Question 1:

a. A 6” (150mm) Sch XXS API 5L Gr. X 60 crude oil flow line is designed to convey 3000 bbl/day from a wellhead platform to the central production platform (CPP) 5km away. The pipe is laid at elevation –20 m water depth, while the wellhead and production platforms are both at elevation 12m above mean sea level(MSL). If the inlet gauge pressure of the flowline is 160 bar, determine the arrival gauge pressure at the CPP. Assume grade of crude oil is Bonny light and ignore all minor energy losses.

b. (i) List and briefly describe any five (5) defects that could compromise the integrity of a flowline of welded steel design.

(ii) State three objectives of a defect assessment scheme.(iii) List its benefits to a pipeline asset owner and to the public.

Question 2:In order to ensure continued structural integrity of the flowline using APIAPI 579-1/ASME FFS-1 standard

as a basis, briefly describe the key elements of a “fit-for-service” defect assessment scheme you would recommend to the owner of the flowline described in Question One (1) above.

State three objectives of such a scheme and its benefits to the owner and to the public/environment.

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Question 3:

A 10” (254 mm) nominal dia. sch. XXS API 5L Gr. B pipeline conveying multi-phased fluids has been assessed and found to have a corrosion feature of 3.5 mm deep with average length of 105.12 mm. Determine whether or not the pipeline can continue to be safely operated in its “as built” state, otherwise “re-rate” the pipeline using ASME B31 strength criteria as basis.

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