An innovative experimental apparatus for the analysis of natural gas hydrate erosion process using cavitating jet

Natural Gas Hydrate (NGH) develops and exists in pores of soil sediments under deep seabed and permafrost regions. A cavitation jet is an efficient method of rock breaking, especially for soft hydrate sediment erosion. This paper presents an experimental apparatus that was developed to synthesize NGH and hydrate-bearing sediments and analyze the drilling efficiency of the cavitation jet. The visualization study of fluid flow and breaking mechanism can be conducted over a temperature range varying from -20 °C to 100 °C and up to a maximum confining pressure of 20 MPa. This apparatus is mainly composed of the pressure control and injection system, the cooling system, the cavitation system, and the reaction vessels into which the lab-fabricated temperature/pressure/resistivity sensor probe is inserted. The basic principles of this apparatus are discussed, and a series of experiments were performed to verify that the cavitating jet can be practically applied in the exploitation of NGH reservoirs.