Rod String Latching Tool Without Integral Release Mechanism
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Solution Overview
Problem
Current on-off tools in the petroleum industry often prematurely un-latch due to a small gap between housing and bushing members, leading to premature release of the rod string, causing downtime and monetary loss, with no known solution to prevent repeated disengagement.
Innovation Solution
A 'on only' rod string connection device without an integral release mechanism, featuring an upper mechanism with internal threads and a smooth bore section, and a lower mechanism with a bushing and pin, utilizing a slip member and biasing member to securely engage the rod string, and optionally a shear coupling for disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an on-off tool is used to connect and disconnect rod string sections, then the tool provides both connection and disconnection functionality, but the small gap between housing and bushing members causes premature un-latching under reciprocating motion
Solution Approach 1:
The invention extracts the release mechanism from the connection tool, creating a separate disconnection system. The housing member no longer contains an integral release mechanism, eliminating the gap between housing and bushing members that caused premature un-latching. Disconnection is achieved through a separate shear coupling or left-handed threaded coupling instead of the original clutch-based release mechanism.
Solution Approach 2:
The invention segments the connection and disconnection functions into separate mechanisms. The housing member with slip member handles connection, while a separate shear coupling or left-handed threaded coupling handles disconnection. This segmentation eliminates the problematic interaction between housing and bushing members during reciprocating motion.
2Ease of operation
If the on-off tool is designed with an integral release mechanism, then disconnection can be achieved through clutch rotation, but the gap closure under reciprocating motion causes premature release
Solution Approach 1:
The release mechanism is extracted from the housing member, eliminating the source of the problem. The housing member now only contains the slip member and biasing member for connection, while disconnection is handled by a separate shear coupling or left-handed threaded coupling that is not affected by reciprocating motion.
3Ease of manufacture
If a small gap is provided between housing member and bushing member, then the tool can be assembled, but the gap closes under reciprocating motion causing premature un-latching
Solution Approach 1:
The bushing member is extracted from the housing member assembly, eliminating the gap issue. The housing member now only contains the slip member that engages with the pin on the rod, while the bushing member is a separate component that threads onto the housing after assembly, preventing any gap-related premature un-latching.
4Productivity
If the on-off tool is used for rod string connection, then connection can be made through threading, but disconnection requires premature un-latching due to gap closure
Solution Approach 1:
The release mechanism is extracted and replaced with a shear coupling or left-handed threaded coupling that provides controlled disconnection without premature un-latching. This eliminates repeated premature releases that cause downtime and production loss, while maintaining efficient connection through the threaded housing member.
Solution Approach 2:
The shear coupling or left-handed threaded coupling is designed to prevent premature disconnection before it occurs. These couplings maintain secure engagement during reciprocating motion and only allow intentional disconnection when needed, preventing the harmful premature release effect.
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
Prevents premature un-latching of the rod string, ensuring reliable connection and reducing downtime and production loss by maintaining engagement under reciprocating motion, allowing for secure attachment of the upper section to the plunger assembly.
Implementation Method 1
a biasing member to securely engage the rod string
Data Source
AI summary
In an oilwell produced by a downhole pump operated by the reciprocation of a string of rods disposed within a string of tubing, a system connects an upper section of the string of rods to a plunger assembly. The system has an upper mechanism attached to the upper section of the string of rods, where the upper mechanism has a housing member having an internal bore section having an approximate inverted conical profile. The upper mechanism has a slip member which is configured to be received into the inverted conical profile. A lower mechanism attaches to the plunger assembly. The lower mechanism has an upward end comprising a pin which, upon engagement by the upper mechanism, is received into the slip member and firmly retained within the slip member. Once the pin is engaged within the slip member, the pin is retained within the slip member until it can be manually released.