煤矿井下煤层密闭取心装置

Study on Coal Seam Airtight Coring Facility in Coalmines

现有煤矿井下煤层气含量测试取样装置在提心过程中煤心暴露,致使损失气测算不准,影响煤层气含量测定精度,而油气田上使用的密闭(保压)取心装置需在地面配合绳索取心工具使用,且费用高昂,不适合井下煤层。USC-Ⅰ型煤矿井下煤层密闭取心装置为一个双筒单动式取心器,包括依次连接的取心钻头、外筒和钻杆接头;外筒内悬挂有内筒,内筒上端连接有球座分水接头和悬挂总成,内筒下端连接有内筒密闭球阀;内筒和外筒之间设置有液压关闭机构,液压关闭机构上端与球座分水接头相连接,下端与关闭球阀半滑环相连接。选取陕西彬长矿业集团胡家河煤矿作为现场应用地点,以该矿井主采的4#煤层作为取心测试对象,利用施工区的1个钻孔,分别进行了普通取心筒和密闭取心装置测定气含量,测定结果表明:该取心装置可使煤心在提取过程中处于密闭状态,减少样品中的气体损失,有效提高煤矿井下煤层气含量测定的准确性。

The underground sampling facilities now available for CBM content test in coalmines have a defect of coal core exposing,thus caused incorrect measuring of lost gas, and impact CBM content measuring accuracy; while the airtight（pressure-tight） coring facilities used in oil and gas fields should be matched with wire-line coring tools on surface, thus expensive and unfit for underground coal seams. The USC-1 coalmine underground airtight coal coring facility is a swivel barrel corer, including coring bit, outer barrel and drill rod sub connected in turn; within outer barrel, an inner barrel hanging, on upper end of inner barrel connected a ball-seat swivel and hanging assemblage, on lower end connected an inner barrel airtight ball valve; a hydraulic closing setup installed between inner and outer barrels; the upper end of hydraulic closing setup connected with ball-seat swivel, while the lower end connected with closing ball valve semi-slip ring. Taking the Hujiahe coalmine of the Shaanxi Binchang Mining Group as the application site, main mineable coal No.4 as the coring test target, using a borehole in the site carried out common coring barrel and airtight coring facility gas content determination respectively, the result has shown that the later can make the coal core under airtight status during the coring, thus can reduce sample gas loss, thus can effectively improve coalmine underground CBM content measuring accuracy.