职称英语2015版 课文详解 第九课.doc

9. Oil and Gas Generation 油气生成1. Petroleum（石油） is a result of the deposition（沉积物） of plant or animal matter in areas which are slowly subsiding（下沉）. These areas are usually in the sea or along its margins in coastal lagoons or marshes（沼泽）, occasionally（偶尔） in lakes or inland swamps（沼泽）. Sediments are deposited along with the organic matter（有机质） and the rate of deposition of the sediments must be sufficiently rapid（迅速） for the organic matter to be preserved（保存） by burial before being destroyed by decay（腐烂）. As time goes on（随着时间的推移） the organic material is buried deeper and hence is exposed to higher temperatures and pressures. Eventually （最终）chemical changes result in the generation of petroleum. Ultimately the subsidence will stop and may even reverse.1.石油是动植物在缓慢沉降区沉积演化而成的。这些地区通常是在海里，或者在海边的泻湖或沼泽中，偶尔在湖泊或内陆沼泽中。有机质和沉积物一起沉积下来，沉积速度必须足够快，才能使部分有机质在腐烂毁坏之前埋藏保存起来。随着时间的流逝和这个地区继续慢慢下沉，有机质埋藏德更深，从而处于更高的温度和压力之下。最后经过化学变化生成了石油。而下沉最终会停止甚至可能反过来上升。2. As the great weight of the overlying rocks（上覆岩层） and sediments pushed downward, the organic material was squeezed out of （压出）its original sedimentary mud into adjacent（临近的） sandstones. Small globules of oil collected together in the pores of the rock and eventually migrated（迁移） upwards through layers of porous rock. Indeed, some of it eventually reached the surface and collected in large pools of tar（焦油）, which are called“seeps”or“shows”. However, some petroleum did not reach the surface. Instead（反而）, its upward migration was stopped by an impervious or impermeable layer of rock. It lay trapped in porous reservoir rocks, such as sandstone（石灰岩） or limestone（石灰岩）, far beneath the surface.2.由于上覆岩层的重量和沉积物的不断下压，迫使石油离开它们的出生地，运移到附近砂岩中。油滴聚集在岩石空隙中，最终通过空隙性岩层向上运移。最后，部分石油到达地面形成大的焦油池。石油到达地表的地方叫做“油苗”或“油气显示”。然而，一些石油不能渗透到地面，在向上运移时被一些不渗透的岩层阻挡，于是就圈闭在远离地面以下的空隙性储油岩中，如砂岩或石灰岩。3. Four prerequisites are necessary for（对有必要的） oil and gas to accumulate in commercial quantities in an area:（1）The oil originates in（起源于） a source bed（生油层）, and a marine shale, once a black mud rich in（富有） organic compounds, is thought to（被认为） be a common source rock. (2)The oil then migrates to（移动到） a permeable reservoir rock（储集岩）, and to do this it may travel for long distances both vertically（垂直的） and horizontally（水平的）. Oil cannot move through the tiny openings of the shale（页岩） source beds rapidly enough to be extracted profitably. (3)A nonpermeable layer（不渗透层） must occur above a reservoir bed. Since oil is lighter than water, it tends to move upwards through openings（开口） and cracks（裂缝） until it encounters impervious（不渗透的） beds that it cannot penetrate（穿透）. The oil may then accumulate beneath the impervious layers. Some gas occurs in solution within the oil, and if enough is present it separates out（分出） to occupy（占据） the uppermost（最高的） region of such a trap. (4)A favorable structure （有利的构造）must exist to concentrate the oil, and anticlines, salt plugs, and faults are common examples.3.石油或天然气要聚集到具有开采价值的数量，必须具备四个先决条件：（1）石油源于生油层，海相页岩（曾经是一种富含有机化合物的黑色软泥）被认为是一种常见的生油岩。（2）石油然后经过长途垂直和水平运移，聚集到渗透性储集岩中。在页岩生油层的细小孔道中，石油不能快速流动，因而开采不经济。（3）在储集岩层纸上必须有不渗透层。因石油比水轻，总是通过各种空隙和裂隙向上运移，直至遇到不能渗透的岩层才停止。然后石油就会聚集在非渗透岩层之下。石油中含有溶解气，如果高于饱和度，溶解气就会游离出来占据圈闭的最上部地区。（4）必须具备有利的构造才能把石油聚集起来，背斜、盐栓和断层就是常见的例子。4. Traps4. 圈闭的类型5. A trap is the place where oil and gas are barred from （被禁止）further movement. Geologists（地质学家） have classified petroleum traps into two basic types: structural（构造） traps and stratigraphic（地层） traps. Structural traps are traps that are formed because of a deformation in the rock layer that contains the hydrocarbons（烃类）. About 80 to 90 percent of the known petroleum reserves（储量） occur in structural traps.5. 圈闭是阻止石油和天然气进一步运移的地方。地质学家把油气圈闭分成了两大基本类型：构造圈闭和地层圈闭。构造圈闭是由于含有碳氢化合物的岩层变形而形成的圈闭。大约80%90%的油藏都发现于构造圈闭之中。6. An anticline, the simplest and commonest form of petroleum accumulation（积聚）, is an upward fold in the layers of rock, much like an arch（拱形） in a building. A porous and permeable（渗透的） reservoir rock must be sealed above by an impermeable（不渗透的） cover bed which is fine-grained, relatively impermeable bed such as clay, shale, marl, or salt. Petroleum migrates into the highest part of the fold（褶皱）, and its escape is prevented（阻止） by an overlying bed of impermeable rock.6. 背斜圈闭是一种最常见的简单石油储集类型，其岩石向上折起，形状就像拱形的建筑物。在多孔渗透性储集层之上必须要有细粒不渗透的盖层封闭，如粘土、岩层、泥灰岩或盐。石油运移进入褶皱的顶部，其上面的不渗透岩石便阻止了石油溢出。7. Fault（断层） traps are also common. Again, there must be a porous and permeable reservoir rock that is sealed above by a fine-grained, relatively impermrable bed. But the real trap is provided by the fault, which prevents further updip migration （迁移）either by the fine-grained material in the fault itself or by the brining of a fine-grained relatively impermeable bed on the other side of the fault to the position that truncates the reservoir.7. 断层圈闭也是很常见的。断层圈闭同样也必须具有多孔可渗透储集层和相对来说渗透性较差的细粒盖层。但真正的圈闭是由断层所形成的。由于产生了断层，存在于断层中的一些细粒物质会使石油不能再继续向上运移：另外，当断层切过储油层时，断层另一侧不渗透细粒物质层也会在储油层被切断的地方将油层封住，使石油无法继续向上运移。8. A salt dome formed when a mass of（大量的） salt flows upwards under the pressure resulting from the weight of the overlying sediments. The salt dome bows up sedimentary beds and seals off（封闭） disrupted beds and so provides traps over and around the sides of the dome.8. 上覆沉积物的重量所产生的压力使大量的盐向上蠕动，形成了盐丘。盐丘将沉积岩层向上拱成穹形，并封闭了断开的岩层，这样就在盐丘的上面和周围形成了圈闭。9. The trapping mechanism of stratigraphic traps is from stratigraphic rather than（而不是） structural causes. In these, the essential features(基本特征) remain a porous and permeable reservoir rock sealed by a fine-grained relatively impermeable rock, but the configuration （结构）of these to form a trap arises from（由引起） the particular（特别的） sedimentary process and nature（性质） of the resulting sediments. The most obvious forms if stratigraphic trap are fossil coral reefs（珊瑚礁）. In these, the voids（空隙） in the reef reservoir contain（包含） the petroleum which is prevented from（阻止） leaking out（泄露） by the clay or shale in which t