Cementing Plug Anti-Rotation and Cleaning Mechanism
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Solution Overview
Problem
Current cementing plugs in oil drilling are difficult to break and often leave residual drilling fluid and slurry on the casing wall, leading to inefficiencies and potential blockages, which prolong the cementing operation and affect seal quality.
Innovation Solution
A cementing plug design featuring a first plug body with a chamber and anti-rotation portion, and a second plug body with inclined protuberances for effective scraping and sealing, ensuring the plug can be fixedly connected to the slurry and securely broken without rotating, while the protuberances efficiently clean the casing wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the cementing plug is designed with a simple structure without anti-rotation features, then the device complexity is reduced, but the plug rotates during drilling making it difficult to break and potentially blocking the borehole
Solution Approach 1:
The cementing plug is divided into two separate bodies (first plug body and second plug body) with distinct functions. The first plug body contains the chamber and anti-rotation portion, while the second plug body provides sealing. This segmentation allows each component to be optimized independently, resolving the contradiction by adding necessary anti-rotation features without unnecessarily complicating the overall structure.
Solution Approach 2:
The anti-rotation portion is nested within the chamber of the first plug body, and the second plug body connects to the first plug body to block the chamber upper end. This nested arrangement integrates multiple functions (containment, anti-rotation, sealing) into a compact structure, improving breaking efficiency without excessive complexity.
2Device complexity
If the cementing plug is designed without cleaning portions, then the device complexity is reduced, but drilling fluid and slurry remain on the casing wall affecting cementing quality
Solution Approach 1:
The outer sidewalls of the plug bodies serve dual purposes: maintaining structural integrity and providing cleaning portions with protuberances that scrape the casing wall. This multi-functionality resolves the contradiction by integrating cleaning capability into the existing plug structure without adding separate complex cleaning mechanisms, thereby improving cementing quality while maintaining reasonable structural complexity.
3Device complexity
If the cementing plug uses a single body design, then the device complexity is reduced, but the sealability and cleaning effectiveness are insufficient
Solution Approach 1:
The cementing plug is segmented into two bodies with distinct functional zones. The first plug body handles the chamber and anti-rotation functions, while the second plug body provides additional sealing and cleaning surfaces. This segmentation improves sealability by distributing sealing surfaces across multiple components without creating excessive complexity.
Solution Approach 2:
Different regions of the plug bodies are designed with different properties: the first plug body has a chamber and anti-rotation portion for structural stability, while the second plug body emphasizes sealing and cleaning functions. This local differentiation optimizes each region for its specific function, improving overall reliability without unnecessary complexity.
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 design allows for efficient breaking of the cementing plug without rotation, preventing borehole blockages and ensuring a clean, sealed casing, thereby reducing operation time and improving cementing quality.
Implementation Method 1
an upper end of the first body being provided with a pressure portion, which fractures when subjected to a pressure larger than a predetermined value so that the chamber is in communication with the upper end of the first body
Implementation Method 2
the at least two cleaning portions are provided on outer sidewalls of the first body and the second body, respectively, for scraping off residuals on an inner wall of a casing
Data Source
AI summary
The present disclosure relates to a cementing plug comprising a first plug body (bottom plug), a second plug body (top plug), and a plurality of cleaning portions. The first plug body comprises: a first body provided therein with a chamber opening towards a lower end thereof, and an upper end of the first body being provided with a pressure portion; and an anti-rotation portion provided on an inner wall of the first body, and capable of being connected to slurry entering the chamber to limit a rotation of the first plug body. The second plug body comprises a second body. The plurality of cleaning portions is provided on outer sidewalls of the first body and the second body along a length direction thereof, for scraping off residuals (mud cake) on an inner wall of a casing.