预抽煤层瓦斯消除空白带钻孔布置方式的优化

Optimization of Borehole Layout to Eliminate Drainage Blind by Pre-pumping Coal Seam Gas

在有效抽采半径一定的条件下,为了消除钻孔抽采瓦斯在煤层中形成的抽采盲区空白带,可对钻孔布置方式进行调整,主要措施有"三花眼"布孔方式与缩短抽采钻孔间距布孔方式。这2种布孔方式为了消除空白带需要布置的钻孔个数与原来布置的钻孔个数基本相当,所需布置的抽采钻孔个数均约是原来的2倍,造成了部分煤层区域的重复抽采,浪费了大量的资源。为了减少施工抽采钻孔的个数,提出了一种新的钻孔布置方式:沿煤层走向布置钻孔的间距为3R(R表示有效抽采半径)、沿煤层倾向布置钻孔的间距为1.5R,或沿煤层倾向布置钻孔的间距为3R、沿煤层走向布置钻孔的间距为1.5R,此时需要布置的抽采钻孔个数仅约是原来的1.54倍。此种钻孔布置方式既能消除钻孔抽采瓦斯在煤层中形成的空白带,又能减少施工抽采钻孔的个数,节约了大量资源,提高了钻孔抽采效率。

Under the condition of a certain effective extraction radius,in order to eliminate extraction blind blank zone formed in coal seam gas borehole drainage,borehole layout can be adjusted,the main measures include ＂ delta mode＂ borehole layout and shortening borehole distance layout. In order to eliminate drainage blind spots,the number of borehole needs to be laid roughly equal to the original; the numbers of boreholes needs to be laid are about 2 times than the original,which causes some coal area repeated drainage,and wastes a lot of resources. In order to reduce the number of construction borehole,this paper presents a new borehole layout method that lay outing along the coal seam borehole distance of √3R（ represents the effective drainage radius）,lay outing inclination the coal seam borehole distance of 1. 5R or lay outing inclination the coal seam borehole distance of √3R,lay outing along the coal seam borehole distance of 1. 5R. The number of boreholes needs to be laid at this time is only about 1. 54 times than the original. Such layout method can eliminate blank zone formed in coal drainage gas,but also reduce the number of construction borehole,and save a lot of resources and improve the efficiency of borehole drainage.