Abstract
Oil and gas have been produced off the east coast of Trinidad for over 30 years. Production from the authors’ affiliated operations currently originates from eight main fields and is transported between satellite/complex platforms and to onshore terminals through about 50 individual pipelines. Despite excellent service history, the operator recently committed itself to implementing a major work program to clearly demonstrate functional integrity of the main oil and gas lines. This program is a formidable challenge because pigging of pipelines was rarely performed over the years, and in most cases, basic facilities (e.g., pig traps) are lacking.
Following risk-ranking, several pipelines were targeted for initial rehabilitation. However, work was first directed to short infield oil lines to develop the basic facilities design, installation and pigging skills. These trials not only successfully removed huge amounts of sand and scale, but also revealed many pitfalls to be avoided with the main pipelines. Of importance, the effectiveness of various cleaning tools was evaluated, methods to free stuck pigs established and solids handling routines developed. Following a now understood methodology, main oil line pig traps were installed, pipelines were progressively pigged clean and intelligent pig inspected. Unfortunately, little went as planned. Overall outcomes are discussed, as are the numerous problems, solutions, surprises and successes encountered along the way. The experiences demonstrate that through commitment and hard work, valuable older pipelines can be functionally reinstated for years of future service.
