Downhole Cutter Spring Mechanism Wireline Severing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing downhole cutting tools face challenges in effectively cutting wireline due to insufficient momentum for hammer action tools and the logistical difficulties of explosive charge tools, particularly in well deviations and international transportation.
Innovation Solution
A downhole tool utilizing a resiliently compressible member with concentrically arranged spring washers to store and release compressive force, triggered by a shear pin mechanism upon impact, which drives a cutter to sever the line and a grabber to retain the line for retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a momentum reliant cutting tool is used, then the tool structure is simple, but the tool cannot cut wireline with diameter larger than 0.56 cm due to insufficient momentum
Solution Approach 1:
The spring mechanism is pre-compressed and stored in a locked state before use. The cutting action is prepared in advance by compressing the spring to store elastic potential energy, which is then released to drive the cutter when the lock is triggered, eliminating the need for momentum during actual cutting
Solution Approach 2:
The spring mechanism provides a sudden periodic release of stored energy to drive the cutter. The spring is compressed during the descent phase and then releases its energy in a periodic impulse when triggered, creating the necessary cutting force without relying on continuous momentum
2Reliability
If an explosive charge cutting tool is used, then the cutting capability is improved, but transportation and handling becomes difficult due to explosive regulations
Solution Approach 1:
The explosive chemical energy system is replaced with a mechanical spring energy storage system. The spring mechanism stores and releases mechanical energy to drive the cutter, providing the same cutting capability without the transportation and handling restrictions associated with explosives
Solution Approach 2:
The energy source parameter is changed from chemical energy (explosives) to elastic potential energy (spring). This parameter change maintains the high power output needed for cutting while eliminating the regulatory and safety issues associated with transporting and handling explosive materials
3Force
If the cutting tool is dropped from great height to gain momentum, then the cutting force is sufficient, but the drop time and tool retrieval time increase
Solution Approach 1:
The spring is pre-compressed during tool assembly or before deployment, storing the necessary energy in advance. This eliminates the need for a long drop to build momentum, as the cutting force is prepared beforehand through spring compression rather than gravitational acceleration
Solution Approach 2:
The system transitions from a static gravity-dependent momentum system to a dynamic spring-driven system. The spring can be compressed to any desired level to achieve the required cutting force, and the tool can be deployed immediately without requiring a specific drop height or time to build momentum
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
Enables effective cutting of wireline without the need for explosives, ensuring the subsurface safety valve can be reinstated and allowing for efficient retrieval of the cutting tool and severed line in a single operation.
Implementation Method 1
a resiliently compressible member for storing a compressive force
Implementation Method 2
triggered by a shear pin mechanism upon impact
Implementation Method 3
trigger mechanism for releasing the compressive force as a driving force when the trigger mechanism is activated
Data Source
AI summary
A downhole tool mechanism for applying a driving force, such as a cutter tool for cutting a line captured within the tool, comprises a resiliently compressible member for storing a compressive force; a retaining device for maintaining storage of the compressive force until released; a trigger mechanism for releasing the compressive force when the trigger mechanism is activated. In one form the resiliently compressible member comprises a plurality of concentrically arranged spring washers each having a radial slot therein for receiving a line along the length of the resiliently compressible member. In the cutter form, there is a cutter arranged to cut the line when the trigger mechanism is activated, and the trigger mechanism is activated when the tool receives a shock force to one or both ends.