Reservoir Treatment

PetroCare® reverses and inhibits the formation of H2S

PetroCare® Process - The Treatment and Prevention of Reservoir Souring Encourages Biological Oxidation of Hydrogen Sulphide and Inhibits its Production in Oil Reservoirs

Biological Reservoir Souring

Reservoir souring can be caused by the activity of Sulphate Reducing Bacteria (SRB) which produce hydrogen sulphide from their metabolism of sulphate present in reservoir and injection waters.

Reservoir souring and hydrogen sulphide production has traditionally been an expensive problem both to treat and prevent. The additional cost elements can include :

• Installation of expensive production equipment upgrades, downhole and topside, to cope with hydrogen sulphide in the production streams.
• Loss of market value of produced hydrocarbons because of high sulphide content.
• Deferment of production revenues as a result of lower well productivities caused by deposition of iron sulphide deposits in the reservoir.

The PetroCare® Concept

Fluids containing low concentrations of nitrate are widely used in waste water treatment to inhibit biological production of hydrogen sulphide. The nitrate is used by naturally-occurring denitrifying bacteria in their oxidation of sulphides to sulphate.

The activity of the denitrifying bacteria, stimulated by the presence of nitrate, also inhibits further sulphide production by SRB. During this process the nitrate is consumed and the end-products are benign substances, namely sulphate, nitrogen gas and carbon dioxide.

The PetroCare® process is:

• based on the same concept, providing indigenous denitrifying bacteria present in hydrocarbon reservoirs with nitrate, which stimulates their biological oxidisation of sulphide and inhibits any further sulphide production
• a concentrated water-based nitrate formulation designed for delivery to the reservoir through dosing into the injection water stream.
• non-hazardous and has a HOCNF Category 0 or Group E classification.

Typical Properties
Density	1.41 kg/dm3
Crystallisation point	-20 C
pH	5 - 7

The dosing rate is determined by a number of factors (e.g. H S level in reservoir, water injection rate, water quality etc.).

The PetroCare® Service

Our technical support staff and product specialists are on hand at all times to provide expert advice on cost-effective dosing rates for specific fields and reservoirs. We are a global player in nitrate-based formulations and, with an extensive network of regional supply points, we can supply the PetroCare® solution to customers throughout the world.