Oil was initially discovered in the Hebron Project Area in the Ben Nevis I-45 well in 1980. The hydrocarbon that was discovered in this first round of drilling was deemed uneconomic, for the time, due to the poor reservoir quality.
Test results showed uneconomic rates of oil in the Ben Nevis reservoir, and gas / condensate in the A Marker and Lower Hibernia reservoirs. The initial I-45 discovery was followed by two phases of delineation drilling. In the first phase of delineation drilling in 1981, the Hebron I-13 well was drilled to evaluate the potential of the 'Hebron horst' fault block. The well was drilled to assess the structurally highest point of the fault block at the Hibernia and Jeanne d'Arc reservoirs, and tested oil in these reservoirs. The well also penetrated the Ben Nevis reservoir in the downthrown fault block to the south, and tested oil. The West Ben Nevis B-75 well was drilled in 1985 to evaluate the fault block between the I-45 and I-13 wells. This well tested oil in the Ben Nevis, A Marker, and Jeanne d'Arc reservoirs. The North Trinity H-71 was also drilled in 1985 to assess these reservoirs, but found no significant amounts of hydrocarbon.
In 1996, a second phase of delineation drilling began to test if there was an economic upside to the Hebron Project Area. The D-94 well was drilled to test the Ben Nevis reservoir on the 'Hebron horst' fault block in early 1999. The well encountered over 1 Billion barrels Stock Tank Original Oil In Place (STOOIP) and better reservoir and oil quality than observed in the I-13 well.
The D-94 well encountered the same oil water contact as identified in the I-13 well, indicating that the I-13 fault block was in communication over geologic time with the D-94 fault block. As a result, the Ben Nevis L-55 well was drilled in 1999 to evaluate the potential for higher structure and better reservoir quality in the Ben Nevis reservoir of the Ben Nevis fault block. The well encountered higher structure than the I-45 well and a gas cap to the pool. The Hebron M- 04 well was drilled in 2000 to investigate a seismic incised valley-fill feature at the top of the Jeanne d'Arc horizon (H sand), and to extend and gather data on the existing Ben Nevis, Hibernia, and Jeanne d'Arc reservoirs. The well tested oil in the Ben Nevis and Jeanne d'Arc H sand. This second phase of delineation drilling added significant recoverable resources to the Hebron Project Area and helped to resolve subsurface uncertainty.
Sept 2011: Began site preparation work at Bull Arm which included road upgrades, refurbishing buildings and establishing site services. This work continued throughout most of 2012, including the installation of concrete batch plants and tower cranes.
Dec 2011: Received Comprehensive Study Report approval which enabled the construction of the bund wall for the dry dock area where the GBS is being built.
Oct 2012: Began the skirt installation of the steel skirts, officially starting GBS construction.
2013: Began topsides (living quarters) assembly.
May 2013: Cut first steel at the KOS fabrication facility in Marystown and began fabrication of the lower and intermediate decks of the drilling support module (DSM).
Q3 2013: Utilities/Process Module - first steel cut
Q4 2013: Derrick Equipment Set - first steel cut
October 2013: Paint hall extension and other major facility upgrades completed in Marystown.
2014 : The structural fabrication of the lower and intermediate decks continued. In total, 4 decks will comprise the DSM structure. Multi-discipline outfitting of the DSM began in the 2nd quarter of 2014.
2014-2015: Derrick Equipment Set - fabrication
December 2015: Completed DSM was transported to Bull Arm
Q4 2015: Completed DES transported to Bull Arm
2014 - 2016: Utilities/Process Module - fabrication
September 2016: Completed UPM arrives at Bull Arm