Numerical simulation on the flow field characteristics and impact capability of liquid nitrogen jet

Abstract

With the rapid progress of petroleum engineering, liquid nitrogen jet is expected to be used for perforation and jet fracturing, and then provide a new method for unconventional reservoirs efficient development. In order to research the flow field characteristics and evaluate the impact capability of liquid nitrogen jet, a computation fluid dynamic model was built by coupling the nitrogen physical property equations to simulate the flow field of liquid nitrogen jet. The results indicated that given the same simulation conditions, the impact pressure of liquid nitrogen jet was equivalent to that of water jet. The liquid nitrogen jet presented more excellent impact capability than water jet because of its higher axial and radial velocities. The impact capability of liquid nitrogen jet increased with the growth of nozzle pressure drop and nozzle diameter, decreased with the increasing of standoff distance, and was slightly influenced by fluid temperature. The confining pressure hardly affected the impact capability of liquid nitrogen jet, so it can be neglected in the engineering application. This study uncovered the flow field characteristics of liquid nitrogen jet and could provide theoretical guidance for the application of perforation and fracturing with liquid nitrogen jet.

Complex Flow Mechanism and Pressurization Effect of Liquid Nitrogen Jet Fracturing Formation Perforation Tunnel

“…Cai et al [21] evaluated the flow field structure of liquid nitrogen jet by establishing a two-dimensional CFD model. In order to evaluate the flow field structure of a liquid nitrogen jet, Cai Chengzheng et al established a two-dimensional CFD model [22]. They established a computational fluid dynamics model by coupling the physical characteristic equations of nitrogen and simulated the flow field of a liquid nitrogen jet.…”

Numerical simulation of the flow field structure of liquid nitrogen jet

“…Thus, the rock breaking and cracking capabilities will be enhanced significantly if the LNJ is used in the drilling or fracturing processes. Many previous investigations indicated that LNJ has stronger impact capability and better coal breaking performance than water jet because liquid nitrogen cooling can generate additional cracking effect on rock [7][8][9][10] The LNJ involves the heat transfer and the change in fluid properties. Thus, its flow field and jet structure will become more complex than those of the water jet will.…”