Wellbore Acidizing Separation Fluid for Corrosion-Free Perforation

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Solution Overview

Problem

Existing acidizing methods face issues of downhole tool corrosion and acid strength loss due to prolonged exposure to acidic solutions, leading to formation damage and reduced effectiveness.

Innovation Solution

A method involving separation of acid from downhole tools during perforation operations using a separation fluid, followed by displacement of the acid into perforations to maintain its strength and prevent formation damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If acid is introduced into the wellbore before perforation, then the acid can be in position for immediate treatment, but the downhole tools suffer corrosion and the acid loses strength

Engineering Contradiction:

Improvetime delay between perforation and acid treatmentVSAvoiddownhole tool corrosion resistance

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The wellbore fluid column is segmented into distinct zones: a separation fluid zone containing the downhole tools, and an acid zone above it. This segmentation prevents direct contact between the acid and tools while maintaining both components in the wellbore simultaneously, eliminating the time delay without causing corrosion or acid strength loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A separation fluid acts as an intermediary substance between the acid and the downhole tools. This intermediary layer physically isolates the tools from the corrosive acid environment while allowing the acid to remain in position above, ready for immediate treatment after perforation occurs.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of time

If acid is introduced into the wellbore before perforation, then the acid can be in position for immediate treatment, but the acid strength decreases due to prolonged exposure

Engineering Contradiction:

Improvetime delay between perforation and acid treatmentVSAvoidacid strength

Core Design Contradiction:

Loss of timeVSLoss of substance

Solution Approach 1:

The fluid column is segmented to create a protective barrier that isolates the acid from premature reaction with formation materials. The separation fluid zone below and the acid zone above maintain distinct chemical environments, preserving acid strength while eliminating time delay.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separation fluid serves as a protective intermediary that prevents the acid from contacting the formation or perforations before the intended treatment time. This intermediary layer preserves the acid's chemical integrity and strength until the moment of perforation when immediate treatment is required.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If acid contacts perforations immediately after creation, then treatment is efficient, but formation damage occurs due to uncontrolled acid reaction

Engineering Contradiction:

Improveacidizing efficiencyVSAvoidformation damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The perforations are created first as preliminary openings into the formation, establishing controlled access points. Only after these precise pathways exist does the acid contact the formation through the perforations, ensuring efficient treatment while preventing uncontrolled widespread acid reaction that would cause formation damage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The conventional sequence is inverted: instead of introducing acid first and then perforating, the perforation operation is performed first to create controlled entry points, and only then does the acid make contact with the formation. This reversal ensures that acid reaction is confined to predetermined pathways, maximizing efficiency while minimizing formation damage.

Inventive Principle:

Principle #13The other way round (Inversion)

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

Protects downhole tools and maintains acid effectiveness, preventing formation damage by ensuring the acid does not contact the perforations until displacement, thus enhancing the acidizing process.

Implementation Method 1

pumping a volume of a separation fluid into the wellbore sufficient to submerge the BHA in the separation fluid

Methodology Applied

Scientific EffectPhysical separation through fluid displacement:

Implementation Method 2

The acid also enlarges the pore spaces in the fracture face and in the formation

Methodology Applied

Scientific EffectChemical dissolution:

Implementation Method 3

hydrochloric acid (HCl), which reacts with carbonate, sandstone, shale and the like

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 4

pumping a volume of a displacement fluid into the wellbore to displace the separation fluid and allow the acidic composition to reach the perforations

Methodology Applied

Scientific EffectFluid displacement:

Data Source

PatentUS12523134B2Method for acidizing a formation

Publication Date: 2026.01.13 OVINTIV CANADA ULC

AI summary

A method for perforating a formation and stimulating the formation with an acidic composition is provided. In particular, the method comprises using a separation layer to separate the acidic composition from perforating tools during perforation. The present invention can be used in combination with fracturing such as hydraulic fracturing.