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Abstract Uncertainty in structural complexities and rock heterogeneities is a major challenge that controls oil exploration and drilling operations in the rift basins of Sudan. Wide ranges of depositional environments developed within these reservoirs: e.g., fluvial, shallow and deep lacustrine, fluvio-deltaic systems. Multi-phase rift development from rift initiation to late post-rift introduced good oil traps and very heterogeneous reservoir rocks situations. Advances in seismic inversion techniques and AVO analysis maximize the probabilities of valid interpretation and lithology delineation in such rift structures thereby reducing the associated uncertainty limit. Accuracy of interpretation depends on the quality of seismic data. Therefore, there is an urgent need to introduce innovative techniques in seismic processing to improve seismic resolution prior to any inversion work. This paper explains an-integrated workflow using seismic data conditioning and inversion methods applied for detailed interpretation and advanced reservoir characterization applications in these rift basins. The seismic data conditioning and inversion workflow implementation comprises three main steps: beginning with data conditioning (seismic and logs), wavelet estimation, and relative acoustic impedance inversion. The conditioned seismic and relative acoustic impedance volumes are used to improve horizons and faults. This interpretation can be used further to build a low-frequency models for absolute acoustic impedance inversion and porosity transformation.
- Africa > Sudan (1.00)
- Asia > Middle East > Yemen (0.96)
- Asia > Middle East > Saudi Arabia (0.96)
- (3 more...)
- Geology > Geological Subdiscipline (0.98)
- Geology > Rock Type (0.91)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment (0.56)
- Africa > South Sudan > Upper Nile > Melut Basin > Block 7 (0.99)
- Africa > South Sudan > Upper Nile > Melut Basin > Block 3 (0.99)
Abstract Stylolites are partings within rocks that exhibit complex mutual column and socket interdigitization. These features can exhibit pronounced roughness on several scales. Stylolites, under deep-burial conditions, could permit circulation of undersaturated fluids and become reservoirs allowing also deep commercial gas production. However, the impact of stylolites on variations in thermal conductivity in carbonates is not well-known. This study was undertaken to investigate the heterogeneity in thermal conductivity in a variety of carbonate specimens containing different types of stylolites. A total of 9 carbonate samples from Turki were used in this study. These sampes were imported into Malaysia by a local factory. The stylolites were classified into three types. Type 1 (sharp-peak) has well defined and high density (4 amplitudes per cm) fractures. Type 2 (simple wave-like) is intermediate whereas type 3 (sutured) has poorly defined and low density (< 1 amplitude per cm) fractures. The thermal conductivity of type 2 (mean = 3.30 W m-1K-1) was the highest and that of type 3 (mean = 1.35 W m-1K-1) was lowest. Similar trends were recorded for non-stylolitic faces of the three carbonates specimens mentioned above. Faces with stylolites showed a high degree of variability in terms of thermal conductivity when estimated at various points. Surfaces with stylolites tend to show different thermal conductivity values than non-stylolitic faces. The reduction in porosity, type of stylolite and a possible effect of different orientation of the carbonate minerals in the stylolites, appears to perturb the homogeneous distribution of thermal conductivity in these carbonates. The study indicates that thermal conductivity estimation is point-dependant. The perturbations created by the stylolites would result in spatial variations in thermal conductivity with possible implications of differences in thermal maturation of hydrocarbon resources at the micro-site levels.
- Geology > Mineral (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (0.32)
Abstract There are tremendous spatial and temporal variability within the sedimentary rock types of the Belait (Early-Mid Miocene) and Lambir (Mid-Miocene) Formations in North Eastern Sarawak. With the current renewed interest in oil and gas exploration in this part of Malaysia, evaluating the distributions of hydrocarbon resources in both Formations will be of valuable interests for the industry. The IR spectra of both Formations showed presence of aliphatic and aromatic components. Total organic carbon results for both Formations show that majority of the samples from the Belait Formation possess much higher percentage of organic carbon contents than the Lambir Formation. In comparing the E4/E6 values, it is observed that the high E4/E6 values give rise to more aromatic components and low E4/E6 values show strong presence of aliphatic peaks in the spectra. Positive relationship exists between the mean pore size and E4/E6 in the Lambir Formation, whereas, in the Belait Formation, the same trend is observed between the porosity and E4/E6 ratios. Variability in these geochemical patterns indicate that there are differences in the quality of hydrocarbon between the Formations. The study shows that the variation of aromatic and aliphatic bonds found in the samples suggests differences in terrestrial origin and marine origin and a complicated depositional pattern temporally and spatially. Variability in the kerogen type discussed above indicates differences in the quality of hydrocarbon between the Formations. Heterogeneity within the same samples here suggests that different rates of migration might occur within the reservoir quality rocks of the Lambir Formation. This indicates differences in show type between both Formations. This study reemphasizes the importance of FTIR in current emerging trends in hydrocarbon research. Introduction North-West Borneo has been producing oil and gas since the 1903 with first onshore well drilled around Miri area in 1910 (Liechti et. al., 1960). Common rock Formations in this area includes Belait Formation (Mid - Upper Miocene), Lambir Formation (Lower - Upper Miocene), Tukau Formation (Lower Oligocene) and the Mid-Miocene Miri Formation (Figure 1). The Belait Formation which is found in the North Eastern Sarawak has been interpreted as coastal and coastal plain deposits from a range of sedimentary environments associated with a relatively large delta (Wilford, 1961) or as fluviatile (Hutchinson, 2005). Towards the coast the environment changes into fully marine, and accordingly the Belait Formation merges gradually into the more marine Lambir or Miri Formations or the uppermost part of the Setap Shale Formation (Liechti et. al., 1960). The Formation consists predominantly of sandstones and alternating shales with minor limestone and marl in some places (Haile, 1957; Liechti et. al., 1960; Hutchinson, 2005).
- Phanerozoic > Cenozoic > Neogene > Miocene > Middle Miocene (0.65)
- Phanerozoic > Cenozoic > Neogene > Miocene > Upper Miocene (0.45)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.79)