Seismic Monitoring of an Old Underground Blow-out – 20 Years Later

In January 1989 Saga drilled a well into a rotated Jurassic fault block on the Steinbit Terrace in block 2/4 in the North Sea. At 4734 m the well kicked, and the drill pipe started to come out of the hole. The well was cut on the 20th January, and it developed into an underground blow out. Shallow seismic surveys were performed 4, 6, 10 and 12 months after the blow out. Last year, Statoil acquired 5 2D lines over the well location again. The old and the new data are now 4D processed again, and initial interpretation will be presented. Based on preliminary results from fast track processing of the 2009 data it seems reasonable to conclude that there has been some gas migration into shallower sediments. However, the co-processing of the old and new datasets is required to verify this initial conclusion.