Study On The Hydraulic Energy Self - Increasing Device Of Pulsed Jet

Under the recent drilling conditions, there are two ways to improve the bottom-hole hydraulic energy and achieve greater rate of penetration (ROP), those are: ②Transporting more hydraulic energy to the bottom hole; ②Efficiency utilization of bottom-hole hydraulic energy. Because of the limitations of hardware infrastructure and the cost, the feasibility of transporting more hydraulic energy to the underground is not great in the short term. Therefore, to study how to use the bottom-hole hydraulic energy efficiently is of great significance for improving ROP.This paper investigates the current research situation both at home and abroad, summarizes and analyzes the methods of efficiency utilization of existing bottom-hole hydraulic energy. On this basis, the mechanism of enhancing down-hole device ROP is determined. The analysis shows that under the current technical conditions, there are two practical methods to utilizing bottom-hole hydraulic energy efficiently:pulse jet and down-hole hydraulic energy increase. According this, the pulse down-hole hydraulic self-enhancement device is designed.In order to verify the feasibility of the pulse down-hole hydraulic power self-enhancement device, the computational fluid dynamics analysis software ANSYS FLUENT 13.0 is used in this paper, and its dynamic mesh function is used for detailed numerical simulation and analyse of the pulse down-hole hydraulic self-enhancement device inner cavity flow field. The numerical simulation results show that the pulse down-hole hydraulic self-enhancement device can effectively sucks the drilling fluid from the annulus, and it achieves the desired effect of formatting pulse fluctuations at the device outlet. The results verify the feasibility of the device.By changing the main parameters such as diameter of the suction valve, the piston stroke, the inlet velocity and diameter of the main flow channel, this paper discusses the influence of these parameters on the device effects. It reached the following conclusions: ①the impact on the pulse amplitude value by changing the diameter of suction valve is very small; ②the change of inlet velocity and diameter of the main flow channel only affect the strength of the impulsive effect and have no impact on the pulse amplitude;③piston stroke plays the critical role in pulse amplitude value and pulse effect strength.The numerical simulation results verify the active mechanism’s exactitude of the pulse down-hole hydraulic power self-enhancement device. The pulse down-hole hydraulic power self-enhancement device as a new effective down-hole pulse generate device, can achieve the aim of generating pulse jet and increasing the bottom-hole hydraulic energy.