Tengiz; 1985
Tengiz Oil Field, located in Kazakhstan, on the far NE portion of the Caspian Sea, was discovered in 1979 by a consortium of Exxon, Chevron, Lukoil and KazMunay; Chevron operated the field under the name Теңіз мұнай кен орны, or Tengizchevroil (TCO).
The field is a massive Carboniferous reef underlying Permian age shales. Its depth is 10,000-12,000 feet TVD and this reef could be seen in 2-D sesimic data.
The first well drilled in 1979 produced 40,000 BOPD or more from a vugular carbonates section that was 2,000 feet thick. And Lordy, was it over-pressured; estimated BHP initially pushed 13,000 PSI.
The field is 12 miles long and 13 miles wide and at discovery had an estimated 12 G BO of recoverable oil in it. TCO is always tinkering with it and in 2017 Chevron estimated flow rates from Tengiz were a little south of 600,000 BOPD.
After the intial discovery in 1979 TCO spent little time trying to delineate the size of the field and in 1985 made a big 'ol boo boo drilling the No. 37 well on the right. The well lost mud returns in cavernous reef then within minutes that mid came back around and caught the rig on fire. Within less than a hour the derrick collapsed, fell and took the BOP stack over with it. It blew out the hydrill and both wings of the drilling spool.
It was, as they say in Russia, a very big, hot son of a bitch.
The government of Russia did not like the idea of Americans coming over and fixing their problems, even when their problems were operated by Chevron, who in 1985 was a good client of Boots and Coots, Inc. in Houston. Russia had its own blowout company and this No. 37 well in Tengiz was their problem.
The Russians did what they often do in their well control methodology, they started shooting artillery rounds into the fire to break up melted drilling rig and pull the pieces away with dozers and Athey wagons copied from U.S companies. The rig set on a concrete foundation because of unstable sand and that had to be broken up. Eventually they cleared enough debris away to actually set glycerine charges over the well BOP stack with Athey booms.
The BOP stack gave away to a constant barrage of armor piercing rounds from military tanks and the nearly 11,000 feet of drill pipe blew out of the hole. With that the fire started going straight up and work could begin in earnest around the broken casing strings. With the fire going straight up to 300 meters its flow rates rivaled that of the great fire in Algeria in 1962.
A deep hole was dug and a venturi tube set over the fire. Casing strings were cut and a flange was jacked up over the surface casing.
The capping stack was devised to hinge up over the flow, a sort of fold over device, and it took three attempts to make that work, the final attempt successful on New Years Day, 1985. I think this capping process was necessary for lack of a crane big enough to snub the stack down directly over the flow. In some of the videos below you can see how problematic it was to fold the stack over the flow.
A snubbing unit was rigged up over the capping stack.
By September 1986, 10 months after first blow out, the well was pumped dead with mud. Multiple attempts were made over the ensuing year to recomplete the well and make a producer of it but all were unsuccessful as casing failure all up and down the well was rampant and lacked cement separation.
Today the well is plugged but numerous shallower zones above the blowout source are monitored closely from a sub surface blowout standpoint and vertical cross flow over an 8,000 vertical section. Its a mess. Still. Chevron, I assume, is still the operator of the well thru TOC, though I am unclear how that works since Russia's invasion of Ukraine. Someday Chevron is going to have a God awful mess to clean up all over the world, including this sub-surface blowout in Tengiz. Visit McElroy Field in Crane, Texas and you'll see what I mean; thats a BIG mess.
This is a series of four bad quality videos of Tengiz No. 37, all worth watching if you are into this sort of thing and all very interesting.
Russia for the most part handled its well control problems for years but its no coincidence, probably, that as soon as the Soviet Union dissolved and Kazakhstan/Turkmenistan became their own countries, American well control companies now handle well control events in that part of the world. Cudd, for instance, and some old colleagues of mine, caught a big blowout in in Turkmenistan in 2006, right.
The Tengiz No. 37 well burned abnormally hot for a long period of time and turned sand near the well bore, and down wind, into a very unique form of Obsidian-like glass called, Tengizite. It was mined as deep as five meters below the surface and comes in an array of different colors and transparencies.
Product Description
An unusual cabochon of pale blue and white banded Tengizite.
Tengizite is the name given to this non-natural Obsidian glass. It formed as a result of an explosion at an oil field in Tengiz, Kazakhstan which began in 1985 and took around 12 months to extinguish, with temperatures reaching up to 3000 degrees Farenheit. A 300 metre column of smoke was reported to be visible from 85 miles away.
The sedimentary soil, rocks (and even industrial equipment such as bulldozers) melted under the heat of the blaze, resulting in a thin layer of this vitreous colour-banded substance.
Very little material has been fashioned and, needless to say, availability is extremely limited.
Image 5 shows the cabochon in transmitted light. The brown streaks running through the stone can not be seen in direct light and are the remnants of the rocks from which the glass was formed.
weight: 20.32 carats
shape: Freeform cabochon
dimensions: 45.25 x 30.09 x 9.32 mm
treatment: None
References
Research Gate
Chevron Publications
Wikipedia
Sage Journals
Oil and Gas Journal
note: there have been some recent well control events in Tengiz that can be found on the internet, with colored photography, are incorrectly labled Tengiz 37 well, but have nothing to do with events of 1985
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