Saver Sub Assembly Split Ring Quill Replacement
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Solution Overview
Problem
The existing threaded connections in well drilling equipment, such as the quill, are prone to fatigue and external bending loads, leading to costly downtime, significant handling charges, and high replacement costs due to the need for partial disassembly and replacement of the entire quill.
Innovation Solution
A saver sub assembly that attaches to the main quill with a split ring and body to distribute weight and torque, using O-rings for sealing and preventing fluid leakage, allowing for quick and non-damaging replacement without the need for threading, thus avoiding the need for total quill replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded connections are used in the quill to attach drill string and blow out preventer, then the connection can withstand drilling torque and tensile load, but the threads may fail due to fatigue and bending loads causing significant downtime and high replacement costs
Solution Approach 1:
The invention divides the quill into two separate components: a main quill and a saver sub. The saver sub is a replaceable component that attaches to the main quill via a non-threaded connection (such as a friction fit or interference fit), while the drill string and blow out preventor attach to the saver sub. This segmentation allows the saver sub to be replaced independently when worn or damaged, without replacing the entire main quill, thus reducing downtime and costs while maintaining the strength and reliability of the overall connection.
2Ease of repair
If the entire quill must be removed for replacement when threads fail, then a re-cut or replacement can occur, but extensive disassembly and handling charges increase downtime and costs
Solution Approach 1:
By segmenting the quill system into a permanent main quill and a replaceable saver sub, the invention enables localized replacement of only the worn component. The saver sub can be quickly detached from the main quill using a simple non-threaded connection, allowing rapid replacement without the need to disassemble the entire quill or perform time-consuming threading operations, significantly reducing downtime and handling charges.
3Reliability
If the quill is removed and replaced, then the connection can be restored, but the size and weight of the quill generate significant handling charges and repair bills
Solution Approach 1:
The invention segments the quill system so that only the saver sub, a smaller and lighter component, needs to be manufactured and replaced when worn. The main quill remains in place and is not subjected to replacement costs. This reduces manufacturing costs significantly, as the saver sub is much smaller and less complex to manufacture than a complete quill assembly, while still maintaining connection reliability through the saver sub's threaded connections to the drill string and blow out preventor.
4Force
If threaded connections are used, then the quill can withstand drilling loads, but the threads are susceptible to fatigue and external bending loads over time
Solution Approach 1:
The invention segments the load-bearing path by placing the threaded connections in the replaceable saver sub rather than in the permanent main quill. The saver sub absorbs the fatigue and bending loads through its threaded connections to the drill string and blow out preventor, while the main quill experiences reduced cyclic loading. When the saver sub's threads show signs of fatigue, the entire saver sub is replaced as a unit, extending the service life of the main quill while maintaining full drilling load capacity.
Data Source
AI summary
A saver sub assembly has a body capable of coupling with a quill, and a split ring capable of coupling with the quill and the body and capable of keeping the quill and body together. The body has splines to prevent relative rotation between the quill and the body. The body may be hollow, and/or have a split ring retainer to maintain the position of the split ring. The saver sub assembly may also have one or more O-rings positioned between the body and the quill. The body of the saver sub assembly may have a threaded pin for engaging a drill string.