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Closures of the Cambrian and Ordovician – Silurian play systems and its oil reserves.
Source publication
Al-Sirhan area in southeast Jordan is studied for its hydrocarbon potentiality. Petrophysical studies including
porosity, permeability, water saturation, and hydrocarbon saturation are done using wire line logs for candidate reservoirs. Total organic carbon analysis is done for two candidate source intervals. Seismic investigation is also done usin...
Context in source publication
Context 1
... was found that within Salib Formation, only 50% of the existing hydrocarbons are moveable and thus can be extracted. The reserve within every closure is calculated also depending on the area of the closure as seen in Table (2). According to the previous volumes, the nine major closures contain oil up to 1735 million cubic meters. ...
Citations
... Many researchers studied the Sirhan Basin area to assess the potentiality of the petroleum system in southeastern Jordan (e.g., Konert et al., 2001;Al-Basha, 2007;Abul Khair et al., 2008;Naylor et al., 2013;Alsharhan, 2014;Lüning and Kuss, 2014). ...
... Abul Khair et al. (2008) studied the Sirhan Basin in terms of its hydrocarbon prospectivity and considered the Dubeidib sandstone's potential for hydrocarbons accumulation. Nevertheless, this study considered the Sirhan Basin as a very high-risk place for petroleum exploration due to the small sizes of closures, bad reservoir quality, and the existence of growth faults within the basin. ...
... Few researchers focused their interest on understanding the petroleum system within the Sirhan Basin in southeastern Jordan (e.g., NRA, 2004;Abul Khair et al., 2008). These studies are not enough to understand the continuity and exact geometry of reservoirs. ...
The Sirhan Basin in southeastern Jordan has been crucially studied to assess its petroleum system using seismic profiles and well-logging data. The integration between these datasets used for interpretation and correlation provides better visualization of both the lateral changes in litho-facies and the physical properties that are fundamental to building up a comprehensive lithological and structural model. This model allows explaining the petroleum system precisely and its essential elements, including petroleum source rocks, migration paths, reservoir rocks, seal rocks, and traps within the target formation (Dubeidib Formation from Ordovician age).
The seismic sections were used to interpret the Base and Top of the Dubeidib Formation, as well as the pre-existing fault systems that cut these reflections. Time structure and depth maps were created using the horizons-picking process. Several growth and normal faults were mapped out in the vicinity of the study area. Some of these faults were determined previously within the study area only as lineaments on the surface topography. The faults are NW-SE-trending, the same as the Al Karak Wadi Alfaiha fault and the pre-rift structures formed related to the opening of the Red Sea trend.
The well-logging data were used to identify the petroleum system plays, and hydrocarbon-bearing zones and model the facies and physical properties. This allows us to understand and visualize the lateral changes to explain the petroleum system correctly and its essential elements. As a result, three reservoirs were identified within the Dubeidib Formation. Play-1 reservoir's porosity is considered fair to moderate, while the permeability is poor, the good permeability intervals are due to fractures as mentioned in the geological and drilling reports. Play-2 reservoir is deemed a poor reservoir due to the low porosity and permeability within this interval, as mentioned in the drilling reports. In addition, the Play-3 reservoir is classified as a good reservoir due to successive clean sandstone layers caped by shale streaks.
Accordingly, the quality of Dubeidib reservoirs and the shale dominance considered the Dubeidib Formation as “unconventional” for many reasons. The tested oil from well WS-4 was negligible and existed within the fractured intervals only. Furthermore, the thick shale layers within the Dubeidib succession, Silurian ‘hot shale’, and Hiswa shale made possible tight gas reservoirs since they may have entered the gas generation window within the basin.
The present study shows, without any doubt, some potential structures for hydrocarbon in Sirhan Basin. These structures were not tested before, especially within the graben block, where faults made possible traps therein. In addition, there is a positive structure within the southeastern part of the study area, which could form a potential structural trap as an anticline structure.
Finally, the wells were drilled around well WS-4 with the old-fashioned way of tapping the ‘mother lode’. Thus, it can be concluded that Sirhan Basin is still poorly explored, although the proven potentiality comparison to the other similar basins in the Risha gas field, Iraq, and Saudi Arabia.
... They are followed by the terrestrial clastics of the upper Ram Group, e.g., the Amud Fm. sandstones, which attain ca 1.2 km thickness in the nearest deep wells. They are succeeded by the marine Khreim Group with about 100 m Sahl as Suwwan Fm. micaceous silty shales, probably organic rich near the transgressive base (Abul Khair et al. 2008), overlain by ca 650 m Umm Tarifa Fm. of fine micaceous sandstones, quartz-rich siltstones (Cruziana Facies) and some graptolite shale interlayers, topped by the Sahara glaciation unconformity, on which follow ca 20 m of the Trebeel Fm. glaciomarine clean sandstones. ...
The deeply eroded Waqf as Suwwan ring structure was recently discovered to be a large impact, the first identified in the near east. Large-scale reflection seismic structure shows the impact situated high on the northeastern flank of the Jordan Uplift sloping into Wadi Sirhan Basin. If exhumation is linked to the Arabia–Eurasia collision, a likely time window for the impact event may be latest Eocene to Late Oligocene. Impact into a shallow sea seems an optional scenario. Old reflection seismic lines offer limited insight into the deep structure of the rim and part of the central uplift of the complex crater. An important structural clue is provided by a well-resolved seismic horizon of a yet tentative correlation with a Paleozoic black shale. The central gravity high is compatible with a mass surplus by the uplift of denser Paleozoic basement below the central uplift. The gravity model further indicates a ring of dense Paleozoic sediments rising from below into the ring syncline. Seismics show presumably radial synclines in the central uplift which are interpreted by centripetal constrictional flow during crater collapse. Beneath the final crater’s outer boundary, a shallow-dip normal fault zone, subtle seismic structure in uncollapsed footwall segments reveal an asymmetry of strain. The asymmetry is attributed to the cratering flow by an oblique impact directed toward NE. The finding provides independent support to an earlier suggestion of impact obliquity based on vergency of folds exposed on the central uplift.
