Bidirectional Powered Mechanical Jar for Stuck Downhole Tools
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Solution Overview
Problem
Downhole tools or components in oil or gas wellbores often become stuck due to exceeding the rig's capabilities or tensile strength, necessitating a method to free them without relying on static forces that exceed the drill string's capacity.
Innovation Solution
A controllable, powered bidirectional jarring tool assembly is introduced, featuring a jar with a stroker tool and hydraulic ram, utilizing a catch mechanism to selectively engage and disengage hammers, allowing for bidirectional jarring forces by compressing springs and transferring potential energy into kinetic energy to free stuck tools or components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical jar with preset forces is used, then the device structure is simple, but the jarring force cannot be adjusted during operation
Solution Approach 1:
The patent applies dynamics by replacing the static preset force mechanism with a dynamic hydraulic system. The hydraulic cylinder can adjust the jarring force in real-time based on operational needs, allowing the system to adapt to different stuck conditions while maintaining a relatively simple overall structure through the use of fluid power technology.
2Force
If over-pull forces are applied to accumulate potential energy, then the jarring force can be generated, but the drill string may exceed its tensile strength
Solution Approach 1:
The patent introduces a hydraulic cylinder as an intermediary energy storage and transmission device. Instead of directly applying excessive tensile forces to the drill string, the hydraulic system accumulates energy fluid pressure and transfers it to generate the jarring force, thereby protecting the drill string from exceeding its tensile strength while still achieving the required impact force.
3Ease of operation
If a hydraulic jar with flow restriction is used, then the jarring force can be controlled, but the operation time is extended due to metering delay
Solution Approach 1:
The patent applies parameter changes by using a variable or adjustable flow restriction in the hydraulic system. This allows the operator to optimize the metering rate based on the specific situation - using a faster rate when time is critical and a more controlled rate when precise force management is needed, thereby balancing the trade-off between control and time loss.
4Adaptability or versatility
If a double acting jar is used to provide bidirectional jarring force, then the versatility is improved, but the device complexity increases
Solution Approach 1:
The patent implements universality by designing a single hydraulic cylinder system that can generate jarring forces in both upward and downward directions. The hydraulic system serves multiple functions - controlling force magnitude, adjusting timing, and enabling bidirectional operation - through a unified mechanism, thereby achieving versatility without proportionally increasing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively enables the controlled release of jarring forces in both axial directions, allowing for the efficient unstickage of downhole tools and components, enhancing operational capabilities in drilling and well servicing systems.
Implementation Method 1
a hydraulic ram axially movable within the housing and operable to move the stroke rod in the first and second axial directions
Implementation Method 2
a first spring disposed within the housing and urging the first hammer toward the anvil in the first axial direction
Data Source
AI summary
A method for jarring allowing the operator to selectively control the jarring force while the tool is downhole and a powered bidirectional mechanical jar therefor, is disclosed. The jar includes a housing, an anvil fixed within the interior the housing, first and second hammers movably disposed within the housing at obverse sides of the anvil, first and second springs disposed to urge the hammers towards the anvil, and a rod with a radial catch that selectively engages and disengages the hammers so as move the hammers to compress the springs and thereafter release the hammers to be accelerated against the anvil. A actuator operates the catch. By controlling the movement of the rod, the spring compression and resultant jarring intensity can be controlled. A stroker tool may be provided to move the rod.