依兰矿区钻探施工泥浆选型的研究

Drilling Mud Selection in Yilan Mining Area

依兰矿区第三系上部的砂泥岩段,因泥岩的水敏水化作用及粗砂岩易坍塌等原因造成,区内钻孔孔壁极不稳定,经常发生粘卡钻具事故。为抑制泥岩的水敏水化,阻止泥岩水化和井壁岩石剥落,增强其防塌能力,在选择腐植酸钾做主剂的基础上选择CMC作降失水增粘剂,选择分子量为300万～500万、水解度30%的聚丙烯酰胺(PAM)作絮凝剂,以加速岩屑沉降,控制固相侵入,降低失水。在钻遇半胶结泥岩时,为防止缩径、坍塌,采用在泥浆中加入重晶石粉,把泥浆比重调整到1.15～1.20g/cm^3,利用泥浆液柱压力控制泥岩缩径和孔壁坍塌。通过实验及现场应用,为该区选择的KHM-CMC-PAM高聚物泥浆配方,能有效地防止水敏性易塌地层的粘卡钻事故,具有护壁防塌、提高钻效等技术效果。

There is sandstone and mudstone member in Upper Tertiary System of the Yilan mining area. In this member, because of mudstone water sensitive hydration and coarse-grained sandstone is easy to collapse, thus result in borehole wall very unstable, and drill pipe sticking is very often. To suppress mudstone water sensitive hydration, prevent borehole wall rock flake away, we selected potassium humate major constituted CMC as water loss reducing anchoring agent, 3-5 million molecular weight, 30% degree of hydrolysis PAM as flocculating agent to accelerate debris subsiding, control solid phase intruding and reduce water loss. To prevent borehole shrinkage and collapse through mud column pressure, therefore add barite powder in drilling mud to adjust mud unit weight to 1.15-1.20g/cm^3. After laboratory testing and field application, a formula of KHM-CMC-PAM high polymer has adopted in this area and its effectiveness proved.