Evaluating the Performance of a Composite-Reinforced Steel Drilling Riser via Full-Scale Testing for HPHT Service

ABSTRACT

A program was undertaken to evaluate the performance of a composite-reinforced steel riser for deepwater HPHT service via full-scale testing. This program was sponsored by the RPSEA (Research Partnership to Secure Energy for America) Deepwater Program that involved the design, fabrication, and testing of three prototype test samples. Lincoln Composites completed the design, analysis, and fabrication of test samples that were subjected to internal pressure, bending, and impact loadings. Stress Engineering Services, Inc. was responsible for destructively testing the samples. The design requirements for the riser included the following: 10,000 ft water depth, internal pressure of 15,000 psi, top tension capacity of 3,000 kips, 20-year service life, service temperature ranging from 32 to 180 °F, and a drift diameter 19.5 inches. The purpose in testing was to demonstrate that an acceptable design margin exists between the design and limit state conditions. The results of the test program demonstrated that a safety factor of 2.60 exists when comparing the 15 ksi design conditions to the burst pressure for one of the test samples that was included in this program. The failure for this particular sample occurred at 39,086 psi. During testing, strain gages were used to monitor strain on the outer surface of the carbon material. Good correlation was observed between the target design conditions based on finite element work and the data recorded during testing. With increased drilling at deeper water depths, including high pressure and high temperature conditions, the demands for game-changing technology is essential if the offshore industry is to operate safely and economically at these environmental conditions.

Alexander, C., Vyvial, B., Cederberg, C., Baldwin, D., “Evaluating the Performance of a Composite-Reinforced Steel Drilling Riser via Full-Scale Testing for HPHT Service”, Proceedings of the 6th International Offshore Pipeline Forum (IOPF 2011), October 19-20, 2011, Houston, Texas, USA.