Frac Plug Retention Mechanism for Tubular Position Stability
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Solution Overview
Problem
Current frac plugs in oil and gas production often shift within tubular sections, preventing full compression of sealing elements and allowing extrusion during reservoir stimulation or milling operations.
Innovation Solution
A frac plug design featuring a plug body with composite material outer sleeves and metal inner cores, along with a slip mechanism that engages the tubular section to maintain position and ensure full compression of the sealing element, even during milling or grinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a central mandrel with upper and lower slips is used to hold the frac plug in place, then the plug can be positioned within the tubular section, but the plug may shift when a sealing ball is installed and the sealing element may not fully compress if slips become fully engaged prior to full compression
Solution Approach 1:
The frac plug body is divided into multiple segments or components including a central mandrel, slips, and a sealing element arrangement that allows independent compression. The slips are positioned to engage the tubular section independently from the sealing element compression mechanism, enabling sequential action where slips engage first to secure position, then the sealing element compresses fully without interference.
Solution Approach 2:
The slips are designed to engage the tubular section in advance before the sealing element compression is finalized. This preliminary engagement stabilizes the plug position and prevents shifting during subsequent sealing ball installation and sealing element compression, ensuring both position stability and full sealing element compression.
2Device complexity
If the sealing element is positioned between the slips, then the arrangement compact, but the sealing element cannot fully compress if the slips become fully engaged prior to full compression
Solution Approach 1:
A compression mechanism or intermediary structure is introduced between the slips and the sealing element. This intermediary allows the sealing element to be compressed independently of the slip engagement status, ensuring full compression can be achieved even after slips have engaged the tubular section. The intermediary transmits compression force to the sealing element while being isolated from the slip engagement forces.
3Ease of operation
If current frac plug design is used, then installation is simple, but the plug allows extrusion of the seal during stimulation or movement during milling or grinding operations
Solution Approach 1:
The frac plug incorporates dynamic retention features such as movable retention elements or adjustable locking mechanisms that adapt during different operational phases. During installation, the plug is simple to deploy, but during stimulation or milling operations, the retention features actively engage to prevent extrusion and movement, providing enhanced reliability when needed without complicating the installation process.
Data Source
AI summary
A frac plug is provided. The frac plug includes a plug body, a sealing element, and a slip. The plug body includes a first sub and a second sub. The first sub includes a first composite material outer sleeve, and a first metal inner core engaged with and structurally supporting the first composite material outer sleeve. The second sub includes a second composite material outer sleeve, and a second metal inner core engaged with and structurally supporting the second composite material outer sleeve. The sealing element is circumferentially disposed about the first sub and, when actuated, seals an annulus between the frac plug and a tubular section. The slip is disposed between the first sub and the second sub and, when actuated, engages the tubular section.