Abstract: Mud volcanoes occur in many petroliferous basins and are associated with significant drilling hazards. To illustrate the type of information that can be extracted from limited petrophysical datasets in such geomechanically complex settings, we use P-wave velocity data to calculate the mechanical properties and stresses on a two-dimensional vertical section across a mud volcano in the Azeri-Chirag-Guneshly field, South Caspian Basin. We find that: (1) the values of the properties and stresses calculated in this way have realistic magnitudes; (2) the calculated pore fluid pressures show spatial variations around the mud volcano that potentially highlight areas of fluid recharging after the most recent eruption; and (3) the information obtained is sufficient to provide helpful indications of the width of the drilling window. Although calculations of this kind may be readily improved with more sophisticated petrophysical datasets, the simplicity of this approach makes it attractive for reconnaissance surveys designed to identify targets worthy of further investigation in developing our understanding of mud volcano geomechanics, or which could be used to help formulate drilling strategies. Correction notice: The original version was incorrect. All instances of mbsf (metres below seafloor) should have read mbsl (metres below sea-level).

Abstract This book combines interdisciplinary research results using structural geology, geophysics, sedimentology, stratigraphy, palaeontology, palaeomagnetism and subsidence modelling obtained through the MEBE (Middle East Basins Evolution) Programme and other groups in the South Caspian and Northern and Central Iran. A great part of the volume is devoted to Northern Iran (Alborz, Binalud and Koppeh Dagh belts), dealing mainly with the Late Palaeozoic and the Mesozoic Eras. Two papers present subsidence models of the South Caspian Basin since the Jurassic and three papers focus on Central Iran. The data and models in this compilation of papers present a detailed picture and a very comprehensive understanding of the Late Palaeozoic to Cenozoic evolution of the South Caspian and North Iran to Central Iran basins. Geodynamic evolution and sedimentation are mainly controlled by the closure of the Palaeo–Tethys due to collision of Eocimmerian blocks with south Laurasia, opening of the South Caspian Basin, and Neo–Tethys ocean closure associated with Arabia–Eurasia collision.

Single-grain, laser-ablation inductively coupled plasma–mass spectrometry analyses of detrital apatites from Pliocene sandstones in the South Caspian Basin (Azerbaijan) and Devonian-Carboniferous sandstones from Clair oil field, west of Shetland (UK), demonstrate that apatite geochemistry has significant potential in provenance analysis. Apatites in Pliocene sandstones deposited by the paleo-Kura River system, which drained the Lesser Caucasus region, were derived largely from mafic to intermediate and alkaline rocks. Apatite populations in Pliocene sediments transported by the paleo-Volga River system, which drained the Russian Platform, show greater compositional diversity and indicate supply from granitoids or other acidic rocks together with subordinate mafic to intermediate and alkaline rocks. Apatites in the Devonian-Carboniferous succession west of Britain were derived predominantly from acidic rocks, either directly from Archean gneisses or indirectly from metasedimentary rocks. In the two case studies, the most useful discriminators of apatite provenance proved to be La/Nd and La + Ce/ΣREE. Since apatite is stable during burial in sedimentary basins, apatite geochemistry can be used to determine provenance of sandstones from the full range of diagenetic environments, although the instability of apatite during weathering means that the method will be difficult to apply to sandstones with prolonged weathering history. At present, identification of provenance using apatite geochemistry is limited by the lack of a comprehensive database on apatite compositions in some of the potential source rocks, particularly those of metamorphic origin. The role played by sediment recycling is another factor that requires consideration when reconstructing source areas on the basis of apatite compositions.

Abstract Throughout time, the greater Caspian area has maintained its position as one of the major petroleum provinces in the world. Its early history as a prolific producer of oil is well known. Caspian region exploration dates to the seventh century B.C., during the time of the Median Kingdom in today's southern Azerbaijan. Oil played an important role in the everyday lives of these ancient tribes of the region, and it is still a very important commodity today. The past two decades have seen many important advances in our knowledge of the geological evolution of hydrocarbon-bearing sedimentary basins. The success of modern exploration is, to a large extent, based on new advances in both deep and 3-D seismic imaging, as well as improved pressure-prediction and pre-drill oil and gas quality predictive methodologies, to mention just a few. Nevertheless, large areas of the greater Caspian region have remained unexplored due to a variety of factors such as deep-water conditions and zones with high pore-pressures in the South Caspian Sea and The Black Sea, and vast shallow-water regions with harsh winter ice conditions in the North Caspian Sea. This publication contains 12 extended abstracts and 6 full-length papers that discuss technology development, challenges in estimating proven and potential reserves, outcrop-based studies of potential reservoirs, regional tectonics and geodynamic evolution, and source rock and stratigraphic analyses of the greater Caspian area.