Hydraulic Release Tool
The Hydraulic Release Tool (HRT) operates by using the drilling fluids and mud pumps on the rig. The unique design of the HRT allows operation with any type of fluid. The shear pin design of the tool does not require high shear pressures, thus the in place rig pumps are sufficient to operate the tool.
The design of the HRT is different than other release tools in the manner of which it grips to the body of the tool in which it is releasing. Many of the release tools on the market rely on gripping either the inside and/or outside diameter of the tool it is releasing. These types of grips are unable to withstand high torsional values. The HRT relies on pins to connect to the tool it is releasing. These pins can withstand extremely high torsional loads which allow rotation of strings down hole at high torque without tool failure. The compressive and tensile strengths of the HRT are designed to API standards.
Functioning of the tool requires a ball to be pumped from surface down inside of the drill pipe, to the tool to activate the release. Plastic balls are pumped from surface. When fluid displacement is unwanted through pumping, steel balls can be used to reach the tool without fluid displacement. Once the ball has reached its seating position within the tool, pump pressure is applied to shear the shear pins. Once the shear pins are sheared, the HRT piston slides down while relocating, dislodging the drive pins from the tool to release. Disengagement from the released tool is achieved by simply lifting the HRT up. The repositioning of the piston allows drainage/circulation of the drill string after release.
When releasing, the neutral point of the HRT is not critical. The HRT can be released in a compressive state which eliminates the use of other tools required to find free point. With the aid of the HRT torque blocks, the tool can release with induced torsion loads as well.