The air-driven down-hole hammer drilling is still very effective and speedy in well drilling in karst limestone area.
在水文水井中，气动潜孔锤钻进仍可发挥它高效率、高速度的作用。
2
According to this problem, casing oil stolen prevention sealing valve was developed, matching with down-hole oil-gas separator and gas lift valve lift technology.
针对这一难题，研制了套管防盗油密封阀，并配套应用了井下油气分离器与气举阀助流举升工艺技术。
3
The man poured petrol down the hole and then lit a match in an attempt to kill the offending arachnid.