Deepwater Gulf of Mexico 2004: America's Expanding ... - OCS BBS

Beneath the 3,000-ft (914-m) water depth, other currents migrate around the deep waters of the GOM.
Until recently, these deep currents were thought to be minimal and were not a major consideration in most
structure designs. In 1999, industry reported significant currents on the OCS below 3,000 ft (914 m).
This information led to a Safety Alert and subsequent study of deep currents by MMS (Hamilton et al.,
2003). This study revealed significant deep currents of up to 2 kn at some locations. The effects of all
currents must be considered in the design of deepwater floating production facilities, drilling rigs, and
their ancillary equipment, such as steel catenary risers and mooring systems.
Recent incidents have revealed the need for more accurate data in hind-casting and forecasting events and
in daily operations. As a result, MMS is proposing to issue an NTL titled “Ocean Current Monitoring on
Floating Facilities.” This NTL could establish and implement a program where operators of deepwater
offshore production facilities and mobile offshore drilling units (MODU’s) collect data on ocean currents
and submit them for publication on an industry-sponsored Internet website. Data collected on currents
will improve fatigue forecast models and establish responsible design criteria, resulting in increased
reliability of deepwater structures, thereby reducing risk to human lives, offshore facilities, and the ocean
environment.
CHALLENGES AND REWARDS
Significant challenges exist in deepwater in addition to environmental considerations. Deepwater
operations are very expensive and often require significant amounts of time between the initial
exploration and first production. Despite these challenges, deepwater operators often reap great rewards.
Figure 16 shows the history of discoveries in the deepwater GOM. There was a shift toward deeper water
over time, and the number of deepwater discoveries continues at a steady pace. Note that the last frame
of this figure only represents a 3-year span and that several recent discoveries are not shown in this frame
because they have not been assigned a discovery date yet. (The Reserves and Production section of this
report explains how discovery dates are assigned.)
Figure 17 shows how major and nonmajor oil and gas companies compare in terms of deepwater project
discoveries. (Appendix E lists those companies defined as majors.) In the past, major companies were
responsible for the majority of discoveries and led the way into the deepest waters. However, the number
of discoveries by nonmajor companies has surpassed that by major companies. In addition, nonmajor
companies have made numerous recent discoveries in the deepest waters of the frontier.
In addition to the significant number of deepwater discoveries, the flow rates of deepwater wells and the
field sizes of deepwater discoveries are often quite large. These factors are critical to the economic
success of deepwater development. Figure 18 illustrates the estimated sizes and distributions of
80 proved deepwater fields. In addition to their large sizes, deepwater fields have a wide geographic
distribution and range in geologic age from Pleistocene through Paleocene. Note that only recently have
reservoirs older than Miocene been encountered.
The growing number of large deepwater fields on production requires increasing support from onshore
service bases. Most producing deepwater fields have service bases in southeast Louisiana (figure 19).
Pending exploration plans (EP’s) and development operations coordination documents (DOCD’s) filed
with MMS indicate that support from southeastern Louisiana will continue to grow and that additional
support will come from southwest Louisiana, Mississippi, and the Texas coast (figure 20). Although
expanding along the Gulf Coast, shore-based support for deepwater operations is likely to remain
concentrated in southeastern Louisiana.
Figure 21 illustrates existing and potential hubs for deepwater production. For purposes of this report,
deepwater hubs are defined as surface structures that host production from one or more subsea projects.
These hubs represent the first location where subsea production surfaces and the connection point to the
existing pipeline infrastructure. Note that potential hubs are moving into deeper waters, expanding the
infrastructure, and facilitating additional development in the ultra-deepwater frontier.
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