Zinc-Free High-Density Aqueous Brine for Downhole Stability

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Solution Overview

Problem

Conventional high-density aqueous brines used in oilfield applications, such as calcium bromide, often crystallize at temperatures that are too high for downhole use in high-pressure environments like the Gulf of Mexico, leading to precipitate formation, and alternatives like zinc-containing brines require costly environmental mitigation due to regulatory concerns.

Innovation Solution

A zinc-free high-density aqueous brine composition is developed using a combination of water and inorganic bromide salts, specifically calcium bromide and cesium bromide, which achieves densities of 15.0 ppg or greater and true crystallization temperatures of 20°F (-6.7°C) or less, making it suitable for downhole applications without the need for zinc.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional calcium bromide aqueous brine is used to achieve high density, then density increases, but true crystallization temperature becomes too high causing precipitate formation

Engineering Contradiction:
ImprovedensityVSAvoidtrue crystallization temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The invention changes the chemical composition parameters of the brine by incorporating multiple inorganic bromide salts (calcium bromide, cesium bromide, and lithium bromide) in specific proportions. This compositional parameter change allows achieving density of 14.2 ppg or greater while maintaining true crystallization temperature at 20°F or lower, resolving the contradiction between high density and low crystallization temperature

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite brine system combining multiple inorganic bromide salts rather than relying on a single salt. The synergistic effect of calcium bromide, cesium bromide, and lithium bromide creates a composite material that simultaneously achieves high density and low crystallization temperature, preventing precipitate formation in downhole applications

Inventive Principle:
Principle #40Composite materials

2Temperature

If zinc bromide is added to calcium bromide brine to achieve high density and low crystallization temperature, then crystallization temperature decreases, but environmental regulatory costs increase

Engineering Contradiction:
Improvetrue crystallization temperatureVSAvoidenvironmental pollution
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The invention extracts zinc bromide from the brine composition entirely, eliminating the environmental pollutant while maintaining the desired performance characteristics. By removing zinc and replacing it with environmentally friendly alternatives (cesium bromide and lithium bromide), the brine achieves the same low crystallization temperature without triggering EPA regulatory requirements and associated mitigation costs

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive environmentally regulated zinc with cheaper, unregulated inorganic bromide salts that do not require environmental mitigation measures. This substitution reduces both material costs and environmental compliance costs while maintaining functional performance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 zinc-free brine composition effectively prevents precipitate formation over time, ensuring clarity and stability at both ambient and elevated temperatures, thus addressing the temperature and regulatory issues of existing high-density brines, while being environmentally friendly and cost-effective.

Implementation Method 1

a high density, zinc-free aqueous brine can be prepared from a combination of water and two or more inorganic bromide salts where the inorganic bromide salts include calcium bromide and cesium bromide

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP3323869B1High density aqueous well fluids
Publication Date: 2021.04.07 ALBEMARLE CORP

AI summary

This invention provides zinc-free aqueous brine composition, These zinc-free aqueous brine compositions have a density of about 14.3 pounds per gallon to about 15.8 pounds per gallon, and a true crystallization temperature of about 20°F or less, and comprise water and two or more inorganic bromide salts, where the inorganic bromide salts include calcium bromide and cesium bromide. Processes for forming these zinc-free aqueous brine compositions are also provided..