Geophysical interpretations in the Celtic Sea and South Western Approaches

Seven wells have been drilled and released in the South-Western Approaches and western English Channel area. Four were drilled by the Institute of Geological Sciences for the Department of Energy in 1977~~!f.g a semi-submersible drilling vessel, Zephyr (88/2-1, 87/14-1Aand 83/24-1). (Evans et a1 1981). 86//8-1 and 72/10-1A were drilled by the Atlantic Drilling Company for the British National Oil Corporation in 1979 using a drilling vessel Atlantic 1. 87/12-1A was drilled by BP Petroleum Development Limited in 1979. Fig 1.1 shows the positions of these wells and the known solid geology of the area (after Evans 1985 a, b; Evans 1982; Evans et a1 1984; Holder et a1 1983 and Taylor et a1 1980). This report consists of: a) Brief details on each well b) Tables showing the depths of noticib1e, sudden changes in sonic log velocities in each w~ll. c) Tables showing sonic log ve10cities~ depth and lithology throughout each well. d) A graphic log for each well.