Fiber-Laden Fluids for Cement Plug Suspension in Wellbores
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Solution Overview
Problem
Existing methods for preventing the commingling of cement plugs with other fluids in subterranean wells often require custom fluid compositions or specialized hardware, which can be time-consuming and impractical.
Innovation Solution
The use of fiber-laden fluids with a crowding factor exceeding 50, composed of linear or curved fibers, to create a high yield stress suspension that separates and supports cement plugs, preventing commingling with other fluids in the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrodynamic techniques (adjusting rheological properties) are used to prevent cement plug downward movement, then the cement plug stability is improved, but the fluid composition must be custom designed which increases complexity and time consumption
Solution Approach 1:
The invention changes the rheological parameters of the support fluid by adding fibers with specific properties (length, concentration, aspect ratio) to achieve high yield stress and plastic viscosity, eliminating the need for custom fluid composition design while maintaining cement plug stability
Solution Approach 2:
The invention creates a composite support fluid by combining standard drilling or completion fluid with fibers (natural or synthetic), utilizing the composite structure to achieve the required rheological properties without custom fluid formulation
2Reliability
If mechanical methods (inflatable packers, umbrella-shaped tools) are used to support cement plugs, then the cement plug stability is improved, but specialized hardware and wellhead equipment are required which increases device complexity and operation time
Solution Approach 1:
The invention replaces mechanical support devices (packers, umbrellas) with a rheologically engineered fiber-laden fluid that provides mechanical support through its yield stress and viscosity properties, eliminating the need for complex hardware while achieving the same stabilizing effect
Solution Approach 2:
The fiber-laden support fluid is pumped through existing drillpipe or tubulars using standard wellhead equipment, allowing the fluid itself to perform the support function without requiring specialized deployment hardware or additional mechanical devices
3Ease of manufacture
If fiber-laden fluids with crowding factor exceeding 50 are used to create high yield stress suspension, then the fluid composition complexity is reduced, but the fiber concentration and specific parameters must be precisely controlled
Solution Approach 1:
The invention establishes specific parameter ranges for fibers (concentration, length, aspect ratio, crowding factor >50) that provide a target zone for formulation, making it easier to achieve the desired high yield stress while maintaining control over the rheological properties
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 approach effectively prevents the downward movement of cement plugs by creating a stable, high-yield stress suspension that maintains separation between fluids, eliminating the need for custom fluid designs and specialized hardware.
Implementation Method 1
The fibers are present at a concentration sufficient to impart high yield stress to the support fluid. The yield stress arises from fiber entanglement.
Implementation Method 2
If no precautions are taken, the slurry will likely fall to the bottom of the hole. The support fluid provides a barrier to prevent the heavier cement slurry from mixing with the lighter drilling or completion fluid.
Data Source
AI summary
Methods for servicing subterranean wells are disclosed. Particularly, the use of a fiber-laden fluid to separate and prevent the commingling of two stationary process fluids after placement in the borehole of a subterranean well, or in a tubular body installed in a subterranean well. The fiber-laden fluids prevent the cement plug from descending through drilling fluid to the bottom of the well. It obviates the need for mechanical devices such as packers, or special adjustment of the process fluids' rheological properties.