Figure 1. Deepwater fxed platform and compliant
tower installation and removal in the GoM.
Source: BOEM 2016.
1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014
Figure 2. Deepwater foater installation and removal in GoM.
Source: BOEM 2016.
1988 1991 1994 1997 2000 2003 2006 2009 2012 2015
ENGINEERING, CONSTRUCTION, & INSTALLATION
Deepwater GoM installation
and decommissioning trends
Mark J. Kaiser
Center for Energy Studies,
Louisiana State University
Academy of Chinese
The Gulf of Mexico (GoM) is one of the most actively explored eepwater basins in the world. When projects are sanctioned, they require extensive planning, engineering, and construction work to complete. This fourth installment of the series reviews deepwater GoM
installation and decommissioning activity trends and uses end-of-life
production data to infer economic limits.
Operators pursue side track drilling and tieback opportunities to
maximize the value of their assets and to ‘keep the pipes full,’ and
when opportunities become scarce, they may actively market their
infrastructure for third-party processing or seek to divest.
Near the end-of-production, when all possible opportunities are
exhausted and the structure can no longer serve a useful purpose,
planning for decommissioning begins.
Only a few deepwater structures are installed or removed annually
and these activity levels are not expected to change in the future.
In recent years, the number of fixed platforms installed throughout
the GoM have diminished significantly, especially in shallow water,
and in the deepwater similar trends have been observed.
Fixed platforms and compliant towers
In total, 64 fixed platforms and three compliant towers have been
installed in water depth greater than 400 ft (122 m), and circa 2016,
there are 48 fixed platforms and three compliant towers in the region.
Shell’s Cognac platform in MC 194 was the first structure installed
in water depth greater than 1,000 ft (305 m) and is currently operated
by EnVen Energy Ventures. Bullwinkle, the deepest fixed platform in
the GoM, was installed by Shell in 1988 in 1,353 ft (412 m) water depth
and is currently operated by Fieldwood Energy Offshore.
Six fixed platforms have been installed in water depths greater
than 1,000 ft and all are currently active. They include, besides Cognac and Bullwinkle, Virgo, Amberjack, Pompano, and the recently
The three compliant towers Lena, Baldpate, and Petronius were
installed in 1,000 ft, 1,648 ft (502 m), and 1,754 ft (535 m) water depth,
respectively. ExxonMobil is currently performing environmental
studies and seeking a permit to reef Lena in-place via partial removal.
Baldpate and Petronius are still prolific producers.
Active inventories of deepwater fixed platforms have peaked and
structure decommissioning is expected to dominate future trends.
In total, 52 floating structures have been installed in the GoM and
five floaters have been decommissioned, leaving an active inventory
of 47 circa 2016. Floaters have been installed at a pace far exceeding
removals and active floater inventories continue to increase.
Placid Oil installed the first semisubmersible in the GoM in 1988
in 1,534 ft (468 m) water depth at the GC52/Llano field. The first TLP
was installed by ConocoPhillips in 1989 at the Jolliet field. Neptune
was the first spar installed in 1996 by Oryx Energy in 1,930 ft (588 m)
water depth, and the first FPSO was installed by Petrobras in 2011 in
8,300 ft ( 2,530 m) water depth at the Cascade/Chinook field.
From 1985-1999, TLPs with dry tree wells and topsides integrated
with the hull at quayside dominated installations.
From 2000-2007, 30 floater developments were sanctioned and
marked the introduction of large newbuild semis and the widespread
acceptance and adoption of wet tree developments. Most TLP and spar
developments during this period were integrated offshore.
In the aftermath of Hurricanes Katrina and Rita in 2005, updated
metocean criteria was adopted and a new set of developments were
installed over the past decade.
Projects sanctioned or under construction circa 2016 include: Appomattox (semi) sanctioned in 2015; and Stampede (TLP) and Big
Foot (ETLP) sanctioned in 2016.