桑树坪二号井顶板梳状孔水力压裂瓦斯强化抽采技术

    Investigation of gas enhanced extraction technology by hydraulic fracturing of comb hole in the coal seam roof of Sangshuping No.2 well

    • 摘要: 桑树坪二号井本煤层钻孔施工困难,煤层透气性差,瓦斯抽采浓度低,流量小。通过在桑树坪二号井北区3号煤层顶板砂岩中实施顶板梳状长钻孔并进行分段水力压裂,以提高矿井瓦斯防治效果,探索适合矿井的瓦斯防治技术手段。采用前进式分支孔工艺施工完成1个钻孔,主孔长度588 m,施工8个分支孔,总进尺1 188 m,其中,煤层段227 m,岩层段961 m,钻孔主孔距煤层顶部0~3.28 m。共分4段进行水力压裂,累计注水2 012 m3,最大泵注压力8.74 MPa。施工完成后3个月内钻孔日均抽采瓦斯纯量约1 500 m3,压裂钻孔百米钻孔瓦斯抽采纯量是水力割缝钻孔的1.2倍,是常规钻孔的4.0倍。初步证明了顶板梳状长钻孔水力压裂技术在煤矿瓦斯防治领域的适用性。

       

      Abstract: It is difficult to drill holes in the coal seam of Sangshuping No.2 well.The permeability of the coal seam is poor, the concentration of gas extraction is low, and the flow rate is small.In order to improve the effect of mine gas prevention and control, comb-shaped long drilling and hydraulic fracturing are carried out in the roof sandstone of No.3 coal seam in the north area of Sangshuping No.2 well, and the technical means of mine gas prevention and control are explored.One drilling hole is completed by using forward branch hole technology.The length of the main hole is 588 m, and eight branch holes are constructed with a total footage of 1 188 m.Among them, the coal seam is 227 m, the rock seam is 961 m, and the distance between the main hole and the top of the coal seam is 0-3.28 m.Hydraulic fracturing is carried out in four stages, with cumulative water injection of 2 012 m3 and maximum pump injection pressure of 8.74 MPa.Within three months after completion of the construction, the average daily gas extraction purity of drilling holes is about 1 500 m3.The gas extraction purity of 100-meter drilling holes in fracturing holes is 1.2 times that of hydraulic slotting holes and 4.0 times that of conventional drilling holes.The applicability of roof comb-shaped long borehole hydraulic fracturing technology in the field of coal mine gas prevention and control is preliminarily proved.

       

    /

    返回文章
    返回