Study on Energy Conversion Efficiency and Structure Optimization of the Multorifices Nozzle for Radial Jet Drilling

Abstract

Underground gas storage (UGS) is a crucial method for mitigating seasonal fluctuations in natural gas consumption. However, in China, UGS is primarily achieved through the conversion of abandoned gas reservoirs with limited storage capacity. Radial jet drilling (RJD) is an effective technology for the secondary development of depleted reservoirs. The multiorifice nozzle is a critical component that can efficiently break rock and create radial holes to increase gas production. In this study, we investigate the impact of nozzle structure on energy conversion efficiency through numerical simulations and experiments. Additionally, we design a swirling multiorifice nozzle and verify its effectiveness in field applications. Our findings indicate that the nozzle pressure drop and vorticity are primarily generated at the acute angle of the orifices. The number of forward orifices is directly proportional to energy loss, while the discharge coefficient and hydraulic performance initially increase and then decrease. Swirling multiorifice nozzle have fewer backward orifices, so they have less energy loss and a larger discharge coefficient. It has achieved better rock-breaking results in field applications. In conclusion, this study provides theoretical guidance and technical support for the secondary development of gas storage.

Experimental Study of Different Radial Jet Drilling Parameters and Operation Regimes for Effective Well Stimulation

“…Studies [12][13][14] show that the application of waterjet radial drilling technology is most effective in environments with increased oil viscosity, which typically have stagnant zones in low-permeability areas of the reservoir. In studies [15,16], methods of statistical analysis were used to demonstrate that the waterjet radial channel technology is more effective in comparison with the technology of hydrochloric-acid treatment of bottomhole formation zone and the technology of "reperforation/quick-gain perforation". In [5], the authors describe the experience of modeling the process of drilling radial channels in a fractured type of reservoir, which is evaluated as successful further in the study; in particular, the waterjet channel in the fractured type of reservoir connects the existing fractures, thereby improving filtration in the reservoir zone under effect.…”

“…Studies [12][13][14] show that the application of waterjet radial drilling technology is most effective in environments with increased oil viscosity, which typically have stagnant zones in low-permeability areas of the reservoir. In studies [15,16], methods of statistical analysis were used to demonstrate that the waterjet radial channel technology is more effective in comparison with the technology of hydrochloric-acid treatment of bottomhole formation zone and the technology of "reperforation/quick-gain perforation".…”