Offshore Pipeline Design Technology

Abstract

Offshore pipeline design encompasses all types of pipelines: from waste water outfall lines that extend seaward for shore, continental shelf pipelines (0–600 ft or 200 m), oil and gas production pipelines, some of which terminate onshore, and others that end at another offshore facility; deepwater oil, gas, and water injection lines in depths from 600 ft/200 m out to 10,000 ft/3300 m; and ultradeep pipelines, 10,000 ft and deeper. Waste water outfall lines are excluded in this text as the design of these generally requires a different mindset for the designer. While a 48′‐diameter oil or gas pipeline is considered large, an outfall line may be 4 or 5 times larger, and is usually a concrete pipe. Steel pipe, in diameters between 4″ (102 mm) and 24″ (610 mm), will accommodate most of the deepwater pipeline scenarios likely to be encountered by the offshore pipeline designer. Steel pipe diameters up to 60″ (1524 mm) have been designed and used in shallower water, notably for tanker loading/discharge pipelines. Since the subject of this article is virtually limitless in depth, knowing what to cover and what to leave out was difficult. Many books would be required to completely cover all aspects of offshore pipeline systems. Some very good books have been written, recently at a somewhat accelerated pace, that are worth reading. Rather than including a précis of these books, technical papers, and articles published in trade journals, a reference list is included to help the reader investigate each topic beyond the presented scope. Regarding presentation, this article focuses on the engineering principles used for designing and optimizing offshore pipeline systems rather than in‐depth theories. Derivation of mathematical models is beyond the scope of this encyclopedia.

An Overview of Flow Assurance Heat Management Systems in Subsea Flowlines

“…One of the most significant aspects of flowline design is in the prediction of temperature profile along the flowline during the thermal design process [51,55,56]. This is because temperature details are needed for flowline analyses including corrosion protection, lateral or upheaval buckling, expansion analysis, wax deposition, and hydrate prediction analysis [51,[57][58][59][60][61]. Often, the solids deposit (wax, asphaltene, hydrate, and scales) determines the conditions of thermal and hydraulic designs [62][63][64].…”