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