Thixotropic Wellbore Seal Placement Precision
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Solution Overview
Problem
Existing methods for sealing annular spaces between well tubulars and surrounding formations in oil recovery are inefficient, particularly in deviated wells, due to issues with precise placement and excessive dispersion of sealing fluids.
Innovation Solution
A method using a thixotropic epoxy, phenolic, or polyester-based sealing substance with adjustable density and properties compatible with in-situ conditions, allowing precise placement and curing to form seals without slumping or excessive dispersion, utilizing a system with positive displacement pumps and controlled mixing for accurate delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a liquid epoxy material is used for sealing, then the material can flow and fill the annular space, but it exhibits excessive axial dispersion and cannot be placed precisely at the desired location
Solution Approach 1:
The patent changes the physical parameters of the sealing material by adding thixotropic agents to the epoxy composition. This causes the material to exhibit shear-thinning behavior: it becomes less viscous under shear stress (allowing pumping and controlled injection) but increases in viscosity when stationary (preventing dispersion). This parameter change enables precise placement while maintaining flowability during delivery.
Solution Approach 2:
The sealing composition dynamically changes its viscosity based on shear rate. During pumping and injection, the high shear rate reduces viscosity for easy flow. Once placed and shear is removed, viscosity increases to prevent axial dispersion. This dynamic rheological behavior allows the material to adapt to different operational phases.
2Manufacturing precision
If excessive amounts of epoxy material are used to overcome axial dispersion, then placement precision may improve, but material usage and cost increase
Solution Approach 1:
By modifying the rheological parameters of the epoxy through thixotropic agents, the patent enables precise placement with controlled quantities of material. The increased viscosity at rest prevents the need for excessive material to compensate for dispersion, allowing accurate sealing with optimal material usage.
3Ease of operation
If the sealing substance density is not matched to in-situ conditions, then the material may be easier to pump, but it will disperse axially due to density differential
Solution Approach 1:
The patent adjusts the density parameter of the sealing composition by selecting appropriate fillers and base materials to match the in-situ fluid density. This density matching eliminates buoyancy-driven axial dispersion while the thixotropic properties ensure the material remains pumpable during injection. Both parameters (density and viscosity) are optimized simultaneously.
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 precise and controlled sealing with reduced material usage, maintaining coherence and flow around tubular diameters, facilitating site-specific sealing with improved precision and efficiency.
Implementation Method 1
the sealing substance has thixotropic properties, which are compatible with the parameters determined in step a)
Implementation Method 2
utilizing a system with positive displacement pumps and controlled mixing for accurate delivery
Implementation Method 3
providing a sealing substance which is a setting epoxy based, phenolic based, or polyester based fluid
Data Source
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AI summary
The present invention relates to a method for providing one or more seals in an annular space between a well tubular and the surrounding formation or between pipes of a wellbore system for providing sectioning thereof.