Hydrophobic Polymer Stability in Alkaline Treatment Fluids

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Solution Overview

Problem

The production of water from hydrocarbon-producing wells is a significant technical and economic challenge due to the high mobility of water, which can flow to hydrocarbon zones, necessitating costly separation and disposal, and existing relative permeability modifiers are unstable under various downhole conditions, such as high pH and temperature, leading to precipitation and potential damage to the formation.

Innovation Solution

A treatment fluid comprising a hydrophobically modified hydrophilic polymer relative permeability modifier and anionic surfactants, such as poly(ethylene oxide) carboxylates or sulfonates, is used to maintain the modifier in a dissolved state above pH 8 and temperatures up to 200°F, preventing precipitation and maintaining stability in subterranean formations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a relative permeability modifier is used to reduce water production, then water permeability is reduced, but the modifier precipitates under high pH and temperature conditions

Engineering Contradiction:

Improvestability of relative permeability modifierVSAvoidprecipitation of modifier

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A surfactant is introduced as an intermediary substance that mediates between the relative permeability modifier and the aqueous phase. The surfactant forms micelles that solubilize the hydrophobic modifier molecules, preventing precipitation while maintaining the modifier's functionality in high pH and temperature environments.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical environment parameters are modified by adjusting pH and adding surfactants to create conditions where the relative permeability modifier remains soluble. The surfactant concentration and type are optimized to maintain modifier stability across the expected downhole temperature and pH range.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If crosslinked polymers are used to block water flow, then water production is reduced, but zonal isolation techniques are required which increase complexity

Engineering Contradiction:

Improvewater production reductionVSAvoidzonal isolation requirements

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The requirement for zonal isolation techniques is extracted and removed from the treatment system. Instead of requiring physical isolation of treatment zones, the relative permeability modifier is applied throughout the formation where it selectively reduces water permeability based on its interaction with water and hydrocarbon phases, eliminating the need for complex zonal isolation infrastructure.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If relative permeability modifiers are used to maintain minimal effect on hydrocarbon flow, then hydrocarbon permeability is preserved, but the modifiers are unstable under downhole conditions

Engineering Contradiction:

Improvehydrocarbon flow maintenanceVSAvoidstability of relative permeability modifier

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

A composite treatment system is created by combining the relative permeability modifier with surfactants and other compatible substances. This composite formulation maintains the modifier's ability to preserve hydrocarbon permeability while the surfactant component provides stability under downhole conditions, preventing precipitation and degradation.

Inventive Principle:

Principle #40Composite materials

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 solution effectively reduces water permeability without significantly affecting hydrocarbon permeability, extending the operational range of relative permeability modifiers and preventing downhole precipitation, thus enhancing hydrocarbon production and well longevity.

Implementation Method 1

the at least one surfactant is operable to maintain the relative permeability modifier in a dissolved state in the treatment fluid above a pH of about 8

Methodology Applied

Scientific EffectSolubilization: Solvation

Implementation Method 2

relative permeability modifiers are capable of reducing the flow of water through a subterranean formation while having a minimal effect on the flow of hydrocarbons

Methodology Applied

Scientific EffectRelative permeability modification: Surfactant

Data Source

PatentUS8470746B2Methods relating to the stabilization of hydrophobically modified hydrophilic polymer treatment fluids under alkaline conditions

Publication Date: 2013.06.25 HALLIBURTON ENERGY SERVICES INC

AI summary

The present invention relates to methods and compositions for treating a water- and hydrocarbon-producing subterranean formation with a relative permeability modifier, and more specifically, to improved treatment fluids, methods for preparing treatment fluids, and methods for use thereof in a subterranean formation. Methods of the present invention comprise providing a treatment fluid comprising a relative permeability modifier, at least one surfactant, and an aqueous phase base fluid; and placing the treatment fluid in a subterranean formation. The relative permeability modifier comprises a hydrophobically modified hydrophilic polymer. The at least one surfactant is operable to maintain the relative permeability modifier in a dissolved state in the treatment fluid above a pH of about 8.