A beginner's attempt @ understanding the complexity of the Gulf of Mexico disaster

2. In 2001, Gulf of Mexico was separated into two areas that included structurally
controlled and stratigraphic controlled features (Milkov and Sassen.)
Hemipelagic drape
Mass wasting
Salt deformation
Salt diapir
Fan- linear strip facies
Depositional lobe facies
HALOKINESIS
Discontinuous conduits ~70km²
Basins

3. GOM Geomorphic Features
Stratigraphic Controls -
• Hemipelagic drape - “ Unexpected
seafloor rugosity and low relief (<10m) of
discontinuous conduits 70 km². ” (K.Maier,
et al.) Covers inactive levee system during
interglacial cycles.
• Mass wasting - gravitational collapse of
low-grade rocks with steep angle of repose.
Include reaction textures that indicate
multiple metamorphic episodes.
• Linear strip facies - unconsolidated
sediment channels of distribution.
• Depositional lobe facies –
“Depositional lobes the above cyclic
pattern is diagnostic of fan-fringe areas.”
( D. Stow, et al.)
All of the above stratigraphic controls are
sensitive due to the need for a constant
reciprocity between facies of high gradient
alluvial fans and braided tracts of low gradient
sediment.
Structural Controls -
• Salt deformation – features associated with
faults and their seeps where advection of labile
hydrocarbons causes redox and concretions of
authigenic carbonates to precipitate in the
diagenetic processes.
• Salt diapir – salt supplies rise and transform
into crestal grabens or piercements causing trapped
pockets of hydrates
Press Play
The extensive nature of these structurally
controlled gas hydrates has led to further
investigation into determining their complexity.

4. Minerals associated with gas hydrate formation
Aragonite
Psuedomorphs of rods (where
cleavage maybe more
conspicuous and have an
“inner fuzziness”) found
crossing gas cavities.
Precipitates in cyclic pore
waters associated with redox
activity. Clear aragonite
crystals with calcite globules.
(shown below.)
In 2004, the saturation of pore fluids was indexed (the carbonate saturation index) that included the by-
products aragonite, dolomite, and magnesium-calcite. Their precipitates circulate in pore-waters or settle
as hard-grounds often associated with changes in current swept regimes that date back to the Pliocene.
This has furthered our understanding of hydrothermal events their extensive chemical
complexity.
Dolomite
Early deposits underlie other
minerals. Fill voids and allow for
cementation in diagenesis . Difficult
to differentiate between other
carbonates, though under
cathodoluminescence ferrous
content shows defined zonation .
(Dolomite plumes w/iron.)
Magnesium Calcium
Advective and convective
fluids that take part in a
biogeochemical turnover,
thermal processes that result
in changing
compression/extension
regimes of the lithosphere
24%
Dolomite
10% High Content
Magnesium Calcite
w/ Dolomite
46% High Content Magnesium
Calcite
10% Aragonite
10% Low Content
Magnesium Calcite

5. In 2006, we learned more about current hydrocarbon systems when expulsions
of an active mud volcano was found along with their associated features:
• Brine lake – collapsed salt diapir.
• Symbiotic vestimentiferans - bath in redox
chemicals released from inverted haloclines.
• Mussel Communities – The bivalve species,
Bathymodioulus Childressi , the most extensive bed
of mussels at a brine seep found at depths of 2200m.
at these depths (below heart urchins trails in ..)
Hydrate Stability Zone –
Measured by a Bottom Simulating Reflector (BSR) that
shows discontinuous stratigraphy. Gas and sand bearing
sediments. Gulf of Mexico is the only known place
where hydrate structures I, II, and structure H occur.
Global climate cycles and drilling activities that result in
temperature and pressure changes causing the caged
hydrates to become disassociated.
Atwater Valley lease block 340 at 2200-m depth. The
green laser dots are 10-cm apart. Photo courtesy of S.
Lessard-Pilon.
Hydrate Caged Structure I
Hydrates in piston cores

7. Thermodynamics of hydrocarbons is an ever
evolving arena that we have yet to fully understand.

8. THE GULF OF MEXICO DISASTER
THE END OF THE DECADE DISASTER
On April 20, 2010, in the region of the Mississippi Canyon block 252, the Deepwater Horizon
offshore rig exploded causing 11 deaths and 4.9 billion barrels of oil to leak into the sea. An
event often overlooked as historical, we found that there was a lot to learn about “mother
natures kick.”

9. 2009 was the first time in 30 years that the world experienced a decline in energy consumption by
1.1%, mostly due to the .06% drop in world GDP, only to experience the nations largest accidental oil
spill in the summer of 2010. Energy production, shipments, and prices were not significantly
affected, though the vast damage to the Gulf Coast culture and habitat was insurmountable .
Cultural Disturbance:
The Louisiana fishing industry was severely affected. A
distinct niche to the Gulf Coast economy and its
livelihood. To date the majority of the coast has been
reopened for fishing, though long-term effects are the
focus of concern. With the allotment of millions of
dollars at hand many committees have been
established, including the Oyster Advisory Committee.
(below Louisiana shell-fishing in the days after the
spill.)
Endangered Species of Louisiana:
* Sturgeon, Gulf ( Acipenser oxyrinchus desotoi)
*Whale, humpback ( Megaptera novaeangliae)
*Sea turtle, loggerhead ( Caretta caretta)
*Pearlshell, Louisiana ( Margaritifera hembeli)
*Earthfruit, Tiny-Tim ( Geocarpon minimum )
*Brown Pelican
Along with many other plants and natural
habitats. To date, the majority of funding has
gone to establishing barrier berms in protecting
the shoreline.

10. Though during an economic downturn, it was a time
when our nations innovation peaked.
Social and Historical Context
“ A unique event in human history, a unique event in
biological history. It is non-repetitive, a blip in the
span of time.” M.King Hubbert’s, seminal speech,
1956.
In the aftermath of the spill many questions were
left unanswered. As weeks went by and those were
unable to stop the 100,000 gallons of petroleum
pouring into the ocean an open-call for solutions was
issued. As our economy was heading into deep
despair, such a disaster sparked creativity
throughout the nation. Urgency in the clean-up was
on the mind of most, as many offered their sound
home-grown ideas:
Press play
While others were making attempts at more
technical solutions (see shut-off valve .)
This was a historical turning point for safety
and regulation in the oil and gas industry. The
Department of Interior split the Mineral
Management Services (MMS) into three entities,
after years of questionable practice. As
investigations proceeded, attention focused on
failure of the blowout preventer (BOP) stack. A
British Petroleum employee simply stated the
cause as “mother natures kick,” The Truth
Channel, JustinTv.com. A more in-depth portrayal
explains the “kick” as part of the problem
resulting from an influx of hydrocarbons.

11. The oil and gas industry along with scientific communities across the globe were given
a new insight into the dynamics of hydrocarbons and their associated structures.
1. Kick n. [Drilling]
“ A flow of formation fluids into the wellbore during
drilling operations. The kick is physically caused by the
pressure in the wellbore being less than that of the
formation fluids, thus causing flow. This condition of lower
wellbore pressure than the formation is caused in two ways.
First, if the mud weight is too low, then the hydrostatic
pressure exerted on the formation by the fluid column may
be insufficient to hold the formation fluid in the formation.
This can happen if the mud density is suddenly lightened or
is not to specification to begin with, or if a drilled formation
has a higher pressure than anticipated. This type of kick
might be called an underbalanced kick. The second way a
kick can occur is if dynamic and transient fluid pressure
effects, usually due to motion of the drillstring or casing,
effectively lower the pressure in the wellbore below that of
the formation. This second kick type could be called an
induced kick.” Schumlberger.com, Oilfield Glossary
Cause and Results of a Kick:
In the Deepwater Horizon a “kick” resulted from
failure in the cementing process of the well and its
associated constituents. Cement casings each have to
achieve zonal isolation around the drill string.
Ultimately, the cement casing is what protects the
production conduit that is emplaced in the sand facies.
The following has been determined by the THE BUREAU
OF OCEAN ENERGY MANAGEMENT, REGULATION AND
ENFORCEMENT to be the contributing causes to the
explosion:
Cement Slurry Mix - It is here that fluid dynamics play a
crucial role in the overall process. Determining the
specific densities and weight of all fluids is necessary to
balance pressures between the formation and the drill
pipe. Nitrogen is an additive that allows the mixture to
be less dense decreasing the chance of fracture to the
formation. The pumping rate must then be faster with
the addition of nitrogen,200 scf/bl. It was advised that
the Deepwater Horizon pump rates be reduced even
though more risk would be involved with the nitrogen
process. Intervals of nitrogen added as steps simulated
the ramping of nitrogen causing a wide range in its
density throughout the slurry mix resulting in nitrogen
breakout, when it seeps out of its suspension into the
concrete.

12. A failure in one component has a devastating domino-effect.
Shoe -track Barrier: Nitrogen breakout
compromised this barrier located at the bottom
of the well. This structure is a guide with space
in between the shoe and a collar that sweeps
the hydrocarbons from entering the wellbore.
Lock-down sleeve – Ensures a safe connection
between the production casing and the
wellhead. It allows the casing hangar to be held
securely.
Business Insider,” 5 Burning Questions Tony Hayward Must Answer Before
Congress.” Guy Rubin
Opening where hydrocarbons entered.
A successful pressure measurement of
a 5,200 psi was obtained.
Though mud was not displaced prior.
Rather than gradually setting the lock
down sleeve, the Deepwater Horizon
team rushed the procedure and it was
not well set.

13. Man-made structures now have to be a more homogenous part of
hydrothermal formations and their associated communities.
Deepwater Horizon MC252 location is in
the area of the abyssal plain consisting of
laminated sands and shale. Here the
cement casing is subject to greater risk of
hydrocarbon seepage.
Location of Bush Hill, a gas hydrate mound
with active seafloor vents and
methantrophic communities.. In a salt
deformation province they undergo
constant shifts and are highly perturbed .

14. Hydrothermal dynamics are specific in their nature.
• An 1° increase in the temperatures at
these sites resulted in a doubled
release of methane at the hydrothermal
vents.
• Nitrogen is key element in that it is
needed in preservation of the biological
constituents of hydrothermal
communities and the cementing
process of offshore structures.
• At hydrate seep sites methane
oxidation takes place along with other
fluid upward and downward advection.
• Well set placement of drilling
components in hydrocarbon bearing
zones is detrimental as they entail
specific risks.
* Pictured below hydrothermal probes
“ Final Technical Report on: Controls on Gas Hydrate Formation and
Dissociation, Gulf of Mexico: In Situ Field Study with Laboratory
Characterizations of Exposed and Buried Gas Hydrates” M. Kastner, et al.

15. As we all learned in chemistry class, the wrong measurements
can explode in our face! Money cannot outweigh time and
preciseness when dealing with hydrocarbons!