/library/oar/handle/123456789/78191 2026-06-19T06:43:33Z /library/oar/handle/123456789/78590 Title: The Mesozoic structuring in South-East Malta with reference to the Tectonic evolution of the Central Mediterranea Abstract: The complex, structural evolution of the Mediterranean was largely controlled by the relative oblique motion of Eurasia and Africa claiming the Late Carbonifrous to mid Cretaceous to the Present time. This motion provided the driving force to a series of tectonic events that led to the formation of several sedimentary basins in the Pelagian Block of the Central Mediterranean. During the Late Carboniferous to Mid Cretaceous, the block experienced multi-phase rifting, accompanied by basin formation due to the closure of the Tethys and oceanisation of the Neotethys. This contrasted with the rifting and structural reactivation of basins in the Late Senonian, causeJ by the multi-phase closure ofthe Neotethys. Throughout this time, the Pelagian Block remained attached to the north African plate margin and responded to changing stress regimes by unJc1going tlanstensional anJ transpressive structural deformation and the formation of several sedimentary basins, some of which are oil prolific. Description: M.SC.GEOLOGY 2003-01-01T00:00:00Z /library/oar/handle/123456789/78513 Title: The validity of the magnetic method in discriminating Jurassic Volcanics from hydrocarbon traps : a case study in offshore Malta Abstract: The capability to discriminate between Jurassic volcanic mounds and hydrocarbon traps can determine to a large extent the success of exploration for petroleum in the Ragusa Basin north of Mallet. The suitability of the magnetic method as a discriminating tool over Area 3 north of Malta is investigated through the application of an inverse modelling algorithm to an area adjacent to the Valletta 1 well. Although the results of the inverse process are indicative of magnetic bodies at Jurassic depths, the anomalous field generated by the calculated bodies deviates from the actual field. An application of a forward process to generate the anomaly due to a model based on a structure defined by Amoco and incorporating depth and susceptibility data as measured from the Valletta 1 well is also included. The generated anomaly is not visible on the field data. Description: M.SC.GEOSCIENCES 1995-01-01T00:00:00Z /library/oar/handle/123456789/78250 Title: Quantitative petrophysical analysis using AVO and AVA Abstract: Processing methods that do not only account for kinematic (related to travel times) but for dynamic (related to amplitudes) aspects of seismic reflection data, have become more and more important in recent years. Such methods provide information on the subsurface properties that is useful for reservoir characterization. One technique is based on the amplitude-variation-with-offset (AVO) and amplitude-variation-with-angle (AVA) of seismic reflection data. The technique attempts to explain seismic amplitude anomalies in terms of the nature of the fluid in the pore space of a reservoir. This objective makes it an important exploration tool that greatly improves and expands the applicability of petrophysical interpretation of seismic data. This study provides a review of the theoretical and practical aspects of the AVO /A challenge to elate. Robust inverse modelling using L1 and L2 norm in least square estimation applied to contaminated AVO modelled gathers are compared. L1 norm fitting does much better job than L2 norm fitting with multiple or linear noise existing, whereas the inverse is true for random noise contamination. Uncertainties in AVO /A forward modeling are quantified by crossplotting the AVO /A parameters using the standard deviation method to describe the dispersion, an elliptical region whose properties can be exploited to determine how well AVO /A will work as a hydrocarbon discriminant. Results from this analysis showed that AVO /A has good success in discriminating between brine saturation and oil/gas saturation, and not as successful in discriminate between different hydrocarbon saturation. Overall, the method provides a means by which a quantitative index can be computed for AVO /A risk assessment. Finally, AVO /A attributes are evaluated and studied for hydrocarbon indication in offshore Malta by comparing results with predicted synthetic hydrocarbon related bright spots. The AVA analysis results show that an offshore anomaly is the result of lithology changes unrelated to the presence of hydrocarbons. Description: M.SC.GEOSCIENCES 2004-01-01T00:00:00Z