SURFACE FACILITIES of INJECTION WATERFunction
To prepare the water chemically that depending on the source of the injection water, o The water might need treatment.
To pressuring water to the desired injection pressure // wellhead injection pressure before it is piped to the injection wells.
Major equipment
Sea water lift pumps Coarse filters Fine filters De-oxygenation tower Boosters pumps Main injection pumps Chemical dosing system
o FLOCCULANT, SCALE INHIBITOR ,CORROSION INHIBITIOR ,CHLORINATION ,BACTERICIDE ,OXYGEN SCAVENGER
Basic flow of surface facilities for injection water
Lifting and filtering process
De-oxygenation and injection process
Surface Water treatment process
Sea water lifting and filteration
Water from sea is Lifted with seawater lift pumps and fed to Coarse Filters and fine filters for filtering.
1. Seawater lift pump
Submersible pump units of multistage centrifugal units
Specifically designed to surpass the corrosive characteristics of seawater.
consist of special copper and aluminium anodes housed within a steel
framework and fed with an electrical current from a control panel.
Seawater environment are highly corrosive since it contain high
concentration of salts( NACl ) , dissolved oxygen, CO2 and
biological marine life ( sulfate reducing bacteria )
Operates below water level and close to the center of line
Prevent any air locks that can cause pumps
to cease proper operation
premature damage of the component.
Function o To minimize intake of algae, shells and debris o To prevent blockages in seawater lines caused by the growth of
barnacles and mussels. Screens are used to filter any large debris prior to water
reaching the on-site filtration system.
2. Filter ( sand and other solids)
a. Coarse filter equipped with wedge wire internals, which can be
cleaned, backwashed either manually or automatically. particles are filtered to 20 microns
Centrifugal filters are used initially to remove larger solids.
Duplex coarse strainer basket filters out particulates(down to 25 microns) before the water is transferred to thenext stage in the filtration process. The strainer is one ofmany options available to meet your specific requirements
b. Fine filter filtration is done using either sand, walnut shells or dual
media filtration. However, as weight becomes more & more of a factor, walnut shell filtration should be considered offshore.
particles are filtered up to 2 microns.
c. Guard filters used to protect pumps and the formation from oversized particulate which may
have come through the system
Cartridge filters provide final filtration down to 2 micronsto protect your reservoir while meeting the requirements flow rates.
FILTERING SYSTEM
LIFTING and FILTRATION SCHEMATIC DIAGRAM
De-oxygenation ( de-aeration ) and pumping (injection)
Filter Seawater will pass through the de-oxygenation tower to remove the oxygen and pump into the main injection feed.
1. De-oxygenation tower
Packed Tower o Using a stripping gas only, if gas is available.
This is the most economical method of de-aeration.o using a vacuum system to pull a vacuum on the tower,
causing the water to flash, with the water vapor acting as the scrubbing gas.
This is the second most economical method of de-aeration.
o using chemical means by the use of catalyst working in conjunction with either
nitrogen or hydro-gen, which is used for the catalytic regeneration.
These gasses must be generated. The catalysts are expensive, need replacement, and
these systems have not been used for large flow rates as yet.
This is the most ex-pensive method of de-aeration.
Function
Preventing corrosion and bacterial growth (sulfur reducing bacteria) in the
reservoir that can produce toxic hydrogen sulfide and clog rock pores Vacuum pumps and Oxygen scavenger chemical dozed facilitates
oxygen removal in the towers.
2. Pumping
Booster pumps Multi-stage centrifugal or Positive Displacement pumps
boost the water up to the required injection pressure before discharging it to the injection wells.
Scale inhibitors, Bactericide and corrosion inhibitor chemicals are dozed in the discharge of booster pumps.
Main injection pumps
Discharges the treated water to Water Injection subsea pipelines to wells and well platforms for injecting in to water injection Wells.
DEOXYGENATION and PUMPING ( INJECTION ) SCHEMATIC DIAGRAM
REFERENCES
http://www.marinespecialists.com/marineairsystems/products/Sea_Water_Pumps.html
http://fluidtechnologies.org/SEAWATERINJECTIONSYSTEM.html
http://petrowiki.org/Waterflood_design#Surface_facilities_for_injection_water
WEATHERFORD Temporary Water Injection Services