subject: The Generation Mode of Offshore Oil [print this page] The Generation Mode of Offshore Oil The Generation Mode of Offshore Oil
Since ancient times, people have had a sense of respect and fear toward seas and oceans. At the same time, the exploration of ocean resources has been always hard. With the development of technology, it is known that the amount of offshore oil takes up nearly 34 percent of the whole amount of petroleum all over the world. Nowadays, the whole world pays more and more attention to the exploration of offshore oil.
Ocean is the largest geographical unit of water body. Superficial area of the earth is 520 million square kilometers, and that of ocean is 360 million square kilometers which is about 71 percent of the earth's total superficial area. Therefore, there is no question that ocean is a large resources storehouse containing abundant resources. Among all these resources in the oceans, offshore oil is one of the richest natural resources on the earth.
The area of continental shelf which lies deeper than 300 meters in the world reaches 28 million kilometers, 57 percent of which is the sedimentary basins containing rich petroleum resource. Abundant petroleum resource has been found between continental slope and continental rise which lies outside of continental shelf. Because of the limitation of exploration techniques, it is difficult to judge correctly the amount of the new found petroleum resource. It is estimated that among 300 billion tons of workable reserves of the global petroleum, 135 billion tons lie inside of continental shelf.
Tens of thousands years ago, the climate was warmer and more humid than today. At the bays and bayous, there were full of oxygen in the sea water. In addition, with the help of sufficient sunshine, abundant nutrient and organic matters brought into oceans by rivers, it was beneficial for halobios (such as fish, plankton) to reproduce in large amount rapidly. It is calculated that the remains of the global plankton living 100 meters deeper to sea level can produce as much as 60 billion tons of organic carbon. So much organic carbon is just raw material of submarine oil.
However, offshore oil cannot form just depending on these remains of marine animals. Some other conditions and processes are needed. Each year nearly 16 billion tons of sediments are brought to seas and oceans. These large numbers of sediments bury the remains of marine animals layer by layer. If a certain place is in the process of sinking, the sediments and the remains of marine animals buried will be thicker and thicker. Thus, the remains of marine animals become disconnected with air. In addition, they are located in an anoxic environment with thick rock formation, high temperature and rich bacteria. These remains of marine animals generally become scattered petroleum after a long-term decomposition.
It is difficult to explore scattered petroleum. So thegeneration of offshore oil can not leave geological structure which makes petroleum gather together. Shallow continental shelves are considered as the best places to generate and store petroleum. The sedimentation of numerous silts creates nice conditions for petroleum storage. Therefore, the stratums which can not only generate petroleum but also store it should be found in order to explore offshore oil.
