CO2 Flooding ConferenceMidland, Texas

December 3-7,2012Reciprocating Downhole Pumps

Joe Schoenfeld-Engineering ManagerQuinn Pumps

a Division of Lufkin Industries

OverviewOverviewDownhole Corrosion-CO2

API 11AX

API 11AX Materials

Key Environmental Parameters Influencing Corrosion of Metals

Actual Pump Materials

Other Considerations

Downhole CorrosionDefinition of corrosion

• The chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties

CO2

• CO2 corrosion pits are round based, deep with steep walls and sharp edges

• pitting is usually interconnected in long lines but will occasionally be singular and isolated

API 11AX

Specifications for Subsurface Rod Pumps and Fittings

• API publications exist to facilitate the broad availability of proven, sound engineering and operating practices

• API publications do not infringe on using other sound engineering practices

• API publications currently cover pump sizes from 1-1/4” to 3-3/4” whether they be insert or tubing pumps

• Pumps designed and manufactured to these standards insures that they meet the dimensional (Section 6) and material requirements (Section 9) as specified in API 11AX

• The dimensional requirements assure the interchangeability and standardization of all component parts and standard materials

Materials For API 11AX Pumps

• ASTM classification of different steels

• 10XX – Plain carbon steels• 41XX – Chrome-Moly steels• 86XX – Nickel-Chrome-Moly steel• 61XX – Chrome-Vanadium steel• 72XX – Titanium-Chrome steel

• NACE MR-01-75 and API put hardness restrictions on material that can be used in the downhole operations (material dependent)

• NACE MR-01-75 and API adopted 22-23 HRC as the maximum hardness for majority of metals to be used downhole

• ISO 15156

Materials For API 11AX Pumps

Pump Barrel Materials (Plated Barrels) Table A

ID Description Inside Surface Condition

Base Core Hardness

Base Material Min. Yield

ksiA3 Chrome on

Brass0.003 min thickness 900-1160 HV 100* Thickness per side

55-62 HRA Inhibited Admiralty Brass

60

ID Description Hardness Base Material

C1 Tungsten Carbide

Ball HRA 88-89Seat HRA 88-89.5

Tungsten with Cobalt binder

Pump Materials for Balls and Seats Table D

Key Environmental Parameters Influencing Corrosion of Metals

• CO2 content• H2S content• Oxygen and other oxidizing agents• Operating temperature and pressure• Organic acids (pH)• Metal ion and metal concentrations• Flow velocities• Solids production• Biological activity• Condensing conditions• Halide (containing the chloride ion)

Actual Pump Materials

Actual Pump MaterialsActual Pump Materials

Other ConsiderationsOther ConsiderationsPump Tracking Program Gas Accessories

Chemical Program Hart Gas Lock Breaker

Vertical/Directional Wellbores Dartt Valve

Gas Separators Side Kicker

Rod/Tubing Wear Top Check

Plastic Line Tubing Close Valve Spacing