I have an old copy of some of Aramco piping specs fromm 2003 revsions as I did a lot of pipeline work for them. In SAES-L-410 Design of Pipelines, the following is exerpt related to design for pigging:
The following requirements shall apply for pipelines designed to allow passage
of scrapers, instrumented type as well as cleaning type.
18.7.1 The Project Proposal should identify the specific type of scrapers to be
used to assess in designing scraper trap size and minimum bend radius.
18.7.2 Additional design requirements for permanent scraping facilities,
including the scraper traps, appurtenances and associated piping shall
be in accordance with SAES-L-420.
18.7.3 Pipeline Bends
Long radius bends shall be used in pipelines with permanent scraping
facilities. The bend radius shall be not less than eight diameters (8D) for
lines up to 8-inch NPS, 5D for lines of 10-inch NPS through 14-inch
NPS, and 3D (either bends or forged elbows) for lines of 16-inch NPS
and larger if 5D cannot be used because of space limitation, or difficulty
in procurement, subject to review and approval by the Chairman of
Piping Standards Committee.
18.7.4 Valves and Tees
The valves shall be full bore type to allow for the passage of scrapers.
Tee shall be barred-tees type where needed.
18.7.5 The pipeline shall not be multi-diameter.
The last sentence may apply to the bend you are refering to but if it is just the bends and not entire pipeline they may give you an exception.
Also SAES-L-420 Scraper Trap Station and Appurtenances states:
5.14 A proposed pipeline shall not have valves, fittings or connections installed that
may impede the travel of the scraper.
7.5 Bends
Long radius bends shall be used in pipelines with permanent scraping facilities.
The bend radius shall not be less than eight diameters (8D) for lines up to 8-inch
NPS, 5D for lines of 10-inch NPS through 14-inch NPS, and 3D (either bends or
forged elbows) for lines of 16-inch NPS and larger if 5D cannot be used because
of space limitation, or difficulty in procurement, subject to review and approval
by the Chairman of Piping Standards Committee in Consulting Services
Department.
Assuming this material in the bend is the same as the rest of the pipeline and the right bend radius then no real issue, but you will need to machine down the excess inner wall at the weld, usually at an angle of 1:4 to match the main pipe thickness and prevent any scrapers from getting damaged.
you don't want to end up with a sharp step or corner and also you would find it difficult to weld it.
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