论龙永煤田坑柄矿区钻孔结构设计

针对龙永煤田坑柄矿区钻进过程中普遍存在的＂硬、漏、塌、涌、斜＂等复杂现象,在多年的实践基础上,摸索出一套适合本区的钻孔设计结构和钻进方法：开孔用φ130mm合金钻头钻至完整岩层,下φ127mm孔口套管,然后用S95mm金刚石钻具将上部硬岩钻穿,至稳定岩层后下φ89mm套管,最后用φ76.5-77.5mm合金金刚石钻头钻至终孔。另外,把S75mm钻具的钻头外径由φ75mm增加到φ77＋0.50mm,一方面可保证经过改扣的φ89mm套管能够继续作为技术套管使用;另一方面也有利于排除岩屑、防止糊钻、缩径卡钻、冲蚀孔壁、降低泵压、减轻抽吸和压裂孔壁造成的钻孔漏水坍塌等故障,更好的起到护壁防塌效果。经统计,该钻孔结构设计将钻孔的平均时效提高到1.68m/h,提高了50%;平均钻效达到626.34m/钻月,提高了21%;单孔最高钻效达到782.27m/钻月。

Borehole Structure Design in Kengbing Mine Area,Longyong Coalfield

In allusion to the complicated phenomena of ＂hard rock, current loss, wall sloughing, water inrush and borehole deviation＂ during drilling in the Kengbing mine area, Longyong coalfield, based on practices in many years, tracked out a set of borehole structure designs and drilling methods. Spud-in with φ130mm carbide bit drills to the intact strata, lowering down a φ127mm conductor then to use S95mm diamond bit penetrates upper hard rocks straight to the stable strata, then lowering down φ89mm casing, finally to use φ76.5-77.5mm diamond-enhanced carbide bits drill to total depth. Besides, to increase S75mm bit outside diameter from φ75mm to φ77＋0.50mm, thus can ensure rethreaded φ89mm casing can be the intermediate casing right along on the one hand; and in favor of debris removal, bit burnt, diameter shrinkage tool sticking, and wall scouring erosion prevention, pump pressure and sucking off reducing, prevent of fluid leakage and wall sloughing caused by fracturing to have better wall protection on the other hand. By the statistics, the designs have improved mean hourly capacity to 1.68m/h, about 50% higher; average monthly capacity 626.34m/drilling month, about 21% higher than that of past; maximum single borehole drilling capacity 782.27m/drilling month.