Polymer Viscosity in High Salinity Brines via Divalent Cations
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Solution Overview
Problem
The challenge lies in preparing subterranean formation treatment fluids with adequate viscosity using produced water or environmental water sources, which often have high salinity and chemical complexity, making it difficult to achieve sufficient viscosity for effective hydraulic fracturing and other treatment operations.
Innovation Solution
The method involves admixing a viscosifying amount of polymer with at least one divalent cation, such as barium, calcium, or magnesium, with environmental water to form an admixture that increases viscosity by 10% to 50% over a specified time period, allowing for the creation of effective treatment fluids for fracturing and other subterranean treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If produced water or environmental water with high salinity is used as the base fluid, then water availability and ecological impact are improved, but the ability to achieve adequate viscosity is worsened
Solution Approach 1:
The patent changes the chemical parameters of the base fluid by adding divalent cations (Ca2+, Mg2+) to environmental water with high salinity. This parameter change enables the polymer to achieve adequate viscosity (10-50 cP) despite the challenging water quality, resolving the contradiction between using available water and achieving required viscosity
Solution Approach 2:
Divalent cations serve as intermediaries between the environmental water and the polymer viscosifier. These cations facilitate the polymer's thickening action in high-salinity conditions, acting as a mediator that enables viscosity achievement without requiring fresh water
2Reliability
If polymer concentration is increased to achieve adequate viscosity, then viscosity is improved, but the chemical complexity and sensitivity to water quality is worsened
Solution Approach 1:
Divalent cations act as intermediaries that simplify the chemical system by enabling polymers to achieve adequate viscosity in high-salinity environmental water. This approach reduces chemical complexity compared to using multiple additives or complex formulations to compensate for poor water quality
Solution Approach 2:
The patent modifies the chemical environment by adding divalent cations, which changes the water's interaction with polymer. This parameter change allows standard polymers to function effectively without requiring complex chemical formulations or high polymer concentrations
3Reliability
If fresh water is used instead of environmental water, then viscosity control and fluid performance are improved, but cost and ecological impact are worsened
Solution Approach 1:
The patent converts the harmful aspect of environmental water (high salinity and chemical complexity) into a beneficial outcome by using divalent cations to enable polymer thickening. This allows the use of environmentally friendly produced water or municipal wastewater instead of fresh water, reducing ecological impact while maintaining adequate fluid performance
Solution Approach 2:
By changing the chemical parameters of environmental water through divalent cation addition, the patent makes previously unusable water sources suitable for fracturing applications, eliminating the need for fresh water and reducing the harmful ecological impact of water consumption
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 enables the formation of viscous treatment fluids that can be pumped into wellbores at sufficient pressure to treat subterranean formations, providing effective viscosity and stability for proppant transport and fracture creation, even in high-temperature environments, while reducing the need for fresh water and minimizing ecological impact.
Implementation Method 1
admixing a viscosifying amount of a polymer and at least one divalent cation with the environmental water to form an admixture, where the viscosity of the admixture increases
Data Source
AI summary
Methods of treating a subterranean formation penetrated by a wellbore include providing environmental water, admixing a viscosifying amount of a polymer and at least one divalent cation with the environmental water to form an admixture, and pumping the admixture through the wellbore at a rate and pressure sufficient to treat the subterranean formation. The viscosity of the admixture increases after the at least one divalent cation, the viscosifying amount of polymer and the environmental water are admixed. Such viscosity increase may be at least about 5% over at least a 10 minute period after the admixture is prepared. The divalent cation(s) may be selected from the group consisting of barium, calcium, copper(II), iron(II), magnesium, manganese(II), strontium, tin(II), zinc, and mixtures thereof. Further, the divalent cation(s) may be provided in the form of a salt with one or more anions selected from acetate, bicarbonate, nitrate, chloride, bromide, iodide, sulfate ion, and mixtures thereof.