Water Hammer in Offloading Systems: Contribution of Detailed Modeling to Design and Safety

This paper (SPE 134140) was accepted for presentation at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September 2010, and revised for publication. Original manuscript received 1 June 2010. Revised manuscript received 20 October 2010. Paper peer approved 8 November 2010. Summary The second-largest oil spillage in Norwegian petroleum history occurred on 12 December 2007 when the Statfjord A offloading system ruptured. Results of numerical simulations of pressure transients in the offloading system are presented. Of particular interest is the influence of acoustic properties of pipeline sections on propagation of pressure transients. The damaged-offloading-system geometry and characteristics, as well as the acoustic properties, are described. The paper describes numerical simulations of pressure transients in the offloading pipeline. The paper shows how detailed modeling and accurate estimation of acoustic velocities influence local maximum increases in pressure in an offloading system.