Salt Tectonics and Suprasalt Plays in the Mersin Basin, Eastern Mediterranean

Pinar Hacikoylu, Arzu Aktepe, Erhan Kansu, and Nazif Sahin

This integrated study summarizes the geological and the geophysical framework for the Pliocene gas plays in the Mersin Basin conducted by Turkish Petroleum Corp. Prior to this date only two wells were drilled in the Mersin offshore region and both targeted the early-middle Miocene reefal limestone deposits in the subsalt system. With the recent Pliocene discoveries in the Mediterranean Region and the interpretation of recently acquired 2-D seismic data, new insights emerged to the exploration strategy of Turkish Petroleum Corp. in this region.

During and shortly after the Messinian salinity crisis, the Mersin Basin experiences a slight tilting which causes the salt to act as a regional detachment level. During Pliocene time with the loading of the sediments mostly from northnorthwest, sliding of salt intensifies towards south. As a result of gravity-sliding system, all of the characteristic features of salt tectonics can be identified at the Mersin Basin which are present in extensional, transitional and compressional zones. Especially in the extensional zone, growth faults are associated with large-scale rollover structures which forms both four-way and three-way dipping structural-stratigraphical thick Pliocene traps. Lower Pliocene fluvio-deltaic deposits are potential good reservoir units with thick sand bodies which are interbedded with thick calcareous shales and these shales have excellent sealing capacity.

Several DHIs are observed along growth faults within the Lower Pliocene on the stack data and AVO analysis concludes Class-III AVO response in several zones in this sequence. High sedimentation rates, observed organic matter in the cores recovered from a well, and suitable thermal regime during Pliocene suggests high potential of biogenic gas generation in the Mersin Basin.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013