Search
Filters

51315-5447-Mystery of SAGD Produced Gas Corrosivity and Corrosion Mitigation Strategy

 The new passivation mechanism in steam-assisted gravity drainage (SAGD) process is discussed through theoretical approach in this paper.  A corrosion mitigation program was implemented that included the pigging both slug and batch corrosion inhibitors chemistry analysis corrosion rate (CR) monitoring and non-destructive tests.

Product Number: 51315-5447-SG
ISBN: 5447 2015 CP
Author: Qiang (John) Liu
Publication Date: 2015
$0.00
$20.00
$20.00

In the steam-assisted gravity drainage (SAGD) process casing gas from the producer consists of approximately 90% steam and 10% produced gas. The produced gas (PG) contains approximately 15% CO2 and 0.8% H2S with temperatures up to 180ºC. CO2 corrosion modelling predicts a corrosion rate of 600 mpy (15 mm/y). Mackinawite modelling predicts 270 mpy (6.75 mm/y). The prediction from both corrosion models indicates PG has very severe corrosivity at these conditions. However results from corrosion coupon/probe monitoring in the associated pipeline indicated much lower corrosion rate (< 0.25 mm/y) at these high temperatures but a higher corrosion rate at cooler temperatures. Corrosion product analysis supported that a passivation film of pyyrhotite and magnetite was forming at temperatures above 90ºC. The new passivation mechanism is discussed through theoretical approach in this paper.In addition to the corrosion caused by PG methanol that was injected to the casing gas laterals for preventing dead legs from freezing also aggravated the corrosivity. A corrosion mitigation program was implemented that included the pigging both slug and batch corrosion inhibitors chemistry analysis corrosion rate (CR) monitoring and non-destructive tests. The program was effective in reducing the corrosion rate to 3 mpy (0.075 mm/y) and the operational reliability of the pipeline was maintained.

Key words: conference papers, 2015 conference papers, downloadable, SAGD, produced gas, corrosion rate, passivation, film corrosion products, corrosion inhibitor, chemistry, casing, gas pipeline

In the steam-assisted gravity drainage (SAGD) process casing gas from the producer consists of approximately 90% steam and 10% produced gas. The produced gas (PG) contains approximately 15% CO2 and 0.8% H2S with temperatures up to 180ºC. CO2 corrosion modelling predicts a corrosion rate of 600 mpy (15 mm/y). Mackinawite modelling predicts 270 mpy (6.75 mm/y). The prediction from both corrosion models indicates PG has very severe corrosivity at these conditions. However results from corrosion coupon/probe monitoring in the associated pipeline indicated much lower corrosion rate (< 0.25 mm/y) at these high temperatures but a higher corrosion rate at cooler temperatures. Corrosion product analysis supported that a passivation film of pyyrhotite and magnetite was forming at temperatures above 90ºC. The new passivation mechanism is discussed through theoretical approach in this paper.In addition to the corrosion caused by PG methanol that was injected to the casing gas laterals for preventing dead legs from freezing also aggravated the corrosivity. A corrosion mitigation program was implemented that included the pigging both slug and batch corrosion inhibitors chemistry analysis corrosion rate (CR) monitoring and non-destructive tests. The program was effective in reducing the corrosion rate to 3 mpy (0.075 mm/y) and the operational reliability of the pipeline was maintained.

Key words: conference papers, 2015 conference papers, downloadable, SAGD, produced gas, corrosion rate, passivation, film corrosion products, corrosion inhibitor, chemistry, casing, gas pipeline

Also Purchased