal seam.It is generally believed that biogenic coalbed gas has a value for σ13C1＜-5.5%,C1/C1+＞0.95.The H isotope ratio is controlled by both the environment and the generation mechanism:typically σD1＜-20%.Biogenic methane formed by CO2 reduction has more σD1 than that formed by acetate fermentation.     

新集矿区煤层气地面开发技术探讨

作为国家煤层气示范开发区,针对新集矿区的地质条件及煤层气储存特点,选用地面垂直井开发煤层气的工艺技术,通过开发试验现场的＂1＋3＂井组工程的三口试生产井,成功地产出了煤层气,获得了单井最大日产气量3 728m3,排采三年后日产气量仍维持1 000m3。对其中的钻井、储层保护、水力压裂、排水、采气方面的关键技术的研究和实施,建立起一套适用于新集矿区地质条件及中国国情的煤层气钻井、完井、压裂和采气工艺技术。试验区地面垂直井开发煤层气的成功实施,也为矿区治理矿井瓦斯,提供了新的途径。     

Numerical Simulation Study of Goaf Methane Drainage and Spontaneous Combustion Coupling

In order to study the coupling problem between methane drainage and spontaneous combustion of residual coal in the collapsed zone after mining ignitable coal seams with high methane, we have analyzed the effects of different methane drainage modes on spontaneous combustion of residual coal through numerical simulation.The results show that deep and large flux methane drainage modes increases the air leakage from work faces to the goaf and formed new spontaneous combustion zones induced by drainage near vents, which increases the risk of self-ignition of coal-reducing the self-ignition period and enlarging the scale of self-ignition.The spontaneous upstream combustion oxidation of the main fire zone can be suppressed when both drainage and nitrogen injection were adopted.Our research results provide an effective technical measure and theoretical basis to determine the best methane drainage scheme and drainage parameters.     

湖南煤层（瓦斯）气研究现状及开发利用前景

介绍了湖南省煤田地质概况，煤层气赋存规律及特征，矿井瓦斯抽放现状与效果，并对煤层气资源进行了初步评价。     

前进式预埋管法抽放采空区瓦斯的试验研究

以采空区瓦斯涌出规律为基础，探讨了采空区瓦斯的治理原则；并以平煤（集团）公司十矿２０１３０综采面为试验点，进行了前进式预埋管法抽放采空区瓦斯的试验研究．研究结果表明：该技术不仅对解决采空区上隅角瓦斯积聚问题具有重要作用，而且还为采空区瓦斯资源的开发利用提供了实用技术．     

Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area

Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy re-sources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en-gineering theories, the design principles of design and structure of wells of pressure relief coaibed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a sig-nificant effect on gas production of coalbed methane wells.