Dual Detached Wiper Plug Cementing System
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Solution Overview
Problem
Conventional cementing string assemblies often experience premature release of the upper wiper plug during the release of the lower wiper plug, leading to inadequate cementing of the liner in the wellbore, increased drilling downtime, and higher costs due to the need to retrieve and re-run the cementing string.
Innovation Solution
The cementing string assembly design includes a lower wiper plug securely attached to the liner via a wiper plug hanging collar, which is independent of the upper wiper plug, preventing incremental forces from being exerted on the upper wiper plug, thus preventing premature release. This design features a detachable lower wiper plug with a retractable pin or shear pin mechanism that allows for controlled release without affecting the upper wiper plug, ensuring proper cementing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lower wiper plug is releasably secured to the upper wiper plug, then the cementing string assembly can be compact and easier to handle, but releasing the lower wiper plug exerts forces on the upper wiper plug causing premature release
Solution Approach 1:
The patent divides the wiper plug system into separate independent components: the upper wiper plug remains releasably secured to the liner hanger running tool, while the lower wiper plug is separately releasably secured to the liner via a hanging collar. This segmentation eliminates the force transmission path from the lower to the upper wiper plug, preventing premature release while maintaining operational ease.
Solution Approach 2:
The hanging collar acts as an intermediary component between the lower wiper plug and the liner. It provides a dedicated attachment point for the lower wiper plug that is independent of the upper wiper plug's attachment mechanism, thereby isolating the release operations and preventing force-induced premature release of the upper wiper plug.
2Productivity
If the upper wiper plug is prematurely released, then the cementing operation can be completed faster, but proper cementing of the liner string is inhibited requiring re-drilling and re-cementing
Solution Approach 1:
By segmenting the wiper plug attachment system into independent components, the patent ensures that the upper wiper plug remains securely attached during the lower wiper plug release operation. This prevents premature release and ensures proper cementing quality without requiring re-drilling and re-cementing, thus maintaining both productivity and reliability.
3Device complexity
If the lower wiper plug is releasably secured to the upper wiper plug, then the device complexity is reduced, but the upper wiper plug experiences incremental forces during release
Solution Approach 1:
The patent segments the attachment system so that the lower wiper plug connects to the liner through a separate hanging collar rather than to the upper wiper plug. This eliminates the force transmission path while maintaining relatively simple attachment mechanisms, achieving a balance between device complexity and force management.
Data Source
AI summary
A cementing string assembly for cementing a liner in a wellbore includes a drill pipe, a liner hanger running tool attached to the drill pipe, a liner releasably secured to the liner hanger running tool, an upper wiper plug disposed within the liner and releasably secured to the liner hanger running tool or to the liner, and a lower wiper plug disposed within the liner and releasably secured to the liner downhole of the upper wiper plug. The lower wiper plug is detached from the upper wiper plug. The lower wiper plug is releasably secured to an inner surface of the liner by a wiper plug hanging collar and is releasable from the liner independent of the upper wiper plug and without exerting forces on the upper wiper plug. The cementing string assembly prevent premature and unintentional release of the upper wiper plug while releasing the lower wiper plug.