best practices gas capture 瓦斯抽采管理.ppt

* * Meeting and Training for Gas Drainage Best Practices Gas Capture 瓦斯抽采管理 * Drainage of medium quality gas is often feasible but it requires use of an effective method of standpipe sealing 采用有效的封孔方法、提高封孔质量，对于提高抽采效果切实可行。 Knowledge of the technique is not enough. Good performance comes from ATTENTION TO DETAIL 然而，技术仅为一个可行的手段，目前更需要关注的是细节 * Best Practices Gas Capture * Gas content 瓦斯含量 How much gas in the coal seam (gas content in-situ) 原始瓦斯含量 Water Content 含水量 Water will come from the borehole when pressure is reduced (vacuum applied)钻孔负压适当有助于积水排出 Permeability 煤层透气性 Emission level – suitable vacuum for gas drainage 影响瓦斯涌出—需要合适的负压 Attenuation 衰减系数 The reason for regulation 调节的主要原因 Determines the drainage radius 与抽采半径有关 Parameter for Drainage 抽采参数 * Mining Stress Zone and Gas Release 采动影响和瓦斯涌出 Principle of regulation is to maintain pure gas flow and concentration 35% 调节的原则是确保瓦斯浓度稳定在35%以上，流量稳定不减少 Phase 1 - Water is released from the strata and into the borehole 阶段1 排水 Phase 2 - Connect the range with water trap – vacuum 10-15kPa to drain water阶段2 连 接 支管，负压为10-15kPa，利于排水和瓦斯涌出 Phase 3 - Decay so regulation is very important 阶段3 瓦斯涌出衰减阶段，为调节的关键阶段 Phase 4 - Stable emission with stable vacuum阶段4 稳定涌出阶段，需要保持负压稳定 * Management for Pre-Drainage (Inseam)本煤层预抽管理 * Phase 1 Totally closed 阶段1 没有瓦斯，钻孔完全关闭 Phase 2 25-30kPa to capture methane from the above coal seams and goaf gas 阶段2 采用25-30Kpa捕捉采空区和上覆盖煤层涌出的瓦斯 Phase 3 Regulation period – reduce vacuum pressure阶段3 调节阶段—降低负压 Phase 4 Closed borehole because borehole crushed and may drain air and cause spon comb 阶段4 关闭钻孔，防止空气进入采空区导致自燃危险. Principle of regulation is to maintain pure gas flow and concentration 35% 调节原则：CH4%35% Management for Roofhole顶板钻孔抽采管理 * Phase 1 Totally closed 阶段1 浓度低，完全关闭 Phase 2 Open with suitable vacuum 阶段2 打开钻孔，采用