Downhole Slip Assembly with Axial Biasing Cone
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Solution Overview
Problem
Existing slip mechanisms in downhole packers are susceptible to dislodgment due to pressure fluctuations in hydrocarbon wells, necessitating an improved mechanism to maintain slips in an energized state and enhance frictional engagement.
Innovation Solution
A slip assembly with a mandrel, plurality of slips, and biasing members that apply axial force to cylindrical cones, ensuring the slips remain radially outward and energized, even during pressure variations, through the use of axially compressible biasing members and cooperatively arranged ramped surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional slip mechanisms are used in downhole packers, then the packer can be set and unset, but the slips are susceptible to dislodgment due to pressure fluctuations
Solution Approach 1:
The biasing member applies a continuous preliminary force to the cone, which in turn maintains continuous force on the slip. This preliminary action counteracts the dislodging effect of pressure fluctuations before they can cause the slip to disengage, thereby preventing the harmful effect rather than merely responding to it.
Solution Approach 2:
The biasing member is pre-loaded to maintain the cone in a state of continuous engagement with the slip. This preliminary positioning ensures that the slip remains engaged with the casing even when pressure fluctuations occur, maintaining reliable engagement without requiring active control during pressure variations.
2Stability of the object's composition
If slips are forced radially outward during setting, then the packer is secured in position, but the slips may be dislodged by pressure reversals
Solution Approach 1:
The biasing member continuously applies force to the cone to maintain slip engagement, creating a preliminary counter-action against pressure reversals. This continuous force ensures that even when well pressure reverses or fluctuates, the slip remains engaged with the casing, preventing dislodgment and maintaining packer position stability.
3Ease of operation
If springs are used to urge slips into positions, then the slips can be actuated, but the mechanism becomes more complex
Solution Approach 1:
The biasing member serves multiple functions: it maintains the cone in a loaded state, applies continuous force to the slip, and counteracts pressure fluctuations. By combining these functions into a single component rather than using separate springs and actuators, the design achieves ease of operation while minimizing the increase in device 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 solution effectively maintains slips in an energized state, enhancing grip and preventing axial displacement, even under fluctuating well pressures, thereby improving the reliability and stability of packer engagement.
Implementation Method 1
at least one biasing member comprising a generally cylindrical body coaxially provided over the mandrel adjacent the first end of the at least one cone body, the biasing member being axially compressible and adapted to apply an axial force against the cylindrical body
Implementation Method 2
the second end having a wedge surface, whereby the inner surface extends farther towards the slips that the outer surface; wherein the wedge surface of the cone body is oppositely directed to the ramped surface of the slips, and whereby axial advancement of wedge surface towards the ramped surface forces radially outward movement of the slips
Implementation Method 3
each of the slips having: a longitudinal axis generally parallel to the longitudinal axis of the mandrel; a first face, directed radially away from the mandrel; a second face, directed towards the mandrel; and first and second ends; at least one of the first and second ends having a ramped surface provided on the second face
Data Source
AI summary
A slip assembly comprises a plurality of slips provided over a mandrel of a downhole tool, at least one generally cylindrical cone body slidably provided over the mandrel, and at least one biasing member coaxially provided over the mandrel and adapted to apply an axial force against the cylindrical body to maintain the slips in a radially extended position when the tool is set.