Self-crosslinking polymers for wellbore strengthening
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Solution Overview
Problem
Conventional wellbore fluids face challenges in maintaining stability and preventing fluid loss in formations with high permeability or fractures, especially at elevated temperatures, leading to instability and reduced production due to damage from filter cake formation and degradation of natural polymers.
Innovation Solution
The use of a wellbore fluid comprising a non-oleaginous internal phase, an oleaginous external phase, and a combination of latex-containing copolymers formed from natural polymers and latex monomers, along with additional lost circulation materials, which form a filter cake that increases the breakdown pressure by at least 500 psi, providing enhanced stability and filtration control up to temperatures greater than 400°F.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional wellbore fluids are used in high permeability formations, then fluid loss control is attempted, but the formation permeability is damaged due to filter cake formation
Solution Approach 1:
The patent changes the chemical composition parameters of the wellbore fluid by incorporating specific polymers (polyacrylamide, polyvinyl alcohol, carboxymethyl cellulose) and chemicals (crosslinking agents, surfactants) that modify the fluid's interaction with the formation. This allows the fluid to form a weaker, more permeable filter cake that blocks fluid loss while preserving formation permeability.
Solution Approach 2:
The patent uses composite material principles by combining multiple polymer types and chemical additives in the wellbore fluid formulation. This composite approach creates a synergistic effect where the combination of polymers and crosslinking agents produces a filter cake with optimized properties that balances fluid loss control with formation protection.
2Loss of substance
If natural polymers are used in wellbore fluids, then fluid loss control is improved, but the polymers degrade at elevated temperatures
Solution Approach 1:
The patent modifies the thermal stability parameter of natural polymers by incorporating crosslinking agents that create crosslinked polymer networks. This crosslinking structure prevents polymer degradation at elevated temperatures while maintaining the fluid loss control properties of the natural polymers.
Solution Approach 2:
The patent creates a composite polymer system by combining natural polymers with synthetic crosslinking agents and surfactants. This composite formulation enhances the thermal stability of the polymer mixture while preserving its ability to control fluid loss through filter cake formation.
3Loss of substance
If filter cake is formed to prevent fluid loss, then fluid loss is reduced, but the drilling window is reduced due to increased breakdown pressure
Solution Approach 1:
The patent changes the mechanical strength parameters of the filter cake by controlling the polymer concentration, crosslinking density, and surfactant content. This creates a filter cake with optimized permeability and strength characteristics that provides effective fluid loss control while maintaining a wider drilling window.
Solution Approach 2:
The patent applies local quality principles by creating a filter cake with non-uniform properties - the outer region provides strong sealing to prevent fluid loss, while the inner region maintains higher permeability to preserve formation integrity and allow for wider drilling pressure ranges.
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 effectively prevents fluid loss and maintains wellbore stability across a wide temperature range, delaying fracture propagation and extending the drilling window, while minimizing damage to the formation permeability.
Implementation Method 1
The wellbore fluid comprises a non-oleaginous internal phase; an oleaginous external phase; at least one two-dimensional platelet-like material; a first latex-containing copolymer comprising at least one copolymer formed from at least one natural polymer and at least one latex monomer; and a second latex polymer distinct from the first latex polymer
Implementation Method 2
crosslinkable or absorbing polymers, loss control material (LCM) pills, and cement squeezes have been employed. These additives have found utility in preventing mud loss, stabilizing and strengthening the wellbore
Data Source
AI summary
Wellbore fluids, and methods of use thereof, are disclosed. Wellbore fluids may include a non-oleaginous internal phase; an oleaginous external phase; at least one two-dimensional platelet-like material; a first latex-containing copolymer comprising at least one copolymer formed from at least one natural polymer and at least one latex monomer; and a second latex polymer distinct from the first latex polymer.