Evidence of shallow gas above the Connemara oil accumulation, Block 26/28, Porcupine Basin

Abstract The results of a site survey investigation, carried out in Block 26/28 of the Porcupine Basin, suggest the presence of shallow gas above the Connemara oil accumulation. The evidence for shallow gas at or close to the sea bed consists of a series of features interpreted as gas or fluid escape structures. The presence of gas at depth is suggested by two different features: an anomalously high-amplitude seismic reflector, interpreted as a gas-charged sand layer, and some isolated, seismically disturbed zones, which are identified as gas chimneys on both high-resolution 2D seismic and conventional 3D seismic data.