Guest geological storytelling by David Middleton
You see the story yet? It’s all pretty much here.
In a language you can’t yet understand, but it’s here.
A tale of upheaval and battles won and lost.
Gothic tales of sweeping change, peaceful times, and then great trauma again.
And it all connects to our little friend.
That’s what we are, we geologists.
Storytellers.
Interpreters, actually.
That’s what you gentlemen are going to become.
And how does this relate to the moon? From 240,000 miles away you have to give the most complete possible description of what you’re seeing.
Not just which rocks you plan to bring back but their context.
That and knowing which ones to pick up in the first place is what might separate you guys from those little robots.
You know, the ones some jaded souls think should have your job.
You see, you have to become our eyes and ears out there.
And for you to do that, you first have to learn the language of this little rock here.
–David Clennon as Dr. Leon (Lee) Silver, From the Earth to the Moon, Episode 10, Galileo Was Right, 1998
HBO’s 1998 From the Earth to the Moon miniseries was a sort of follow-on to the great movie Apollo 13… It’s a must see for space program fanatics. I particularly like this episode because my childhood interest in the space program led me toward the sciences and ultimately geology. Future Apollo 17 astronaut Harrison “Jack” Schmitt recruited his former field geology professor to train the Apollo 15 lunar module team and their backup crew how to become field geologists. It reminds me of why I love geology so much. I’ve also had the great honor of meeting Dr. Schmitt at the 2011 American Association of Petroleum Geologists convention in Houston. Shaking hands with someone who not only walked on the Moon, but also got to throw a rock hammer farther than any geologist ever has before or since, was pretty fracking cool.
The late Scott Carpenter, Jack Schmitt and my old friend and former colleague James Reilly were the featured speakers at the All Convention Luncheon. AAPG has a really cool video of their talk.
While we usually aren’t 240,000 miles away from the stories we are trying to unravel. We are often 10,000 to 20,000 feet above the rocks that contain the story. In many cases, these rocks have no surface outcrops. Apart from well cuttings, sidewall cores and occasional whole cores, we never actually see the rocks. We often have to unravel the story from gravity, magnetic and seismic surveys, electric logs of wells that have been drilled into these rock formations, our imaginations and a firm understanding of “the language” of the rocks .
The Jurassic Period (Oxfordian) Norphlet formation is a great example of geological interpretation and storytelling…
In 1979, NASA’s SkyLab was still in orbit; Jimmy Carter was President; the US was suffering from the Second OPEC Oil Crisis; the Sony Walkman was introduced; and Terry Bradshaw’s Pittsburgh Steelers took Super Bowl XIII from the Dallas Cowboys. I was Exploration Manager for Mobil in New Orleans, and the Mobile Bay Field was discovered.Today, Jimmy Carter has been a former President for over 30 years; the Walkman is an antique; and Terry Bradshaw is a 61‐year old actor and sports commentator. However, Mobile Bay is still producing gas and will continue to do so for at least another thirty years.
An oil or gas discovery often comes from a combination of luck, sound technical and management decisions, overcoming legal, environmental, and operational difficulties ‐ and perseverance at critical times. This story of the discovery of gas at 20,450 feet in the Mobile Bay #76‐1 well in 1979 includes all of the above. Located in the very heart of a major Gulf Coast recreational and historical area ‐ an offshore Civil War Battlefield no less ‐ Mobile Bay #76‐1 presented a unique set of technical and environmental challenges. This presentation describes the technical aspects of how this discovery came about, but unlike most such papers, the passage of time allows the author an opportunity to provide a new generation of geologists a glimpse of how the industry and the technical story has evolved. The real story here is one from a personal and human perspective and how the character and experience of some of the individuals involved had such a great impact on the successful and surprising outcome.
Weldon G. Frost. Adapted from oral presentation at forum, History of Petroleum Geology, at AAPG Annual Convention and Exhibition, New Orleans, April 11, 2010
I was a senior in college when Mobil made the Mobile Bay discovery.
Before they could even spud Mobile Bay #76‐1, Mobil had to wage a legal battle with numerous groups opposed to drilling in Mobile Bay. Mobil won its legal battle under the conditions that the well would be totally zero-discharge, including collecting any rainwater that fell on the rig, and had to post a $55 million bond. Then they had to overcome Hurricane Frederic and the challenges of drilling a 20,000′ high pressure-high temperature (HPHT) well in 1979. However, it was worth taking on the challenges. The Mobile Bay #76‐1 encountered a 412′ gas column in the Jurassic Norphlet formation, with an initial test rate of 12.6 million cubic feet of natural gas per day (mmcf/d). It was the discovery well for the Mary Ann Field, 163 TCF (trillion cubic feet) of natural gas from 1979-1994, and the Mobile Bay Norphlet play, 693 TCF from 1979-1994.
Correction, the italicized passage should be:
It was the discovery well for the Mary Ann Field, 163 BCF (billion cubic feet) of natural gas from 1979-1994, and the Mobile Bay Norphlet play, 693 BCF from 1979-1994.
The exploration well success rate was remarkably high, particularly for a Jurassic play, especially since the discovery was “accidental”.
High Exploration Success Rate Seventeen Norphlet wells were spudded between 1981 and 1984, 13 of which became gas discoveries-an extraordinary accomplishment before 3D seismic. Besides Mobil’s Mary Ann discovery, three state Norphlet discoveries and one federal Norphlet discovery subsequently became development projects based on discoveries before year end 1984.
Through year end 1997, 75 Norphlet wells have been drilled in state and federal waters off Coastal Alabama-28 exploration, the balance delineation and development wells. These wells discovered 20 gas fields . Twenty Norphlet discoveries for 28 exploration wells represents a 71 percent success ratio . All but three of discovered fields are producing gas. Mobil abandoned the West Dauphin Island Field as uneconomic . Exxon maintains its 867 Field lease and plans to produce it in 1998 . Chevron and its partners, Conoco and Murphy, have filed a Development and Production Plan to develop Destin Dome. Exxon has drilled the most wells, 20; Mobil has drilled 19.
Mobil amended its original application to change the target from 16,500 to 21,500 feet-changing the target from Smackover to Norphlet-two years after the original application. One wonders what would have happened if Mobil had drilled to Smackover at 16,500 feet in 1970. Mobil’s decision to drill below the Smackover to the Norphlet in their original exploration of Lower Mobile Bay has been a bonanza for State of Alabama coffers and American consumers, even if the prices received for the gas have been sharply lower than operators anticipated . The Coastal Alabama/Panhandle Florida Norphlet trend is one of the most important U. S . gas producing regions.
Wade et al, 1999
The play is still producing, but the most recent Mobile Bay discovery was in 1992 (Seni et al., 1997). It is now well on down the decline curve and the Mobile Bay 76 “A” platform was “reefed” in 2003.
Unfortunately for Chevron, Conoco and Murphy the State of Florida blocked the development of their Destin Dome discoveries.
While the Norphlet formation in Mobile Bay and Destin Dome was too hot for oil (>400 °F), recent deepwater Norphlet discoveries have encountered oil. In deepwater, a shallower geothermal gradient has kept the rocks cooler (~280 °F) since the Jurassic Period (Nadeau, 2015). Shell’s 700 million barrel Appomattox discovery (~7,000′ water depth) is expected to come on production in late 2019 or early 2020. Recent geochemical analyses indicate that the Mobile Bay’s Norphlet gas was actually oil as recently as 120 million years ago (Mankiewicz et al., 2009).
Weldon Frost’s presentation is available online at the AAPG’s Search and Discovery website. It’s a great story and it’s part of a larger story…
“A tale of upheaval and battles won and lost. Gothic tales of sweeping change, peaceful times, and then great trauma again.”
Well maybe not Gothic… but definitely “tales of sweeping change, peaceful times, and then great trauma again.”
The Norphlet formation was deposited about 150 to 155 million years ago in a salt-filled desert basin that would soon become the Gulf of Mexico. It was a massive complex of sand dunes and interdunal wadis stretching from Ark-La-Tex to M-A-Fla to the deepwater of the Gulf of Mexico. In the Ark-La-Tex (Southern Arkansas, East Texas and North Louisiana) the Norphlet was deposited as alluvium (sediments deposited by rivers, streams, lakes, etc.) In M-A-Fla (Mississippi, Alabama and Florida) and the Gulf of Mexico, it was deposited by eolian (wind-driven) processes. Norphlet production is from massive ancient sand dunes… at depths ranging from 20,000′ to 30,000′ feet below sea level.
This raises two questions:
- How did sand dunes, deposited in a desert, 150 million years ago, wind up buried under 20,000′ of rocks and sediments, under the ocean in water depths exceeding 7,000′?
- How can geologists possibly know these were sand dunes? There are no surface outcrops of the Norphlet formation.
I’ll try to answer the second question first.
How do geologists know that the Norphlet formation was deposited as sand dunes?
We know what modern sand dunes look like.
Figure 4. Great Sand Dunes National Park & Preserve, Colorado. (US National Park Service)
We know how they form.
We also have examples of ancient sand dunes that are exposed in outcrops. The Jurassic Navajo Sandstone in Zion National Park is a magnificent example of the Norphlet’s slightly older Western cousin.
We also have a pretty good idea of what to look for in sandstone to determine its nature of deposition. Steep cross-bedding is a common feature of sand dunes.
Vision Exploration Norphlet cross bedding
The Norphlet sand dunes were so quickly buried by Upper Jurassic Smackover formation, that the geomorphology (land forms) of the dunes have largely been preserved for over 150 million years.
By observing modern geological processes we can usually deduce the depositional environment (paleo-climate and paleo-geography) of sedimentary rocks.
How did the Norphlet sand dunes get buried under 20,000′ of rock under the ocean?
For starters, the Gulf of Mexico (GOM) did not exist 150 million years ago, at least not in anything remotely similar to its current configuration.
The Gulf of Mexico is a small ocean basin lying between the North American plate and the Yucatan block. Following initiation in the Middle Jurassic, sea-floor spreading continued approximately 25Myr. Spreading was asymmetric, creating a broad area of attenuated transitional continental crust beneath the northern basin. Initially, widespread, thick salt deposits accumulated across much of the basin; mobilization of this salt by subsequent sedimentary loading has created a complex suite of gravity tectonic structures. Most salt is now allochthonous, forming extensive stocks and canopies. By the end of the Mesozoic, thermal subsidence had created a deep basin floor, flanked by continental shelves. The resultant basin contains a succession of Late Jurassic through Holocene strata that is as much as 20km thick. Sediment supply from the North American continent has filled nearly one-half of the basin since its inception, primarily by offlap of the northern and northwestern margins.
Galloway, 2008.
During the Late Triassic Period, the North American and South American plates began to pull apart, creating a rift basin where the modern US Gulf Coast and Gulf of Mexico basins exist today (Smith et al., 2018). During the Middle Jurassic Period the basin was intermittently open to the Pacific Ocean and would fill with seawater. When the openings were closed, the proto-Gulf of Mexico would dry out, depositing thick layers of halite (rock salt) and other evaporites, predominately anhydrite (Dribus et al., 2008).
The Gulf of Mexico has always lain in the hot, arid subtropics. As a small ocean basin peripheral to the Atlantic, the Gulf has experienced extended geological intervals when connection to the world ocean was restricted. The first, and most dramatic result of aridity and restriction was deposition of widespread salt, the Louann, over much of the basin floor (Fig. 1B). This salt layer formed the foundation onto which subsequent sediment would be deposited. Salt deposition continued for several millions of years, creating a unit as much as several kilometers thick. Later, the arid tropical climate facilitated widespread deposition of limestone on shallow-water platforms whenever clastic sediment supply to the basin was low (Fig. 2, pdf). Later periods of restricted circulation in the Gulf favored burial and preservation of organic matter in marine sediments, setting the stage for formation of rich petroleum source rocks.
Galloway et al., 2009 Geo ExPro
The Jurassic Louann Salt formation underlies much of the Gulf Coast and Gulf of Mexico.
The Norphlet formation was deposited on top of the Louann Salt. Shortly after Norphlet deposition, a protracted period of sea level rise began. The Upper Jurassic Smackover formation is a carbonate sequence deposited during a marine transgression and high stand across much of the Gulf Coast and Gulf of Mexico. The Smackover exhibits a wide variety of facies ranging from organic-rich mudstones, to oolitic shoals, to patch reefs. It is one of the most prolific oil & gas reservoirs from East Texas to the Florida Panhandle. It is also possibly the most prolific source rock in the entire Gulf Coast/Gulf of Mexico Region (Walkinshaw, Norphlet). The Norphlet is generally only productive where the Smackover lacks porosity (Walkinshaw, Smackover). The Smackover is both the source and the seal for Norphlet oil & gas reservoirs.
Dr. William Galloway, of the University of Texas Jackson School of Geosciences, summarized the depositional history of the Gulf Coast/Gulf or Mexico in this must read paper (I must read it, because he let me have a copy of it)…
Depositional history can be generalized in seven phases: (1) Middle-Late Jurassic evaporite and carbonate deposition in a broad, shallow, restricted to open marine basin. (2) Latest Jurassic-Early Cretaceous sand-rich clastic progradation from the northern margins. (3) Late-Early Cretaceous development of a rimmed carbonate shelf. (4) Late Cretaceous mixed clastic and carbonate aggradation of the continental margins. (5) Resurgent Paleogene clastic progradation and filling centered in the NW basin. (6) Miocene progradation and basin filling centered in the central and NE Gulf. (7) Late Neogene climatically and eustatically influenced progradation along the central Gulf margin. In contrast to the broad, progradational sediment wedge of the northern Gulf, the Florida margin is a primarily aggradational carbonate platform.
Galloway, 2008.
Figure 7 clearly demonstrates the importance of sea level cycles in the depositional history of the GOM. Also note that all of the source rock formations were deposited when atmospheric CO2 was above 1,000 ppm and the Earth was considerably warmer than it is today. The temperature and CO2 plots have 10 million year resolutions; they are highly smoothed.
Sediment loading resulted in a series of down-to-the-basin growth faults, extensive deformation of the Louann Salt and eventual mobilization of the salt into “allocthonous” bodies, which caused compressional features to form where the salt was primarily moving laterally.
This is a generalized Upper Cretaceous paleogeography map of the Gulf of Mexico with an isopach (thickness contours) of the total Cenozoic sedimentary section (Seni et al., 1997).
Even though the high temperature Norphlet gas pays of Mobile Bay and Destin dome are at about the same depth below the seafloor as the lower temperature Norphlet oil pays in Mississippi Canyon and DeSoto Canyon, the overburden is considerably different.
100 million years of generally rising sea level, followed by 50 million years of generally falling sea level… All punctuated by high frequency cycles of rising and falling sea level… Accompanied by down-warping and stretching of thin transitional continental crust and halokinesis (salt movement) buried a 150-million year old desert 20,000′ below the seafloor of the Gulf of Mexico… Unless sea level rise wasn’t related to climate change prior to 1988…
Climate change buried a desert 20,000 feet beneath the Gulf of Mexico seafloor!
How about that, geology fans?
Brett Cullen as Apollo 15 Mission Commander Dave Scott, From the Earth to the Moon, Episode 10, Galileo Was Right, 1998
“A tale of upheaval and battles won and lost.”
Mobil’s battles to drill Mobile Bay #76-1 didn’t end the “war.” The first five deepwater Norphlet wells were either dry holes, filled with solid hydrocarbons or contained insufficient volumes of oil. Even when Shell made their 700 million barrel Appomattox discovery, its development was not a sure thing. During the price crash of 2014-2016, Shell’s Appomattox team was able to innovate, reduce costs and improve efficiencies to the point that the project’s break-even price was less than $50/bbl.
Other battles remain to be fought. Most of the Norphlet play is off limits to exploration and production (E&P) activities because it is in the Eastern Gulf of Mexico (AKA Offshore Florida); as is almost all of the Mesozoic resource potential in the GOM OCS… So, the battle goes on…
Norphlet & Smackover BOEM Assessments PDF
I’ll just close with another space theme and one of my favorite sources for pertinent quotes, Tim Allen… “Never give up! Never surrender!”
Expanded References (the post would have been too long if I covered all of them)
“Areas Under Restriction.” Bureau of Ocean Energy Management, www.boem.gov/Areas-Under-Moratoria/.
Berner, R.A. and Z. Kothavala, 2001. GEOCARB III: A Revised Model of Atmospheric CO2 over Phanerozoic Time, American Journal of Science, v.301, pp.182-204, February 2001.
Chowdhury, Abu. “Salt Geology and Hydrocarbon Plays in the Northeastern Gulf of Mexico.” Search and Discovery Article #10215, AAPG Datapages, Inc., 10 Nov. 2009, www.searchanddiscovery.com/documents/2009/10215chowdhury/index.htm.
Douglas, Scott W. “The Jurassic Norphlet Formation of the Deep-Water Eastern Gulf of Mexico: A Sedimentologic Investigation of Aeolian Facies, Their Reservoir Characteristics, and Their Depositional History.” Baylor University, 2010. (A great master’s thesis… makes me want to go back to college… Except they don’t have keg parties now… So maybe I won’t.)
Dribus, John R., et al. “The Prize Beneath the Salt.” Oilfield Review, Schlumberger, 2008.
Francis, Thomas. “Appomattox: an Energy Project That Defied the Odds.” Shell Global, www.shell.com/inside-energy/an-energy-giant-born-against-the-odds.html.
Frost, Weldon G. “The Somewhat Accidental Discovery of the Mobile Bay Gas Field: A Story of Perseverance and Good Fortune .” Search and Discovery Article #110133 , AAPG atapages, Inc., 16 June 2010, www.searchanddiscovery.com/documents/2010/110133frost/ndx_frost.pdf?q=%2BtextStrip%3Anorphlet+-isMeetingAbstract%3Amtgabsyes.
Galloway, William. (2008). “Chapter 15 Depositional Evolution of the Gulf of Mexico Sedimentary Basin”. Volume 5: Ed. Andrew D. Miall, The Sedimentary Basins of the United States and Canada., ISBN: 978-0-444-50425-8, Elsevier B.V., pp. 505-549. (Special thanks to Dr. Gallloway for sending me a copy of this)
Galloway, William E., et al. “Gulf of Mexico.” GEO ExPro, 2009, www.geoexpro.com/articles/2009/03/gulf-of-mexico.
Hood, Kenneth C., L. M. Wenger, O. P. Gross, S. C. Harrison, 2002. “Hydrocarbon Systems Analysis of the Northern Gulf of Mexico: Delineation of Hydrocarbon Migration Pathways Using Seeps and Seismic Imaging”, Surface Exploration Case Histories: Applications of Geoschemistry, Magnetics, and Remote Sensing, Dietmar Schumacher, Leonard A. LeSchack
Karlo, John F, and Robert C Shoup. “Classifications of Syndepositional Systems and Tectonic Provinces of the Northern Gulf of Mexico.” Search and Discovery Article #30004, AAPG Datapages, Inc., 2000, www.searchanddiscovery.com/documents/karlo/index.htm.
Mancini, Ernest A. & Bearden, Bennett & M. Mink, Robert & P. Wilkerson, Richard. “Norphlet Formation (Upper Jurassic) of Southwestern and Offshore Alabama: Environments of Deposition and Petroleum Geology.” AAPG Bulletin, vol. 69, 1985, doi:10.1306/ad462b14-16f7-11d7-8645000102c1865d.
Mankiewicz, Paul J., et al. “Gas Geochemistry of the Mobile Bay Jurassic Norphlet Formation: Thermal Controls and Implications for Reservoir Connectivity.” AAPG Bulletin, American Association of Petroleum Geologists, Oct. 2009, archives.datapages.com/data/bulletns/2009/10oct/BLTN08171/BLTN08171.HTM.
Mello, Ulisses & D. Karner, Garry & Anderson, Roger. (1995). Role of salt in restraining the maturation of subsalt source rocks. Marine and Petroleum Geology. 12. 697-716. 10.1016/0264-8172(95)93596-V.
Miller, Kenneth & Kominz, Michelle & V Browning, James & Wright, James & Mountain, Gregory & E Katz, Miriam & J Sugarman, Peter & Cramer, Benjamin & Christie-Blick, Nicholas & Pekar, S. (2005). “The Phanerozoic Record of Global Sea-Level Change”. Science (New York, N.Y.). 310. 1293-8. 10.1126/science.1116412.
Nadeau, P H. (2015). Deepwater Horizon Study Group: Lessons learned from the… Deepwater Horizon Study Group 3 Working Paper – January 2011 10.13140/RG.2.1.1447.3125.
Royer, D. L., R. A. Berner, I. P. Montanez, N. J. Tabor and D. J. Beerling. CO2 as a primary driver of Phanerozoic climate. GSA Today, Vol. 14, No. 3. (2004), pp. 4-10
Schoell, Martin & Carlson, Robert. (1999). Diamondoids and oil are not forever. Nature. 399. 15-16. 10.1038/19847. (Nor are diamondoids diamonds. They are hydrocarbons… black gold, Texas tea)
Scotese, C. R., 2001. Atlas of Earth History, Volume 1, Paleogeography,
PALEOMAP Project, Arlington, Texas, 52 pp. Early Jurassic. Late Jurassic.
Seni, S. J., and others, editors, 1997, Atlas of Northern Gulf of Mexico Gas and Oil Reservoirs, Volume 1 – “Miocene and Older Reservoirs”: The University of Texas at Austin, Bureau of Economic Geology, Atlas of Major Oil and Gas Reservoirs, 199 p. (Affectionately referred to as “The Old Testament” around here. Volume 2 – Pliocene and Pleistocene Reservoirs is “The New Testament”)
Smith, Thomas, et al. “New Insights Revealed Into the Hydrocarbon Potential Along the Gulf of Mexico Conjugate Margins.” GEO ExPro, 2018, www.geoexpro.com/articles/2018/12/new-insights-revealed-into-the-hydrocarbon-potential-along-the-gulf-of-mexico-conjugate-margins.
United States, Department of the Interior, Bureau of Ocean Energy Management. “ Oil and Gas Resources as of Jan 1, 2014: OCS Report BOEM 2017-005.” Oil and Gas Resources as of Jan 1, 2014: OCS Report BOEM 2017-005, BOEM, 2017. https://www.boem.gov/BOEM-2017-005/
Wade, W.W., J.R. Plater, and J.Q. Kelley . 1999. History of Coastal Alabama Natural Gas Exploration and Development, Final Report. OCS Study MMS 99-0031 . U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, La. 189 pp.
https://www.boem.gov/ESPIS/3/3201.pdf
Walkinshaw, Steve. “ THE NORPHLET FORMATION ARKOSES, DUNES AND AN IMPORTANT RULE OF THUMB.” Vision Exploration, L.L.C. – The Norphlet Formation, www.visionexploration.com/norphlet.htm.
Walkinshaw, Steve. “THE SMACKOVER OF ALABAMA & MISSISSIPPI A PROLIFIC SOURCE ROCK AND RESERVOIR.” Vision Exploration, L.L.C. – The Smackover Formation, http://www.visionexploration.com/smackover.htm.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
David: This retired mudlogger/geologist thoroughly enjoys your stuff. It reminds me why I love geology. One of my colleagues at Newmont Mining Corp said that geologists are like people who are looking at a book and trying to figure out the story having only a couple of pages to look at. I wish I had had more geophysics (aka geo-wizardry) when I was in college. I do the best I can. I love geology in all its varying flavors. It has been a rewarding career. I have been blessed to see so much geology; from glacial outwash terranes in Northern Michigan (drumlins, kettles, kames, etc) to pre-Cambrian granites, gneisses in Canada and virtually everything in between. I even got to walk across the Grenville Front just south of Sudbury, Ont. crossing from 2.5 ga granites to 1.8 ga gneisses and amphibolites. Keep up the good work.
I grew up in the Danbury CT area. Newmont had a lab in Danbury. One of my high school friend’s father was a Newmont geologist. He got me a couple of job interviews and one job offer… But I had a better offer in Dallas from Enserch Exploration.
I like to compare geologists and geophysicists to the Six Blind Men and the Elephant…
It was six men of Indostan,
To learning much inclined,
Who went to see the Elephant
(Though all of them were blind),
That each by observation
Might satisfy his mind.
The First approach’d the Elephant,
And happening to fall
Against his broad and sturdy side,
At once began to bawl:
“God bless me! but the Elephant
Is very like a wall!”
The Second, feeling of the tusk,
Cried, -“Ho! what have we here
So very round and smooth and sharp?
To me ’tis mighty clear,
This wonder of an Elephant
Is very like a spear!”
The Third approach’d the animal,
And happening to take
The squirming trunk within his hands,
Thus boldly up and spake:
“I see,” -quoth he- “the Elephant
Is very like a snake!”
The Fourth reached out an eager hand,
And felt about the knee:
“What most this wondrous beast is like
Is mighty plain,” -quoth he,-
“‘Tis clear enough the Elephant
Is very like a tree!”
The Fifth, who chanced to touch the ear,
Said- “E’en the blindest man
Can tell what this resembles most;
Deny the fact who can,
This marvel of an Elephant
Is very like a fan!”
The Sixth no sooner had begun
About the beast to grope,
Then, seizing on the swinging tail
That fell within his scope,
“I see,” -quoth he,- “the Elephant
Is very like a rope!”
And so these men of Indostan
Disputed loud and long,
Each in his own opinion
Exceeding stiff and strong,
Though each was partly in the right,
And all were in the wrong!
MORAL,
So, oft in theologic wars
The disputants, I ween,
Rail on in utter ignorance
Of what each other mean;
And prate about an Elephant
Not one of them has seen!
Blind Men and the Elephant – A Poem by John Godfrey Saxe via All About Philosophy
Newmont’s lab in Danbury was Newmont Metallurgical Services. I worked for them for a time. They moved the lab to Salt Lake City in the late eighties. NMS was responsible for all metallurgical work that Newmont was doing outside of the Carlin Trend in Nevada. We processed ore samples from all over the world. Process mineralogy and metallurgy are the stuff of hard rock mining. It was an interesting place to work.
The job offer back in 1981 was as a metallurgical lab tech… And my friend’s dad, John Alrich, was from Salt Lake City… small world.
Schlumberger had a facility in Ridgefield CT back then… It used to be a decent State.
John Alrich hired me as a met lab tech in ’89. Small world indeed.
I went to high school with his son Chuck. John gave me a lot of good advice back then – Don’t ever work for the government.
Reminds me of the old story about three men being interviewed for a job. A geologist, a mining engineer, and a geophysicist. The interviewer asked them all the same question. “What does 2 + 2 equal. The replies were as follows:
Geologist; That’s a number between 3 and 5
The mining engineer (after consulting his calculator): 3.999999999999…
The geophysicist: What do you want it to be.
The geologist & geophysicist are the other way around and the geologist says, “How big does it need to be?”
That works too.
” We often have to unravel the story from gravity, magnetic and seismic surveys, electric logs of wells that have been drilled into these rock formations, our imaginations and a firm understanding of “the language” of the rocks .”
yup, geology is a good example of observational science. The thing you are studying is bigger than
any lab. It’s hard to make testable predictions about the future. And you work for the “best explanation”
and you have to make all sorts of assumptions.
you might call it a forensic science
but it works. and there are no controversies…
Your sarcasm is almost as subtle as mine… 😉
First time in this thread I’ve disagreed with you.
Mosher’s sarcasm is just low level rhubarb.
Apart from that, your geoscience evidence here is what we geologists like. I’m particularly delighted with the clarity of that pre-stack seismic section.
Just for Mosh…
“you might call it a forensic science” What does that mean? Is that like death being a terminal illness?
It’s actually an apt description. Geologists try to figure out how things happened by learning the “language” of the rocks… kind of like archaeology being forensic history. If climate science only operated the same way… 😎
1981 had 3-D seismic. I was there at Unocal writing 3-D software to walk through volumetric data at that time. That was applied to Gulf of Thailand Erawan field operations. VP of international geophysics took graphs from my programs to present at an oil conference in Texas that year.
I think the first 3d might have been in the 70’s. I think that Thailand survey was featured in Alastair Brown’s classic book on 3d interpretation.
The oldest 3d I ever interpreted was shot in the early to mid-1980’s in East Cameron South Addition over a field I’ve worked since 1988 for 4 different companies. Back then, there was no navigation data on the streamers, feathering was a huge problem.
The first 3D’s were in the 1970s. I left seismic processing in 1979 but one of my last jobs there was to process a 3D over Pharr-Donna field in far south Texas. That was for ARCO and was done in early 1979, but we were not the first ones to do a 3d. I don’t know who was.
I know that they shot a pseudo-3d over part of the Baltimore Canyon area in the mid-70’s. It sort of depends on how you define 3d. It also took a while to figure out how to interpret them. Was it GSI that had the “SeisCrop” table? I knew people who preferred to work off the hard copy.
Enserch got into deepwater with Placid in 1983 IIRC. By 1988, when I started working in the offshore group, we had one Landmark workstation and something called a “Dipix”. We had mostly “postage stamp” 3d surveys over some of our blocks, a mix of proprietary and spec data. And we had boxes and boxes of the old Tomlinson 2d data. I think the first regional spec 3d we licensed was the Western Geophysical survey over Garden Banks in 1989… But we could only look at about 2 blocks at a time.
Now we have continuous 3d over most of the Gulf… I can’t imagine going back to working 2d on paper again… I think I forgot how… And I started out in 1981 in East Texas working late 60’s to mid-70’s unmigrated six-fold 2d… 😉
Thanks David.
I really do have a couple of other things I need to do.
My only connection to the Gulf of Mexico (seems another lifetime)
was on a fishing ship out of the Tampa area.
Caught Grouper and watched bow riding Dolphins.
Not a bad connection… 😎
David,
I’m missing one essential factor in Fig. 8. Where is the rifting axis, that caused the Lauann Salt to depart from the Campeche salt ? Did the rifting heat have anything to do with maturation of source rocks or not?
That’s not well-understood. This article sheds some light on it…
https://www.geoexpro.com/articles/2018/12/new-insights-revealed-into-the-hydrocarbon-potential-along-the-gulf-of-mexico-conjugate-margins
I don’t think we know enough about the Campeche side of the Gulf yet. If AMLO doesn’t reverse the reforms that allowed US and other non-Pemex oil companies access to Mexico, I think we’ll learn a lot in the near future.
On the Northern Gulf side, it’s pretty clear that the deepwater and ultra-deepwater have “cooler” geothermal gradients than the shelf or EGOM carbonate platform, and are much more oil-prone.
Note in the link that Mr. Middleton has posted that the GoM block rotates between the 152ma and 132ma maps. That may help explain.
Absolutely fascinating to read, and I feel I’m getting educational jolts from posts like this to better understand what’s beneath my feet.
Please keep up the great work!
high and dry. if it’ important, I will read about it more often and maybe even understand halfway! thankx, good read!
high and dry. if it’ important, I will read about it more often and maybe even understand halfway! thankx, good read!
/ how to fetch ‘electric logs’?
Electric logs (gamma ray, resistivity, spontaneous potential, neutron density, sonic, etc,) have been recorded for decades by owering a wireline instrument package into the wellbore.
Today, we can actually put the instrument package on the drill string and log while drilling (LWD). The instrument package pulses the data back to the surface through the drilling fluid, giving us nearly real-time data.
Dr. Silver seems to be a magnetic personality. He pulled out a white rock in the movie and told them to be on the lookout for anorthosite, with white plagioclase crystals. David Scott seems then to have found one on the Moon, the Genesis Rock.
Great scene!
Still, I’m not sure why that rock is so important even today.
https://airandspace.si.edu/exhibitions/apollo-to-the-moon/online/science/lunar-rocks.cfm
They thought that the original Lunar crust was formed of anorthocite. They thought that the highlands were the best place to look for anorthocite. When they explored the highlands, they found lots of anorthocite.
So where on Earth did Dr. Silver find such a sample?
Earth is pretty much made of the material as the
EarthMoon… with some significant differences.https://en.m.wikipedia.org/wiki/Anorthosite
‘During the Middle Jurassic Period the basin was intermittently open to the Pacific Ocean and would fill with seawater.’ Very interesting.
Bear in mind that the farther back in time, the greater the uncertainty and the more diverse the interpretations become.
Chris Scotese maintains a paleo-map project. This is hi interpretation of Jurasssic paleogeography…
Early Jurassic 195 Ma
Late Jurassic 152 Ma
Scotese, C. R., 2001. Atlas of Earth History, Volume 1, Paleogeography,
PALEOMAP Project, Arlington, Texas, 52 pp. http://www.scotese.com/earth.htm
David, always enjoy your articles. Old geology joke:
Teacher: Johnny, what’s the longest river in the world?
Johnny: The Nile, I guess!
Teacher: Johnny, you can’t go through life just guessing!!
Johnny: Oh yes I can. I’m going to be a geologist!
http://www.geologyin.com/2017/08/top-ten-signs-you-might-be-geologist.html
Yep.. that ternary diagram has got it right!
Heh. Love the eutectics shown. ;p
Did the Chicxulub Impact 65 million years ago alter the formations you describe in any way that can be measured now? Is there a Iridium later as an event marker for example?
Not in the Northern Gulf of Mexico. However, it did on the Mexico side of the Gulf. The Chicxulub crater was discovered by Pemex.
https://en.wikipedia.org/wiki/Chicxulub_crater
The reservoir rock of the Cantarell giant oil field is a carbonate breccia, related to the impact.
https://en.wikipedia.org/wiki/Cantarell_Field
There was som fairly substantial platform collapse:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JB012615
This was apparently significant even off the US East Coast. That was one big quake, magnitude >9.
The Flood?
Gen 7:they went ins9 ide the ark to Noah by twos, male and female, just as God had commanded Noah. 10 And seven days later the floodwaters came upon the earth.
11 In the 600th year of Noah’s life, in the second month, on the 17th day of the month, on that day all the springs of the vast watery deep burst open and the floodgates of the heavens were opened.j 12 And the rain poured down on the earth for 40 days and 40 nights.
Titus 1:2 and is based on a hope of the everlasting life that God, ((who cannot lie)), promised long ago;
If you put Genesis side-by-side with the modern scientific understanding of the evolution of the Earth, there are a lot of consistencies.
tty
Well, the sequence of events in Genesis matches exactly what we now believe happened in the Big Bang and its nuclear physics transformation of energy cooling down to light then to matter which then consolidates to matter in orbits and planets and suns and moons; it referenced today’s theories of continental drift and the creation of life in the oceans before the land, birds (dinosaurs) before mammals and domesticated animals, and humans last.
Remarkable documentation (as a story) for a bunch of itinerant shepherds who could not count past 70 x7 , had no zero nor decimal points nor powers-of-ten, and wandered 40 years in the desert.
By the way, if you look closely at the language, you’ll also see that “everything was created” first … THEN it evolved (changed) into something else. And, more inspiring, the plants (microbes and algea’s) did grow first, clearing the the original atmosphere by consuming the dark clouds of CO2 and iron into today’s vast beds of rusty ore while releasing oxygen – just so that the sun and moon and stars could be revealed. They were already created and had been formed, it’s just that you could not see them trough the clouds.
How would you explain all of this to the people of 5000 BC?
…Cat memes.
*runs away and hides*
★★★★★
Highly entertaining and informative— as usual.
Thanks.
David – This is a fantastic post!
Reminds me of my days as a young pup at Exxon. My first project was to map the Norphlet in Destin Dome (now off limits to exploration). Chevron had a dual-anticlinal prospect called Dolphin (originally called Dolly Parton for reasons you can probably guess).
Yeah… we never use double entendres when naming prospects… 😉… /sarc
Back in 2004, we had a deep Miocene prospect in East Cameron South Addition, nowhere near any Miocene production or even control. When we filed the EP, I had to provide a name for tbe objective. I called it the NFI Sand… (No Fracking Idea Sand). When asked, in a politically correct environment, what NFI stood for… I said, “No Fossil Indicator”… 😅
Dave, congratulations on putting together and conducting this ongoing master class. Between your knowledge and the contributions of the experts in the commentary, I can’t imagine one could find a more knowledgable and informative short course on oil production at any university or conference. For those of us in other fields, (information science in my case) this is a unique insight into where our energy comes from. The time scales and geological process are just amazing if not fracking amazing.
One thought occurs to me in looking at your chart of CO2, sea level and temps. Over time, the CO2 levels have been declining, as geologic release processes have not kept up with sequestration. During the last glacial cycle, the level approached the point where plant growth was slowed, if not stalled altogether. Humans, even modern sapiens, have lived through a number of glacial cycles. Isn’t it interesting that after the last one, we took advantage of the warmth to developed the means to harness agriculture and amplify our food supplies, then figured out how to harness fire to amplify our physical energy and warmth.
In the process, what we are actually doing is recharging the “biospherical CO2 battery” to ensure that we all survive the next cycle. Some have suggested that the CO2 warming might prevent the end of the Holocene. Personally, I don’t think so – Mama Gaia is pulling really big levers. What it could do is keep the plants alive till the warmth returns again.
By the way, as a matter of information and thermodynamics, all life forms are information machines that must harvest more energy than they need for survival in order to grow, reproduce and evolve. They do it as quickly as possible until their morphology prevents them from obtaining more. The plants did it big time during the Jurassic, Carboniferous and less so currently. We are also doing it now. It is not a matter of political correctness, sustainability or anything else. We WILL use all available energy because that is the force that drives life forward.
Thanks again. I started reading over dinner on the deck before sunset. My wife got ticked off and left and before I noticed anything else, it was dark, my wine glass was empty and a praying mantis was crawling across my laptop screen.
That From the Earth to the Moon episode almost makes me want to teach geology… 😉
Thanks David, a great review that a 1970 LSU CHEM E can understand.
Great job. You are a redit to.your profession
I am puzzled about how the Smackover sourced
the underlying Norphlet. Any simple references to suggest for enlightenment?
“Up” is relative…
Thanks. Again, a great job. I worked GOM and Gulf Coast back in the dark ages with 6 fold data. Somewhat later I discovered Hagedoorn and had a lot of fun hand migrations seismic sections with diffraction curves. Explaining that to geologists usually evoked that “Smoke and Mirrors, you wiggle pickers are all weird” look. But when the interpretations drilled out they came around.
I started out in East Texas reprocessing old 6 fold data shot by Petty Ray for Getty and Lone Star Producing (Enserch when I worked for them). The data looked a lot like the line Weldon Frost said the Maryann discovery was made on.
I don’t see “migration” anywhere on the processing sequence… And the Norphlet structure sure looks like an unmigrated salt roller.
Back in about 1986 or 1987 Enserch had an internal geophysical symposium and I gave a funny presentation on my reprocessing project. I still have the slide set buried somewhere in my home office… One of these days I need to get it converted to jpeg’s.