Viscosifier Polymer Fluid for High TDS Brine
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Solution Overview
Problem
High total dissolved solids (TDS) in aqueous carrier fluids, such as seawater or produced water, typically reduce the viscosity of fluids used in petroleum extraction, limiting their effectiveness in drilling, completion, and hydraulic fracturing processes.
Innovation Solution
The use of a treatment fluid comprising a viscosifier polymer, a crosslinking agent, and a polymer composition of polyvinyl alcohol and polylactic acid, which maintains viscosity even in the presence of high TDS, ensuring effective fluid transport and fracture creation in subterranean formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high TDS aqueous carrier fluids (seawater, produced water) are used, then resource availability and cost are improved, but fluid viscosity decreases adversely
Solution Approach 1:
The patent converts the harmful effect of high TDS on viscosity into a beneficial effect by selecting polymers whose viscosity is enhanced by salt presence. Specifically, hydrophobic polymers like polyacrylonitrile and polyacrylic acid exhibit increased viscosity in high TDS environments, transforming the previously detrimental high-salt condition into a favorable viscosity-enhancing factor.
Solution Approach 2:
The patent changes the chemical parameters of the treatment fluid by incorporating specific polymer compositions (polyacrylonitrile, polyacrylic acid, and their copolymers) that respond positively to high TDS conditions. This parameter change allows the fluid to maintain or enhance viscosity despite the presence of high dissolved solids, thereby resolving the contradiction between using available high-TDS water and maintaining fluid viscosity.
2Stability of the object's composition
If fresh water is used as base component, then fluid viscosity is maintained, but resource scarcity and cost increase
Solution Approach 1:
Instead of avoiding high TDS conditions, the patent embraces them by using polymers that thrive in saline environments. The selected polymers convert the high-salt condition from a harmful factor into a beneficial one, allowing the use of abundant seawater or produced water while maintaining or enhancing viscosity performance.
Solution Approach 2:
The patent fundamentally changes the fluid composition parameters by replacing fresh water-based systems with high-TDS tolerant polymer systems. This parameter change enables the use of scarce fresh water to be replaced by abundant seawater or produced water, while the specific polymer selection ensures viscosity stability or enhancement in the high-salt environment.
3Quantity of substance
If brine or sea water with high TDS is used, then resource availability is improved, but polymer viscosity performance deteriorates
Solution Approach 1:
The patent identifies and utilizes polymers that exhibit the opposite behavior to conventional polymers: instead of degrading in high TDS, these polymers (polyacrylonitrile, polyacrylic acid) show enhanced viscosity performance in saline conditions. This converts the previously harmful high-TDS environment into a beneficial condition for viscosity generation.
Solution Approach 2:
The patent employs composite material strategies by using copolymers (e.g., acrylonitrile-acrylic acid copolymers) that combine the beneficial properties of different monomers. These composite polymer structures provide both high-TDS tolerance and enhanced viscosity performance, ensuring reliable fluid behavior in brine or seawater-based formulations.
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 treatment fluid maintains viscosity at 140° F. and 140° C. across a range of shear rates, enhancing the carrying capacity and fracture formation efficiency in subterranean operations, even with high TDS aqueous carrier fluids, thus overcoming the adverse effects of TDS on fluid viscosity.
Implementation Method 1
a treatment fluid comprising a viscosifier polymer; an aqueous carrier fluid comprising high total dissolved solids; and a polymer composition comprising at least one of polyvinyl alcohol and polylactic acid
Implementation Method 2
the treatment fluid has a viscosity at 140° F. and at a shear rate of about 0.1 s−1 to about 1000 s−1 of about 30 cP to about 10,000 cP
Data Source
AI summary
A method comprises obtaining or providing a treatment fluid comprising a viscosifier polymer; an aqueous carrier fluid comprising high total dissolved solids; and a polymer composition comprising at least one of polyvinyl alcohol and polylactic acid. In some embodiments, the treatment fluid has a viscosity at 140C and at a shear rate of about 0.1 s−1 to about 1 s−1 of about 1,500 cP to about 10,000 cP. The method includes placing the treatment fluid in a subterranean formation.