Novel integrated techniques of drilling–slotting–separation-sealing for enhanced coal bed methane recovery in underground coal mines

Coal bed Methane (CBM), a primary component of natural gas, is a relatively clean source of energy. Nevertheless, the impact of considerable coal mine methane emission on climate change in China has gained an increasing attention as coal production has powered the country's economic development. It is well-known that coal bed methane is a typical greenhouse gas, the greenhouse effect index of which is 30 times larger than that of carbon dioxide. Besides, gas disasters such as gas explosive and outburst, etc. pose a great threat to the safety of miners. Therefore, measures must be taken to capture coal mine methane before mining. This helps to enhance safety during mining and extract an environmentally friendly gas as well. However, as a majority of coal seams in China have low-permeability, it is difficult to achieve efficient methane drainage. Enhancing coal permeability is a good choice for high-efficiency drainage of coal mine methane. In this paper, a modified coal-methane co-exploitation model was established and a combination of drilling–slotting-separation–sealing was proposed to enhance coal permeability and CBM recovery. Firstly, rapid drilling assisted by water-jet and significant permeability enhancement via pressure relief were investigated, guiding the fracture network formation around borehole for high efficient gas flow. Secondly, based on the principle of swirl separation, the coal–water–gas separation instrument was developed to eliminate the risk of gas accumulation during slotting and reduce the gas emission from the ventilation air. Thirdly, to improve the performance of sealing material, we developed a novel cement-based composite sealing material based on the microcapsule technique. Additionally, a novel sealing–isolation combination technique was also proposed. Results of field test indicate that gas concentration in slotted boreholes is 1.05–1.91 times higher than that in conventional boreholes. Thus, the proposed novel integrated techniques achieve the goal of high-efficiency coal bed methane recovery.

[1]  Regina Sander,et al.  Methodology for the economic assessment of enhanced coal mine methane drainage (ECMM) as a fugitive emissions reduction strategy , 2012 .

[2]  Baiquan Lin,et al.  Variation of methane adsorption property of coal after the treatment of hydraulic slotting and methane pre-drainage: A case study , 2014 .

[3]  Bingxiang Huang,et al.  Hydraulic fracturing after water pressure control blasting for increased fracturing , 2011 .

[4]  C. Özgen Karacan,et al.  Coal mine methane: A review of capture and utilization practices with benefits to mining safety and to greenhouse gas reduction , 2011 .

[5]  D. Lashof,et al.  Relative contributions of greenhouse gas emissions to global warming , 1990, Nature.

[6]  Baiquan Lin,et al.  Combustion characteristics of low concentration coal mine methane in divergent porous media burner , 2014 .

[7]  Quanle Zou,et al.  Variation in the Pore Structure of Coal after Hydraulic Slotting and Gas Drainage , 2014 .

[8]  Jishan Liu,et al.  Complex evolution of coal permeability during CO2 injection under variable temperatures , 2012 .

[9]  L. Connell,et al.  A probabilistic assessment of enhanced coal mine methane drainage (ECMM) as a fugitive emission reduction strategy for open cut coal mines , 2014 .

[10]  Sun Xin,et al.  Fugitive coal mine methane emissions at five mining areas in China , 2011 .

[11]  Yuanping Cheng,et al.  An analysis of fatal gas accidents in Chinese coal mines , 2014 .

[12]  A. Formigoni,et al.  Effect of microcapsulation on absorption processes in the pig , 1997 .

[13]  Yuan Liang.  Theory of pressure-relieved gas extraction and technique system of integrated coal production and gas extraction , 2009 .

[14]  Jacek Sobczyk,et al.  A comparison of the influence of adsorbed gases on gas stresses leading to coal and gas outburst , 2014 .

[15]  G. M. Alam,et al.  Global warming and climate change: prospects and challenges toward long-term policies in Bangladesh , 2013 .

[16]  Hua Guo,et al.  An assessment of mine methane mitigation and utilisation technologies , 2005 .

[17]  M. Masuko,et al.  Prevention of oxidative degradation of ZnDTP by microcapsulation and verification of its antiwear performance , 2008 .

[18]  Wojciech M. Budzianowski,et al.  Value-added carbon management technologies for low CO2 intensive carbon-based energy vectors , 2012 .

[19]  John P. Carter,et al.  Vertical stress changes in multi-seam mining under supercritical longwall panels , 2013 .

[20]  Hani S. Mitri,et al.  Enhanced coalbed gas drainage based on hydraulic flush from floor tunnels in coal mines , 2016 .

[21]  Guangling Zhao,et al.  Greenhouse gas emissions reduction in China by cleaner coal technology towards 2020 , 2015 .

[22]  Quanlin Hou,et al.  Macromolecular and pore structures of Chinese tectonically deformed coal studied by atomic force microscopy , 2015 .

[23]  G. Yin,et al.  Geomechanical and flow properties of coal from loading axial stress and unloading confining pressure tests , 2015 .

[24]  C. M. White,et al.  Sequestration of Carbon Dioxide in Coal with Enhanced Coalbed Methane RecoveryA Review , 2005 .

[25]  Maria Alzira Pimenta Dinis,et al.  Unconventional coal reservoir for CO2 safe geological sequestration , 2013 .

[26]  N. Buchmann,et al.  Spatial variability of methane: attributing atmospheric concentrations to emissions. , 2014, Environmental pollution.

[27]  Baiquan Lin,et al.  Stress redistribution of longwall mining stope and gas control of multi-layer coal seams , 2014 .

[28]  Ji Qianhui.  Research and Application of Auger-air Drilling and Sieve Tube Borehole Protection in Soft Outburst-prone Coal Seams , 2014 .

[29]  Baiquan Lin,et al.  Mechanism of strata deformation under protective seam and its application for relieved methane control , 2011 .

[30]  G. Aydin,et al.  Mine ventilation air methane as a sustainable energy source , 2011 .

[31]  Experimental Study of the Laws Between the Effective Confining Pressure and Mudstone Permeability , 2014 .

[32]  Ram Balachandar,et al.  An experimental and numerical study of water jet cleaning process , 2011 .

[33]  Yingke Liu,et al.  Failure analysis of borehole liners in soft coal seam for gas drainage , 2014 .

[34]  Nallamuthu Rajaratnam,et al.  PLANE TURBULENT IMPINGING JETS , 1973 .

[35]  Lei Wang,et al.  Drainage and utilization of Chinese coal mine methane with a coal–methane co-exploitation model: Analysis and projections , 2012 .

[36]  Yong Qin,et al.  Mechanism of CO2 enhanced CBM recovery in China： a review , 2008 .

[37]  Ting Liu,et al.  A novel ECBM extraction technology based on the integration of hydraulic slotting and hydraulic fracturing , 2015 .

[38]  Fangtian Wang,et al.  Implementation of underground longhole directional drilling technology for greenhouse gas mitigation in Chinese coal mines , 2012 .

[39]  Zhaihui Chen.  Sealing performance of flexible gel sealing material of gas drainage borehole , 2013 .

[40]  Tsuyoshi Ishida,et al.  Strain monitoring of borehole diameter changes in heterogeneous jointed wall rock with chamber excav , 2000 .

[41]  Hao Xu,et al.  Experimental research on coal permeability: The roles of effective stress and gas slippage , 2014 .

[42]  Baiquan Lin,et al.  Kinetic characteristics of coal gas desorption based on the pulsating injection , 2014 .

[43]  A. Saghafi,et al.  Potential for ECBM and CO2 storage in mixed gas Australian coals , 2010 .

[44]  Muhd Zaimi Abd Majid,et al.  A global review of energy consumption, CO2 emissions and policy in the residential sector (with an overview of the top ten CO2 emitting countries) , 2015 .

[45]  D. Jiang,et al.  Comparison of the characteristics of rock salt exposed to loading and unloading of confining pressures , 2016 .

[46]  Yuanping Cheng,et al.  CMM capture engineering challenges and characteristics of in-situ stress distribution in deep level of Huainan coalfield , 2014 .

[47]  Yuanping Cheng,et al.  Evaluation of coal swelling‐controlled CO 2 diffusion processes , 2014 .

[48]  Xueqiu He,et al.  Status and future tasks of coal mining safety in China , 2012 .

[49]  Maziar Arjomandi,et al.  The working principle of a vortex tube , 2013 .

[50]  Huang Fei,et al.  On the failure pattern of sandstone impacted by high-velocity water jet , 2015 .

[51]  Yuanping Cheng,et al.  Methane and coal exploitation strategy of highly outburst-prone coal seam configurations , 2015 .

[52]  Zhiyong Hao,et al.  Pressure-relief and permeability-increase technology of high liquid–solid coupling blast and its application , 2014 .

[53]  Xueqiu He,et al.  Electromagnetic emission graded warning model and its applications against coal rock dynamic collapses , 2011 .

[54]  Yuanping Cheng,et al.  The elimination of coal and gas outburst disasters by ultrathin protective seam drilling combined with stress-relief gas drainage in Xinggong coalfield , 2014 .

[55]  Baiquan Lin,et al.  Stress evolution with time and space during mining of a coal seam , 2011 .

[56]  Longhole waterjet rotary cutting for in-seam cross panel methane drainage , 2010 .

[57]  Zhiyong Hao,et al.  Establishment and application of drilling sealing model in the spherical grouting mode based on the loosing-circle theory , 2012 .

[58]  M. Mazzotti,et al.  Enhanced coalbed methane recovery , 2009 .

[59]  J. Dorian,et al.  Growing Chinese coal use: dramatic resource and environmental implications , 2008 .

[60]  Peter V. E. McClintock,et al.  Development of turbulance in subsonic submerged jets , 2004 .

[61]  K. Wolf,et al.  Differential swelling and permeability change of coal in response to CO2 injection for ECBM , 2008 .

[62]  K. Warmuziński,et al.  Harnessing methane emissions from coal mining , 2008 .

[63]  R. Lama,et al.  Management of outburst in underground coal mines , 1998 .

[65]  G. Pisarev,et al.  Effect of the ‘end of the vortex’ phenomenon on the particle motion and separation in a swirl tube separator , 2012 .

[66]  W. Gunter,et al.  Deep coalbed methane in Alberta, Canada: A fuel resource with the potential of zero greenhouse gas emissions , 1997 .

[67]  T. G. Sitharam,et al.  Micromechanical modeling of granular materials: effect of confining pressure on mechanical behavior , 1999 .

[68]  G. Dion,et al.  Greenhouse Gas Emissions , 2015 .

[69]  Lei Wang,et al.  Environmental impact of coal mine methane emissions and responding strategies in China , 2011 .

[70]  Junhua Xue,et al.  Mining-induced strata stress changes, fractures and gas flow dynamics in multi-seam longwall mining , 2012 .

[71]  End Use.  Annual energy outlook : with projections to ... , 1983 .

[72]  Xu Tang,et al.  Depletion of fossil fuels and anthropogenic climate change—A review , 2013 .

[73]  Luke D. Connell,et al.  Coal swelling strain and permeability change with injecting liquid/supercritical CO2 and N2 at stress-constrained conditions , 2011 .

[74]  Pathegama Gamage Ranjith,et al.  Effects of effective stress changes on permeability of latrobe valley brown coal , 2011 .

[75]  Jun Li,et al.  Investigation on mechanical properties and damage evolution of coal after hydraulic slotting , 2015 .

[76]  Yuanping Cheng,et al.  Characteristics of mining gas channel expansion in the remote overlying strata and its control of gas flow , 2013 .

[77]  Tso-Liang Teng,et al.  A numerical study on high-speed water jet impact , 2013 .

[78]  Wang Enzhi.  Experimental study of the laws between the effective confirming pressure and rock permeability , 2007 .

[79]  Qingquan Liu,et al.  Addressing the CO2 emissions of the world's largest coal producer and consumer: Lessons from the Haishiwan Coalfield, China , 2015 .

[80]  K. Baris,et al.  Assessing ventilation air methane (VAM) mitigation and utilization opportunities: A case study at Kozlu Mine, Turkey , 2013 .

[81]  Wojciech M. Budzianowski,et al.  Modelling of CO2 content in the atmosphere until 2300: influence of energy intensity of gross domestic product and carbon intensity of energy , 2013 .

[82]  Luke D. Connell,et al.  Impact of coal seam as interlayer on CO2 storage in saline aquifers: A reservoir simulation study , 2011 .

[83]  B. Nie,et al.  Study on law of raw coal seepage during loading process at different gas pressures , 2015 .

[84]  J. Sulem,et al.  Effective stress law for the permeability of a limestone , 2008, 0808.4084.

[85]  Baiquan Lin,et al.  Pulsating hydraulic fracturing technology in low permeability coal seams , 2015 .

[86]  Baiquan Lin,et al.  A new technique for preventing and controlling coal and gas outburst hazard with pulse hydraulic fracturing: a case study in Yuwu coal mine, China , 2015, Natural Hazards.

[87]  Hongguan Yu,et al.  Preferential adsorption behaviour of CH4 and CO2 on high-rank coal from Qinshui Basin, China , 2014 .

[88]  Mohd Ariffin Abu Hassan,et al.  Methane emission by sectors: A comprehensive review of emission sources and mitigation methods , 2012 .