Pump-out Plug Frangible Retainer Pressure Threshold
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Solution Overview
Problem
During downhole subterranean well operations, existing technologies face challenges in effectively managing the flow of cement compositions and spacer fluids, particularly in ensuring that pumpable cement compositions are introduced and set correctly within the wellbore while preventing premature expulsion of shut-off plugs, which can disrupt the cementing process.
Innovation Solution
The use of a pump-out plug system, where a detachably connected plug is positioned in a port of a downhole tool, held by a frangible retainer or shear pin, which is expelled into the annulus only when sufficient pressure is applied, allowing fluid delivery before being sealed off by a closing sleeve, ensuring controlled cement composition placement and prevention of premature plug expulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plug is used to prevent fluid flow through the port, then fluid flow control is improved, but the plug may be prematurely expelled into the annulus disrupting the cementing process
Solution Approach 1:
The frangible retainer is pre-installed in the port to hold the plug in place before cementing operations begin. This preliminary protective action ensures the plug remains secured during tool deployment and initial cement placement, preventing premature expulsion while allowing controlled release when needed.
Solution Approach 2:
The frangible retainer is designed with specific mechanical properties that change under different pressure conditions. It maintains high strength at low pressures to secure the plug, but is engineered to fracture at a predetermined higher pressure threshold, enabling controlled plug expulsion when cementing pressure reaches the desired level.
2Productivity
If pressure is applied to expel the plug into the annulus, then cement composition delivery is improved, but the plug may be expelled too early before proper cement placement
Solution Approach 1:
The frangible retainer is engineered with a specific fracture pressure threshold that serves as a precise trigger point. This parameter-based design ensures the plug is expelled only when cementing pressure reaches the predetermined level, providing accurate timing for the transition from plug-secured flow to open annulus flow, thereby maintaining cement placement precision.
Solution Approach 2:
The frangible retainer acts as an intermediary mechanism between the plug and the pressure system. It mediates the pressure transmission by remaining intact at lower pressures to maintain plug security, then fracturing at the threshold pressure to enable controlled plug release, thus bridging the transition between secured and expelled states.
3Reliability
If a frangible retainer is used to hold the plug, then plug retention is improved, but the retainer itself may fail prematurely
Solution Approach 1:
The frangible retainer is designed with controlled material properties that create a strength threshold. It maintains sufficient strength to securely hold the plug during normal operations and tool deployment, but is engineered to fail at a specific higher pressure threshold. This parameter-based design ensures reliable retention during critical phases while enabling predictable release when needed.
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
This solution ensures reliable and controlled delivery of cement compositions into the wellbore, allowing for effective cement setting and stabilization of the casing, while preventing premature plug expulsion and maintaining fluid flow control, thus enhancing the efficiency of the cementing process.
Implementation Method 1
a detachably connected plug (26) positioned in a port (32) of a downhole tool (12), held by a frangible retainer (52) or shear pin (114), which is expelled into the annulus (16) only when sufficient pressure is applied
Data Source
AI summary
A downhole tool has a tubular body defining an outer wall. A port is defined in the outer wall and a plug is received in the port. The plug is detachably connected to the outer wall and expellable into an annulus between the tubular body and a wellbore in which the downhole tool is placed upon the application of pressure in an interior of the tubular body.