Divalent Brine Fluid Rheology via Ester Modifiers

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Solution Overview

Problem

Conventional drill-in fluids using organic polymers degrade rapidly in divalent salt environments at elevated temperatures, leading to system instability and inadequate rheological and fluid loss control.

Innovation Solution

Incorporating a rheological modifier comprising a carboxylic acid ester or a phosphate ester blended with ethoxylated glycol into divalent brine based downhole treatment fluids to enhance rheological properties, fluid loss control, and lubricity at temperatures above 200°F.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If organic polymers are used to control rheological properties in conventional drill-in fluids, then rheological control is achieved in fresh water, but the system becomes unstable and polymers rapidly degrade in divalent salt environments at elevated temperatures

Engineering Contradiction:

Improvesystem stabilityVSAvoidpolymer stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the rheological modifier from conventional organic polymers to carboxylic acid esters and phosphate esters blended with ethoxylated glycols. This parameter change enables the fluid to maintain stability and functional performance in divalent salt environments at elevated temperatures, resolving the degradation issue of conventional polymers.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material formulation by blending carboxylic acid esters or phosphate esters with ethoxylated glycols. This composite approach creates a rheological modifier that is specifically designed to be compatible with divalent brine bases, providing both rheological control and system stability in high-temperature downhole conditions where conventional single-component polymers fail.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional organic polymers are used in divalent brine based fluids, then some fluid loss control is achieved, but fluid loss control and lubricity are inadequate at elevated temperatures

Engineering Contradiction:

Improvefluid loss controlVSAvoidfluid loss and lubricity deficiency

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing carboxylic acid esters and phosphate esters blended with ethoxylated glycols. This parameter change provides superior fluid loss control and enhanced lubricity at elevated temperatures, directly addressing the harmful deficiencies of conventional polymers in divalent brine environments.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11773309B2Divalent brine fluids having improved rheology and multifunctional properties

Publication Date: 2023.10.03 BAKER HUGHES CO

AI summary

A method of improving rheological properties of a divalent brine based downhole treatment fluid at an elevated temperature comprises adding to the divalent brine based downhole treatment fluid a rheological modifier, which comprises a carboxylic acid ester, or a phosphate ester blended with an ethoxylated glycol, or a combination comprising at least one of the foregoing in an amount effective to improve the rheological properties of the divalent brine based downhole treatment fluid at a temperature of greater than about 200° F. The divalent brine based downhole treatment fluid comprises calcium bromide, calcium chloride, zinc bromide, zinc chloride, or a combination comprising at least one of the foregoing.