Self-Degrading Filter Cake for Uniform Wellbore Treatment
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Solution Overview
Problem
In oil and gas wells, high permeability zones often divert treatment fluids away from lower permeability zones, leading to incomplete treatment and the need for separate fluid treatments to remove filter cakes, which can be costly and complex, and may re-establish uneven permeability patterns.
Innovation Solution
A self-degradable filter cake or layer composed of hydrolytically unstable, formation-fluid dissolving, or slow-dissolving materials is formed across the well formation, providing controlled permeability and uniform treatment distribution without the need for additional fluid treatments to remove the filter cake, using materials like polylactic acid (PLA) or oil-soluble resins that degrade over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a filter cake is formed using conventional materials, then treatment fluid distribution is improved, but separate removal treatment is required increasing cost and complexity
Solution Approach 1:
The filter cake is designed to self-degrade through hydrolysis of ester bonds in the polymer structure, eliminating the need for separate removal treatments. The degradation occurs automatically under downhole conditions, with the filter cake breaking down into soluble monomers that can be produced with the well flow.
Solution Approach 2:
The filter cake material uses hydrolytically unstable polymers with controlled degradation rates achieved by adjusting polymer composition, molecular weight, and crystallinity. This allows the filter cake to maintain its function during treatment then automatically degrade after serving its purpose.
2Reliability
If a filter cake is removed using separate fluid treatment, then the filter cake is eliminated, but compatibility issues arise and cost increases
Solution Approach 1:
The filter cake automatically degrades through hydrolysis without requiring separate removal fluids, eliminating compatibility issues between removal treatments and the formation. The degradation products are water-soluble monomers that pose no harm to the formation.
Solution Approach 2:
The hydrolytic instability that could be seen as a weakness is converted into a benefit, where the same chemical bonds that allow the polymer to degrade also enable it to break down into harmless, water-soluble monomers that can be easily produced with the well flow.
3Reliability
If filter cake is removed, then the formation is cleared, but uneven permeability is re-established leading to incomplete dissolution
Solution Approach 1:
The filter cake degrades uniformly throughout its structure through hydrolysis, preventing the re-establishment of uneven permeability patterns. The degradation occurs from throughout the bulk material rather than requiring fluid penetration and dissolution from the outside in.
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 self-degradable filter cake ensures uniform treatment distribution across all formation zones, reducing treatment costs and complexity by eliminating the need for separate filter cake removal steps and maintaining formation integrity after treatment.
Implementation Method 1
the components degrade, erode, and/or dissolve over time in contact with production fluids or other fluid generally encountered in oil and/or gas well
Implementation Method 2
formation-fluid dissolving, or slow-dissolving materials
Data Source
AI summary
Systems and methods for treating formation intervals including forming a low permeability layer on a surface of the interval and pumping a treating fluid, where the treatment fluid is diverted through the layer permitting improved treatment uniformity across the formation or intervaland permitting a longer interval to be treated, where the layer comprises self-degradable material that degrade over time without harm to the formation or interval surfaces.