Crosslinked Polyvinyl Alcohol Drilling Fluid Viscosifier

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Solution Overview

Problem

Maintaining high viscosities of drilling fluids to effectively suspend and remove cuttings and control fluid loss is challenging, especially under high temperature conditions, and existing drilling fluids face issues with high salt concentrations and shear rates.

Innovation Solution

A drilling fluid composition incorporating a viscosifier such as poly(vinyl alcohol) copolymers, crosslinked poly(vinyl alcohol), or crosslinked poly(vinyl alcohol) copolymers, which provides high viscosity at low shear rates, high temperatures, and high salt concentrations without the need for hydroxyl-containing aluminum compounds or silicate compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional drilling fluids are used to maintain viscosity, then cutting suspension is achieved, but viscosity deteriorates under high temperature conditions

Engineering Contradiction:

Improvehigh temperature conditionsVSAvoidviscosity

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the drilling fluid by using crosslinked poly(vinyl alcohol) copolymers with specific molecular weights and crosslinking densities. These parameter changes enable the fluid to maintain stable viscosity under high temperature conditions where conventional fluids would deteriorate.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite polymer structures combining poly(vinyl alcohol) with copolymer components and crosslinking agents. This composite material approach creates a viscosifier that is thermally stable and maintains its viscosity-enhancing properties under downhole high temperature conditions.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If ionic polymer thickeners are used to increase viscosity, then fluid suspension improves, but performance deteriorates at high salt concentrations

Engineering Contradiction:

ImproveviscosityVSAvoidhigh salt concentrations

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive, salt-sensitive ionic polymer thickeners with crosslinked poly(vinyl alcohol) copolymers that are insensitive to salt concentrations. This substitution allows the drilling fluid to maintain consistent viscosity performance whether using fresh water or high-salinity brines as the base fluid.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If high viscosity is maintained to suspend cuttings, then cutting removal improves, but fluid loss control becomes challenging

Engineering Contradiction:

ImproveviscosityVSAvoidfluid loss

Core Design Contradiction:

Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The crosslinked poly(vinyl alcohol) copolymer viscosifier performs multiple functions simultaneously: it maintains high viscosity for cutting suspension and provides effective fluid loss control. This multi-functionality resolves the contradiction between needing high viscosity for cutting removal and preventing fluid loss into the formation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If poly(vinyl alcohol) copolymers are used as viscosifier, then viscosity at high salt concentrations improves, but formulation complexity increases

Engineering Contradiction:

Improvehigh salt concentration toleranceVSAvoidformulation complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent optimizes specific parameters of the poly(vinyl alcohol) copolymer including molecular weight, degree of hydrolysis, and copolymer composition ratios. By carefully controlling these parameters, the formulation achieves salt tolerance without requiring complex multi-component systems, thus limiting formulation complexity while maintaining performance.

Inventive Principle:

Principle #35Parameter changes

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 drilling fluid composition achieves superior viscosity and fluid loss control under challenging conditions, enabling efficient cutting suspension and fluid management in drilling operations.

Implementation Method 1

The drilling fluid composition includes a viscosifier including at least one of a poly(vinyl alcohol) copolymer, a crosslinked poly(vinyl alcohol), and a crosslinked poly(vinyl alcohol) copolymer

Methodology Applied

Scientific EffectPolymer viscosification:

Implementation Method 2

The poly(vinyl alcohol) copolymer or the crosslinked poly(vinyl alcohol) copolymer is at least one of a graft, linear, branched, block, and random copolymer

Methodology Applied

Scientific EffectThermal stability of crosslinked polymers:

Data Source

PatentUS10920122B2Drilling fluid composition including viscosifier and method of using the same

Publication Date: 2021.02.16 HALLIBURTON ENERGY SERVICES INC

AI summary

The present invention relates to drilling fluid compositions and methods of using the same. In various embodiments, the present invention provides a method of treating a subterranean formation including obtaining or providing a drilling fluid composition including a viscosifier including at least one of a poly(vinyl alcohol) copolymer, a crosslinked poly(vinyl alcohol), and a crosslinked poly(vinyl alcohol) copolymer. The method also includes placing the composition in a subterranean formation.