Pollultion of groundwater by leaking wells - January 1, 1993

The two pollution incidents at the Singleton Oil Field (now operated by IGas but operated by a different company when the incidents occurred) occurred in the early 1990s, and were caused by failure of cement behind the conductor and the 9 5/8-inch casing. This was identified as a result of five groundwater monitoring boreholes installed at the Singleton Oil Field in 1993. The leak was from the well cellar (cement lined cavity in which the well head sits) via the pre-installed conductor and the 9 5/8-inch casing, both of which appear not to have been adequately cemented in-situ in at least one well. A thorough investigation commenced in 1997, including the drilling of a number (>11) of additional boreholes, and the carrying out of tracer tests and CCTV examination under the auspices of, and in consultation with, the UK Environment Agency.