An innovative experimental apparatus for the analysis of natural gas hydrate cavitation erosion process using laser-induced cavitation

Abstract

Natural gas hydrates (NGHs) are an emerging source of clean energy distributed in the pores of soil sediments in deep seabed and permafrost zones with abundant reserves. Cavitation contains enormous energy, thus allowing radial cavitation jets to improve drilling and production rates of NGHs. This paper presents an experimental apparatus that was developed to synthesize NGHs and generate cavitation bubbles by laser for the analysis of the erosion rules of NGHs by cavitation in a reservoir environment. The apparatus consists of a working fluid injection and pressure control system, a temperature control and circulation system, a laser-induced cavitation system, a visual reaction vessel, and a data acquisition and measurement system. The laser-induced cavitation erosion on NGHs and multi-bubble interaction experiments can be conducted over temperatures and pressures in the range of 0–20 °C and 0–12 MPa, respectively, in a visualized reaction vessel. Hydrophones and high-speed photography were utilized for monitoring and analyzing the erosion process within the visualized reaction vessel. In addition, bubble groups of different components in various environments can also be tested in this apparatus to obtain the interaction characteristics under different conditions. This paper discusses the basic structure and principle of the apparatus and conducts a series of experiments to verify the effect of cavitation erosion on hydrate and the feasibility of using cavitation to increase production in hydrate exploitation.