Introduction

This is a double-acting hydraulic jar designed for simple operation, variable hitting loads, and extended periods of continuous jarring in a wide range of drilling conditions. Using a patented hydraulic time-delay/mechanical-release system, the HDJ combines downhole reliability and long operating life under a wide range of drilling conditions and hostile environments.

Features

• Provides a maximum torque with minimal backlash to ensure effective transmission of drillstring torque. A full torque in either direction can be transmitted at all times without affecting the magnitude or time lag of the jarring operation. The splines and all other working parts of the tool are enclosed within the hydraulic chamber, where they are fully protected and lubricated. 
• With a fluid-isolated, high-pressure chamber in place to lubricate and isolate the moving seals, impact shoulders, and mandrel from downhole debris, thus ensuring operational integrity. 
• Virtually unaffected by downhole temperatures, with very little heat generated when in use, thus resulting in a consistent time lag to trip the HDJ, even in deep, high-temperature holes. 
• Allows for zero bleed-off during jarring, eliminating the need to apply any compensation to the brake load. 
• Controlled overpull at the surface, enabling the driller to increase or decrease the impact to the stuck point by simply increasing or decreasing the load applied to the jar. 
• With no moving parts in the hydraulic metering mechanism, it incorporates large flow paths and is protected from contamination. 
• Recocking is performed rapidly by returning to neutral and jarring again in either direction. 
• All connections torqued to the charted makeup torque to eliminate the risk of back-offs downhole.

Specifications

Model		QY79	QY89	QY95	QY108	QY121	QY165	QY178	QY203	QY241
OD in（mm）		80	90	96	109	122	167	181	206	244
ID in（mm）		25	32	32	38	50	57（70）	70	76	76
Operating Temperature(℃)		204
Tensile strength(KN)		600	750	1000	1350	1950	3750	4650	6030	8500
Torsional strength（KN·m）		6	7	8	16	25	70	80	135	165
Allowable release force KN	Upward jarring	150	180	200	250	350	700	800	1000	1250
	Downward jarring	60	90	100	120	180	350	400	500	650
Upward/Downward jarring stroke in（mm）		10 7/16					12 1/2
		265					317.5
Total stroke in（mm）		20 7/8					25
		530					635
connection		2 3/8REG NC23	2 7/8REG NC26	2 7/8REG NC26	NC31	NC35 NC38	NC50	NC50	6 5/8REG	7 5/8REG

This is a double-acting hydraulic jar designed for simple operation, variable hitting loads, and extended periods of continuous jarring in a wide range of drilling conditions.