Downhole Plug Nose Force Segmentation for Obstruction Penetration
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Solution Overview
Problem
Existing wellbore plugs often prematurely set due to obstructions, causing unintended sealing and operational challenges during fracking or zone isolation operations.
Innovation Solution
A plug design featuring a center mandrel attached only at the front end, utilizing shear devices to apply force only to the nose of the plug, preventing premature setting and allowing for later removal to enable fluid flow and potential chemical or electronic package deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If weight is applied to the rear of the plug to force it into the wellbore, then the plug can be positioned at the desired location, but the plug may prematurely set if an obstruction is encountered
Solution Approach 1:
The plug is segmented into two functional zones: the nose portion that receives and transmits setting forces, and the body portion that contains the sealing elements. The center mandrel is attached only to the nose, isolating the force application point from the sealing mechanism. This segmentation allows the nose to be pushed forward by wireline tension while the body remains protected from premature compression and setting.
Solution Approach 2:
The center mandrel acts as an intermediary component that transmits the setting force from the wireline to the plug nose without directly loading the plug body. The mandrel serves as a mechanical mediator that decouples the force transmission path from the sealing mechanism, enabling controlled setting while preventing premature activation of the slips and elastomer.
2Reliability
If the plug is designed to set upon encountering resistance, then sealing is achieved, but operational flexibility is lost as the plug cannot be removed or modified
Solution Approach 1:
The plug design incorporates dynamic characteristics through the controllable setting mechanism. The slips and elastomer remain in a dormant state during run-in, allowing the plug to be deployed and repositioned if needed. Setting is activated only when wireline tension exceeds the shear strength of the mandrel-nose connection, at which point the plug transitions from a movable to a fixed state. This dynamic behavior provides operational flexibility while ensuring reliable sealing when required.
Solution Approach 2:
The plug is designed with preliminary preparation features including the center mandrel attachment to the nose and the pre-positioned slips and elastomer. These components are prepared in advance but remain inactive during run-in. The mandrel-nose connection is designed to shear at a predetermined load, allowing the plug to transition from the run-in state to the set state. This preliminary action enables the plug to maintain adaptability during deployment while ensuring reliable sealing when the setting condition is met.
3Strength
If the mandrel remains attached to the plug body during setting, then structural integrity is maintained, but force application to the nose is insufficient to overcome obstructions
Solution Approach 1:
The mandrel attachment is segmented to connect only to the plug nose rather than the entire plug body. This segmentation creates a localized force transmission path where wireline tension is applied directly to the nose through the mandrel. The nose can therefore be pushed forward with concentrated force to overcome obstructions, while the plug body maintains its structural integrity through the internal arrangement of slips and elastomer that are activated only after the nose penetrates the obstruction.
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
Enables controlled setting and later removal of the plug, preventing premature sealing and allowing for fluid flow and deployment of chemicals or sensors, enhancing operational flexibility and data collection during wellbore operations.
Implementation Method 1
By connecting the mandrel to the plug only at the nose of the plug the body of the plug is drawn into the well behind the nose so that should the plug encounter an obstruction within the wellbore force applied to the plug on its leading nose via the center mandrel is applied only to the nose of the plug in order to overcome the instruction and without applying a load to the rear of the plug which would otherwise cause the plug to prematurely set
Data Source
AI summary
In wellbore completions it is sometimes desirable to seal the wellbore against fluid flow or to anchor a component within the wellbore. However, running such a plug into the wellbore has been problematic on occasion such as when the nose of the plug encounters an object within the wellbore such as a sand bridge or other obstruction. In those instances, the way of the tubular pushing the plug into the wellbore combined with the nose of the plug being unable to pass the instruction causes the plug to prematurely set. Such an instance the plug may need to be drilled out in order to proceed. In the present embodiment the tubular used to move the plug into the well is attached to the nose of the plug so that the force provided to the plug by the tubular is transmitted only to the nose of the plug preventing the plug from presetting and allowing the plug to push past or through an obstacle within the wellbore. In addition is envisioned that the plug may incorporate compartment that the plug within which may be placed a chemical, electronics, sensors, or other items as desired by the operator.