The Kola Superdeep Borehole is the result of a scientific drilling project of the Soviet Union on the Kola Peninsula. The project attempted to drill as deep as possible into the Earth's crust. Drilling began on 24 May 1970 using the Uralmash-4E, and later the Uralmash-15000 series drilling rig. A number of boreholes were drilled by branching from a central hole. The deepest, SG-3, reached 12,262 metres (40,230 ft) in 1989, and is the deepest hole ever drilled, and the deepest artificial point on Earth.
The Kola borehole penetrated about a third of the way through the Baltic continental crust, estimated to be around 35 kilometres (22 mi) deep, reaching rocks of Archaean age (greater than 2.5 billion years old) at the bottom. The project has been a site of extensive geophysical studies. The stated areas of study were the deep structure of the Baltic Shield; seismic discontinuities and the thermal regime in the Earth's crust; the physical and chemical composition of the deep crust and the transition from upper to lower crust; lithospheric geophysics; and to create and develop technologies for deep geophysical study.
To scientists, one of the more fascinating findings to emerge from this well is that the change in seismic velocities was not found at a boundary marking Harold Jeffreys's hypothetical transition from granite to basalt; it was at the bottom of a layer of metamorphic rock that extended from about 5 to 10 kilometers beneath the surface. The rock there had been thoroughly fractured and was saturated with water, which was surprising. This water, unlike surface water, must have come from deep-crust minerals and had been unable to reach the surface because of a layer of impermeable rock.
Another unexpected discovery was the large quantity of hydrogen gas, with the mud flowing out of the hole described as "boiling" with hydrogen.
Interestingly, it seems that drilling technology has come a long way in the last decade.
Since 2003, six of the world's 10 record-setting extended reach drilling wells have been drilled at the fields of the Sakhalin project, using the Yastreb rig. It has set multiple industry records for depth, rate of penetration and directional drilling.
Record breaking Yastreb Rig built and operated by Parker Drilling
On 28 January 2011, the world's longest borehole was drilled at the Odoptu field, with a measured total depth of 12,345 meters (40,502 ft) and a horizontal displacement of 11,475 meters (37,648 ft), in 60 days!
Graphic of Odoptu field with a measured total depth of 12,345 meters (40,502 ft) and a horizontal displacement of 11,475 meters (37,648 ft)
Sakhalin fields the Chayvo, Arkutun-Dagi and the Odoptu had been discovered some 20 years before by the Soviets at the time of the Production Sharing agreement in 1996. However, these fields had never been properly assessed and a reevaluation of the commercial viability had to be carried out. To do this, factors such as the reservoir quality, producibility and well locations had to be found. 3-D seismic is the most common way to determine much of this however shallow gas reservoirs interfered with the seismic signals and blurred the images somewhat.
Parker Engineering and the Yastreb Rig details
Two campaigns of 3-D seismic was carried out along with a number of appraisal wells into the Arkutun-Dagi and Chayvo fields. The results were initially average from the appraisal wells with hydrocarbons being successfully tested, but there was a still a large amount of uncertainty involved with the project. However, in late 1998, a revaluation of the 3-D seismic data using the most advanced seismic-visualization techniques then available indicated that the hydrocarbon depth on the edge of the field could be significantly deeper than first thought. In 2000, the Chayvo 6a delineation well confirmed what was suspected, a 150 meters (490 ft) oil column. This provided the certainty that the field was commercially viable in the hostile environment with a potential to be a 1-billion-barrel (160×106 m3) field.
More interesting are the geopolitical aspects of the deep oil discovery and the new Russian order. The consortium Sakhalin Energy had a contract to produce gas and oil without a local partner. However, in 2005-2006 the consortium was heavily criticized due to environmental issues and the legal proceeding on violation of the Russian environmental regulations were initiated. Under legal and political pressure, the consortium was forced to sell a majority stake to Gazprom. On 21 December 2006, Gazprom took control over a 50%-plus-one-share stake in the project by signing an agreement with Royal Dutch Shell. Russian President Vladimir Putin attended the signing ceremony in Moscow and indicated that environmental issues had been resolved.
Who knew that Vladimir was such a environmentalist?
Seeing that these new oil fields are being discovered at 12km depth, the argument for abiotic oil starts to look plausible if not probable.