NUMERICAL SIMULATION OF SEAWATER INTRUSION IN UNDERGROUND OIL STORAGE CAVERN IN ISLAND ENVIRONMENT
ZHANG Bin1,2, LI Yutao1,2, SHI Lei1,2, PENG Zhenhua3, LI Junyan3
1. School of Engineering and Technology, China University of Geosciences(Beijing), Beijing 100083;
2. Key Laboratory of Deep Geodrilling Technology, Ministry of Land and Resources, Beijing 100083;
3. Petrochemical Engineering Co., Ltd., CNOOC, Qingdao 266101
Seawater intrusion is an important factor affecting the safety of construction and operation of underground water-sealed oil caverns. In the island environment, massive excavation of underground caverns can significantly change the natural groundwater seepage field of the island, causing seawater intrusion. On the one hand, seawater intrusion can increase the risk of water inrush. On the other hand, the chloride ion in the seawater can cause erosion of the structure and facilities of underground caverns, which can affect the service life of the underground oil storage cavern. Therefore, consideration is necessary about the water-sealed reliability and the stability of rock masses in the construction of groundwater oil storage cavern in island environment. Attention must be paid on seawater intrusion. Scientifically deployed water curtain systems can effectively reduce the risk of seawater intrusion. The study is based on the related theory of pollution transport, and uses finite element numerical simulation method. A simulation of seawater intrusion is carried out about the proposed large scale underground oil storage cavern of an island in Zhejiang province. Research results show the follows. Without fresh water curtain system, excavation of underground caverns can cause seawater intrusion. Horizontal water curtain system can weaken seawater intrusion to a certain extent on the basis of satisfying the reliability of water-sealed. Vertical water curtain system can obviously inhibit the occurrence of seawater intrusion. The research results provide a theoretical basis for the study of seawater intrusion in underground oil storage cavern in island environment.