Aqueous Dissolver Fluid for Inorganic Scale Removal

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Solution Overview

Problem

Inorganic scales accumulate on surfaces during hydrocarbon extraction operations, leading to production restrictions and costly equipment damage, as conventional methods require extended time periods and secondary acid steps for effective dissolution.

Innovation Solution

An aqueous dissolver fluid comprising a phosphonoalkyl aminopolycarboxylic acid chelating agent, a wettability modifier with anionic alkyl or aryl sulfonate, a pH-adjusting agent, and water is used to contact and dissolve inorganic scales in a single step, eliminating the need for secondary acid steps and achieving rapid dissolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If conventional aqueous dissolver fluid is used to dissolve inorganic scales, then dissolution can be achieved, but extended time periods (days) are required and secondary acid steps are needed

Engineering Contradiction:

Improvetreatment timeVSAvoiddissolution efficiency

Core Design Contradiction:

Loss of timeVSProductivity

Solution Approach 1:

The patent modifies the chemical composition parameters of the dissolver fluid by incorporating specific chelating agents (EDTA, NTA, or HEDTA) at optimized concentrations (0.1-10% w/v), along with surfactants and corrosion inhibitors. These parameter changes enable the fluid to achieve effective scale dissolution within hours rather than days, directly resolving the time-efficiency contradiction

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The dissolver fluid is formulated as a composite composition combining multiple functional components: chelating agents for scale dissolution, surfactants for wetting and emulsification, corrosion inhibitors for equipment protection, and pH buffers for stability. This composite approach enables simultaneous achievement of rapid dissolution and operational safety without requiring secondary treatment steps

Inventive Principle:

Principle #40Composite materials

2Productivity

If strong mineral acids are used for scale removal, then dissolution efficiency is improved, but equipment damage and safety risks increase

Engineering Contradiction:

Improvedissolution efficiencyVSAvoidequipment damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs biodegradable chelating agents (EDTA, NTA, HEDTA) that perform the dissolution function effectively but are environmentally benign and do not cause long-term equipment damage like strong acids. These agents provide sufficient dissolution efficiency while being inherently safer and more environmentally compatible

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The chelating agents act as intermediaries that facilitate scale dissolution through complexation reactions rather than aggressive acid attack. The surfactants serve as additional intermediaries to enhance fluid penetration and contact with scale deposits, achieving efficient dissolution without the harmful effects of strong mineral acids

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If organic solvent flush steps are added before aqueous dissolver fluid, then scale removal efficiency is improved, but process complexity and cost increase

Engineering Contradiction:

Improvescale removal efficiencyVSAvoidprocess steps

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the functions of pre-flush and dissolver into a single integrated aqueous formulation. The dissolver fluid contains surfactants that provide both the wetting/emulsification functions traditionally requiring separate organic pre-flush steps, and the chelating agents that perform scale dissolution. This merging eliminates secondary treatment steps while maintaining or improving removal efficiency

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11518926B2Removal of a mineral phase from a surface associated with a wellbore

Publication Date: 2022.12.06 HALLIBURTON ENERGY SERVICES INC

AI summary

The compositions for removing a mineral phase from a surface composition for removing a mineral phase of inorganic sulfate scale include a phosphonoalkyl aminopolycarboxylic acid chelating agent; a wettability modifier comprises a dibasic ester and a surfactant, wherein the surfactant comprises one or more of an anionic alkyl sulfonate or an anionic aryl sulfonate; a pH-adjusting agent; a scale converting agent; and water. The methods for removing a mineral phase from a surface include contacting the mineral phase with an aqueous dissolver fluid that is one of the present compositions; and removing the oil wet mineral phase from the surface with the aqueous dissolver fluid. The compositions and methods provide enhanced remediation of mineral phases from surfaces associated with wellbores.