Salt cavern storage tank expanding method

The invention relates to a groove expanding method for a salt cavern reservoir, and belongs to the technical field of salt rock stratum brine mining and cavity building. According to the salt cavern storage tank expanding method, through reciprocating regulation and control of a gas-liquid interface and combination of forward circulation and reverse circulation combined operation, the situation that the liquid level of injected clear water rises too fast, and then a small-size pointed cone bottom tank is formed in the tank building period is prevented; through reciprocating regulation and control of a gas-liquid interface, saturated brine in the bottom tank of the storage cavern can be discharged in time, and the side wall of the bottom tank of the storage cavern can be corroded for multiple times; through reverse circulation operation, the purpose of guaranteeing transverse size expansion of the bottom groove of the storage cavern can be achieved; after the normal circulation tank expanding and cavity formin