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Petroleum Geology of Libya

Review of the Second Edition
This article appeared in Vol. 14, No. 2 - 2017

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The first edition of Petroleum Geology of Libya, by Don Hallett, was published in 2002, so a second edition is welcomed. With Daniel Clark-Lowes as co-author, the book is written by two petroleum geoscientists with 40 years of experience between them. 

Petroleum Geology of Libya. Second Edition, 2016. Don Hallett and Daniel Clark-Lowes, Elsevier. Divided into eight parts, it commences with a historical review of Libyan petroleum exploration after the discovery of oil in a water well near Tripoli in 1926, followed by the story of petroleum exploration, detailed decade by decade down to the post-Qaddafi period. 

Part 2 gives an excellent resumé of the plate tectonics history of North Africa in general and Libya in particular, while Part 3 describes Libyan stratigraphy – a challenging task that the authors attack with commendable vigor. The pre-oil industry terminology, largely proposed by pre-WWII geologists, principally Professor Ardito Desio working in the 1920s and ’30s, was used in Raymond Furon’s Géologie d’Afrique (1960) and the Lexique Stratigraphique Internationale (Burollet, 1960). However, when oil exploration began each company developed its own nomenclature for the rocks in its concessions. Barr and Weegar (1972) attempted to synthesize this chaotic stratigraphy. Hallett and Clark-Lowes bravely try to integrate these earlier stratigraphic terms with the Libyan Stratigraphic Code of the Qaddafi era, which itself had confused non-Arabic speakers and older geologists by changing the spelling of many of the stratigraphic terms and place names and over the years renaming some of the fields. The Hassaouna Formation became the Hasawnah, the ‘h’ and the ‘a’ in Sabratha were transposed to become ‘Sabratah’, Gialo became Jalu and so on. Amazingly, Russeger’s 1837 term ‘Nubian’, which he applied to Lower Cretaceous Sandstones in Upper Egypt, has survived, although now used to describe any barren sandstone of uncertain age across the Saharan and Arabian deserts. Still alive in the 21st century, it has confused generations of stratigraphers; at one time more was written about the terminology of the ‘Nubian’ than about the rock itself. In this book it is used both as a stratigraphic term and as a facies and is applied to rocks that range in age from Triassic to Albian. The authors helpfully guide the reader through this terminological fluxoturbidite of Libyan stratigraphic and topographic nomenclature. 

Structure and Petroleum Geology 

Part 4 describes the geological structure of Libya, detailing the evolution of the Murzuk, Kufra, Sirt and Ghadames Basins and the arches that delineate them. These descriptions usefully extend into Tunisia, Algeria, Niger, Chad, Sudan and Egypt, and into the offshore Mediterranean basins; page 226 describes how the US Navy bombed a sea mount – the first hostile sea mount in history? The structural evolution is based on an extensive database of wells and outcrop sections, but does not integrate these data with the paleocurrent studies that have thrown much light on the complex evolution of the Kufra and Murzuk Basins. Part 5 describes the geochemistry of Libyan source rocks, proven and potential, sequence by sequence and basin by basin, illustrating how far this branch of petroleum geoscience has advanced. When the first oil was discovered in Libya no geologist had ever heard the word ‘kerogen’. 

Integrating the previous two chapters, Part 6 delineates the petroleum systems and play fairways of the Murzuq, Ghadames, Sabratah and Sirt Basins – intellectually one of the most challenging and worthwhile parts of the book. Part 7 describes the 15 major fields of Libya and Part 8 speculates on future petroleum exploration potential. Perhaps wisely, it omits any speculation about the potential for unconventional hydrocarbons such as shale gas and oil. 

A Monument 

The book contains many full color illustrations, though perhaps fewer seismic lines than one might have expected, probably for reasons of client confidentiality. Most of the figures are from previously published work, but some come from Nubian Consulting reports.

It concludes with a comprehensive bibliography and index. The former seems to include every paper ever published on Libyan petroleum geology, together with a number of unpublished oil company reports that presumably still survive in a few company offices, veneered by Saharan dust. 

The Petroleum Geology of Libya is essential reading for anyone brave enough to explore for petroleum in this resource-rich country. This book may be a greater monument than the authors and readers realize. There was a short window of opportunity for geologists, largely though not exclusively Western ones, to explore the Sahara in general and its geology in particular. Wellard (1964) records that from 1789 to 1889 nearly 200 Western explorers died in the Sahara Desert. Only five survived to publish the results of their research. It was only in the last half of the 20th century, and the first decade of the 21st, that Saharan scientific research could be pursued in relative safety. As Raymond Furon said (1960): “African geology is the work of only two generations, the work of a few brave men, who devoted their lives to their passion and many of whom died for their pains, sometimes murdered, sometimes victims of the desert or the jungle.” 

At the present time and for the foreseeable future exploration in Libya for petroleum or any other resource, or even for pure science, may be a high risk endeavor. The authors of the second edition of Petroleum Geology of Libya have skillfully carved a monument to those who contributed to the knowledge of the petroleum geology of Libya. This monumental book may last for many years – though probably not as long as Ozymandias’ statue.

  • Getting stuck in Libyan stratigraphy is similar to being stuck in sand! (Source: Richard Selley)

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