Book-Review-of-The-Petroleum-Geology-of-Iraq-_2010

Book review

Book Review of “The Petroleum Geology of Iraq ”,A.A.M Aqrawi,J.C.Goff, A.D.Horbury, F.N.Sadooni.Scienti ?c Press Ltd.,Beacons ?eld,UK,424PP (2010).ISBN:978-0-901360-36-8Iraq places fourth in the world ranking of proven conventional oil reserves.According to the BP Statistical Review of World Energy (June 2010),this amounts to 115billion barrels,behind only Saudi Arabia,Venezuela,and Iran.The present reserve to production ratio for Iraq is greater than 100years,though this will most likely change as infrastructure is rebuilt and new ?elds are brought on-line.Despite this prominence within the petroleum industry,rela-tively little published information is available regarding the geology of Iraq,let alone speci ?c topics related to the petroleum geology of this https://www.360docs.net/doc/116213785.html,ing a well-known search engine for geo-science literature,I tried the combination of “stratigraphy ”in the abstract and “country name ”in the title,abstract,or key words.As a reference point,this yielded 1365peer reviewed journal arti-cles and books for the United Kingdom.Egypt returned 47hits,and Saudi Arabia 20.Yet I only found 5references for https://www.360docs.net/doc/116213785.html,ing more speci ?c key words such as “re ?ection seismics ”or “petroleum systems ”generally resulted in no returns for Iraq.Important publi-cations on the geology of Iraq do exist,for example in van Bellen et al.’s Lexique Stratigraphique International (1959),but these are often dif ?cult to obtain,and geologic methodology has changed and advanced.“The Petroleum Geology of Iraq ”therefore ?lls a signi ?cant vacuum for those of us interested in learning about this intriguing and economically important geologic province,and comes at a time when the rush is on to initiate the next phase of exploration and development of Iraq ’s oil and gas ?elds.

The immediate impression one has upon opening this book is that it is extensively illustrated,with numerous color maps,strati-graphic cross-sections,chronostratigraphic charts,?eld photo-graphs,thin-section photomicrographs,measured sections,and well logs.Several of the ?gures are fold-out pages.The illustrations alone make it a gold mine for the explorationist or regional geolo-gist attempting to bring themselves up to speed on the stratig-raphy and general structure of the Iraqi basins.The quality of the ?gures is generally excellent and most are very well designed.The print style is pleasing and the binding appears to be very durable.The book is a collaboration of four authors,all of whom have extensive geologic experience in Iraq and other parts of the Middle East.The Preface notes that each Chapter had a primary and secondary author,and then the entire text was edited by all.In multi-author volumes such as this,there sometimes appear signi ?cant differences in style,focus or even methodology and approach between different chapters.Aqrawi,Goff,Horbury and Sadooni,and perhaps Christopher Tiratsoo who managed the edit-ing for Scienti ?c Press Ltd.,have done an excellent job at prevent-ing this from occurring.The writing style throughout the book is very smooth,consistent and enjoyable.

The book is divided into ten chapters,with the ?rst being a general introduction to the sources of data available to the authors,general organization of the volume,several country-scale maps,and a generalized stratigraphic column.Unfortunately this stratigraphic column assigns the petroliferous and geologically important Nahr Umr to Mishrif Formations to the “Middle Creta-ceous ”,which will be confusing to many readers as this is not a formally recognized stratigraphic term.Digging through subse-quent chapters you ?nd it spans the Upper Aptian to Early Turonian,thereby lumping together strata above and below the Late Albian unconformity,one of the best documented and most important tec-tonostratigraphic events of northern Gondwana.This brings us to what I found to be perhaps the most signi ?cant shortcoming of this book –references to the geology of Iran and adjacent countries on the Arabian plate are extensive and form an important strength of the presentation,as they should,yet correlation and comparison to the stratigraphies and basin evolution of the rest of northern Gondwana (save a few words about Paleozoic plate reconstruc-tions)are generally lacking.More comparison with parts of Gond-wana to the south would have broadened the appeal of the book,and helped highlight topics requiring future research,as the mega-sequence scheme the book follows (adapted from Sharland et al.,2001)is not completely applicable to North Africa.

Chapter 2is a brief history of oil exploration in Iraq,including the exploitation of bitumen by the ancients and the role of live hydro-carbon seeps.This is really fascinating material,and ends with biog-raphies of the authors of the Iraq Lexicon mentioned above.Chapter 3discusses the tectonic evolution of Iraq.Most of the ?gures in this chapter are very nicely presented,including some superb geologic cross-sections.However in a few the type is too small to comfort-ably read and the details of the geology are lost;it would have been better to eliminate a few ?gures (such as 3.18)and to have allotted more space to the others.On technical points,the authors prescribe to the interpretation that northern Neotethys closed in the Eocene;this partly depends on what “closed ”means and the authors surely recognize (and their maps support)that a marine seaway persisted from the future Indian Ocean to the future Medi-terranean up until the Middle Miocene.The view presented of present-day plate boundaries is inaccurate (a spreading center does not pass through the Bab el Mandab between Yemen and Eritrea –it runs west of Danakil;nor is it agreed that a spreading center reaches the northernmost Red Sea),and the timing of the onset of sea-?oor spreading in the Gulf of Aden and Red Sea is not in agreement with published interpretations.

Chapters 4to 8comprise the real heart of this book,and provide details about the litho-and chronostratigraphy,structural setting,and reservoir and source rock potential of each of Iraq ’s sedimen-tary formations,from the Precambrian to Cenozoic.The general format for each chapter is to ?rst give a brief overview of the mega-sequence(s)under consideration,including structural setting,

basin

Contents lists available at ScienceDirect

Marine and Petroleum Geology

journal ho mep age:www.elsevier.co m/lo cate/marp

etgeo

doi:10.1016/j.marpetgeo.2010.09.002

Marine and Petroleum Geology 27(2010)2076–2077

evolution,stratigraphy and biostratigraphy.This is followed by details for each Iraqi formation,organized into supersequences (or Periods for the Paleozoic).Next comes a discussion of petroleum systems components,and the chapter ends with some concluding remarks.Each formation is typically illustrated by various combina-tions of lithologic and/or wireline logs,some?eld photographs and photomicrographs,correlation panels,isopach maps,facies models, and paleogeographic interpretations.The amount of information presented is very impressive.These?ve chapters will certainly be a key source of stratigraphic and subsurface information for anyone working the basins of Iraq,either as an explorationist or from a regional perspective.

Chapter9takes the petroleum systems components from the previous?ve chapters and integrates this information into a very thorough discussion of the petroleum systems of Iraq.As Hashim Alkhersan,the former Director General of the Iraqi Oil Exploration Company,emphasizes in the Foreword to the book,less than200 exploration wells have been drilled in this country,or about1 well per2500sq km.The future exploration and development potential of Iraq is clearly immense.In Chapter10,the authors present their thoughts about what some of the important chal-lenges in this future may be.

This book is one of the most useful documents written about the geology of Iraq,and is of interest far beyond just petroleum exploration.At100pounds sterling for a copy,it probably won’t appear on the bookshelves of geoscientists with just a casual interest in Iraq,and unfortunately won’t be affordable for many of my North African colleagues,nor their institutional libraries. Many maps lack the position of well control used in their construc-tion,and some cross-sections or stratigraphic columns are dif?cult to locate on any of the provided maps.Numerous paleogeographic maps are“simpli?ed Cambridge Carbonates Ltd(a company co-owned by one of the authors)map based on published data.”In my opinion this is inappropriate,as the reader has no way to verify the nature of the data used to construct the map.It is also disap-pointing that the authors were unable to obtain any re?ection seismic data for publication,and the reliability of many of the structural cross-sections is therefore dependent on what is often widely spaced well control.But these are minor complaints compared to the overall quality and signi?cance of this impressive book.In fact,there are few examples of compilations of this quality and depth for other countries in the region.I commend the authors on their efforts and am certain“The Petroleum Geology of Iraq”will play an important role in the next phase of Iraqi oil and gas exploration.

References

Sharland,P.R.,Archer,R.,Casey,D.M.,Davies,R.B.,Hall,S.,Heward,A.,Horbury,A., Simmons,M.D.,2001.Arabian plate sequence stratigraphy.GeoArabia Special Publication,2.Gulf Petrolink,Bahrain,387pp.

Van Bellen,R.C.,Dunnington,H.V.,Wetzel,R.,Morton,D.M.,1959.Lexique Strati-graphique International,III,Asie,fasc.10a,Iraq.Centre National de la Recherche Scienti?que,Paris,333pp.

William Bosworth

Apache Egypt Companies,Cairo,Egypt

E-mail address:bill.bosworth@https://www.360docs.net/doc/116213785.html,

1September2010

Available online25September2010

Book review/Marine and Petroleum Geology27(2010)2076–20772077