ALBERT

Description: Poly-phase deformation of a compressional nature is a common feature in the post-rift evolution of passive margins and rifts. The compressional mode of deformation in these sedimentary basins, originally formed by extension in an intraplate setting, is characterized by a spectrum of spatial wavelengths spanning several tens of kilometres up to several hundreds of kilometres. The actual mode of compressional deformation appears to be strongly affected by the rheological structure of the underlying lithosphere, the level of the regional intraplate stress field, and the geometry of the rifted basin configuration prior to late-stage compressional reactivation. The interplay of plumes and intraplate compressional deformation can lead to temporal transitions from basin inversion to lithospheric folding. These modes of deformation lead to substantial differential vertical motions, late-stage anomalies in subsidence and uplift patterns. The development of innovative combinations of numerical and analogue modelling techniques is the key to differentiating different modes of compressional deformation of passive margins and extensional basins.

Description: Prospect interdependencies, if present and positively correlated, result in a higher standard deviation of the portfolio volumetric expectation curve, compared to a portfolio with independent prospects. This wider uncertainty range offers options for companies to increase the expected cumulative net present value (NPV) of the exploration portfolio. To investigate these effects on exploration portfolios, a methodology has been developed for modeling these dependencies spatially and updating them in time as new information is acquired. The methodology integrates Bayesian belief network techniques into a stochastic exploration business process simulator. Applying this methodology to the Netherlands gas portfolio clearly demonstrates an increase in both the range and expected value of NPV of the expected recoverable volume from the exploration portfolio. Proper tuning of the exploration strategy, using an efficient frontier approach, and regular updating of portfolio economic forecasts increase the probability of realizing the upside at minimum risk when compared to independent prospect portfolios. The staged decision strategy and the value of information underlying the gradual increase of expected NPV can also be calculated and visualized through decision tree analysis techniques. Manuscript reviewed by special issue editor Jan-Diederik van Wees holds an M.Sc. degree in geology (1989) and a Ph.D. in tectonics from the Vrije Universiteit, Amsterdam (1994). After various research assignments at Shell and the university, he joined TNO in 1999 and holds a part-time professorship at the Vrije Universiteit. His research interests include tectonic modeling of lithosphere and basins, and technoeconomic and coupled modeling for geoenergy applications. Harmen Mijnlieff holds an M.Sc. in geology (1989) from the University of Utrecht, the Netherlands. He worked as a sedimentologist, petrographer, and geological consultant for an E&P consultancy company. In 1994, he joined the Geological Survey of the Netherlands, which was incorporated in TNO in 1997. He presently works as geologist and advisor on hydrocarbon exploration and production issues to the Dutch Ministry of Economic Affairs. Jan Lutgert holds an M.Sc. degree in geology (1986) from the University of Utrecht. He joined TNO in 1987 and has worked as a geologist and petrophysicist, both in geoenergy research projects, and as a geological consultant for various clients in the oil industry (Lukoil, Shell, Maersk, Petroleum Development Oman a.o.). He currently works as an advisor on hydrocarbon production and licensing issues to the Dutch Ministry of Economic Affairs. Jaap Breunese holds a Ph.D. in physics and mathematics from the University of Leiden (1982). He has been an advisor to the Dutch government in the areas of energy and mining and E&P policy for 25 years now. His research and advisory work at TNO covers all topics that relate to the use of the subsurface to technical, legal, economic, environmental, and societal issues, including resource assessment and production forecasting. Christian Bos holds an M.Sc. degree in petroleum engineering from Delft University of Technology and joined TNO in 1991 to engage in consultancy and R&D on reservoir simulation, probabilistic reserves estimation, production forecast uncertainty quantification, and decision making under uncertainty. From 2000–2004, he was a best practice lecturer of the Norwegian E&P forum for forecasting and uncertainty evaluation (FUN). For the TU Delft executive Master of Petroleum Business Engineering course, he teaches the decision and risk analysis module. Before joining TNO, he was with various Shell E&P operating companies for 11 years, where he held positions in drilling operations and in reservoir engineering. Peter Rosenkranz holds an M.Sc. degree in geophysics (1974) from the Utrecht University. After several assignments at Shell and DSM Energy, he joined EBN in 1992 where he is responsible for EBN's exploration activities. He has a special interest in Monte Carlo exploration models, including economics. Filip Neele holds a Ph.D. in seismology from the Utrecht University (1993). After a position as an assistant professor in seismology in Utrecht, he joined TNO in 1996 to conduct electro-optical research. His current research interests include CO2 storage capacity, storage monitoring, and CO2 transport system analysis

Description: A backstripping analysis of 225 wells located within the Sirt Basin, Libya, provides new constraints on the development of the Sirt Basin. Four tectonic phases are identified from Late Jurassic to present. The presentation of contour maps of subsidence and crustal stretching allows spatial and temporal variations in stretching to be visualized. A close match is observed with stretching phases documented for other African basins, consistent with discrete phases in the opening of the Tethys and Atlantic. Rifting and reactivation appear to be primarily controlled by the orientation of the basin and the underlying basement structure with respect to stress directions. The tectonic subsidence curves have also been forward modeled with an automated modeling technique to quantify the variation in timing and the magnitude of rifting. The tectonic subsidence history of the Sirt Basin is characterized by periods of stretching, alternating with periods of relative tectonic quiescence and thermal subsidence. Stretching started at the centers of the troughs and migrated toward the platform crests. Abdulbaset M. Abadi studied geology at Al Fatah University, Tripoli, Libya. He obtained an M.S. degree in geology at ITC (Enschede, Netherlands) in 1989. From 1997 to 2002, he was engaged in a Ph.D. research on the Sirt Basin tectonics at Vrije Universiteit, Amsterdam, and ITC. At present, he is working at the Petroleum Research Center in Tripoli. Jan-Diederik van Wees holds an M.S. degree in geology (1989) and a Ph.D. in tectonics from Vrije Universiteit, Amsterdam (1994). After various research assignments in Shell and the university, he joined TNO in 1999 and holds a part-time professorship at Vrije Universiteit. His research interests include tectonic modeling of lithosphere and basins and technoeconomic and coupled modeling for geoenergy applications. Paul van Dijk studied in the Leiden (geology) and Utrecht (structural geology with economic geology and geophysics) universities, Netherlands. He obtained his Ph.D. at James Cook University (Australia) on a thesis on syndeformational copper mineralization in the Mount Isa region. In 1987, he joined the ITC (Enschede, Netherlands), where he is currently the program director of the applied earth science courses. Sierd Cloetingh holds an M.S. degree and a Ph.D. in geophysics at the Universiteit Utrecht. He is the scientific director of the Netherlands Research Centre of Integrated Solid Earth Sciences (ISES). He serves in many international functions, including the president of the International Lithosphere Project. His research interests include solid earth geophysics, tectonics, intraplate deformation, lithospheric dynamics, sedimentary basin evolution, and sea level change.

Description: The large thickness of Upper Carboniferous strata found in the Netherlands suggests that the area was subject to long-term subsidence. However, the mechanisms responsible for subsidence are not quantified and are poorly known. In the area north of the London Brabant Massif, onshore United Kingdom, subsidence during the Namurian-Westphalian B has been explained by Dinantian rifting, followed by thermal subsidence. In contrast, south and east of the Netherlands, along the southern margin of the Northwest European Carboniferous Basin, flexural subsidence caused the development of a foreland basin. It has been proposed that foreland flexure due to Variscan orogenic loading was also responsible for Late Carboniferous subsidence in the Netherlands. In the first part of this paper, we present a series of modelling results in which the geometry and location of the Variscan foreland basin was calculated on the basis of kinematic reconstructions of the Variscan thrust system. Although several uncertainties exist, it is concluded that most subsidence calculated from well data in the Netherlands cannot be explained by flexural subsidence alone. Therefore, we investigated whether a Dinantian rifting event could adequately explain the observed subsidence by inverse modelling. The results show that if only a Dinantian rifting event is assumed, such as is found in the United Kingdom, a very high palaeowater depth at the end of the Dinantian is required to accommodate the Namurian-Westphalian B sedimentary sequence. To better explain the observed subsidence curves, we propose (1) an additional stretching event during the Namurian and (2) a model incorporating an extra dynamic component, which might well explain the very high wavelength of the observed subsidence compared with the wavelength of the predicted flexural foreland basin. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

Description: Poly-phase deformation of a compressional nature is a common feature in the post-rift evolution of passive margins and rifts. The compressional mode of deformation in these sedimentary basins, originally formed by extension in an intraplate setting, is characterized by a spectrum of spatial wavelengths spanning several tens of kilometres up to several hundreds of kilometres. The actual mode of compressional deformation appears to be strongly affected by the rheological structure of the underlying lithosphere, the level of the regional intraplate stress field, and the geometry of the rifted basin configuration prior to late-stage compressional reactivation. The interplay of plumes and intraplate compressional deformation can lead to temporal transitions from basin inversion to lithospheric folding. These modes of deformation lead to substantial differential vertical motions, late-stage anomalies in subsidence and uplift patterns. The development of innovative combinations of numerical and analogue modelling techniques is the key to differentiating different modes of compressional deformation of passive margins and extensional basins.