Urtabulak gas field
Urtabulak gas field is located in Uzbekistan
Urtabulak gas field
Location of Urtabulak gas field
CountryUzbekistan
RegionQashqadaryo Region
Offshore/onshoreOnshore
Coordinates38°58′05″N 64°31′08″E / 38.968°N 64.519°E / 38.968; 64.519
OperatorsUzbekneftegaz
Tethys Petroleum (former)
Service contractorsBaker Hughes
Eriell Group
Field history
Discovery1963
Production
Current production of oil1,100 barrels per day (~55,000 t/a)
Year of current production of oilSep 2011
Recoverable oil124 million barrels (~1.69×10^7 t)
Estimated gas in place23×10^9 m3 (810×10^9 cu ft)

The Urtabulak gas field (Russian: Уртабулас, tr. Urtabulas Uzbek: Ўртабулоқ, romanized: Oʻrtabuloq) is a natural gas field located in South Uzbekistan near the Uzbekistan–Turkmenistan border. It is known for being the site of a natural gas well blowout which led to the first use of a nuclear bomb to seal the well.

Geology

The Urtabulak field consists largely of terrigenous sediment layers, with deposits from the Jurassic and Cretaceous present. Exploratory drilling did not uncover any rocks older than the Cenozoic at a depth of 3,430 m (11,253 ft). Sandstones and other similar rocks occupy the field to a depth of 400 m (1,312 ft), with limestones and salt anhydrides covering another 1,030 m (3,379 ft) below that layer, below which is largely marine sediment. Natural gas reserves were estimated at just over 23,000,000 m3 (812,237,335 cu ft) in 1968.[1] The Urtabulak field is considered to be a combination trap, with the gas trapped between an anhydride layer and limestone.[2]

Accident

On 1 December 1963, control during drilling in Well No. 11 in the Southern Urtabulak was lost at a depth of 2,450 m (8,038 ft) after encountering an area of abnormally high pressure natural gas, with pressures exceeding 300 atm (4,409 psi),[3] alongside higher than expected concentrations of hydrogen sulfide.[4] A combination of a wellhead that was not equipped with a blowout preventer and steel that did not have the chemical properties to resist corrosive environments caused the wellhead to fail. An ignition source set fire to the natural gas, ejecting the wellhead from wellbore and melting a portion of the drilling rig.[4]

The fire went on to burn for 1,064 days, consuming an estimated 12,000,000 m3 (423,776,001 cu ft) of natural gas daily,[5] and killed numerous wildlife. The head of the taskforce dedicated to extinguishing the fire, Kamil Mangushev, wrote in his diary that "At night, flocks of migrating birds and clouds of insects, attracted by the light, fell into this fiery dance of death and, falling down, burned, often before even reaching the ground".[6] Attempts to quell the fire were unsuccessful; diverting the gas into nearby wells was hampered by the high hydrogen sulfide concentrations, the lower 1,000 m (1,094 yd) of the well had not yet been cemented either, alongside the exact location of the bottom of the well being unknown as it had not been logged at the time of the accident.[3]

It would be until 1966 that the proposition of detonating a nuclear charge near the well in order to shift the rock layers to seal the well was proposed. Employees of Design Bureau No. 11 in Sarov had already investigated in theory the use of peaceful nuclear explosions and were tasked with resolving the blowout in the Urtabulak gas field.[6] Come fall of 1966, a specialised nuclear explosive with a yield of 30 kilotonnes of TNT (126 TJ) had been developed by the Design Bureau in Sarov for sealing the well. The explosive was lowered into an inclined well near Well No. 11, two of which had been drilled in order to try and achieve the closest proximity to the original well.[3]

With approval from then-General Secretary of the Communist Party of the Soviet Union Leonid Brezhnev, the explosive was detonated at a depth of 1,500 m (1,640 yd) on 30 September 1966.[6] The hole that the explosive was lowered into had also been sealed with cement so as to prevent atmospheric radioactive contamination.[7] Just over twenty seconds later, the fire was successfully extinguished, marking the first time a peaceful nuclear explosion was used to seal a gas well. Almost two years later, a similar detonation with a yield of 47 kilotonnes of TNT (200 TJ) was successfully conducted at the nearby Pamuk gas field to seal another leaking well.[3]

Commercial operation

The discovery of the Urtabulak field was made as part of a larger discovery of hydrocarbons in the Amu-Darya basin, with the Gazli gas field being the first, having been discovered in 1956 with estimated reserves of 25,000 billion cu ft (7.1×1011 m3).[2] Operation of the field began in the 1960s prior to the accident, with exploratory drilling beginning in 1961.[1] The discovery of hydrocarbons came in 1963,[1] and the fire briefly paused commercial activities until 1969.[7]

Baker Hughes under its Cyprian subsidiary operated the Northern Urtabulak under a Production Enhancement Contract (PEC) from 1999 to 2005 in partnership with Rosehill Energy.[8] A Production Enhancement Contract stipulates that contractors must increase production of the assigned field by introducing modern, up-to-date technology and drilling techniques[9] in exchange for a fifty-fifty split of the increased production.[10] Baker Hughes was later charged with bribery under the Foreign Corrupt Practices Act in 2007, having been previously issued a cease-and-desist in 2001.[11] The field was then managed by Canadian energy firm Tethys Petroleum, following the acquisition of the PEC rights in 2009 for US$6.5 million (equivalent to $8,866,294 in 2022) for the field from British firm Rosehill Energy.[10] Tethys also specified in the share purchase agreement that Rosehill cover any legal fees as a result of potential damages by using the Baker Hughes name.[12] Tethys duly fulfilled their duties to increase production by raising production up to 1,100 US bbl (131 m3) per day in 2011,[13] up from 913 US bbl (109 m3) when Tethys acquired the PEC rights in 2009.[14] Techniques employed to help increase production included radial drilling and the use of muriatic acid as a well stimulant.[15] Tethys later announced in January 2014 that it would be exiting Uzbekistan,[16] following accusations by the Uzbek government of crude oil theft.[17]

See also

References

  1. 1 2 3 Nordyke, et al. (28 June 1973). A Review of Soviet Data on the Peaceful Uses of Nuclear Explosions (Report). UCRL. doi:10.2172/4353229. OSTI 4353229.
  2. 1 2 Ulmishek GF (February 2006). Petroleum Geology and Resources of the Amu-Darya Basin, Turkmenistan, Uzbekistan, Afghanistan, and Iran. United States Geological Survey (Report).
  3. 1 2 3 4 Nordyke MD (October 1996). The Soviet Program for Peaceful Uses of Nuclear Explosions. UCRL (Report). doi:10.2172/514386. OSTI 514386.
  4. 1 2 Осадчий, Андрей (2010). "Удар из-под Земли". Наука и жизнь (in Russian). No. 7. pp. 64–65. ISSN 0028-1263. Retrieved 28 June 2023.
  5. ↑ English, Trevor (10 April 2020). "Soviet Engineers Detonated a Nuke Miles Underground to Put Out a Gas Well Fire". Interesting Engineering. Retrieved 29 June 2023.
  6. 1 2 3 "Why did the Soviets use a THERMONUCLEAR WEAPON to extinguish hellish-like fire?". Russia Beyond. 15 September 2022. Retrieved 29 June 2023.
  7. 1 2 Shabad, Theodore (2 December 1971). "Soviet Discloses Nuclear Blast That Put Out Fire in Gas Field". The New York Times. p. 2.
  8. ↑ Azizov, D (18 May 2012). "Tethys signs contract to develop oil field in southern Uzbekistan". Tribune Content Agency. ProQuest 1014137093.
  9. ↑ "Tethys Petroleum acquires new oil field in Uzbekistan". UZ Daily. 16 May 2012.
  10. 1 2 "Tethys Closes Acquisition Of Uzbekistan-Based Subsidiary From Rosehill Energy For US$6.5MM". Hart Energy. 14 April 2009. Retrieved 27 June 2023.
  11. ↑ Norris, Floyd (27 April 2007). "Baker Hughes Admits to Overseas Bribery". The New York Times. Retrieved 29 June 2023.
  12. ↑ "Share Purchase Agreement" (PDF). Tethys Petroleum. 27 February 2009. Retrieved 29 June 2023.
  13. ↑ "Uzbek Well Flows Over 1,100 Barrels of Oil Per Day". Tethys Petroleum (Press release). Tashkent: Marketwire. 17 February 2011. Retrieved 27 June 2023 – via Comtex.
  14. ↑ "Tethys in Urtabulak asset buy". Upstream. 6 March 2009. Retrieved 27 June 2023.
  15. ↑ Elliot, Steve (5 September 2011). "Tethys Petroleum on Radial Drilling Technology Case History: North Urtabulak". ROGTEC. Retrieved 28 June 2023.
  16. ↑ "Tethys Petroleum Pulls Out Of Uzbekistan". Radio Free Europe. 3 January 2014. Retrieved 27 June 2023.
  17. ↑ Uzbekistan Oil & Gas Report - Q2 2014. Uzbekistan Oil and Gas Report (Report). London. 2014. p. 15. ProQuest 1505417429.
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