Laser-Applied DLC-PLC Multilayer Coating for Anti-Scavenging H2S Sampling
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Solution Overview
Problem
Conventional coatings used for protecting reservoir sampling equipment from hydrogen sulfide (H2S) scavenging are ineffective, prone to damage, and require high-temperature reapplication, leading to structural integrity issues and economic costs.
Innovation Solution
A diamond-like carbon (DLC) and polymer-like carbon (PLC) multilayer coating applied via laser-induced PVD at low temperatures, providing a barrier against H2S scavenging and maintaining sample accuracy, with improved wear resistance and friction properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coatings (electroless nickel, weld overlay, polymer-based) are used to protect against H2S corrosion, then the base material is protected by limiting reactions with H2S, but the coatings scavenge H2S and produce sulfur compounds, leading to inaccurate H2S concentration measurements
Solution Approach 1:
The patent introduces a silica-based coating as an intermediary barrier between the H2S-containing reservoir fluid and the metal substrate. This coating is specifically designed to be non-scavenging, meaning it does not chemically react with H2S to form sulfur compounds, thereby preventing measurement errors while still providing corrosion protection. The coating acts as a mediator that allows accurate H2S measurement while protecting the underlying metal equipment.
2Object-affected harmful factors
If silica-based coating is applied by chemical vapor deposition at elevated temperatures above 400°C, then H2S reactivity on metals is reduced, but the coating has limited wear resistance due to shallow thickness and low hardness, and rapid damage occurs during service
Solution Approach 1:
The patent employs a composite coating system consisting of a silica-based outer layer applied over a metal substrate. The silica coating is specifically engineered with enhanced properties including increased thickness (0.5-5 micrometers), improved hardness, and better wear resistance compared to conventional silica coatings. This composite structure combines the chemical inertness of silica with improved mechanical properties to simultaneously achieve H2S resistance and durability.
Solution Approach 2:
The patent modifies key parameters of the silica-based coating including increasing the coating thickness from shallow conventional layers to 0.5-5 micrometers, applying the coating at controlled temperatures, and adjusting the chemical vapor deposition process parameters to achieve optimal density, hardness, and wear resistance while maintaining the non-scavenging property.
3Ease of repair
If conventional silica-based coating is damaged, then the coating must be fully removed and re-applied at qualified location by placing the vessel back to elevated temperatures for extended time, but this process causes reduction in structural integrity due to accumulated thermal cycles and is not effectively repairable at field locations
Solution Approach 1:
The patent designs the silica-based coating system with preliminary considerations for field repairability. The coating is applied in a manner that allows for easy removal and reapplication at field locations without requiring extended high-temperature processing. The coating formulation and application method are specifically optimized to enable repair operations that minimize thermal exposure to the base metal, thereby preserving structural integrity while maintaining the ability to repair coating damage in the field.
4Measurement precision
If inert non-scavenging surface coating is used to create a physical barrier between reservoir sample and underlying material, then surface adsorption is prevented, but the coating must maintain complete inertness to even small amounts of H2S to avoid measurement errors
Solution Approach 1:
The patent applies the silica-based coating with specific local properties optimized for H2S non-scavenging performance. The coating is engineered to have uniform composition and structure throughout, ensuring consistent inertness across the entire coated surface. The silica-based material is specifically selected and formulated to exhibit complete chemical inertness toward H2S, preventing any localized scavenging that could affect measurement accuracy.
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 coating effectively prevents H2S scavenging, ensuring accurate hydrogen sulfide concentration measurement and extending the life of sampling equipment while reducing operational costs and maintaining structural integrity.
Implementation Method 1
inducing placement of the anti-scavenging coating from the carrier tape to the metal substrate through activation of a laser on to the carrier tape
Implementation Method 2
the adsorption of H2S onto metal surfaces... These coatings create a physical barrier between the reservoir sample (oil & gas) and the underlying material, thus helping to prevent surface adsorption
Data Source
AI summary
Embodiments presented provide for the protection of field equipment deployed temporarily downhole and most importantly the non-scavenging of fluid species. In embodiments, an anti-scavenging hydrogen sulfide protective coating is provided to a subterranean reservoir fluid system for the protection of its surfaces with minimal interactions with the reservoir fluids to be collected and subsequently analyzed, particularly for hydrogen sulfide.