MMS

SCIENCE

VOLUME 2 ISSUE 1 

JANUARY/FEBRUARY 2005

THE SCIENCE & TECHNOLOGY JOURNAL OF THE MINERALS MANAGEMENT SERVICE

Discovering

Our Energy

Past and Future

Fair Market

Value and 

Our Nation’s

Energy

Resources

Hunting 

for Oil with

Microfossils

Prospecting

with New Tools

Thunder Horse

Production Unit

Taking

“Pictures”

Below the

Earth’s Surface

OCS Geologic

Mysteries

Discovering

Our Energy

Past and Future

Fair Market

Value and 

Our Nation’s

Energy

Resources

Hunting 

for Oil with

Microfossils

Prospecting

with New Tools

Thunder Horse

Production Unit

Taking

“Pictures”

Below the

Earth’s Surface

OCS Geologic

Mysteries
THE SCIENCE & TECHNOLOGY JOURNAL OF THE MINERALS MANAGEMENT SERVICE

JANUARY/FEBRUARY 2005 Volume 2 Issue 1

3 Geology

Discovering Our Energy 

Past and Future

4 Compiling Data to Evaluate

Resources

Fair Market Value and Our Nation’s

Energy Resources

5 The Gulf of Mexico’s Past

History of Offshore 

Oil and Gas Development

6 Hunting for Oil with Microfossils

8 Searching for Oil and Gas

Prospecting with New Tools

9 Thunder Horse Semi-Submersible

Production Unit

Gulf of Mexico’s New Arrival

10 Taking “Pictures”

Below the Earth’s Surface

11 The Outer Continental Shelf

Geologic Mysteries

12 New Waves

Late-breaking News & Information

For more information about the Minerals Management Service, 

check out our site on the World Wide Web:

www.mms.gov

Subscribe

To receive MMS OCEAN SCIENCE, sign up on the website

www.gomr.mms.gov, click on e-mail subscriptions on the left hand

column, check the box marked Environmental Studies or e-mail

mary.boatman@mms.gov or call (504) 736-2781

MMS

SCIENCE

JANUARY/FEBRUARY 2005 

Volume 2 Issue 1

MMS OCEAN SCIENCE is published 

bi-monthly by the Minerals

Management Service to communicate

recent ocean science and technological

information and issues of interest related

to offshore mineral recovery, ocean

stewardship, and mineral revenues.

Please address all questions,

comments, suggestions, and changes

of address to:

Mary Boatman

MMS OCEAN SCIENCE Editor

Minerals Management Service

1201 Elmwood Park Boulevard

New Orleans, LA 70123

mary.boatman@mms.gov

(504) 736-2781

ABOUT THE COVER

Top: The seismic survey ship Ramform Valiant with

streamers or cables with hydrophones extending from the

stern. Photo courtesy of Petroleum Geo-Services.

Bottom: Authigenic (formed in place) carbonate rock

outcrop on the seafloor of the Gulf of Mexico. 

Photo courtesy of H. Roberts.

All photos courtesy of Minerals Management Service

unless otherwise noted.

Publication services provided by 

Schatz Publishing Group

2 MMS OCEAN SCIENCE Science & Technology Journal
MINERALS MANAGEMENT SERVICE JANUARY/FEBRUARY 2005 3

DISCOVERING OUR ENERGY

PAST AND FUTURE

Americans live in a 

mobile society, fueled by

hydrocarbons. In fact, if

all the passenger vehicles in the United

States were lined up bumper to bumper,

they would reach from the earth to the

moon and back! The amount of fuel

consumed in these vehicles each year is

enough to fill a swimming pool as big as

a football field 40 miles deep. Providing

the fuel to power our mobile lifestyle

and economy requires the exploration

and development of the energy resources

buried in the rocks and sediments

beneath the earth’s surface.

The search for petroleum and the

science of geology are intertwined. The

word “petroleum” itself comes from the

Latin words petra, or rock, and oleum,

oil. The Minerals Management Service

(MMS) employs geologists,

geophysicists, petroleum engineers, and

other scientists and equips them with

state-of-the-art technology to assist with

identifying where resources are located,

how to get to them, and how to

manage them.

To emphasize the crucial role that

geology plays in understanding how oil

and gas resources were formed and to

educate future generations about the

geology of the Outer Continental Shelf

(OCS), MMS has produced “Geologic

Secrets Revealed,” a poster available at

no charge to teachers and educators. (See

page 11 for reduced image.) The poster

explains basic geological processes on

the OCS, the mechanics and technologies of exploration, and where geologists

are looking for future resources.

As our energy needs continue to rise,

geologic information will continue to be

important in the quest to discover new

resources and to understand the

processes of the past that made those

resources possible. Advanced technology

and geological research techniques will

continue to add to the body of geological data, which will make future

discoveries possible.

Above: Strata or layers of sediment with a

borehole from the surface to a layer with

hydrocarbons. The corresponding chart

represents data from the different strata used

to determine the location of the oil or gas. 

Below: Graphs of information collected from a 

variety of instruments or tools lowered into a

borehole. The y-axis is depth below the seafloor.

This type of information is used to determine where

oil and gas are located.

GEOLOGY

Left: Work area with microscope used to

study microfossils (see story on p. 6).
4 MMS OCEAN SCIENCE Science & Technology Journal

COMPILING DATA TO EVALUATE RESOURCES

FAIR MARKET VALUE AND OUR

NATION’S ENERGY RESOURCES

To determine the adequacy of bids

received, MMS analyzes all data at its

disposal. Just as the oil company evaluates the resource to determine its bid,

MMS compiles geologic and seismic data

into a database to evaluate the resource’s

location, depth, hydrocarbon type, trap,

areal extent, and characterization of any

potential hydrocarbon deposits according

to age and thickness. On the basis of

these components, the potential resource

is rated and assigned a degree of risk.

Costs of discovery and production are

estimated on the basis of statistics from

other discoveries, and an estimate of

value is then assigned to the block.

If the highest bid is consistent with

competitive bids received in the sale and

the MMS estimate of value, the company

that submitted the high bid is awarded the

lease. That company then has 5-10 years,

depending on the water depth, to determine the oil and gas potential of their

new lease. Exploratory wells are drilled to

see what is really below the surface. If an

oil and gas field is discovered within that

Announcing the bids at a

public lease sale on the

Outer Continental Shelf

(OCS) is just a part of the

Minerals Management

Service’s (MMS) role in managing our

natural energy resources and providing

fair return to the American people. Even

with the new technologies available, the

search for oil still requires a lot of

speculation and the evaluation of data

collected by remote methods.

The Gulf of Mexico OCS Region,

similar to the other Federal offshore areas,

has been divided into thousands of threemile by three-mile blocks. Twice a year at

scheduled, public lease sales, interested

oil and gas companies submit sealed bids

for each nine-square-mile block they wish

to lease. Bids for each block are

announced and the highest bid noted. It

is then that MMS’s Resource Evaluation

team must determine whether the fair

market value is reflected in the highest

bid. In 2004, MMS evaluated bids on 908

tracts in the Gulf of Mexico (GOM).

period, the lease extends through the

productive life of the field.

Annual reports issued by MMS assess

the total amount of oil and gas found in

existing fields, the cumulative amount of

production from each field, and the estimated amount of oil and gas remaining

to be produced. Relying on active exploration data and seismic mapping, MMS

estimates the amount yet to be discovered

in the lease areas. Current estimates indicate the amount of oil and gas remaining

to be discovered is equivalent to approximately 22 years’ worth of imported crude

oil at current import rates. This demonstrates that the GOM will continue to

play a significant role in the Nation’s

future energy needs for years to come.

Below: The location of the 1,050 fields (875 active

and 175 depleted) in the Gulf of Mexico. The color

of the bar indicates the period in which the field

was discovered. Note the progression of field

discoveries through time into the deeper waters of

the Gulf of Mexico. Recent discoveries have occurred

in water depth greater than 9,700 feet. Source:

Estimated Oil and Gas Reserves, Gulf of Mexico Outer

Continental Shelf, December 31, 2001. OCS Report

MMS 2004-073. 
MINERALS MANAGEMENT SERVICE JANUARY/FEBRUARY 2005 5

Right: A summary of the Gulf of Mexico (GOM) oil

and gas inventory. The first two bars on the left show

the amount of oil and gas that has been drilled and

discovered in the 1,050 GOM fields (875 active and

175 depleted). The middle set of two bars shows the

discovered volumes of oil and gas still available for

future production. This volume is equal to approximately 3 years’ worth of imported crude oil. The final

set of two bars shows MMS's estimate of the amount

of oil and gas remaining to be discovered in the GOM.

This volume is equal to approximately 22 years’ worth

of imported crude oil at current import rates. Source:

MMS Publications 2001-087 and 2003-050.

THE GULF OF MEXICO’S PAST

HISTORY OF OFFSHORE OIL 

AND GAS DEVELOPMENT

T he Minerals Management Service

(MMS) announces the publication

of, History of the Offshore Oil and

Gas Industry in Southern Louisiana: Interim

Report. This report is the first of many

products that will flow from MMS’s

ongoing research effort “The Offshore

Oil Oral History Project.” The threevolume interim report is intended to

showpiece some of the kinds of

materials that will be developed.

Volume I, Papers on the Evolving

Offshore Industry (MMS Publication

2004-049), provides a short overview of

the Oral History Project and its goals, as

well as a series of short, focused,

analytical papers on a variety of subjects

that build a selection of the collected

interviews. For example, in the paper

“The Brave and the Foolhardy:

Hurricanes in the Early Offshore

Industry,” Joseph Pratt discusses how the

industry, by chance, moved into the Gulf

during a period of relative calm in the

Gulf. Nevertheless, even though major

platform design criteria were wave height

and force, these explorers learned

through sad experience that they had

underestimated the size of waves and

failed to consider the threat of

mudslides. In another example, “A Brief

Look at Commercial Diving and the Role

of People, Technology, and the

Organization of Work,” Diane Austin

discusses how returning World War II

veterans created modern commercial

diving in the Gulf when they began to

apply the tools and techniques of the

U.S. Navy to the offshore oil industry.

Volume II, Bayou Lafourche: An Oral

History of the Development of the Oil and

Gas Industry (MMS Publication 2004-

050), demonstrates the wealth of

information contained in oral histories

by constructing a history of the area’s

industry entirely from carefully selected

quotations.

Today, the offshore petroleum industry is enormous and operates worldwide.

However, it was born in the wetlands

and coastal regions of Louisiana and its

birth has been little documented. The

Oral History Project is documenting this

remarkable history through the eyes of

the people who built it, worked in it,

and lived with it. To date, approximately

400 interviews have been collected and

hundreds of photographs have been digitized and catalogued.

Volume III of the interim report,

Samples of Interviews and Ethnographic

Prefaces (MMS Publication 2004-051),

provides hints at the rich materials to be

mined from these projects. This educational material will be made available to

the public upon completion.

To read more about this exciting

project, visit: http://www.gomr.mms.gov/

homepg/regulate/environ/history_

louisiana.html
6 MMS OCEAN SCIENCE Science & Technology Journal

The study of ancient fossil life,

known as paleontology, is

helping geoscientists at the

Minerals Management Service

(MMS) obtain a clearer

picture of relative historical earth events

and, in turn, making the search for

hydrocarbon resources easier. As

scientists ascertain the chronologic ages

of paleontologic events, they can then

describe the nature of geologic processes

that occurred in the area.

Fossils, which are found in the

sediment layer or “strata,” provide clues

as to the depositional environment,

where the organisms lived, and the

geologic time when the surrounding

sediment was deposited. Estimates of the

age of fossils in the strata in which they

are found, as well as in layers above and

below, are calculated according to basic

geologic principle – older strata and

fossils are found below younger layers

and fossils. Using this principle,

geoscientists can determine the “relative

age” of the fossil.

Once fossils are identified, the group

of species found together at a given layer

within the sediment or rock can be

compared with other well-known

successions of rocks. This analysis is

known as biostratigraphy, the separation

of rock units on the basis of the description and analysis of the fossil species

they contain. Relating the fossils at one

stratigraphic level in one area to those in

another area at the same level is known

as correlation. The ideal fossil for

biostratigraphic correlation, known as

the marker or index fossil species, is one

that is easily identifiable, abundant,

prevails over a wide geographic area, and

evolves rapidly.

For biostratigraphic analysis, samples

are collected from wells. The samples are

labeled by well depth and location.

While most fossils are destroyed during

the drilling process, microfossils remain

intact and are identified. A paleontological report is then made, listing the

important foraminifera and coccoliths

and the depth at which they were found.

The paleontologist transfers this fossil

information into a database where the

paleo information from a particular well

FOR OIL WITH MICROFOSSILS

By Robert B. Witrock, Paleontologist, Offshore Resource Evaluation, Gulf of Mexico OCS Region

Top: A scanning electron microscope (SEM) photo

of the coccolith Emiliania huxleyi. Lower left:

Reconstruction of a Middle Cambrian (505 million

years ago) sea bottom based on fossils found in the

Burgess Shale in British Columbia. Above: An early

paleontologist contemplating a fossil trilobite.
MINERALS MANAGEMENT SERVICE JANUARY/FEBRUARY 2005 7

is correlated with adjacent wells,

determining the timing of events.

Looking at groups or the assemblage of

fossils in the well, a paleontologist can

determine what the approximate water

depth, or paleobathymetry, was at the

time of deposition. This critical

information reveals much about the

depositional environment, its organic

productivity, and the potential for

forming hydrocarbons.

Using certain fossil species that

indicate the age of sedimentary strata,

and other species that reveal the water

depth, the geoscientist reconstructs time

slices and cross-sections to tell the geologic history of the area being studied.

The paleontologist can generate various

paleo maps that often coincide with

sedimentation and structural trends.

Integration of microfossil data with

seismic and well log data leads to a more

complete assessment of hydrocarbon

development and reservoir delineation.

Above: An example of the rapid evolutionary

changes in foraminifera over 6.5 million years, from

the early Paleocene (64.5 million years ago), at the

bottom, to the late Paleocene (58 million years

ago), at the top. Upper right: The foraminiferan

microfossil Globorotalia.

Where does oil come from?

Crude oil is a smelly, yellow-to-black liquid usually found in underground

layers called reservoirs. Scientists and engineers explore a chosen area by

studying rock samples from the earth. Measurements are taken and, if

the site seems promising, drilling begins. Above the hole, a structure called a

“rig” is built to house the tools and pipes going into the well. When finished,

the drilled well will bring a steady flow of oil to the surface. 

The world's top five crude oil-producing countries are Saudi Arabia, Russia,

United States, Iran, and China. In the United States, the top five crude oilproducing states are Texas, Alaska, California, Louisiana, and Oklahoma.

Much of the crude oil from Texas, California, and Louisiana is produced

offshore. The amount of crude oil produced (domestically) in the United States

has been getting smaller each year, but the amount produced from the OCS

(primarily from the Gulf of Mexico) has been rising each year.

Pa-le-on-tol-o-gy

n. from the 

Greek word paleo, or

ancient, and the 

Latin ontologia, 

the study of.

The paleontologist plays detective

with beautiful microfossils, searching for

critical clues left untouched or unseen

for millions of years. With geologists and

geophysicists applying the fossil evidence

as age controls onto seismic sections,

well logs, and structure maps, those tiny

microfossils provide an essential

framework for regional geologic

history...and petroleum fields in

particular.

FOR OR MORE MORE INFORMA INFORMATION:

Paleontology at MMS 

http://www.gomr.mms.gov/homepg/

whatsnew/speeches/

PPDM-2002.html

Biostratigraphic Chart for the Gulf

of Mexico

http://www.gomr.mms.gov/homepg/

pubinfo/freeasci/paleo/

freepaleo.html
8 MMS OCEAN SCIENCE Science & Technology Journal

T

he search for oil

and gas is a

challenge that

carries a high

financial risk. Wells

may cost more than $50-70

million each and be drilled to

nearly six miles below the

ocean’s surface. In the early

days of energy exploration,

discoveries were often a

matter of luck. Even today,

the U.S. Energy Information

Administration estimates

13% of all holes drilled in the

U.S. do not find commercial

quantities of oil and gas

(down from 37% in 1973).

Advanced geophysical and

geological tools such as threedimensional seismic imaging,

sophisticated well-logging

tools and techniques,

computer-based petrophysical

analysis, and paleontology

reduce the risk associated with locating

oil and gas reserves.

In the past, geoscientists had to rely

on two-dimensional seismic data

interpretation to define potential

hydrocarbon prospects. The images

scientists assembled were useful, but less

than complete. Today, however,

advanced three-dimensional seismic data

are providing a more detailed

understanding of a prospect. Seismic

data are obtained by using hydrophone

or geophone receivers. These receivers

record the time it takes for a

signal or sound wave (caused

by an air pulse) to travel from

the source to the receiver. As

the signal or wave travels, it

reflects off the layered

sediments it encounters and

returns to the receiver. The

source and receiver are then

moved in a grid pattern

across an area as the process

is repeated.

The data generated

through this method are then

processed to yield a threedimensional image or

“picture” that represents the

subsurface strata and geologic

features (faults, salt domes,

etc.) in the area of investigation. By estimating the

velocity of sound through the

various subsurface strata and

the travel time of the signal

from the source to the

receiver, the depth to a particular

reflector can be estimated. Geoscientists

then translate the seismic data into

maps, cross-sections, and threedimensional models of potential

hydrocarbon accumulations or

prospects.

In the evaluation of a new lease

block, exploratory wells may be drilled

to test subsurface strata and structures for

potential hydrocarbon accumulations.

Logs obtained from these exploration

wells (see figure on page 3) provide

information that can enhance the threedimensional seismic picture of the area.

Well logs are continuous recordings of

specific physical properties of the

subsurface strata encountered during

drilling of an exploratory well. Such logs

may be obtained by wireline logging,

SEARCHING FOR OIL AND GAS

PROSPECTING WITH NEW TOOLS

Above: A spar production platform with three wells

drilled to different depths where oil or gas has

collected or been trapped. In this example, a salt

dome has formed, pushing the sediment layers

upward and causing faults and deformation. 

Oil and gas are trapped where permeable layers

come in contact with impermeable layers. 

Left: A seismic boat collecting information about the

different sediment layers below the seafloor. Sound

is emitted from a source and is reflected by the

different layers. Receivers listen to the sounds and

record the time it takes to travel from the source.

This information is translated into 2-dimensional or

3-dimensional images of the sediment layers.
MINERALS MANAGEMENT SERVICE JANUARY/FEBRUARY 2005 9

GULF OF MEXICO’S NEW ARRIVAL

THUNDER HORSE SEMI-SUBMERSIBLE

PRODUCTION UNIT

which consists of lowering a logging tool

into a well and recording data as the tool

is raised from the bottom of the well.

Logs can also be generated by recording

data as the well is drilled. The MMS has

about 300,000 logs from 44,000 wells in

the Gulf of Mexico.

Logging tools can measure the temperature, electric potential, density,

radioactivity, velocity, resistivity, and

conductivity of the rock formations they

encounter. These measurements are used

to determine the petrophysical characteristics – porosity, permeability, and water

and hydrocarbon saturation – directly

related to the oil and gas producing

potential of the rock. These evaluations

are necessary not only to identify the

rock type and hydrocarbon-bearing

reservoirs but also to identify the type of

hydrocarbon (i.e., gas, oil, condensate),

and to determine the volume of

hydrocarbons in place and the volume

of hydrocarbons that can be successfully

extracted from a reservoir. Detailed

petrophysical analysis is a vital and

necessary step in the exploration for the

development of oil and gas prospects.

Paleontology also provides the

geoscientist with tools to use in the hunt

for hydrocarbons. The study of

microfossils by paleontologists provides

additional clues to the geologic history

of a hydrocarbon prospect. The type of

fossils found in a potential field can help

scientists determine the age and

depositional environment of the strata

or structure being explored.

Today’s geoscientists use many tools

in the exploration for hydrocarbons

beneath the seafloor. Each tool provides

its own unique insights into the

subsurface. As technology advances,

refinements are made and more

advanced tools are developed. The result

is a more accurate and cost-effective

means of oil and gas exploration.

This project has garnered worldwide interest because of

its sheer massiveness. The distance from the base of the hull to top of the drill rig is

just over 450 feet, roughly the height of a 40-story building. The immense deck area is

approximately 3 acres. 

Nearly four years in the making, the Thunder Horse unit will soon make its home

in 6,000 feet of water in the Gulf of Mexico, 150 miles southeast of New Orleans. The

Thunder Horse field is the largest discovery ever made in the Gulf of Mexico. When

fully operational, the unit will be capable of producing an astounding 250,000

barrels of oil and 200 million cubic feet of natural gas per day.

The world’s largest semi-submersible production unit, the 59,500-ton Thunder

Horse production, drilling, and quarters (PDQ) unit, recently arrived at the

Kiewit yard in Ingleside, Texas, following an eight-week journey to the Gulf of

Mexico from Korea aboard the Dockwise Blue Marlin. British

Petroleum Company (BP) will operate this unit.

The topside modules, fabricated in Morgan

City, Louisiana, are being installed onto the

PDQ (hull). Sail out for installation at the BP

Thunder Horse field is slated for the end of the

first quarter of 2005. 

Above: Dockwise Blue Marlin carries Thunder Horse

PDQ. Photo courtesy J. Ray McDermott, Inc. 

Left: Artist’s rendering of Thunder Horse PDQ.

Photo courtesy BP Exploration, Inc.

Below: Dockwise Blue Marlin carries Thunder Horse

PDQ. Photo courtesy Dockwise.
10 MMS OCEAN SCIENCE Science & Technology Journal

TAKING “PICTURES”

BELOW THE EARTH’S SURFACE

subsurface and cover large areas. Other

geological data, such as that provided by

electrical logs and paleontology, enhance

the interpretation of the 3-D subsurface

seismic image of an area of interest.

When used together, each of the data

types allows a clearer image of deep-sea

subsurface structures and hydrocarbon

potential to emerge.

To compile and interpret the massive

quantity of data available from various

sources, geoscientists use high-tech

workstations comprising stand-alone or

networked computers. These workstations use integrated geoscientific

interpretation and reservoir simulation

software to interpret and analyze 2- and

3-D seismic data. In addition, the

workstations help to create geological

and geophysical maps, construct crosssections of buried rock formations, and

manage the immense amount of data

used. The Minerals Management Service

(MMS) currently has 8 terabytes of

seismic data stored on its computers.

The Agency is pursuing the

acquisition of an immersive visualization

center that will display geological and

geophysical data three-dimensionally on

projection walls in theater-like rooms.

Geoscientists wearing 3-D glasses will be

“immersed” in the display. Geoscience

teams may then simultaneously view the

data, making it easier for them to

collaborate. Such collaboration provides

quicker and more accurate interpretations and evaluations of potential

subsurface hydrocarbon resources. 

Using the numerous data types

available and high-tech workstations in a

collaborative environment, geoscientists

from MMS and the oil and gas industry

can more readily identify and evaluate

what lies beneath the ocean floor and

determine which areas may be

economically profitable to develop. With

these data and high-tech data analysis

tools, the “haystack” becomes much

smaller, the needle a bit larger, and the

search much less costly.

F

inding oil and gas resources

located miles beneath the

ocean’s floor may seem like

trying to find a “needle in a

haystack.” However, advancing

technology makes finding that needle a

little easier. To determine whether the

rock strata beneath the ocean floor may

contain oil and gas resources that can be

developed economically, geoscientists

must interpret and integrate large

volumes of geophysical, geological,

petrophysical, and paleontological data.

The interpretation of these data allows

the geoscientist to create an image or

“picture” of the subsurface, which is then

used to determine whether an area has

any potential for oil and gas resources. 

The introduction of threedimensional (3-D) seismic data has

greatly improved the ability of geoscientists to obtain detailed information

about the rich resources available

beneath the ocean floor. The 3-D seismic

data provide accurate images of the

FOR OR MORE MORE INFORMA INFORMATION:

MMS Publication 2001-050

Improved Geohazards and Benthic Habitat

Evaluations: Digital Acoustic Data with

Ground Truth Calibrations

Top: A 3-dimensional cube generated by using

computer modeling from seismic data showing the

sediment layers below the seafloor. 

Above: A 3-dimensional view created from 

2-dimensional seismic data of subsurface features.

Left: An MMS scientist reviewing geophysical data at

a work station.

Seismic 

Cube 3 miles

16,000 feet
MINERALS MANAGEMENT SERVICE JANUARY/FEBRUARY 2005 11

T

he Outer Continental Shelf

(OCS) abounds with rich and

varied biological, chemical,

and geological natural

resources. The oil and gas

resources located on the OCS are

particularly important to the Nation’s

energy future. The unique geology of the

surface and subsurface has made the

OCS a prolific area for hydrocarbon

resources in North America, producing

almost 29% of the oil and 25% of the

natural gas in the U.S.

The area known as the OCS runs

from approximately 3 miles from a

State’s coastline to about 200 nautical

miles from shore. Generally, the continental shelf runs in a gentle slope from

the beach to approximately 600 feet of

water depth. The continental slope is a

relatively steep feature that begins where

the shelf leaves off (600 ft up to 10,000

ft). The continental rise begins at the end

of the slope and is an apron of sediment

between the slope and the abyssal plain,

a relatively flat seafloor.

Hydrocarbons (oil and gas) are

formed when organic matter such as

plant material and animal remains

settles to the bottom of a body of water

and becomes buried by sediment.

Through millions of years, heat and

pressure from natural processes are

applied. Over time, oil and gas are

formed as the organic material is broken

down.

However, hydrocarbons do not

remain where they were deposited. 

They begin to migrate upwards through

porous rocks that serve as pathways. 

The hydrocarbons continue to rise until

they are trapped in pockets between two

strata or layers, one porous or permeable

and the other impermeable. Gas, being

lighter, is usually at the top of the trap,

heavier oil is next, and at the bottom 

is water.

Traps form when rocks fold into

structural highs by tectonic plate activity,

or when faults move layers of rock where

porous rock, such as sandstone or

limestone, presses against impermeable

rock such as shale. The trap must be

sealed by impermeable layers to prevent

oil and gas from escaping and it must

also have enough space for oil and gas to

accumulate.

The Nation’s energy potential may

not rest entirely on conventional

hydrocarbon resources. Scientists are

now studying the possibility that a

unique and puzzling frozen “ice” crystal

may hold the key to future energy

resources. Gas hydrates form when

methane gas and water are subjected to

pressurization and extremely cold

temperatures. When mixed with

sediments on the sea bottom, gas

hydrates form thick layers or mounds.

Discovering a method to transport the

gas from these formations to the surface

is key to their potential use.

As new reservoirs are discovered and

new forms of energy explored, the

responsible stewardship of the OCS

remains a vital part of our National

interest. The Minerals Management

Service continues to study and evaluate

the rich geologic mysteries existing there.

Teachers and educators are encouraged

to order the free “Geologic Secrets Revealed”

poster shown above. To order, please contact:

Minerals Management Service, Gulf of

Mexico OCS Region, Public Information

Office (MS 5034), 1201 Elmwood Park

Boulevard, New Orleans, Louisiana 70123-

2394, or call 1-800-200-GULF.

THE OUTER CONTINENTAL SHELF

GEOLOGIC MYSTERIES

FOR OR MORE MORE INFORMA INFORMATION:

MMS Kids’ Pages

Website: http://www.mms.gov/mmskids/

MMS Kids – Alaska Region

Website: http://www.mms.gov/

alaska/kids/index.htm

Educational Resources

Website: http://www.gomr.mms.gov/

homepg/lagniapp/

lagniapp.html

MMS Pacific Region

Website: http://www.mms.gov/

omm/pacific/kids/educate.htm

“Geological Secrets Revealed: The New Millennium in the Gulf of Mexico” focuses on the geoscientists’ search for

energy resources, including oil, natural gas, and gas hydrates, on and deep below the seafloor of the Gulf of Mexico.
MMS OCEAN SCIENCE

Minerals Management Service

Mail Stop 5431

1201 Elmwood Park Boulevard

New Orleans, LA 70123

FIRST CLASS

POSTAGE 

PAID

PERMIT NO. 1

ADDISON, IL

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NEW WAVES Late-breaking News & Information

Fugro Explorer 

drilling vessel

Photo courtesy of Fugro

Major Hydrate Expedition to be Launched in Spring

A drilling vessel will embark this spring

on a mission in support of the project

Characterizing Natural Gas Hydrates in the

Deep Water Gulf of Mexico: Applications for

Safe Exploration and Production Activities. This

project is funded by a Joint Industry Program

(JIP) by ChevronTexaco to investigate and

obtain information necessary to bring

methane hydrates into the natural gas resource

base and ensure safe drilling operations near

formations. 

The project is a 5-year collaborative effort

to develop technology and collect data to

characterize naturally occurring gas hydrates in

the deep water Gulf of Mexico. 

A series of cored and logged holes will be

drilled in the Gulf of Mexico at Atwater

Canyon Blocks 13 and 14 (AC-13,14) in 2005

and at Keathley Canyon Block 151 (KC-151)

in 2006. These sites were selected on the basis

of observed seafloor hydrate mounds, maps of

gas hydrate indicators, and interpretations of

seismic data. These blocks have all the

characteristics of hydrate deposits, including

bottom-simulating reflectors, wipe-out zones,

mud volcanoes, chaotic-appearing geological

structures, and faults that extend up to the

seafloor. 

Site AC-13,14 lies in 4,000-4,300 feet of

water while KC-151 is in 4,300-4,800 feet of

water. A series of 4-5 holes will be drilled

through the hydrate stability zone at each site.

After the drilling, the seismic lines across each

hole will be calibrated with the data from the

cores and electric logs. It is hoped that with

the combined use of drill hole and geophysical data, reasonably accurate estimates of

the volume of gas hydrate can be made.

Methane hydrates represent a potentially

enormous natural gas resource. Estimates

range as high as 700,000 trillion cubic feet

(Tcf) worldwide, many times the estimated

total of conventional resources of natural gas.

The United States hydrates resource is

estimated at 100,000 to 300,000 Tcf. 

“The Gulf of Mexico JIP is the most

significant offshore hydrate research that will

be done in the next few years, and it will

provide the first real data on safe drilling and

operations, resource assessment, and environmental characterization and protection of

hydrate-bearing sediment in our deepwater

areas,” says Dr. Mike Smith, geochemist at the

Minerals Management Service.