Calcium Bromide Polyol Heavy Fluid Low-Temperature Pumpability
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Solution Overview
Problem
Existing heavy aqueous solutions of calcium bromide used in oilfield wells face challenges in achieving high density while maintaining pumpability at low temperatures, as increasing concentration elevates the crystallization temperature, and zinc bromide alternatives are needed to mitigate corrosion and environmental concerns.
Innovation Solution
A method involving the combination of calcium bromide with low molecular weight polyols like ethylene glycol or glycerol, forming a nonsymmetric ion through hydrogen bonding, and reducing water content to create a high-density, pumpable fluid with a low crystallization temperature, using crystallization inhibitors like nitrilotriacetamide to enhance pumpability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the concentration of calcium bromide is increased to achieve higher density, then the density is improved, but the crystallization temperature is elevated making the fluid unpumpable
Solution Approach 1:
The patent changes the chemical composition parameters by introducing polyols (ethylene glycol, propylene glycol, or glycerol) as hydrogen bond donors and using calcium bromide as hydrogen bond acceptor in specific molar ratios. This chemical parameter change creates a deep eutectic system that fundamentally alters the phase behavior, allowing the fluid to maintain pumpability at much higher densities than conventional aqueous calcium bromide solutions.
Solution Approach 2:
The patent creates a composite heavy fluid system combining calcium bromide (heavy salt) with polyols (hydrogen bond donors) in a deep eutectic configuration. This composite approach leverages the hydrogen bonding interaction between the polyol hydroxyl groups and calcium bromide to form a eutectic mixture with depressed freezing point, achieving both high density and low crystallization temperature simultaneously.
2Quantity of substance
If zinc bromide is added to calcium bromide to achieve higher density, then the density is improved, but the corrosion and environmental harm worsen
Solution Approach 1:
The patent replaces the harmful zinc bromide component with a benign polyol-calcium bromide deep eutectic system. The polyols (ethylene glycol, propylene glycol, or glycerol) are environmentally friendly, non-corrosive alternatives that achieve the same density-enhancing function without the harmful side effects of zinc bromide, effectively substituting a harmful substance with a safe one.
3Quantity of substance
If the water content is reduced to increase density, then the density is improved, but the fluid becomes more prone to crystallization at low temperatures
Solution Approach 1:
The patent changes the solvent system parameters by replacing water with polyols that have lower freezing points and different hydrogen bonding characteristics. The polyol-calcium bromide deep eutectic system maintains fluidity at low temperatures even at high densities, overcoming the limitation of water-based heavy fluids that crystallize when water content is reduced.
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 resulting fluid achieves a density of 15.0-16.0 pounds per gallon with a crystallization temperature around 40°F, maintaining pumpability even after crystallization, and is free from zinc bromide, addressing the limitations of traditional calcium bromide solutions.
Implementation Method 1
The combination of a hydrogen bond donor and calcium bromide as a hydrogen bond acceptor in an appropriate molar ratio forms a higher density clear completion fluid at a low temperature not otherwise obtainable with heavy aqueous solutions of calcium bromide
Implementation Method 2
I believe that, because of the way the composition is made, a portion of each ingredient is combined with some of the other to form a composition including a nonsymmetric ion which is not present in a simple mixture or solution. The formation of the nonsymmetric ion takes place by hydrogen bonding
Implementation Method 3
A method of making the fluid comprises mixing calcium bromide with the polyol(s) in the presence of water and then reducing the water content, thus forming a heavy fluid
Implementation Method 4
using crystallization inhibitors like nitrilotriacetamide to enhance pumpability
Data Source
AI summary
Heavy fluids are made from calcium bromide and at least one hydrogen bond donor such as a low molecular weight polyol or an organic acid. The combination of a hydrogen bond donor and calcium bromide as a hydrogen bond acceptor in an appropriate molar ratio forms a higher density clear completion fluid at a low temperature not otherwise obtainable with heavy aqueous solutions of calcium bromide such as are used in oilfield wells. A method of making the fluid comprises mixing calcium bromide with the polyol(s) in the presence of water and then reducing the water content, thus forming a heavy fluid. A crystallization inhibitor such as nitrilotriacetamide or a particulate silicate is included in the formulation. When the heavy fluid “freezes,” its physical form is somewhat amorphous and pumpable rather than crystalline. The heavy fluid is useful as a drilling fluid as well as a completion fluid and for other purposes in oil recovery processes where extreme density is beneficial.