Last month the Washington University surgeons drilled a small burr hole, about the diameter of a pencil, into the patient's skull.
上个月华盛顿大学的外科医生用钻孔器在这个病人的头骨上钻了一个洞，直径大约和铅笔一样。
The original granite island which had hills up to 120 meters high was drilled and blasted into boulders no bigger than two meters in diameter.
原始的有120米高的花岗岩小岛被钻孔或是爆破直径成不大于两米的大石头。
Drilled formations are complex with unstable wall. Lost circulation, well kick, borehole collapse, diameter shrinkage, sticking and other complex situations often occur.
钻遇地层复杂，井壁稳定性差，井漏、井涌、井塌、缩径、卡钻等井下复杂情况频发；
To raise wire-line drilling efficiency need to: 1. Select casing diameter and depth according to drilling depth, diameter, strata drilled and rock integrity, structure features, weathered layer depth;
提高绳索取心钻进效率要做到：一是根据孔深、钻孔孔径、钻孔所遇地层及其岩性的完整程度、构造特点、风化带发育深度等选择套管的直径及下入深度；
To raise wire-line drilling efficiency need to: 1. Select casing diameter and depth according to drilling depth, diameter, strata drilled and rock integrity, structure features, weathered layer depth;
提高绳索取心钻进效率要做到：一是根据孔深、钻孔孔径、钻孔所遇地层及其岩性的完整程度、构造特点、风化带发育深度等选择套管的直径及下入深度；
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