Regional exploration in the Barrow Sub-basin has dominantly focused on structural traps in the Top Barrow Group. A lack of recent discoveries has focused attention more towards the economic potential of the Early Cretaceous intra-Barrow Group plays. The aim of this study was to interpret the seismic sequence stratigraphy and depositional history of the intra-Barrow Group within the Barrow Sub-basin, with emphasis on the identification of stratigraphic traps and potential locations of economic seal/reservoir couplets within the study area. The study area lies south of Barrow Island, and contains the topsets, foresets and toesets of the ‘Barrow delta’, which are an amalgamation of Mesozoic sandprone fluvial, coastal deltaic and deepwater successions. The final stages of the break-up of Gondwana impacted on the structural development of the Barrow Sub-basin, when a large shelf-margin fluvial/deltaic system built out toward the north to northeast, contributing to northerly shelf margin accretion, with largescale clinoform features and associated depositional environments. The dataset comprises the Flinders 3D seismic survey 1267 km² and 35 well logs. Eleven seismic sequences are identified and a seismic sequence stratigraphic framework tied to the wells has been developed, via detailed sequence stratigraphic mapping, integrated with 3D visualisation techniques with the use of Petrel. These eleven second-order sequences are further subdivided into lowstand, transgressive and highstand systems tracts. The movement of the palaeo-shelf break, slope and base of slope can be traced throughout each sequence, displaying an overall trend of building out in a north to northeast direction. A series of palaeo- geographic maps for each sequence has been developed to illustrate the basin’s evolution. The seismic sequences identified display progradation, followed by aggradation, then downstepping, concluding with progradation and aggradation. A high-resolution sequence stratigraphic study of Seismic Sequence 1 showed that several higher-order sequences can be identified, including numerous lowstand systems wedges, along with associated channel features, which could be targeted as new plays. The sequence stratigraphic framework developed, palaeo-geographic reconstructions and all other interpretations made for this project have been integrated to assess the prospectivity of the intra-Barrow Group over the study area, resulting in the identification of a number of leads and prospectivity summaries for each of the 11 Seismic Sequences identified within the intra-Barrow Group. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1313353 / Thesis (M.Sc.(Petrol.G&G))-- University of Adelaide, Australian School of Petroleum, 2008

Regional exploration in the Barrow Sub-basin has dominantly focused on structural traps in the Top Barrow Group. A lack of recent discoveries has focused attention more towards the economic potential of the Early Cretaceous intra-Barrow Group plays. The aim of this study was to interpret the seismic sequence stratigraphy and depositional history of the intra-Barrow Group within the Barrow Sub-basin, with emphasis on the identification of stratigraphic traps and potential locations of economic seal/reservoir couplets within the study area. The study area lies south of Barrow Island, and contains the topsets, foresets and toesets of the ‘Barrow delta’, which are an amalgamation of Mesozoic sandprone fluvial, coastal deltaic and deepwater successions. The final stages of the break-up of Gondwana impacted on the structural development of the Barrow Sub-basin, when a large shelf-margin fluvial/deltaic system built out toward the north to northeast, contributing to northerly shelf margin accretion, with largescale clinoform features and associated depositional environments. The dataset comprises the Flinders 3D seismic survey 1267 km² and 35 well logs. Eleven seismic sequences are identified and a seismic sequence stratigraphic framework tied to the wells has been developed, via detailed sequence stratigraphic mapping, integrated with 3D visualisation techniques with the use of Petrel. These eleven second-order sequences are further subdivided into lowstand, transgressive and highstand systems tracts. The movement of the palaeo-shelf break, slope and base of slope can be traced throughout each sequence, displaying an overall trend of building out in a north to northeast direction. A series of palaeo- geographic maps for each sequence has been developed to illustrate the basin’s evolution. The seismic sequences identified display progradation, followed by aggradation, then downstepping, concluding with progradation and aggradation. A high-resolution sequence stratigraphic study of Seismic Sequence 1 showed that several higher-order sequences can be identified, including numerous lowstand systems wedges, along with associated channel features, which could be targeted as new plays. The sequence stratigraphic framework developed, palaeo-geographic reconstructions and all other interpretations made for this project have been integrated to assess the prospectivity of the intra-Barrow Group over the study area, resulting in the identification of a number of leads and prospectivity summaries for each of the 11 Seismic Sequences identified within the intra-Barrow Group. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1313353 / Thesis (M.Sc.(Petrol.G&G))-- University of Adelaide, Australian School of Petroleum, 2008

Philosophiae Doctor - PhD / Integrated approaches in the study of petroleum exploration are increasingly becoming significant in recent times and have yielded much better result as oil exploration is a combination of different related topics. The production capacity in hydrocarbon exploration has been the major concern for oil and gas industries. In the present work an integrated approach was made with seismic, well logs and biostratigraphy for predicting the depositional environment and to understand the heterogeneity within the reservoirs belonging to Valanginian (Early Cretaceous) age of Gamtoos Basin, Offshore South Africa. Objectively, the integrated work was mainly based on seismic stratigraphy (seismic sequence and seismic facie analysis) for interpretation of the depositional environments with combination of microfossil biostratigraphic inputs. The biostratigraphic study provides evidences of paleo depth from benthic foraminifera and information about bottom condition within the sedimentary basin, changing of depositional depth during gradual basinal fill during the Valanginian time. The petrophysical characterization of the reservoir succession was based on formation evaluation studies using well logs to investigate the hydrocarbon potential of the reservoir across Valanginian depositional sequence. Further, the static modeling from 2D-seismic data interpreted to a geological map to 3D-numerical modeling by stochastic model to quantify the evaluation of uncertainty for accurate characterisation of the reservoir sandstones and to provide better understanding of the spatial distribution of the discrete and continuous Petrophysical properties within the study area.

This study aims to establish a depositional framework for an area of the Louisiana shelf, north-central Gulf of Mexico. The depositional history of the study area is poorly understood, especially within the last cycle of major eustatic fluctuation (~18, 000 yrs BP – present). Data sets used in this study include pre-existing and previously unanalyzed two-dimensional, highresolution seismic profile records (Acadiana 86 and Acadiana 89), geotechnical foundation boring data (Coleman and Roberts, 1988a), and an industry lease block survey report (Cole, 1983). Seismic sequence stratigraphic methods are employed in this study to analyze seismic profile data. Seismic sequence analysis results indicate the presence of five unconformable surfaces and five seismic facies units. Through correlation of seismic profile data with lithologic and chronologic data, it is possible to conclude that these seismic facies units represent shelf-margin deltaic deposition during the last lowstand of sea level (~18, 000 yrs BP), sourced by the Pearl River. .

De nombreuses études montrent que les transferts de contrainte co- et postsismiques jouent un rôle majeur dans l’occurrence des séquences de séismes. Cependant, la grande majorité de ces études implique des systèmes de failles à la configuration géométrique simple (e.g. failles parallèles ou colinéaires). Dans cette thèse, nous étudions une séquence de séismes s’étant produite au sein d’un système de failles à la configuration géométrique plus complexe (i.e. failles conjuguées), la séquence du NE Lut (1939-1997, NE Iran), afin d’évaluer (1) si les transferts de contrainte favorisent la succession de séismes de la séquence et (2) s’ils permettent sur le long-terme de synchroniser les ruptures des failles du système. Pour cela, nous mesurons d’abord les déformations de surface produites par la séquence afin de mieux contraindre par la suite la modélisation des transferts de contrainte. A partir de la technique de corrélation subpixel d'images optiques, nous mesurons les champs de déplacements de surface horizontaux produits par les séismes de Khuli-Boniabad (Mw 7.1, 1979) et de Zirkuh (Mw 7.2, 1997). Nous montrons que ces séismes sont caractérisés par la rupture de plusieurs segments dont les limites sont corrélées avec les complexités géométriques des failles. Nous interprétons les différences de leurs caractéristiques de rupture (longueur de rupture, glissement moyen, nombre de segments rompus) comme étant dues à des différences de maturité des failles de Dasht-e-Bayaz et d’Abiz. Nous détectons également les déplacements produits par un séisme historique modéré, le séisme de Korizan (Mw 6.6, 1979). C’est la première fois que les déplacements produits par un séisme historique de si petite taille sont mesurés par corrélation d’images optiques. Ensuite, en combinant le champ de déplacements InSAR déjà publié avec les données optiques proche-faille précédemment acquises, nous estimons un nouveau modèle de source pour le séisme de Zirkuh (Mw 7.2, 1997). Nous montrons que les données proche-faille sont essentielles pour mieux contraindre la géométrie de la rupture et la distribution du glissement en profondeur. Le modèle estimé montre que le séisme de Zirkuh a rompu trois aspérités séparées par des barrières géométriques où les répliques du séisme se localisent. Seul le segment central de la faille présente un déficit de glissement en surface que nous interprétons comme étant dû à de la déformation distribuée dans des dépôts quaternaires non consolidés. Enfin, à partir des informations précédemment acquises, nous modélisons les transferts de contrainte au cours de la séquence du NE Lut. Nous montrons que ceux-ci ont favorisé l’occurrence de 7 des 11 séismes de la séquence et que modéliser précisément la géométrie des ruptures est essentiel à une estimation robuste des transferts de contrainte. De plus, nous montrons que l’occurrence du séisme de Zirkuh (Mw 7.2, 1992) est principalement favorisée par les séismes modérés de la séquence. Pour finir, la simulation d’une multitude de cycles sismiques sur les failles du NE Lut montre que les transferts de contrainte, en particulier les transferts postsismiques liés à la relaxation viscoélastique de la lithosphère, sont le principal processus permettant la mise en place répétée de séquences de séismes sur les failles du NE Lut. Enfin, d'après les simulations réalisées, l'ordre dans lequel se sont produits les séismes majeurs durant la séquence du NE Lut est assez exceptionnel. / Many studies show that static and postseismic stress transfers play an important role in the occurrence of seismic sequences. However, a large majority of these studies involves seismic sequences that occurred within fault systems having simple geometric configurations (e.g. collinear or parallel fault system). In this thesis, we study a seismic sequence that occurred within a complex fault system (i.e. conjugate fault system), the NE Lut seismic sequence (1939-1997, NE Iran), in order to assess if (1) stress transfers can explain the succession of earthquakes in the sequence and (2) stress transfers can lead to the synchronization of the NE Lut faults over multiple seismic cycles. To this end, we first measure the surface displacement field produced by the sequence in order to precisely constrain the stress transfer modeling afterwards. We use optical correlation technique to measure the surface displacement fields of the Khuli-Boniabad (Mw 7.1, 1979) and Zirkuh earthquake (Mw 7.2, 1997). We find that these earthquakes broke several segments limited by geometrical complexities of the faults. We interpret the differences in failure style of these earthquakes (i.e. rupture length, mean slip and number of broken segments) as being due to different level of structural maturity of the Dasht-e-Bayaz and Abiz faults. Furthermore, we succeed to detect offsets produced by the 1979 Mw 6.6 Korizan earthquake. It is the first time that surface displacements for such a small historical earthquake have been measured using optical correlation. Then, combining previously published intermediate-field InSAR data and our near-field optical data, we estimate a new source model for the Zirkuh earthquake (Mw 7.2, 1997). We show that near-field data are crucial to better constrain the fault geometry and the slip distribution at depth. According to our source model, the Zirkuh earthquake broke three asperities separated by geometrical barriers where aftershocks are located. No shallow slip deficit is found for the overall rupture except on the central segment where it could be due to off-fault deformation in quaternary deposits. Finally, we use the information acquired in the first parts of this work to model the stress transfers within the NE Lut sequence. We find that 7 out of 11 earthquakes are triggered by the previous ones and that the precise modeling of the rupture geometry is crucial to robustly estimate the stress transfers. We also show that the Zirkuh earthquake is mainly triggered by the moderate earthquakes of the NE Lut sequence. Lastly, the simulation of multiple seismic cycles on the NE Lut fault system shows that stress transfers, in particular postseismic stress transfers due to viscoelastic relaxation, enhance the number of seismic sequences and synchronize the rupture of the faults. The simulations also show that the order in which the Mw>7 earthquakes occurred during the NE Lut sequence is quite exceptional.