Nitrogen injection calculation and field test of the nitrogen dissolution inhibitor of salt-cavern gas storage

As the blanket in a salt-cavern underground gas storage (UGS), diesel has the disadvantages of high cost, difficult oil and water separation and environmental pollution. When nitrogen is used as the blanket, however, it is of low cost and environmentally friendly without pollution. Nitrogen dissolution inhibitor of salt-cavern UGS was tested on site. Then, by virtue of the gas-brine contact control method, the formula for calculating nitrogen injection was established for the scenarios of gas-brine contact at open hole and cavity top in the process of solution mining. Finally, the nitrogen dissolution inhibitor of two stages was tested in the field of Jintan Underground Gas Storage. It is indicated that the calculated nitrogen injection is accordant with the actual value after the loss of 10%-20% is taken into account. Thanks to the test well, the cavity volume is increased by about 5×10⁴ m³, the gas-brine contact is stable and the cavity shape is regular, which is basically in line with the expectation.