Hydraulic drilling jar with hydraulic lock piston

A method, comprising:

• conveying a jarring device into a borehole, the jarring device including a housing, a mandrel received within the housing and movable relative thereto, a pressure chamber defined between the housing and the mandrel and filled with a hydraulic fluid, and a hydraulic lock piston radially interposing the housing and the mandrel and including:
• a pressure piston having first and second ends, first and second fluid flowpaths extending axially between the first and second ends, and a valve plate matable with a bearing ring adjacent the second end;
• moving the mandrel in a first direction relative to the housing and thereby occluding the second fluid flowpath with the bearing ring;
• metering the hydraulic fluid through the first fluid flowpath and thereby regulating movement of the mandrel in the first direction;
• actuating a tripping valve arranged within the pressure chamber once the mandrel moves a predetermined distance in the first direction;
• and
• accelerating the mandrel relative to the housing and generating a jarring force in the first direction.

A method, comprising:

• conveying a jarring device into a borehole on a conveyance, the jarring device including a hydraulic lock piston including a pressure piston having a first end exposed to a pressure chamber, a valve plate matable with a bearing ring adjacent a second end of the pressure piston, and first and second fluid flowpaths extending axially between the first and second ends;
• altering a weight on the conveyance in a first direction at the jarring device and thereby increasing a pressure of hydraulic fluid within the pressure chamber;
• occluding the second fluid flowpath with the bearing ring and metering the hydraulic fluid through the first fluid flowpath;
• and
• actuating a tripping valve arranged within the pressure chamber and thereby generating a jarring force in the first direction with the jarring device.