SURFACE FACILITIES of INJECTION WATER

Function

  • To prepare the water chemically that depending on the source of the injection water,
  • The watermight 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

  • FLOCCULANT, SCALE INHIBITOR ,CORROSION INHIBITIOR ,CHLORINATION ,BACTERICIDE ,OXYGEN SCAVENGER

Basic flow ofsurface facilities for injection water

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

  • Tominimize intake of algae, shells and debris
  • To prevent blockages in seawater lines caused by the growth of barnacles and mussels.
  • Screens areused to filter any large debris prior to water reaching theon-site filtration system.
  1. Filter ( sand and other solids)
  1. 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 strainerbasket filters out particulates

(down to 25 microns) before the water is transferred to the

next stage in the filtration process. The strainer is one of

many 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 microns

to 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
  • Using a stripping gasonly, if gas is available.
  • This is the most economical method of de-aeration.
  • 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.
  • 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 canproduce toxic hydrogen sulfide and clog rock pores
  • Vacuum pumps and Oxygen scavenger chemical dozed facilitates oxygen removal in the towers.
  1. Pumping
  • Booster pumps
  • Multi-stage centrifugal or PositiveDisplacement pumps
  • boost the water up to the requiredinjection pressure before discharging it to the injectionwells.
  • 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

WEATHERFORD TemporaryWater Injection Services