Easy button for H2S removal

If the industry’s activities aren’t complex enough, environmental concerns, product quality, and the protection of equipment require E&P companies to remove impurities such as hydrogen sulfide and mercaptans before the oil and gas is transported.

E&P operators need an easy button to simplify the hydrogen sulfide (H₂S) and mercaptans removal step. A range of treating systems using liquid and solid solutions and service technology companies are available for H₂S and mercaptan removal, each with inherent advantages and disadvantages. The importance of understanding these technologies and how they address E&P requirements cannot be overstated. This knowledge is paramount when considering all operational factors, especially those that contribute to speed to market, maintenance concerns and costs, functionality of the equipment, and making operations more straightforward, all while ensuring the environment is protected, and safety is maintained.

E&P’s H₂S issue

H₂S, a highly corrosive and poisonous gas, can be a significant nuisance to upstream production. This contaminant can be generated naturally or produced by technologies used during the E&P process. Natural synthesis of H₂S can happen in the reservoir due to microbial sulfate reduction (MSR) of sulfate-containing minerals and/or thermochemical sulfate reduction (TSR). Processing derived H₂S production can happen when using E&P technologies such as steam- assisted gravity drainage (SAGD) and hydraulic fracturing used in the production of oil sands and shale oil/gas.

H₂S can manifest in all rig areas where drilling fluid and associated equipment are present, including the rig floor, substructure, shale shakers, mud cleaners, mud pit room, mud pump room, and well test equipment. Drilling and well control equipment not designed to mitigate H₂S could be subject to structural integrity, impeding functionality and operations.

Upstream operators can anticipate H₂S:

• Inherently in associated natural gas (‘sour gas’).
• During break out, also known as ‘run in the hole’, when the drill pipe has been completed, and bottom fluids are displaced to the surface.
• If a drill pipe is extracted from the well too quickly and fluids enter the wellbore.
• During the retrieval of core or fluid samples.
• During the flow test process when the well flow rate, pressure, and water level are monitored and recorded.

E&P operators are known to pay US$15+ million a year in operating costs to remove H₂S, but some existing technologies being used in production fields are inefficient, uneconomical, and in some cases, unsafe.

H₂S removal technologies

A range of regenerative and non-regenerative H₂S removal methods are available, all of which vary in how they capture and release H₂S. Over the years, scavengers have been pivotal in the removal of lower quantities of H₂S. Selecting the most appropriate scavenger involves several factors, including flow rates, H₂S quantities, demand, space, CAPEX, OPEX, and other considerations.

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