Experimental study of the crude oil storage in underground salt cavern sediment void with high impurity salt mines

Using the salt cavern to store crude oil is a mature method widely used in the US, France, and Germany. These countries usually use the top space of the sediment particles of salt caverns to store the crude oil. In China, the bedded rock salt will produce plenty of insoluble sediment particles when solution mining due to the insoluble interlayers and impurities. Thus, a novel crude oil storage method that uses the insoluble sediment particles' void is proposed to enhance the cavern oil storage capacity. Four novel crude oil storage experiments (crude oil preparation, sediment particles preparation, sediment void crude oil storage, and sediment contents detection) were conducted by a series of self-made devices to evaluate the feasibility of sediment void crude oil storage. The optimization of crude oil type, oil recovery and loss process, void structure evolution were discussed. The results show that the average oil recovery ratio of crude oil (Saudi, Iranian, and UAE) is 90.7 % at 50 °C, which indicates that crude oil is suitable for storing in the salt cavern sediment void. The optimization crude oil kinematic viscosity range is less than 10 mm²/s. The surface and inner pores of the sediment will be filled with the brine, which reduces the oil absorption and adhesion. The sediment weight of extraction oil and oil kinematic viscosity have a positive correlation relationship. The research has a reference to the large-scale underground salt cavern oil energy storage.