Downhole Screen Coating for Scale and Asphaltene Prevention
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Solution Overview
Problem
Downhole fluid production screens in wells face issues with scale and asphaltene deposition, leading to blockages and reduced production rates, as existing methods for removal are costly and inefficient, requiring frequent well intervention.
Innovation Solution
A subterranean screen assembly with a coating of amorphous diamond-like carbon doped with silicon and oxygen, or a fluoropolymer, applied to the screen substrate, which reduces deposition of scales and asphaltenes when exposed to corrosive downhole fluids at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical or mechanical methods are used to remove scales from screens, then scale removal is achieved, but well intervention costs increase and non-productive time accumulates
Solution Approach 1:
The patent applies preliminary action by coating the screen with anti-scale materials (such as Teflon or other low-surface-energy coatings) before scale deposition occurs. This preventive coating creates a barrier that reduces scale adhesion and minimizes fouling, eliminating the need for subsequent chemical or mechanical scale removal operations and avoiding well intervention costs and non-productive time
Solution Approach 2:
The patent converts the harmful effect of scale deposition into a benefit by using the scale-forming environment itself to test and validate the effectiveness of the anti-scale coating. The coating is designed to withstand and resist the corrosive and scaling conditions, transforming the harsh downhole environment into a demonstration of the coating's protective capabilities
2Productivity
If screens are exposed to corrosive downhole fluids, then fluid production is achieved, but scale and asphaltene deposition blocks fluid flow
Solution Approach 1:
The patent introduces an intermediary substance (anti-scale coating) between the screen surface and the downhole fluids. This coating acts as a mediator that allows fluid production to continue while preventing direct contact between the scaling fluids and the screen, thereby blocking the mechanism of scale and asphaltene deposition without interfering with productivity
Solution Approach 2:
The patent changes the surface energy parameters of the screen by applying low-surface-energy coatings (such as fluoropolymers with surface energy below 20 mN/m). This parameter change in surface properties reduces the adhesion of scale and asphaltene deposits, allowing the screen to maintain high productivity even when exposed to corrosive fluids containing scaling ions and precipitating organic materials
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 coated screens significantly minimize deposits and maintain integrity during stimulation and acidizing treatments, extending their lifespan and preventing fouling, thus enhancing well production rates without the need for costly interventions.
Implementation Method 1
the coating comprising an amorphous diamond like carbon doped with about 10 to about 30 atomic percent of silicon, about 10 to about 20 atomic percent of oxygen
Implementation Method 2
a polymer comprising a fluoropolymer, a silicone, or a combination comprising at least one of the foregoing
Data Source
AI summary
A subterranean screen assembly comprises a base pipe with end connections to attach to a pipe string and a portion that is perforated or slotted; and a coated screen radially outwardly disposed of the base pipe. The coated screen comprises a screen substrate and a coating disposed on a surface of the screen substrate; the coating comprising an amorphous diamond like carbon doped with about 10 to about 30 atomic percent of silicon, about 10 to about 20 atomic percent of oxygen, or a combination comprising at least one of the foregoing dopants, or a polymer comprising a fluoropolymer, a silicone, or a combination comprising at least one of the foregoing.