Downhole Hydrogen Sulfide Neutralizer with Sacrificial Rods

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Solution Overview

Problem

High concentrations of hydrogen sulfide in subterranean wells pose safety risks to personnel and equipment, and current methods for detecting and managing hydrogen sulfide during drill stem tests are inadequate, leading to potential equipment failure and environmental hazards.

Innovation Solution

A hydrogen sulfide neutralizing tool with sacrificial rods made of materials that produce metal sulfide when exposed to hydrogen sulfide, integrated into a drill stem testing string, which consumes hydrogen sulfide and reduces its concentration by reacting with it, thereby neutralizing the gas and preventing its release to the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrogen sulfide is allowed to reach the surface for reservoir evaluation, then reservoir potential can be properly assessed, but safety risks to personnel and equipment increase significantly

Engineering Contradiction:
Improvereservoir evaluation accuracyVSAvoidsafety risks from hydrogen sulfide
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful hydrogen sulfide gas into beneficial metal sulfide solids through chemical reaction with sacrificial rods. The hydrogen sulfide that would otherwise pose safety risks is transformed into inert metal sulfide debris that can be safely contained and disposed of, thereby eliminating safety hazards while preserving reservoir evaluation capabilities

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The sacrificial rods act as an intermediary substance between the hydrogen sulfide and the surface environment. These rods chemically react with hydrogen sulfide to form metal sulfides, serving as a mediator that prevents direct contact between toxic hydrogen sulfide and surface equipment/personnel while allowing reservoir fluid to be evaluated

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If hydrogen sulfide concentration is reduced through chemical reaction with sacrificial rods, then safety and equipment lifespan are improved, but the tool complexity and material consumption increase

Engineering Contradiction:
Improvehydrogen sulfide concentrationVSAvoidneutralizing tool structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs sacrificial rods made from relatively inexpensive metals such as zinc, aluminum, or magnesium that are consumed in the chemical reaction with hydrogen sulfide. These disposable rods are replaced periodically rather than designing complex reusable neutralization systems, simplifying the overall device while effectively reducing hydrogen sulfide concentrations

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical state of hydrogen sulfide from gaseous to solid metal sulfide through chemical reaction. This parameter change from gas to solid phase makes the substance easier to contain, transport, and dispose of, thereby simplifying safety management despite the chemical transformation process

Inventive Principle:
Principle #35Parameter changes

3Reliability

If drill stem tests are aborted when high hydrogen sulfide concentrations are detected, then equipment failure risk is reduced, but productivity and data collection are compromised

Engineering Contradiction:
Improveequipment failure preventionVSAvoiddrill stem test completion rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements preliminary action by placing sacrificial rods in the neutralizing tool before deploying it to the wellbore. These rods are pre-positioned to react with hydrogen sulfide as soon as formation fluid enters the tool, preventing high concentrations from reaching surface equipment and allowing drill stem tests to proceed without interruption

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the previously harmful high hydrogen sulfide environment into a manageable condition by chemically converting the gas to solid metal sulfides in-situ. This allows drill stem tests to continue even in high hydrogen sulfide formations, maintaining productivity while preventing equipment failure

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 tool effectively reduces hydrogen sulfide concentrations, enhancing safety and extending the lifespan of surface equipment by converting hydrogen sulfide into metal sulfide debris that can be collected, allowing for safer drill stem tests and reduced environmental impact.

Implementation Method 1

A sacrificial rod is located within the tool annular space and is formed of a material that produces metal sulfide when exposed to the hydrogen sulfide

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP4090829B1Downhole hydrogen sulfide neutralizer
Publication Date: 2024.04.24 SAUDI ARABIAN OIL CO
  • EP4090829B1 patent drawingFigure 1
  • EP4090829B1 patent drawingFigure 2~3
  • EP4090829B1 patent drawingFigure 4~5

AI summary

Systems and methods for neutralizing a hydrogen sulfide. A tool shell (26) circumscribes a tubular member (20), defining tool annular space between an outer diameter surface of the tubular member and an inner diameter surface of the tool shell. A sacrificial rod (38) is located within the tool annular space and is formed of a material that produces metal sulfide when exposed to the hydrogen sulfide. An uphole perforation (30) has an opening extending through a sidewall of the tubular member, defining a fluid flow path between the tool annular space and the internal bore of the tubular member. A downhole perforation (34) is located downhole of the uphole perforation and has an opening extending through the sidewall of the tubular member, defining a fluid flow path between the tool annular space and the internal bore of the tubular member.