The experience in estimating the sedimentary basin petroleum potential on the basis of study of mud volcanic breccia clasts (an Example from the Deep Part of the Gulf of Cadiz)

Abstract

Mud volcanism is a natural phenomenon well-known for on-shore and off-shore environments. Its major driving forces are deeply seated fluid accumulations and lithology and tectonism favorable for creating overpressure within deep strata with subsequent breakthrough of solid, liquid, and gaseous products of mud volcanism towards a ground surface. The mud breccia clasts provide information about the sedimentary section (up to several kilometers thick) through which the mud volcano erupted. Geochemical investigation of mud breccia clasts with characteristics of source rocks can help in understanding the petroleum potential of entire basin prior to expensive offshore exploration drilling. This is an especially important and useful method for initial estimation of petroleum potential of deep continental margin basins. The method of geochemical investigation of organic matter in the mud breccia clasts allowed to identify the Miocene and Upper Cretaceous clayey and carbonate deposits in the sedimentary sequence in the deep part of the Gulf of Cadiz as having the highest petroleum potential.