Chelating VES Treatment Fluid for Wellbore Filter Cake Removal
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Solution Overview
Problem
Existing drilling fluids form stable filter cakes that are difficult to remove completely, particularly in long horizontal sections of wellbores, leading to flow capacity issues and reduced injectivity in production wells.
Innovation Solution
A reactive treatment fluid comprising a chelating agent, viscoelastic surfactant, and additives like oxidizing salts and carbonates is used to dissolve and exfoliate filter cakes, including barite and polymeric materials, with a pH-controlled aqueous solution enhancing penetration and removal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drilling fluids are used to form filter cakes, then wellbore stability is improved, but complete removal of filter cakes becomes difficult
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and pH of the treatment fluid to transform the stable filter cake into a removable state. The treatment fluid contains chelating agents, oxidizing salts, and carbonates that chemically react with barite and polymeric materials, changing their solubility and adhesion properties to enable complete removal while maintaining wellbore stability during drilling
Solution Approach 2:
The patent uses composite materials by combining multiple chemical components (chelating agents, oxidizing salts, carbonates, surfactants) in a treatment fluid formulation. This composite approach allows the fluid to simultaneously address different aspects of filter cake removal: chelating agents bind to metal ions, oxidizing salts break down organic polymers, and surfactants reduce surface tension for better penetration, achieving complete removal of complex filter cake compositions
2Object-affected harmful factors
If filter cakes are made highly resistant and stable, then formation fluid invasion is reduced, but flow capacity and injectivity are compromised
Solution Approach 1:
The patent applies the extraction principle by removing filter cake components from the wellbore wall through chemical dissolution and detachment. The treatment fluid extracts barite, polymeric materials, and other filter cake constituents by breaking their chemical bonds and suspending them in the fluid, thereby restoring formation permeability and injectivity while the filter cake's protective function against formation fluid invasion is restored after removal
3Ease of operation
If conventional treatment fluids are used, then some filter cake removal is achieved, but complete removal in long horizontal sections is not possible
Solution Approach 1:
The patent applies continuity of useful action by formulating a treatment fluid that maintains effective chemical activity throughout the entire wellbore length, including long horizontal sections. The fluid contains components that prevent premature precipitation and maintain solubility products, ensuring continuous and complete filter cake removal from the wellhead to the heel of horizontal wells without loss of treatment effectiveness
Solution Approach 2:
The patent uses intermediary substances such as surfactants and chelating agents that mediate between the treatment fluid and filter cake components. These intermediaries enhance penetration into the filter cake matrix, facilitate chemical reactions, and prevent re-deposition of removed materials, ensuring complete removal even in challenging long horizontal wellbore configurations
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 treatment fluid effectively removes filter cakes across the entire wellbore length, including horizontal sections, by dissolving and exfoliating resistant components, thereby improving permeability and injectivity.
Implementation Method 1
a reactive treatment fluid comprising a chelating agent, a viscoelastic surfactant, and additives like oxidizing salts and carbonates is used to dissolve and exfoliate filter cakes
Implementation Method 2
additives like oxidizing salts and carbonates is used to dissolve and exfoliate filter cakes
Implementation Method 3
a reactive treatment fluid comprising a chelating agent, a viscoelastic surfactant, and additives like oxidizing salts and carbonates
Implementation Method 4
a pH-controlled aqueous solution enhancing penetration and removal efficiency
Data Source
AI summary
A reactive treatment fluid for filter cake removal, the reactive treatment fluid including: a base fluid; a chelating agent; a carbonate; an oxidizing salt; an organic acid; a viscoelastic surfactant (VES); and a base.