Abstract
Oil and natural gas exploration in the asturian continental shelf started more than 30 years ago. Seismic surveying was profusely used and more than 2.000 km of seismic reflection profiles were acquired in different prospective campaigns. Two main reflectors “H” –Tertiary Cretaceous unconformity– and “K” –shaly level below the Santonian– were recognized in the profiles. The interpretation of several profiles allowed us to define the structure of the MesoTertiary basin that fills the asturian platform. More than 50 km. of rock were drilled in test wells in the platform between 1975 and 1985 and their main characteristics are also described in this paper. The first offshore well (“C-1”) was drilled in 1975 and showed positive results in Tertiary rocks. The results were satisfactory, given that oil and/or gas were found in more than half of the wells. The main reservoir rocks are in Cretaceous and Paleocene levels, and although Jurassic rocks were the main target, they were scarcely reached in the different prospective campaigns. Long and narrow E-W anticlinal folds are amongst the oil-bearing structures.
