Comparative Analysis of 12,500 ft. Water Depth Steel and Advanced Composite Drilling Risers

Abstract

This paper was selected for presentaijon by the OTC Program Committee following revi_ cA informBlion contained in an abstrad submitted by the authors. Contents cA the paper, as presented, have not been revi~by the Offshore Technology Conference and are subject to CllITllClion by the authors. The material, as presented, does not necessarily reflect any posnion cA the Offshore Technology COnference or its officers. Electronic reproducijon, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Offshore Technology Conference is prohibited. Permission to reprodUce in print is restrided to an abstract of no more than 300 words; Illustrations may not be copied. The abstrad must contain conspicuous acknowiedgment of where and by whom the paper was presented. AbstractWith deepwater drilling becoming an area of increased interest, the National Institute of Standards and Technology (NISn sponsored composite drilling riser program objectives were extended in 1997 to include a comparative analysis of steel and advanced composite drilling risers for drilling in water depths down to 12,500 ft. A water depth of 12,500 ft was established as the maximum water depth thought to be of interest worldwide. Using requirements established by DeepStar and Reading & Bates, Northrop Grumman Marine Systems and ABB Vetco Gray synthesized a steel drilling riser system and an advanced composite drilling riser system such that the two drilling risers could be compared with regard to key system characteristics such as top tension required, buoyancy required, total system weight and stacked volume. This paper presents preliminary results of the comparative study which identified a weight savings of more than 50% and a volume reduction of 33% as benefits gained by the use of advanced composite materials for fabrication of the riser tubulars. Reduced buoyancy requirements are shown to be a major contributor to weight and volume savings, and also to reduced hydrodynamic drag forces. The comparative analysis performed included dynamic analysis in the hang-off modes using the Northrop Grumman developed Modal Dynamic 189Riser Analysis (MODRAN) program. MODRAN allowed comprehensive 3D analyses of coupled transverse and axial dynamics during hang-off for broad ranges of conditions. The differences (and similarities) in hang-off response are described.

Review of Composite Marine Risers for Deep-Water Applications: Design, Development and Mechanics

“…They have piqued the interest of the offshore oil and gas industries, owing to their high specific strengths and stiffnesses, which help with weight reduction and cost savings. Earlier investigations on composite risers have been conducted and showed good results [68][69][70][71][72][73][74][75][76][88][89][90][91]. However, composite applications in composite risers have transiting barriers and are thus seen as an enabling technology [65,119].…”

A review on design, manufacture and mechanics of composite risers

“…The risers had an external diameter of about 230 mm, a joint length of 15 m and were made of hybrid ±20 0 carbon and 90 0 glass composites and can sustain a fatigue life 3 times longer than a steel riser. Other early uses of composites include the development of production (Baldwin et al, 1998;Baldwin et al, 1997) and drilling risers (Andersen et al, 1998a;Andersen et al, 1998b) for deepwater. An example specification of a typical composite riser by Kim (Kim, 2007) is presented in Table 1.…”