The East Crossfield D-1 Gas Gathering System has been in service for seven years transporting extremely sour gas (36% H2S, 12% CO2) through electric resistance welded API 5LX-46 pipe. The pipe was manufactured to specifications in addition to those covered in API 5LX and third party Inspection was utilized. During construction welding operations both preheat and controlled cool down were required. The tubing and flow lines have been inhibited with an oil soluble water dispersible amine inhibitor since commencement of operations. The corrosion rate has been monitored using coupons at the wells, in the gathering system, and at the plant inlet. Data obtained from hydrogen probes and inlet water iron content have proven unreliable for monitoring the corrosion rate. Actual metal thickness data obtained from ultrasonic and radio-graphic inspection have indicated no severe metal loss problems, although some pitting has been detected. Tubing inspection has indicated some fairly severe pitting in the lower part of a tubing string. A reliable short-term monitoring method is needed to indicate the frequency which the tubing should be slug treated with inhibitor. The hydrogen probes installed on the wellheads have not been able to do this, but a more sensitive hydrogen probe may be able to.
