Viscoelastic Scale Inhibitor Fluid for Low Permeability Placement
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Solution Overview
Problem
Scale inhibitor fluids used in hydrocarbon well treatments often struggle to reach low permeability regions, leading to inefficient squeeze treatments and potential blockage, which decreases production rates and causes formation damage.
Innovation Solution
A fully viscosified scale inhibitor composition comprising a sulphonate-functional phosphonated end-capped copolymer or diethylene triaminepentakis(methylenephosphonic acid) combined with a viscoelastic surfactant, such as oleic amidopropyl betaine, that maintains high conductivity and does not require a breaker for fluid recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Newtonian scale inhibitor fluids are used, then the treatment is simple to apply, but the fluid cannot reach low permeability regions effectively
Solution Approach 1:
The patent changes the rheological parameters of the scale inhibitor fluid by adding viscoelastic surfactants, transforming it from a Newtonian fluid to a non-Newtonian fluid with shear-thinning behavior. This allows the fluid to be pumped easily (high ease of operation) while maintaining high viscosity at low shear rates to reach low permeability regions (improved reliability of placement)
2Reliability
If xanthan polymer is used to viscosify the scale squeeze fluid, then the fluid can reach low permeability regions, but the polymer requires a breaker for recovery and damages the formation
Solution Approach 1:
The patent uses viscoelastic surfactants that form temporary wormlike micelles to provide the needed viscosity for reaching low permeability regions. These micelles break down naturally without requiring chemical breakers, eliminating formation damage from residual polymers while maintaining the temporary structural support needed for effective fluid placement
Solution Approach 2:
The patent creates a composite fluid system combining scale inhibitors with viscoelastic surfactants. This composite approach provides the viscosity enhancement needed to reach low permeability zones while the surfactant-based system avoids the formation damage issues associated with traditional polymer viscosifiers
3Reliability
If fully viscosified scale inhibitor composition is used, then the fluid can reach low permeability regions effectively, but the fluid viscosity may be too high for efficient pumping
Solution Approach 1:
The patent employs a dynamic non-Newtonian fluid with shear-thinning characteristics. The fluid maintains high viscosity at low shear rates (during static placement in low permeability regions) but reduces viscosity under high shear conditions (during pumping), thus achieving both effective placement and pumping efficiency
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 composition effectively places scale inhibitors in low permeability regions, reducing formation damage and maintaining high conductivity, thus enhancing hydrocarbon production while eliminating the need for breakers.
Implementation Method 1
a viscoelastic surfactant which is
Implementation Method 2
fully viscosified scale inhibitor composition
Implementation Method 3
a scale inhibitor which is a sulphonate- functional phosphonated end-capped copolymer
Data Source
AI summary
An aqueous composition for treating hydrocarbon wells contains (a) a scale inhibitor and (b) a viscoelastic surfactant, and further contains from 0 to less than1 % by weight of acid selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, citric acid, maleic acid, hydrofluoric acid, and mixtures thereof.