Dual-Acting Filtercake Breaker Fluid for Uniform Acid Distribution
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Solution Overview
Problem
Existing methods for removing filtercake are inefficient in wellbore operations, as they often result in localized higher concentrations of acid and other areas having little to no acid, leading to uneven distribution and permeability is not restored.
Innovation Solution
A dual-acting breaker fluid system utilizing a delayed acid and viscosifier to ensure even distribution and permeability is restored.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a breaker fluid is used to break up filtercake, then the filtercake is removed, but the acid distribution becomes uneven with localized higher concentrations
Solution Approach 1:
The breaker fluid system is segmented into two distinct functional components: a delayed acid component that provides controlled acid release over time, and a viscosifier component that provides controlled thickening. This segmentation allows each component to address specific aspects of the problem independently, with the acid component ensuring uniform distribution through delayed release and the viscosifier component ensuring adequate contact time through controlled viscosity increase.
Solution Approach 2:
The breaker fluid incorporates a delayed acid component that does not immediately release acid upon contact with the filtercake. Instead, the acid release is preliminarily delayed through the use of delay agents or controlled release mechanisms, allowing the fluid to first distribute uniformly throughout the wellbore annulus before acid is released to break down the filtercake. This preliminary delay ensures even distribution and prevents localized high concentrations.
2Duration of action of moving object
If a delayed acid generator is used, then acid is released at a controlled rate, but the fluid viscosity may be insufficient for effective circulation
Solution Approach 1:
The breaker fluid merges two previously separate functions into a single integrated fluid system: the delayed acid generator function and the viscosifier function. By combining these components into one fluid formulation, the system achieves both controlled acid release over an extended period and adequate viscosity for effective circulation. The synergistic interaction between the delayed acid component and viscosifier ensures that the fluid maintains proper rheological properties throughout the delay period while still enabling effective wellbore circulation.
3Ease of operation
If the fluid viscosity is increased to improve circulation control, then circulation is improved, but the acid distribution may be hindered
Solution Approach 1:
The system performs preliminary action by introducing the viscosifier component before the acid release occurs. The viscosifier increases the fluid viscosity in advance, improving circulation control and ensuring the fluid can be effectively pumped through the wellbore. However, because the acid release is simultaneously delayed, the increased viscosity does not hinder acid distribution - the acid is released gradually after the viscosity increase, allowing the viscous fluid to carry the acid uniformly throughout the annulus before the acid begins to break down the filtercake.
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 dual-acting breaker fluid system effectively breaks down the filtercake, ensuring even distribution and permeability is restored.
Implementation Method 1
a delayed acid, wherein the delayed acid generates an acid within the wellbore, wherein the acid causes the pH of the filtercake breaker fluid to decrease to a pH less than or equal to 5, and wherein the acid breaks the filtercake
Implementation Method 2
a viscosifier, wherein the viscosifier increases the viscosity of the filtercake breaker fluid prior to or after the filtercake breaker fluid is located within the wellbore
Data Source
AI summary
A filtercake breaker fluid can include a delayed acid and a viscosifier. The delayed acid can generate an acid downhole that breaks the filtercake. The viscosifier delays the breaking of the filtercake by the acid due to an increase in viscosity of the breaker fluid. The viscosifier can be a hydrophobically modified polymer or a viscoelastic surfactant.