Solid Acid-precursor Fluid for Deep Penetration Fracturing
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Solution Overview
Problem
Current acid fracturing methods face challenges such as rapid acid reaction near the wellbore, corrosion of equipment, and ineffective scale inhibition, leading to reduced well productivity and frequent treatment requirements due to rapid decline in scale inhibitor concentration.
Innovation Solution
A treatment fluid comprising a carrier fluid, a solid acid-precursor that hydrolyzes to form acid in situ, and solid scale inhibitor particles, which are designed to delay acid generation and maintain scale inhibition over time, reducing corrosion and extending treatment effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct acid fluids are utilized in acid fracturing, then acid can react quickly near the wellbore to create flowpaths, but acid fails to penetrate deeply into the formation and causes excessive corrosion of metal parts
Solution Approach 1:
The patent applies preliminary action by injecting scale inhibitor into the formation before acid fracturing treatment. This pre-treatment step ensures that scale inhibitor is already in place to protect metal surfaces from corrosion when acid is subsequently injected, allowing deeper acid penetration without excessive metal dissolution
Solution Approach 2:
The patent uses scale inhibitor as an intermediary substance that mediates between the acid and metal surfaces. The scale inhibitor adsorbs onto metal surfaces forming a protective film that prevents direct contact between acid and metal, thereby reducing corrosion while allowing acid to maintain its etching function on the formation
2Reliability
If conventional scale inhibition treatments are used with flushing fluid, then scale inhibitor chemical can adsorb to formation particle surfaces, but scale inhibition effectiveness is reduced quickly and requires repeated application
Solution Approach 1:
The patent implements continuity of useful action by eliminating the flushing step that removes scale inhibitor. Instead of injecting and then flushing away the scale inhibitor, the treatment allows the scale inhibitor to remain continuously in contact with the formation and metal surfaces, maintaining prolonged scale inhibition effectiveness
Solution Approach 2:
The patent extracts the harmful flushing step from the conventional scale inhibition process. By removing the flushing fluid injection that washes away the scale inhibitor, the treatment preserves the scale inhibitor in place for extended protection without requiring repeated applications
3Loss of time
If acid precursors in liquid phase are used to form acid in wellbore, then acid can form in the formation, but acid reacts very quickly limiting the delay effect and introducing water that exacerbates scale formation
Solution Approach 1:
The patent applies parameter changes by transitioning from liquid phase acid precursors to solid phase acid precursors. This phase change provides better control over acid generation timing and rate, extends the delay effect, and avoids introducing additional water that would exacerbate scale formation in carbonate formations
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 allows for deeper acid penetration and prolonged scale inhibition, reducing the need for frequent treatments and minimizing equipment corrosion, thereby enhancing well productivity and treatment efficiency.
Implementation Method 1
a solid acid-precursor that hydrolyzes to form acid in situ
Implementation Method 2
A treatment fluid comprising a carrier fluid, a solid acid-precursor... and solid scale inhibitor particles
Data Source
AI summary
A method for treating a subterranean formation includes forming a treatment fluid including a carrier fluid, a solid acid-precursor, and a solid scale inhibitor. The solid acid-precursor includes a material that forms an acid at downhole conditions in the subterranean formation. The method further includes adding a solid acid-responsive material into the treatment fluid, where the solid acid-responsive material enhances formation of acid from the solid acid-precursor in acidic conditions. The method includes performing an acid fracture treatment and inhibiting scale formation within the subterranean formation. The solid scale inhibitor allows for long-term scale inhibition after the treatment.