Sulphate Removal Package (SRP)
Where oilfield reservoir formation water contains significant amounts of barium and/or strontium, injection of seawater can cause barium and strontium sulphate scale to be formed. These scales have the effect of reducing reservoir permeability and can also become deposited in production pipe internals. Barium and strontium sulphate scales are notoriously difficult to remove since they cannot be easily dissolved. Squeeze inhibition treatments are often utilised to improve the well permeability but these are extremely difficult to control and cannot be applied to complex sub-sea networks or from floating production storage and off-loading vessels (FPSO). Where pipeline scaling is experienced, this has to be removed by mechanical means.
As an alternative to this, the installation of a Sulphate Removal Plant (SRP), to extract the sulphates from the seawater prior to injection, is often seen as the most economical approach. The SRP uses nano-filtration membranes to remove the sulphates while leaving the other salts (sodium, chloride etc.) substantially unaffected, thus maintaining the stability and permeability of the formation clays.
Each SRP is bespoke as per our clients required scope and can include any of the below skids packaging
The objective of this process is to remove coarse suspended solids that could deposit on process equipment creating scale and corrosion site.
The UltraMEV combines multiple ultrafiltration elements in a single housing reducing footprint, weight and need for interconnecting pipework.
The nanofiltration membranes are specifically designed to remove sulphate ions from seawater used for water injection.
A deaerator removes oxygen and other dissolved gases from water, such as feedwater and is designed to receive a chemically treated and filtered flow stream.
The Multi Media filtration system works on depth filtration principles to treat the SRP / SWRO feed water to remove the majority of particles.
Generally installed downstream of the multimedia filters to perform a guard function ahead of the SR or RO membrane stage
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Reduces seawater ion concentration from around 2,500 ppm to less than 50 ppm at temperatures of < 24ºC).
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Significantly reduces sulphate scale precipitation in production wells
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Reduces the quantity of scale inhibitor required downhole and in topsides equipment
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Eliminates economic and operational impacts resulting from scaling in reservoir
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Increases productivity index by limiting pipe constriction due to scaling
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Assists in maintaining reservoir permeability by limiting formation plugging caused by scaling
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Prevents well souring by controlling sulphate reducing bacteria (SRB) which in turn reduces equipment corrosion problems and the equipment required for scrubbing, removal, and handling of hydrogen sulphide
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Reduces safety hazards associated with hydrogen sulphide
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Has an additional safety benefit by reducing scale and thus the potential of naturally occurring radioactive material which can be attached to the scale
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Meets the stringent design and environmental criteria related to offshore platforms