Casp27 Jul 2018 12:20
The Tengiz field, first discovered in 1979, has recoverable reserves estimated at between six billion and nine billion barrels. The field was jointly developed in 1993 as a 40-year venture between Chevron Texaco (50%), KazMunaiGaz (20%), US ExxonMobil (25%) and LUKArco (5%). The joint venture company is known as TengizChevrOil (TCO). Chevron is the operator of the TCO field.
Prior to its expansion in 2008, the Tengiz oilfield had 53 wells, tapping a column of crude oil around 1.6km thick. When the field was first tapped its oil pressure was 12,000psi, but in 2004 the pressure came down to 10,000psi in most areas and 8,500psi in others. The SGI project used gas injection technology to boost the pressure and increase oil recovery, while the SGP increased the number of producers (wells) and improved and expanded the crude export infrastructure.
So 15 years later before it dropped and with 53 wells drill on it . To be honest I can't find info on a just one well.