PMIDA Descaling Agent for Geothermal Scale Removal

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Solution Overview

Problem

Geothermal scale formation in wells leads to decreased permeability and production efficiency due to its complex and variable chemical makeup, making existing removal methods corrosive, costly, and difficult to implement effectively.

Innovation Solution

The use of N-(phosphonoalkyl)iminodiacetic acids or their salts, such as N-(phosphonomethyl)iminodiacetic acid (PMIDA), as descaling agents that complex metal ions in geothermal scale, allowing for effective dissolution and removal without extensive pH adjustments or cooling, even at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If hydrofluoric acid or hydrofluoric acid-generating compounds are used to remove silica scale, then scale removal effectiveness is improved, but corrosion risk and disposal costs increase

Engineering Contradiction:

Improvescale removal effectivenessVSAvoidcorrosion risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive, hazardous hydrofluoric acid with a biodegradable, non-hazardous descaling agent that can be safely disposed of without special treatment. The descaling agent is introduced into the wellbore, allows scale removal, and then naturally degrades, eliminating disposal costs and hazards associated with HF acid.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The descaling agent acts as an intermediary substance that facilitates scale removal without the corrosive properties of HF acid. It provides the necessary chemical action to dissolve scale while being environmentally benign and safe for use in geothermal wells, bridging the gap between effective scale removal and safety.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of time

If geothermal scale is allowed to form and accumulate, then production continues without treatment intervention, but permeability decreases and production capacity is reduced

Engineering Contradiction:

Improveproduction continuityVSAvoidproduction capacity

Core Design Contradiction:

Loss of timeVSProductivity

Solution Approach 1:

The descaling agent is introduced into the wellbore before scale deposits become severe and problematic. This preliminary treatment prevents significant permeability loss and maintains production capacity by removing scale at early stages, avoiding the need for extensive well intervention later.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The descaling agent provides continuous scale removal action as it circulates through the wellbore and contacts scale deposits. This continuous chemical action maintains production capacity by progressively removing scale without interrupting production operations.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If extensive pH adjustments or cooling are implemented to remove geothermal scale, then scale removal may be achieved, but treatment complexity and operational difficulty increase

Engineering Contradiction:

Improvescale removal capabilityVSAvoidtreatment process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The descaling agent is self-activating and does not require external pH adjustments or cooling to function. It automatically dissolves scale through its chemical properties and remains stable across a wide pH range, eliminating the need for complex pH control systems or well cooling infrastructure.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The descaling agent is designed to function effectively across a wide range of temperature and pH conditions without requiring these parameters to be changed. It maintains its scale-dissolving capability in the high-temperature, variable pH environment of geothermal wells, eliminating the need for parameter adjustment.

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

PMIDA and related descaling agents promote controlled and efficient removal of geothermal scale, reducing corrosion, disposal costs, and environmental impact, while maintaining thermal stability and effectiveness over extended periods.

Implementation Method 1

PMIDA and related descaling agents promote controlled and efficient removal of geothermal scale... by complexing metal ions produced upon interaction of the descaling agent with the geothermal scale

Methodology Applied

Scientific EffectComplexation:

Implementation Method 2

dissolving at least a portion of the geothermal scale with the descaling agent to produce a metal ion

Methodology Applied

Scientific EffectDissolution: Solvation

Data Source

PatentUS10005950B2Methods and systems for removing geothermal scale

Publication Date: 2018.06.26 HALLIBURTON ENERGY SERVICES INC

AI summary

Geothermal wells frequently form deposits of geothermal scale that can detrimentally affect subterranean operations. These deposits can be very difficult to remove from a surface. Conventional procedures for addressing geothermal scale often provide inadequate scale removal, in addition to creating a number of other issues. Methods for removing geothermal scale from a wellbore can comprise: introducing a descaling agent comprising an N-(phosphonoalkyl)iminodiacetic acid or any salt thereof into a wellbore of a geothermal well having geothermal scale present therein; contacting the geothermal scale with the descaling agent; and removing at least a portion of the geothermal scale from the geothermal well using the descaling agent.