Shuttle Tankers in the Oil Export of Cascade and Chinook Fields

Abstract This paper is based on the work performed during the offloading operations in the Cascade and Chinook fields in Ultra Deep Waters of the U.S. Gulf of Mexico. It addresses the tandem offloading from the first FPSO to operate in the Ultra Deep Waters of the U.S. Gulf of Mexico to the first use of purpose-built Jones Act shuttle tankers to perform such operations in the U.S. waters. The paper also covers the experience of the shuttle tankers crew on offloading operations as well as the proved performance of the vessels equipment. The main technical contributions of the work presented in the paper are associated with the unique features of the first use of purpose-built Jones Act shuttle tankers in the Gulf of Mexico, such as: Bow Loading System (BLS); Green Line System; and Differential Absolute and Relative Positioning Sensor (DARPS). The successful use of tandem offloadings from the FPSO to shuttle tankers at Cascade and Chinook fields confirms the adequacy of such solution in the U.S. Gulf of Mexico, and opens the possibility for growth in the Jones Act shuttle tanker fleet. Introduction Produced oil from the Cascade and Chinook (C&C) fields is being successfully and safely exported from the Floating Production Storage and Offloading vessel BW Pioneer (FPSO) to shore via Shuttle Tankers (ST). Petrobras pioneered the tandem offloading concept between FPSO and ST in Ultra Deep waters of the U.S. Gulf of Mexico (USGoM). Petrobras executed the first C&C offloading operation on June 8th, 2012, which was the first tandem offloading operation conducted in the USGoM where produced oil was transferred from a FPSO to a ST via tandem offloading system specifically designed for use over the entire duration of the FPSO operation at C&C fields. This paper describes key aspects associated with the use of STs for oil export in the USGoM, including information on the main characteristics of the STs and offloading operation. The content of this paper includes technical contributions associated with the unique features of the STs, as well as its impact on future USGoM Ultra Deep water field development.