Clair oilfield
The Clair oilfield is an offshore oil field in Scottish territorial waters west of Shetland in water depths of up to . The field is the largest oilfield on the UK Continental Shelf with an estimated 8 billion barrels of oil-in-place, according to the BP Plc’s website. It extends over an area of some , covering five licence blocks. History The Clair reservoir was discovered in 1977, with exploration well #206/8-1a penetrating a oil column in a thick sequence of Devonian to Carboniferous continental sandstone. In the 1980s ten appraisal wells were drilled. This activity demonstrated that the structure extended to an area of some with static oil-in-place, although it failed to confirm the presence of economically recoverable reserves. Two further wells were drilled in 1991, two in 1992 and one in 1995. Two of these wells (206/8-8 and 206/8-9z) demonstrated the potential for commercial flow rates but were not produced for long enough to give confidence in long term reservoir deliverability. In 1996 there was a breakthrough in the drilling and extended well testing (EWT) of well #206/8-10z. The EWT was followed by the side-tracking of an offset well into the pressure sink created by the EWT. The 1996