Study On Fluid-solid Coupling Features Of Fractured Rock Of Huangdao Underground Water-sealed Oil Strorage

Oil is the blood of industry and it is of great significance to establish a certainscale oil reserve system for the stable development of national economy, stabling therelationship between supply and demand and enhancing our ability to respond tointernationalemergencies. For it’s advantages of small investment and land occupationand little damage to environment and low maintenance costs, undergroundwater-sealed oil storage cavern is our preferred form of oil reserves.It is an important factor for the safety of the operation of underground water-sealoil storage to ensure the effectiveness of water-sealed conditions. As for water-sealedconditions, it’s substance is to find out the development law of cracks of crystallinerock forming the country rock of the storage, the occurrence and migrationcharacteristics of groundwater in the cracks and the interaction mechanism amongfractured rock mass under complex stress and strain, fissure water and oil or gas,beloing to rock hydraulics represented by coupling mechanism between hydraulicsand mechanics in fractured rock mass. Relying on the Huangdao UndergroundWater-sealed Cave for National Oil Storage project and supported by the NationalNatural Science Foundation of China (Grant No.40902086), researches in this paperare as follows:(1) The basic geological conditions had been studied, including naturalgeographical conditions, engineering geological conditions and hydrogeologicalconditions. The results proved that geological conditions of the site are excellent forthe construction of large scale underground water-sealed oil storage cavern.(2) Using crystalline rock sample coming from the project site, fluid-solidcoupling triaxial tests with the no filling single fracture smooth and straight had beenlaunched. Changing three-dimensional stress and fissure water pressure, monitoringthroughflow of the fracture and studying the variation of aperture and permeability,the paper find out the qualitative and quantitative relations among permeabilitycoefficient, aperture and three-dimensional stress. Also, awareness of water-sealed conditions to Huangdao Underground Water-sealed Storage can be get according tothe results of the tests.(3) The stability of surrounding rock of a tank had been simulated after theexcavation using UDEC softwear. Changes of stress and displacement undernon-water curtain situation and water curtain had been analyzed after the excavationaccording to the virtual stepped excavation. Also, suggestion to design andconstruction had been proposed.(4) Changes of seepage field in the surrounding rock had been simulated after theexcavation. Variation of groundwater level and its impacts to water-sealed conditionshad been analyzed and water inflow of the caverns had been calculated. The resultsprove that the excavation of the caverns would not evoke great fall of groundwaterlevel and the setting of water-curtain guarantee the water-sealed conditions.