A major consideration for any offshore field development is the need to transport the oil or gas to shore. In numerous situations, this is achieved most efficiently using subsea pipelines. Particularly in developed fields, there can be a complex network of pipelines connecting production wells, platforms and fields through to shore-based terminals. The primary means for ensuring that pipeline assets remain safe and operate effectively is by internal inspection using intelligent pigs. Pig is the term for those tools that can be inserted into a pipe to perform a variety of functions including cleaning, inspection and batching. The majority consist of a hollow steel body surrounded by a series of elastic disks. The disks support the pig centrally in the pipe and provide the pressure seal that allows it to be pushed along the line through the action of a pressure differential. The intelligent pig, when deployed and operated properly, can provide detailed information on the internal state of the line. Inspection, including advanced methods such as magnetic flux leakage or ultrasonic detection, can produce detailed measurements of the degree of cracking and corrosion. Pigs with onboard enertial navigation systems provide accurate measurement of the orientation of the line, while caliper pigs are used to measure internal profile and can indicate deformation of the wall.
|Number of pages||5|
|Publication status||Published - Apr 2004|