新概念英语4册第13课

The Search for oil

The deepest holes of all are made for oil, and they go down to as much as 25,000 feet. But we do not need to send men down to get the oil out, as we must with other mineral deposits. The holes are only borings, less than a foot in diameter. My particular experience is largely in oil, and the search for oil has down more to improve deep drilling than any other mining activity. When it has been decided where we are going to drill, we put up at the surface an oil derrick. It has to be tall because it is like a giant block and tackle, and we have to lower into the ground and haul out of the ground great lengths of drill pripe which are rotated by an engine at the top and are fitted with a cutting bit at the bottom.

The geologist needs to know what rocks the drill has reached, so every so often a sample is obtained with a coring bit. It cuts a clean cylinder of rock, from which can be seen the strata the drill has been cutting through. Once we get down to the oil, it usually flows to the surface because great pressure, either from gas or water, is pushing it. This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe. We endeavour to avoid the old, romantic idea of a gusher, which wastes oil and gas. We want it to stay down the hole until we can lead it off in a controlled manner.

那些可达25000英尺的深洞是为了石油而建造的。但是我们不需要象其他矿物一样，让人亲自下去将石油取出来。这些洞仅仅是直径小于一英尺的钻孔。我的特殊经验大部分都来自于石油。而搜寻石油比其他任何矿业活动都能改善深钻的技术。当确定在那里开始钻探后，我们在地表竖起来一个钻井。钻井必须很高，就象一个巨大的滑轮。我们必须降到地下然后将钻杆拔出来。钻杆的顶端有一个马达使它旋转而底部是一个尖头。

地质学者需要了解钻探到了什么岩石，所以经常会从钻头穿过的岩层中得到一些岩石样本，切割岩石成为圆柱体。一旦我们钻到了石油，由于水或气体强大压力的作用，石油会喷出地表。而我们使用钻杆周围的泥土来控制。我们尽力避免那种老的，夸张的关于喷油井的想法，认为这样会浪费石油和天然气。我们希望石油会保持在钻孔下面直到我们可以利用一种可以控制的方法将其引导出来。