Exploration in the Mediterranean Sea has experienced significant renewed interest over the last decade, with exciting, play-opening discoveries in Israel, Egypt and Libya. ION has taken an Pliocene -- CROP Repro – 4,700 km Miocene Messinian Exploration innovative approach in order to rapidly and cost-effectively develop an integrated dataset to acquired 80s-90s acquired 80s-90s - 4.5-6 km o sets aid understanding of the whole Mediterranean, which can be used as the framework for future 17-20s record MS Repro –17,000 km Eocene exploration programmes and to challenge existing basin models. The dataset consists of newly acquired ‘70s-’80s 2.4 km o sets Oligocene Opportunities in the 10-12s record, dynamite source acquired BasinSPAN data and reprocessed data from both industry and academic sources. These surveys have been processed concurrently to provide a consistent velocity model across the Mediterranean and generate a fully integrated geological and geophysical interpretation Mediterranean Upper Cretaceous using seismic, well, gravity and magnetic data. ION has created a unique dataset in the region to NAGECO The value of a regionally calibrated seismic dataset support the next phase of exploration, with license rounds expected in the near future. LibyaSPAN –– IONION acquiredacquired Lower Mesozoic 2014 – 7040 km LibyaRepro –38,000–38,000 kmkm acquired 2005 10 km o sets 8.5 km o sets 18s record, WiBand processingprocessing 10s record, WiBand re-processing 0 —

Absence of Messinian evaporites on palaeo-high

Thickened Messinian Thickened Messinian evaporites evaporites

2,500 — Significant Oligo-Miocene clastic infill

Well-developed Miocene progradation at shelf-break

Base Cenozoic

5,000 —

Well-developed Eocene shelf-break carbonate facies

Exposed Cretaceous carbonates over Palaeozoic highs Base Cenozoic Post-rift Mesozoic, thickening to East

7,500 —

Syn-rift facies Pre-rift, thinned/absent syn-rift Pre-rift facies Basement

10,000 —

67 GEOExPro October 2017 GEOExPro October 2017 70 Grind-off 4mm fold line fold fold line fold Regional Geology Pre-Messinian Inner arc database to identify new prospects and plays in the Sirt 0 – Forearc basin Outer arc Foreland 2000 – Forearc thrust Deformation The present-day configuration of the Mediterranean and Cyrenaica Ridge areas as well as the eastern margin Backthrust front Basin is dominated by the Cenozoic collision of Africa of the basin. These data create the framework to develop 4000 – 6000 – Pre-M Integrated Seismic and Eurasia, creating compressional and back-arc a new understanding of the entire offshore system from 8000 – Down stepping Subducting sediments Mesozoic extensional tectonic settings. The current tectonic crust to sediment in a basin-scale context and are vital 10000 – of decollement Duplex VERITY AGAR, PAUL BELLINGHAM, NICOLA CLARKE, 12000 – Basement elements and basins have overprinted pre-existing to understanding the petroleum potential of the offshore BETH GILLBARD and KEN MCDERMOTT; ION Tethyan margins that stretch from Algeria to the Eastern Libyan margin. (See Figures 2 and 3 on page 66.) 14000 – Datasets Mediterranean and extend to the Arabian Peninsula. The 16000 – Nile Delta 18000 – The offshore Mediterranean basins are the focus of renewed interest since the 2008 discovery variability in basin types and ages provide significant 20000 – hydrocarbon potential for a wide variety of play types, The Nile Delta region has undergone several phases Figure 5: Geoseismic section (PSDM) of the Calabrian Arc from Sicily to the Ionian Abyssal Plan demonstrating the complex structure of the Arc in Libya, the Tamar and Leviathan discoveries in Israel, and the recent Zohr discovery in with source rocks of Palaeozoic to Cenozoic age. of exploration, but is dominated by Plio-Pleistocene with deformation younging towards the south-east. Thick deformed and undeformed Messinian evaporites dominate the Outer Arc and foreland. Egyptian waters. ION’s regional Mediterranean programme demonstrates the utility and The Mediterranean contains several well-known gas discoveries in stratigraphic and structural traps. Improved sub-salt imaging provides uplift of the sediments and structures below. exploration value of a fully integrated seismic dataset and velocity model across the entire plays: biogenic Pliocene gas offshore Nile Delta; salt- Exploration of deeper Miocene and Oligocene strata Central and Western Mediterranean Exploration basin. Interpretation of these data provides the context to correlate known discoveries into generated structural plays of the Sabratha Basin; and has had varying success and has been slower to develop. with only nearshore fields in the Cretone Basin and those new and complex underexplored areas. the Po Valley/Adriatic Sea gas play. There are also areas However, even with the extensive dataset across the area, Exploration successes in the offshore Ionian, southern academic wells which only penetrated the top of the where commercial discoveries have been elusive and fundamental questions regarding deeper stratigraphy and Adriatic, and Sicilian Channel occurred predominantly Messinian evaporitic section in the deep basin. Inverted areas which have yet to be explored with the potential for structure still remain. Development of new exploration from the 1970s to the 1980s. Oil discoveries within extensional structures in the thick Mesozoic and Cenozoic Sirt Embayment Cyrenaica Ridge new play types. plays in deeper water and older stratigraphy requires the Apulian platform were made in the 1990s and gas strata underlying relatively undeformed Messinian a better understanding of the underlying basement discoveries were made in the Gela foredeep of the Pelagian evaporites are compelling, but are located in ultra-deep Offshore Libya architecture and stratigraphy. ION, in collaboration with Basin beginning in the early 2000s. Despite intensive water (Figure 5). Base Cenozoic Offshore Libya has attracted exploration interest for the Egyptian Natural Gas Holding Company (EGAS), onshore and shallow water exploration, there remains More mature and shallow water areas, such as the some time. The prolific petroleum systems of Libya have acquired a deep, long-offset line across the central and significant underexplored offshore potential, including Pelagian Basin offshore Sicily, Malta and Tunisia, contain generated proven oil discoveries of about 130 Bbo, the western parts of the Nile Delta, imaged to 40 km depth. searching for known plays along strike and new play types. multiple play types and multiple source rock intervals that majority of this onshore. The offshore extensions of these One of the critical observations from these new data is the Both the North African and Southern Eurasian are working in Sicily and Libya/Tunisia. These plays are petroleum systems are largely unexplored. The success >12 km thickness of sediment to the west of the Delta. margins developed as carbonate-dominated platforms likely to be present in the Maltese offshore, but exploration of the 2005 EPSA IV license round highlighted industry The Nile Delta 2D line was processed using ION’s on the margins of the Tethyan Ocean. The complex efforts are hampered by boundary disputes and paucity of interest in the area and the subsequent play-opening WiBand™ broadband processing solution, which Mesozoic palaeogeographies (shallow water platforms data. A younger Oligocene rift basin with a thick post-rift Syn-rift facies Arous Al-Bahar gas discovery in the offshore Sirt Basin in provides deghosting that enhances the bandwidth of and intervening deep water euxinic basins) were section in offshore West Sardinia may also contain an active Inverted pre-rift in core of ridge, 2008 confirmed the continuity of the onshore Cretaceous the data by recovering low-frequency components of controlled by extensional phases and later inversion. petroleum system. Multiple plays in the pre-, syn- and post- Pre-rift overthrusting post-rift facies carbonate play into the Sirt Basin. The potential of Eocene the data and performing multiple suppression prior to Proven hydrocarbon plays in structural traps in the up rift sections are possible, with several source and reservoir marls and limestone reservoirs lying unconformably on waveform inversion. High resolution non-parametric dip platform carbonates are thought to be sourced from intervals that could be sealed by Messinian evaporites or Figure 2: Example line in Cyrenaica area from reprocessed Libya dataset highlighting areas of improved imaging and features of interest. the Cenomanian and Turonian carbonate blocks remains inversion (GMO Tomography) incorporating anisotropy basinal organic-rich mudstones. Pliocene shales. Interpretation of this contiguous dataset poorly understood. Discoveries continue to be made in the combined with the use of full waveform inversion Middle Eocene Alpine orogenic events across the margin across the complex inverted margin of the Maghrebian in Figure 3: more developed Sabratha Basin, but several structures and created the detailed velocity model in the complex strata resulted in the Apennine fold belt having an eastward the Sicily Channel to the Balearic creates a new correlation Example of improvement deeper targets remain undrilled. below the Messinian salt (Figure 4). Interpretation of migrating subduction system and the development of framework between these diverse basins. in imaging Given the proven offshore extension of the enormous crustal events (basement and Moho) using the new foreland and back-arc basins. The east-west trending with modern reserves onshore Libya, creating an integrated depth- migration velocities calibrated with potential field data Maghrebian thrust belt of North Africa, the Calabrian Arc Cost-Effective Exploration processing migrated seismic dataset and basin framework were combined to create high quality depth imaging. and connected north-south trending Italian Apennines Exploration teams constantly strive to understand the offshore Libya. interpretation provides the basis for future exploration. The integration of these data (potential field, refraction show significant variability in the width and deformation basin framework in order to high-grade areas that align The regional framework LibyaSPAN™ data are infilled and PSDM) support the interpretation, addressing style along its strike. Progressively younger foreland with company strategy and identify proven and future with 39,000 km of modern reprocessed 2D data. The questions of crustal structure and the nature of the basin fold-thrust belt settings characterize the compressional successful hydrocarbon plays. The complexities of the processing and imaging of these datasets are fully development. Recent discoveries and the presence of system and are important to hydrocarbon generation and Mediterranean Basin architecture and the variety of play integrated and calibrated using gravity, magnetic, and thick sediment lends support to source rock maturity accumulations sourced from either terrigenous flysch or types highlight the importance of understanding the well control data. The improved imaging provides a continuing beyond the areas previously predicted. mature pre-Alpine Mesozoic strata. regional tectonic and stratigraphic framework to fully assess the remaining potential in the region. Using a fully 2005 Legacy Processing Figure 4: Nile DeltaSPAN A New Look Tomography for lateral variability RFWI + tomography down to Top Messinian velocity model highlighting integrated Mediterranean seismic dataset that crosses the modern techniques used Reprocessing of two legacy data sets, MS (acquired multiple country boundaries, tying mature areas (Sabratha to maximise the accuracy 1970–82) and CROP (acquired 1988–95), using ION’s Basin) with less explored areas in Libya, Malta and Italy, of the velocity model and BasinSPAN processing workflow has been integrated into makes this interpretation and model refinement possible. improve the quality of the ™ deeper imaging. the interpretation and regional velocity model. These data Given the current low price environment, it is critical span the complex and varied domains of the central and for companies to acquire high quality information in a western Mediterranean basins, providing a new look at the cost-effective manner. Combining new acquisition with petroleum systems and multiple play types. reprocessed legacy data and modern integration techniques, RFWI down to Identified analogue plays on the Apulian Platform ION has created a dataset that can be used to understand Top Cretaceous include karsted carbonate reservoirs and shelf-edge the future hydrocarbon potential in the Mediterranean. in high S/N areas carbonate deposits. Fractured carbonate reservoirs in Reference: sub-thrust plays sealed by flysch are another attractive Hallet, D., and Clark-Lowes, D., Petroleum Geology of Libya, Crustal velocities taken from gravity modelling candidate. The Calabrian Arc remains virtually untested Elsevier, Amsterdam, Netherlands, 2016. ION reprocessing

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