The Bohai Sea Oil Exploration and Environmental Protection

Abstract

Abstract A comprehensive review is given in this paper on marine pollution and its management in the Bohai Sea-a internal sea of China. With fast industrialization in the last two decades along the coast of the Bohai Sea, more and more pollutants discharged into the coastal waters and caused environmental disaster-a dying sea. The monitoring results have shown that 90% of the pollutants come from land-based pollution sources, which have a fundamental impacts on marine environmental quality, on marine organisms and resources and on human health. During the last ten years, the government and scientists had set up many projects including monitoring network, environmental survey, loading capacity study and formulation of management framework. However, all the projects have a little effective on the Bohai Sea environmental quality as a whole. In the late of 90's, integrated coastal zone management (ICM) was introduced into China under the support of International Maritime Organization. The approach and methodologies have changed towards the comprehensive Bohai Sea pollution control and environmental management including international organizations, central government, local authorities and stakeholders. Presently, the central government has paid a great attention to the Bohai Sea pollution problems and initiated a "Blue Sea Action Plan" which lays a foundation to the ICM. Finally, pollution control measures are listed including the laws, regulations and environmental quality standards, as well as stipulation of marine environmental management measures. Some suggestions to improve marine environmental quality and to control oil pollution in the Bohai Sea are discussed. Introduction The Bohai sea, consisting three bays Liaodong Bay, Bohai Bay and Laizhou Bay, is an almost enclosed internal sea of China with an area of 77, 000km2 (37° 07'–40° 00' N to 117° 35'–121° 10'E). The coastal line is 2,900km long and the average water depth is 18m, and the maximum depth is 70m in the Bohai Straits. Along the coast, three provinces and one Municipality are surrounding the Bohai Sea namely Liaoning, Hebei, Shandong Province and Tianjin City with a total population of 200 million (Map of the Bohai Sea). The geomorphology of the Bohai Sea is similar with the land, higher in west and lower in east, and all regarded as continental shelf. The sedimentation is increasing size towards the center of the Bohai Sea. The Liaodong Bay seabed mainly consists of fine sands and Bohai Bay mainly consists of silts and fine sands, and Laizhou Bay consists of very fine sands, and the center part consists of sands and fine sands. There are 32 main rivers with an annual discharge of 85,476 million tons of drainage water [1]. According to the estimation made by Jiang, the half water exchange time in the Bohai Sea is 4 years through the Bohai Strait with the Yellow Sea and the total water exchange time is 16–40 years [2]. The Bohai Sea received 2.8 billion tons of wastewater in 1995 with more than 700,000 tons of various pollutants inside. The mariculture wastewater, a self-contamination source, directly released to the sea is estimated 720 million tons daily in the coastal of China and the Bohai Sea makes up 35% of the total [3]. The Bohai Sea is becoming a large waste dumping ground. Oil and Gas Exploitation in the Bohai Sea. The Bohai Sea is a sedimentary basin with rich oil and gas resources. As a seaward extension of the Liaohe, Dagang and Shengli oil fields and as well the Neozoic sedimentary centre in the North China Basin, the Bohai Sea sedimentary basin covers an area of more than 77,000 square kilometres. The sedimentary thickness is over 1,000 meters and the oil-bearing stratum is about 2,730 m, with the thickest 3,200m. The oil-bearing rock system covers an area of more than 24,000 square kilometres. In the Bohai Sea, there are 14 structure belts and more than 230 local structures. According to a preliminary exploration, the reserve in the Bohai Sea is 4,660 million tons for oil, 1,200 billion cubic metres natural gas and the geologic reserve is about 0.4 to 1 billion tons [2]. Oil and Gas Exploitation in the Bohai Sea. The Bohai Sea is a sedimentary basin with rich oil and gas resources. As a seaward extension of the Liaohe, Dagang and Shengli oil fields and as well the Neozoic sedimentary centre in the North China Basin, the Bohai Sea sedimentary basin covers an area of more than 77,000 square kilometres. The sedimentary thickness is over 1,000 meters and the oil-bearing stratum is about 2,730 m, with the thickest 3,200m. The oil-bearing rock system covers an area of more than 24,000 square kilometres. In the Bohai Sea, there are 14 structure belts and more than 230 local structures. According to a preliminary exploration, the reserve in the Bohai Sea is 4,660 million tons for oil, 1,200 billion cubic metres natural gas and the geologic reserve is about 0.4 to 1 billion tons [2].