MINIMUM SEPARATION DISTANCE BETWEEN EXISTING AND NEWLY CONSTRUCTING UNDERGROUND WATER-SEALED OIL STORAGES

During the phased construction of large water-sealed oil storage, the construction of a newly built underground water-sealed oil storage has a certain degree of impact on the water curtain system and the seepage field of the nearby under-production similar underground structure. And then may cause safety risks to the already built storage such as oil and gas leakage. However, for the time being, domestic and foreign research on this issue seems little. This paper is based on a large underground water-sealed strategy oil storage's extension phase-three project. The change of seepage field which is influenced by the new-construction of extension phase-three poses a safety impact on under-production extension phase-two project. This paper back-calculates the permeability tensor based on the field measured data. Then it simulates the stable seepage field of the under-production underground water-sealed oil storage using the software COMSOL Multiphysics. It views the seepage field as the initial seepage field. And it then simulates the evolution law of existing seepage field changes during new cavern excavation. It views the underground water level, water pressure and cavern area line rock seepage as the evaluation index. The analysis is about the new-construction cavern's impact on the water seal reliability of the under-production cavern. The research results show that when the separation distance of these two phase cavern is more than 200m, even if without setting up the central vertical separation of water curtain system, new-construction cavern has no impact on the water seal reliability of the under-production cavern. The minimum safe storage cavern separation distance is 200m. The research results provide a reasonable theoretical support for the feasibility and impact of the construction of similar oil storage in the vicinity of the underground water-sealed oil storage.