Petroleum potential of the interpreted Paleozoic geoseismic sequences in the South Diyur Block, Western Desert of Egypt

ABSTRACT The South Diyur exploration block of nearly 38,000 sq km is located in the Farafra Oasis region in the Western Desert of Egypt. It is a frontier exploration area, the nearest well being Ammonite-1, a dry hole drilled by Conoco in 1979 immediately outside the southwestern corner of the block. The South Diyur Block is located on the probable northeast extension of the Kufra Basin in southeast Libya. Although prolific reserves of oil and gas occur in Paleozoic basins in North Africa and throughout the Middle East, to date, the targets for petroleum exploration in the northern Western Desert have been in Jurassic and Cretaceous rocks. The regional structural surface features in the South Diyur Block are the NE-trending Bahariya and Farafra anticlines interpreted as a deeply eroded and inverted Late Cretaceous structure on the southern extension of the Syrian Arc system. The oldest exposed rocks are a Cretaceous sequence of sublittoral sediments (the Campanian Wadi Hennis Formation) in the core of the anticline. The interpretation of the subsurface is based on 1,175 line-km of reprocessed 1970s-vintage 2-D seismic. Four sequence boundaries have been identified from the seismic data. SB-1 correlates with the Jurassic/Cretaceous boundary in Ammonite-1. SB-2 is regionally correlated with the Late Devonian to Early Carboniferous Hercynian unconformity that overlies deeply eroded and truncated Paleozoic sequences and possibly marks the regionally extensive Late Paleozoic basin inversion. SB-3 near the base of the interpreted Silurian sequence coincides with the ‘hot shale’ petroleum source rock that is present throughout North Africa and the Middle East. SB-4 is interpreted as a major unconformity at the top of an Upper Proterozoic sedimentary section that was misinterpreted as the Precambrian acoustic basement in Ammonite-1. Five seismic sequences relate to the seismic boundaries. SS-1, from the surface to SB-1 is characterized by subparallel seismic stratification and is composed mainly of sandstone with shale interbeds in Ammonite-1. SS-2, bounded by SB-1 and SB-2, is distinguished by parallel to subparallel seismic stratification. In Ammonite-1, the sequence of interbedded sandstone and shale is fresh-water bearing and lacking in top seals, thus reducing its prospectivity. The underlying SS-3 (SB-2 to SB-3) directly underlies the Hercynian unconformity and is characterized by semi-transparent seismic facies that may correspond to a thick Silurian shale sequence. SS-4 (SB-3 to SB-4) of probable Cambrian–Ordovician age has parallel seismic stratification. Deep channels are interpreted as evidence of a Late Ordovician–Early Silurian glacial phase that is present throughout North Africa and the Middle East. SS-5 (below SB-4) is marked by partial subparallel seismic stratification and block faulting. It probably belongs to the Late Proterozoic (Pan-African) phase of block faulting and pull-apart basins. Similar seismic geometries and facies occur in the Kufra Basin in southeast Libya and in many parts of the Arabian Plate, including the prolific petroleum systems of Oman. Exploration plays in the South Diyur Block are a combination of Paleozoic structural and stratigraphic traps associated with prospective fairways, and possible stratigraphic traps in the Late Ordovician–Early Silurian glacial channels. In addition, the interpreted Late Proterozoic sequences (SS-5) warrant further evaluation. In order to identify future exploration plays and drill targets, additional 2-D seismic (4,490 line-km), aeromagnetic and airborne gravity surveys will be integrated with the present seismic data and drilling results from Ammonite-1. This will allow a proper assessment of the magnetic basement, basin configuration and prospective fairways.

Download Full-text

A study on tectonic and sedimentary development in the rifted northern continental margin of the South China Sea near Taiwan

Interpretation ◽

10.1190/int-2015-0209.1 ◽

2016 ◽

Vol 4 (3) ◽

pp. SP47-SP65 ◽

Cited By ~ 5

Author(s):

Wei-Zhi Liao ◽

Andrew T. Lin ◽

Char-Shine Liu ◽

Jung-Nan Oung ◽

Yunshuen Wang

Keyword(s):

South China Sea ◽

Continental Crust ◽

South China ◽

Seismic Data ◽

The South China Sea ◽

Seismic Facies ◽

The South ◽

Northern Margin ◽

China Sea ◽

Breakup Unconformity

A series of Cenozoic rifted basins developed in the northern margin of the South China Sea (SCS). Tainan Basin is one of these rifted basins near Taiwan, lying in the outer margin. We have used reflection seismic data in the deepwater areas and boreholes drilled in the shelf of the Tainan Basin to understand the tectonic and sedimentary development in the northern SCS margin near Taiwan. Four key stratal surfaces (i.e., the base of the Pleistocene Series, the base of the Pliocene Series, the 17 Ma maximum flooding surface [MFS], and a breakup unconformity of approximately 30 Ma in age) and seven seismic facies (i.e., continuous- and parallel-layer seismic facies, wavy seismic facies, chaotic seismic facies, U-shaped canyon-cut seismic facies, imbricated-layer seismic facies, high-amplitude reflector package seismic facies, and extrusive volcanism seismic facies) are recognized from seismic data with ages constrained by borehole stratigraphy drilled in the shelf. We have established a model for Cenozoic tectonic and sedimentary development in the rifted northern margin of the SCS near Taiwan. The occurrence of Paleogene fault-bounded grabens/half-grabens topped by a breakup unconformity and draped by postrift sediments indicates that these deepwater rifted basins developed on the continental crust, attesting that a thinned continental crust underlies the deepwater study area, rather than oceanic crust as reported in some literature. Postbreakup extrusive volcanic bodies, of early Miocene age, were buried by thick deepwater sediments. Fairly continuous stratal surfaces of 17 Ma MFS reveal that volcanic activities ceased to be active since middle Miocene. A series of channel cut-and-fills is observed in late Miocene, Pliocene, and Pleistocene strata beneath and to the south of the modern Formosa Canyon. Two distinct fields of deepwater sediment waves developed since middle Pleistocene are found lying to the west of modern deformation front/Manila Trench and to the north and south of the Formosa Canyon, respectively.

Download Full-text

Africa — Latin America — Asia — Middle East and North Africa

International Review of the Red Cross ◽

10.1017/s0020860400025134 ◽

1986 ◽

Vol 26 (255) ◽

pp. 402-407 ◽

Cited By ~ 1

Keyword(s):

South Africa ◽

Latin America ◽

Middle East ◽

South African ◽

North Africa ◽

Red Cross ◽

South African Government ◽

The South ◽

African Government ◽

International Conference

Following the decision reached on 28 October by the Twenty-fifth International Conference of the Red Cross to suspend the South African government delegation from participation in its work, the ICRC was requested by the South African authorities to suspend its activities in South Africa and to leave the country at the latest by 30 November. The ICRC delegates based in South Africa therefore made the necessary arrangements to close down the delegation and return to Geneva by that date.

Download Full-text

Megaseismic section across the northeastern slope of the Arabian Plate, Iraq

GeoArabia ◽

10.2113/geoarabia110477 ◽

2006 ◽

Vol 11 (4) ◽

pp. 77-90 ◽

Cited By ~ 2

Author(s):

Sabah A.G Mohammed

Keyword(s):

Seismic Data ◽

Structural Features ◽

Oil Field ◽

Western Desert ◽

Arabian Plate ◽

Channel System ◽

Level Data ◽

Seismic Image ◽

Middle Carboniferous ◽

Seismic Lines

ABSTRACT A composite seismic image (Megaseismic Line 7) was constructed across Iraq using 16 pre-existing seismic lines that were recorded between 1975 and 1983. The image is the first of 15 megaseismic lines that will eventually form a rectilinear grid that covers Iraq. It is oriented in a SW-NE direction, and extends approximately 500 kilometers from the Iraq-Saudi Arabia border to the Iraq-Iran border. The seismic lines were recorded using a 48-channel system with either a vibroseis or dynamite source. The maximum offset varies from 2,400 to 5,000 meters. The seismic data was reprocessed using a common datum of 300 meters above sea level. Data quality is good where the source was dynamite and the terrain consists of gravel and sand surfaces; it is poor where vibroseis was used or/and the outcrops were carbonates. The final stacked section and Hilbert attributes (reflection amplitude and instantaneous phase) were displayed at different scales to determine the best perspective for interpretation. A total of 14 reflections, corresponding to Miocene to Permian horizons, were identified using synthetic seismograms from five wells. The horizons generally dip towards the northeast, except at the location of the Tel Ghazal oil field where syndepositional growth is inferred. Various seismic stratigraphic geometries, such as sigmoidal features, onlap, toplap and downlap, were identified and used to define disconformities and angular unconformities. The oldest two horizons that could be picked are from the tops of the Triassic Kurra Chine and Permian Chia Zairi formations. Below the oldest Permian reflection, the middle Carboniferous “Hercynian unconformity” was tentatively picked. The Paleozoic pre-Permian succession is not adequately imaged in the seismic data, nor is the crystalline basement seen. The seismic interpretation was compared to the profiles of the Bouguer gravity anomaly and the total magnetic field, and good correlations were established. The regional line helped identify several previously unknown structural features including the Ma’aniya Depression in the Western Desert, and two anticlinal structures: the first being within that depression and the second directly to the southwest of Tel Ghazal oil field.

Download Full-text

Image improvement of Late Miocene (Messinian) to Plio-Quaternary units in the Algero-Balearic basin

10.5194/egusphere-egu2020-13769 ◽

2020 ◽

Author(s):

Simon Blondel ◽

Fadl Raad ◽

Angelo Camerlenghi ◽

Johanna Lofi ◽

Anna Del Ben

Keyword(s):

Seismic Data ◽

Early Stage ◽

Complex Salt ◽

Western Mediterranean ◽

Seismic Facies ◽

Messinian Salinity Crisis ◽

Transform Fault ◽

The South ◽

Seismic Reflection Data ◽

Multichannel Seismic Data

This study intends to contribute to the understanding of the Mediterranean Salt Giant in the Western Mediterranean, formed about 6 Ma ago during the Messinian Salinity Crisis. It provides reprocessed multichannel seismic reflection data that aim at improving our knowledge of the stratigraphy in the Algero-Balearic deepwater basin and its continental margins, in the absence of lithological information from wells.We investigate the seismic expression of the Messinian salinity crisis from the south-east of the Balearic promontory to the central Algero-Balearic abyssal basin and the salt tectonic processes associated to these facies. Here the segmentation of salt structures has been previously described using shallow chirp sonar data, low-resolution vintage multichannel seismic data and high-resolution multi-channel seismic data post-stack migrated with a constant velocity field. The structure of the northern Algero-Balearic basin is controlled by two abrupt fault scarps oriented SW&#8211;NE (mainly the Emile Baudot Escarpment transform fault) and WSW-ENE (mainly the Mazarron Escarpment transform fault) emplaced during the basin extension, and later intruded by steep and narrow volcanic ridges of Pleistocene age. It is a good analogue to early stage salt tectonic for older and more complex salt giants in the North Sea or the Gulf of Mexico.We reprocessed 2D Kirchhoff PSTM multichannel seismic data acquired by the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale &#8211; OGS (SBALDEEP Cruise of 2005 and SALTFLU cruise of 2012; the latter within a Eurofleet cruise) spanning the South-East continental margin of the Balearic islands and the Algero-Balearic basin. The reprocessing was designed for improving the continuity of the reflectors by applying Kirchhoff PSTM using a detailed velocity model, while preserving amplitude information. The objectives are to better apprehend the structural complexity of the area and to retrieve the amplitude variation within the Messinian units, in an attempt to derive the composition of the salt and the pressure regime.We present preliminary results where we delineate four different domains based on i) the seismic facies, ii) the amount of salt deformation, iii) the thickness of the overburden and iv) the pre-salt configuration. We try to assess the presence of the Messinian trilogy in the south-eastern continental slope. We attempt to reconstitute the paleo-depositionnal environment of the various depositional units, and the effect of crustal structures and salt tectonic gravity spreading and gliding on their syn to post-depositional evolution. Finally, we search for evidence of fluid circulation within the Messinian and the Plio-Quaternary deposits over the study area.

Download Full-text

The Greater Middle East

International Relations ◽

10.1093/obo/9780199743292-0129 ◽

2013 ◽

Author(s):

Bernard Reich ◽

Sanford R. Silverburg ◽

David Ettinger

Keyword(s):

Middle East ◽

Ottoman Empire ◽

North Africa ◽

Arabian Peninsula ◽

World War ◽

The South ◽

Gulf Region ◽

The West ◽

The North ◽

The Mediterranean

Dating back to biblical times, the area we refer to as the Middle East has, throughout the course of history, defied attempts to precisely define it. Until today, the region’s contours remain shrouded in geographic ambiguity. Through the centuries, the Middle East, or parts thereof, has been variously referred to as “Le Orient,” “Proche Orient,” “Anatolia,” “North Africa,” “the Persian Gulf region,” “Arabian Peninsula,” “the Levant,” “the Fertile Crescent,” “Asia Minor,” “the Maghreb,” “Southwest Asia,” “the Caspian region,” and “Greater Middle East.” Merriam-Webster Geographical Dictionary labels it “an indefinite and unofficial term.” Long before being adopted in common parlance, the term “Middle East” was a Western invention used by military strategists and governments in the 19th and 20th centuries to denote areas to the east of western Europe. As part of the Ottoman Empire, it extended from Algeria in the west to Iraq in the east, parts of Russia and Hungary to the north, and the Arabian Peninsula to the south. The term “Near East,” often used synonymously, was popularized after the dismantlement of the Ottoman Empire after World War I, referring to the area at the hub of Europe, Africa, and Asia that served as a crossroads and bridge among the three continents and to the various states around the eastern areas of the Mediterranean Sea. After World War II, the geographical demarcation of the Middle East included areas at the eastern end of the Mediterranean, as well as Greece, Turkey, North Africa, and Iran, reflecting the region’s strategic and geopolitical significance in the wake of the Cold War. Although scholars of the area continue to differ in their definitions of the region, this bibliography will focus on the core region generally regarded as the Middle East, bounded by Turkey to the north, Iran to the east, Egypt to the west, and Yemen to the south. It does not include North Africa, the Sudan, or Central Asia. The first section includes a list of General Overviews and introductory works and those on the region’s Geography, History, Politics, Economics, and International Relations. Important related topics such as Petroleum and Energy and the Arab-Israeli Conflict are also treated. In light of recent developments, we have added the “Arab Spring”. The second section is devoted individually to The Countries of the Middle East. Although the emphasis is on contemporary works, classic titles are included as well, in keeping with the authors’ goal to assist researchers in locating the best works on the region.

Download Full-text