H₂S Scavenger Chemical – Introduction

The world has witnessed a substantial increase in E&P of crude oil to meet the need for globalization, leading to drilling of ‘deemed undesirable’ sites, owing to the presence of higher concentration of acidic gases like hydrogen sulphide, carbon dioxide, etc. These hazardous gases require proper measures before disposal or scavenging. Of these, Hydrogen sulphide/ H₂S is the most threatening one, especially in confined or ill ventilated places.

The characteristic rotten egg smell makes H₂S recognition easy even at lower concentrations. Hydrogen Sulphide is toxic, acidic and extremely corrosive at higher concentrations. Heavier than air, it is found more near base level of the working sites. Then comes its inflammability, which may cause explosive reaction with air molecules. With peroxides, ammonia and other oxidizing chemicals, H₂S often goes through combustible reactions, producing hazardous vapours of sulphur dioxide. In humid conditions, it can even form the highly corrosive sulphuric acid.

Less than 20 ppm of H₂S concentration may cause eye irritation, throat soreness and burning, dizziness. 80 – 100 ppm may cause serious damage to exposed organs including severe vomiting and breathlessness. More than 500 ppm may cause instant loss of consciousness.

Oilfields involve large metallic installations of drilling rig equipment, on-shore, off-shore rigs, work-over rigs where metallic parts is directly exposed to these drilling conditions, viz., H₂S, causing significant damage if unchecked. This gas engages in the electrochemical reaction with metal ions, weakening their key attributes such as strength, stiffness, impact pressure, etc. Hydrogen sulphide acidifies the drilling fluid, catalyzing pitting nature corrosion on pipelines, drilling machinery, etc. The corrosion rate is further accelerated with CO₂, also naturally occurring alongside H₂S. Together, they have the ability to lower the operational life of upstream and midstream processing units in oil and gas facilities.

The problem with H₂S gas cannot be avoided, measures have to be taken to combat and/ or control its effects, with the use of H₂S scavenging chemicals. These chemicals on application remove the sulphide gas from the drilling site that comes out with crude, preventing any kind of oxidizing reaction on/ with the metal surface.

How H₂S scavenger chemicals work? They form an inert compound on reaction with hydrogen sulphide gas, eliminating even the last traces of hydrogen sulphide from the drilling wells, field condensates and natural gas to improve safety and protection of both equipment and personnel, even meeting the oil and gas specifications. H₂S scavengers have been proven to contribute to hassle free performance, with minimal to no impact on further processing at refineries or in wastewater treatment facilities. The cost-effectiveness of the product has gained immense support from the crude unit engineers during gas lift injection and chemical injection and other off-shore production applications. Primary applications of H₂S scavengers ensures following results:

• Promptly removes H₂S gas
• No effect on crude quality
• Eliminate irritating odor
• Improves operational feasibility
• Reduces corrosion in drilling equipment and pipelines
• Reduces maintenance and replacement costs, supporting asset integrity
• Enhances production performance

If there is any one market that is showing an upward trend in terms of production, transactions, infrastructure and development, it is Oil and Gas industry. This sector plays a key role in deciding the fate of the world economy. This sector is accelerated by the uniform increase in drilling oil production, which is directly proportional to the demand for oilfield chemicals.

Oilfield chemical are specialty formulations utilized in oilfields applications and drilling well sites. The efficiency and productivity of the oil field machineries and application areas depends on well site operations that cost-effectively maximizes recovery of oil and gas reserves and minimizes the impact on the environment. Oil field chemicals impart unique capabilities and functionality to the operational sites for well drilling completion and intervention services. Oilfield chemical majorly caters to three sub sectors, viz. Upstream, Midstream and Downstream.

Since Oil and Gas industry involves huge investment in terms of capital, manpower and technology, smooth operations of every functional unit is always expected. It has been observed in recent times the increasing demand of easy and more convenient mechanisms for drilling and extracting applications. The rate at which oil field chemicals are taking over mechanical prospects proves about their conventionality as well as prudential performance on their utilization. Operating machines and mechanisms were subjected to their extreme points just for drilling application which would often lead to shortage of time for calibrating and adjusting the formulations in order to achieve optimal results. But using oilfield specialty chemicals under same limited resource has ensured maximum recovery of the crude products, increasing the working output and efficiency.

Let us look at the advantages of the using these chemicals:

• Improvement in the production at drilling sites and refinery processes
• Provides protection to metallic surfaces from highly corrosive agents that comes out during crude oil extraction, increasing their performance and longevity
• Nearly cent percent extraction of crude from the storage tanks which is usually prone to sludge formation at the bottom
• Using these specialty chemicals proves to be cost effective compared to maximum mechanical efforts
• Saves time and assures monetary benefits for the owners and stakeholders.

Upstream are the on field sites where drilling and extraction of crude oil take place. Looking for potential sites, drilling, and extracting the raw product comes under the upstream working categories. Range of Chemicals that find applications in the upstream are:

• Drilling & Completion Fluid Additives: Deflocculants, Defoamers, pH Controllers, Scale Inhibitors, PHPA LT and PHPA HT, Surfactants
• Cementing Additives: Accelerators, Dispersants, Extenders, Retarders etc.
• Simulation Fluid Additives: Bactericides, Breakers, Mutual Solvents, Polymeric Viscosifiers
• E&P Chemicals: Biocides, De-oilers, Demulsifiers, Scale Inhibitors, Corrosion Inhibitors, Surfactants, Polyelectrolytes, Wax Inhibitors
• Water Injection Chemicals: Calcium Carbonate Scale Inhibitor, Biocides, Corrosion Inhibitors, Defoamers, Flocculation Aid

Another major part of oil and gas industries is midstream. This part involves the transportation of crude oil to various refineries through various oil channels, pipelines, oil-tankers etc.

Midstream chemicals that find applications in this particular sectors are:

• Crude Tank Farms: De-watering Agent, Sludge Breaker, Solid Setting Agents, Tank Cleaning Additives, Crude Oil Tankage, Dehydration, Hydrotesting Inhibitor, Degassing Chemical
• Pipeline Chemicals: Crude Pipeline Corrosion Inhibitor, Hydrotesting Corrosion Inhibitor, Pipeline Cleaning Chemicals

Oil field Downstream: This part involves refining and purification of crude oil for end user applications through various processing and methods. The end use products that follows after refining / purification are petrol, diesel, kerosene, fuel, natural gases, LPG and different other types of petro-chemicals.

Downstream chemicals that find applications in this particular sectors are:

• Pipelines: Viscosity Reducers, Biocides, Drag Reducers, Flow Improvers, Scale Inhibitors, Corrosion Inhibitors, etc.
• De Salter: Demulsifier, Metal Remover Aid, Antiscalants etc.
• Crude Pre-Heat: Antifoulant, Corrosion Inhibitors
• Primary Units: Antifoam, Neutralizing Amine etc.
• Secondary Units: DHDT, FCCU, DCU, Visbreaker
• Auxiliary Units: Merox Unit, ATU, Sour Water Stripper
• Finished Fuel Additives: Octane Boosters, PPD, Lubricity improver etc.

Chemtex Speciality Limited is an esteemed manufacturer and supplier of various oil field and drilling operations chemicals that fulfills all the requirements as per industry standard.