Presentacion H2S

Baker Petrolite Iron Sulfide Treatment Guide

Presentation Contents
When is Iron Sulfide (FeS) a Problem ? How does FeS Form ? Where do most problems occur ? How can FeS be Prevented ? How can Itreat other Scales in the Presence of FeS ?

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When is Iron Sulfide a Problem ?
When it impacts the flow assurance of an asset by causing deposits and blockages or when dealing with the problemleads to corrosion (integrity management) of the system or HSE issues. Common Blockages
in Near Well Bore Region: Reduces Permeability of the Skin in Production Tubing: Causes Blockages to Flow onElectrical Submersible Pump Surfaces (ESP) : blocks inlet valves and reduces thermal efficiency leading to wear pump in Gas Lift Mandrels: Reduces Lifting Capacity in Disposal or Injection wells:Reduces pumping efficiency Common Efficiency reductions in Separators: Pads form at interface and deposits in Electrocoalescers in Produced Water Storage Tanks: Forms pads then oxidizes to form sludges attank bottoms in Slop Oil Tanks: Stabilizes Oil-in-Water emulsions

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How does FeS form ?
Iron sulfides form from the reaction of dissolved iron in the produced brine and dissolved hydrogensulfide in gas phase or arising from bacteria activity.
Hydrogen sulfide which is a gas initially dissolves in the brine and then dissociates; H2S(gas) → H2S(aqueous) H2S(aqueous) → H+ + HS- (aqueous)Dissolution Dissociation At pH of 6.5 predominant form is HS-

FeS precipitates after dissolved H2S reacts with dissolved iron

Fe2+ + 2HS- (aqueous)→ Fe(HS)2 → → FeS (solid)

Precipitation

4Solubilities of Different Scales
SCALE BaSO4 FeS CaCO3 MgCO3 SrSO4 CaSO4.2H2O CaSO4 Na2CO3 NaCl Na2SO4 MgSO4 Common Name Barite Mackinawite Calcite, Aragonite Celestite Gypsum Anhydrite HaliteSOLUBILITY (ppm) 3 5 18 106 140 2090 3104 263,000 370,000 435,000 500,000

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How does FeS form ?..........Sources of Iron
Reservoir

– Naturally occurs in the produced water – Formation...