External Tool Trap with Crush Cylinders for Falling Drill Strings
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Solution Overview
Problem
Conventional internal tool traps fail to cushion the impact of falling drill strings and are ineffective when the tool string is lowered below the trap position, posing safety risks to oilfield workers and equipment.
Innovation Solution
An external tool trap assembly with a collar clamp, energy-absorbing crush cylinders, and a pivotable catcher plate assembly that can be attached to the outside of a lubricator or tool string housing, featuring a funnel receptacle to catch and absorb the kinetic energy of falling equipment, preventing damage and injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an internal tool trap is used to catch falling drill strings, then the tool string can be arrested, but the impact cannot be cushioned and the trap becomes ineffective when the tool string is lowered below the trap position
Solution Approach 1:
The patent applies beforehand cushioning by positioning the catcher plate assembly below the tool string housing and equipping it with energy-absorbing crush cylinders. These crush cylinders are pre-positioned to absorb the kinetic energy of falling tool strings, cushioning the impact before it reaches the arrest mechanism. This resolves the contradiction by maintaining reliable arrest effectiveness while simultaneously cushioning the impact through pre-positioned energy absorption elements.
Solution Approach 2:
The patent transitions from an internal trap mechanism to an external catcher plate assembly positioned in a different spatial dimension - below the housing rather than inside it. This dimensional change allows the trap to remain effective regardless of tool string position, as the catcher plate can arrest tool strings whether they are above or below the original trap position, while the crush cylinders provide impact cushioning in this new spatial configuration.
2Reliability
If the tool trap is positioned inside the housing, then it can arrest tool strings, but it cannot effectively catch tool strings lowered below the trap position
Solution Approach 1:
The patent extracts the trap mechanism from the internal housing environment and positions it externally below the housing. The catcher plate assembly with crush cylinders is positioned in the annular space around the housing, allowing it to capture tool strings at any position - whether above, at, or below the housing level. This extraction resolves the contradiction by maintaining reliable capture capability while significantly improving adaptability to different tool string positions.
Solution Approach 2:
The trap mechanism is relocated to a different spatial dimension - from inside the housing to the external annular space below it. This dimensional relocation enables the trap to operate effectively across a broader range of tool string positions, as the catcher plate can intercept tool strings regardless of their vertical position relative to the housing, thereby improving versatility while maintaining reliability.
3Ease of operation
If a wireline or cable is used to support the tool string, then the tool can be lowered and raised, but the cable can break or disconnect causing serious injury and damage
Solution Approach 1:
The patent applies preliminary anti-action by positioning the catcher plate assembly with crush cylinders below the tool string housing as a preventive safety measure. The crush cylinders are pre-positioned to absorb kinetic energy, and the catcher plate is ready to arrest the tool string in the event of cable failure. This preliminary protective arrangement counteracts the potential harmful effects of cable breakage before they can cause serious injury or damage, while maintaining the ease of operation for normal tool string deployment.
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 external tool trap effectively catches unintentionally released drill strings, dissipates kinetic energy, and allows for safe lowering and raising of tool strings during drilling operations, minimizing damage and risk to personnel and equipment.
Implementation Method 1
dissipating that kinetic energy (produced by loss of control of the tool string) when the tool string's lower or distal end strikes the closed catcher plate assembly (164). Preferably, the step of dissipating that kinetic energy includes directing the energy of the falling tool string through the catcher plate assembly (164) and into a crushable energy absorbing material
Data Source
AI summary
An external trap apparatus (70) and a method for safely controlling drilling tool string components during oil field drilling operations includes a collar clamp (72) affixed to a drilling tool string lubricator (80) and configured with laterally spaced first and second vertical rails (120, 122) depending therefrom and configured to support a coaxially aligned guide plate (232) and a reinforced catcher plate assembly (164) carrying a tool-end receiving funnel receptacle (202) and first and second energy absorbing crush cylinders (160, 162). When the drill string (82) is raised or withdrawn from the well (28), the funnel receptacle (202) can be rotated into coaxial alignment to catch the drill string's end or downhole tool, in the event of an inadvertent loss of control of the drill string (82).