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Elhoud A.M.,Libyan Petroleum Institute
Indian Concrete Journal | Year: 2012

A sudden collapse forming a large hole in the main road which connects Tripoli city center with Furnaj area, in Libya was observed in October 2011. The damage was caused by the sulfate-reducing bacteria (SRB) bacteria which produce acid in the sewage environment. The drastic reduction in the original wall thickness caused leakage in the pipe allowing the sewer to flow uncontrollably resulting in the washing away of the soil and causing cavities under the road. SRB are responsible for the production of sulfide gas and converted to sulphuric acid and are a major factor in the microbial degradation of concrete. The soil movements caused more cavities and left gaps between the soil and the pavement. City authorities engaged a contractor to carry out a deep excavation right upto the level of the buried pipe to understand whether the replacement of the collapsed pipe was the only solution to stop the leakage and prevent further road collapse. The ruptured pipe was removed, and the installation of a new pipe made of glass reinforced plastic (GRP) started. Source

Abdunaser K.M.,Libyan Petroleum Institute
Journal of African Earth Sciences | Year: 2015

The petroleum geology of the western part of the Sirt Basin is reviewed by source, reservoir, traps and seal type in addition to Oil migration by different mechanisms. In general the oil and gas accumulations within Sirt Basin are reservoired in granitic basement, sandstones and carbonates ranging in age from Pre-Cambrian to Oligocene, charged by syn and early postrift, Triassic and intra-Cretaceous organic rich lacustrine and restricted marine shales.This paper offers a broad overview on petroleum systems of the western Sirt Basin as a part of the complex, prolific and mature Sirt Basin which considered as one of tectonically active basins of Mesozoic-Cenozoic age in central northern Libya includes reviewing the potential source rocks and assesses their thermal maturity, petroleum generation potential, organic richness and distribution.Key factors responsible for hydrocarbon distribution described by source rock distribution maps, and hydrocarbon generation areas as well as stratigraphic distribution of oil and gas occurrences with field maps and cross-sections (analogues) and summary reservoir description have been shown.The oil to source correlation scheme suggests that most of the oil in the study area was derived from the Sirte Shale (Upper Cretaceous, Campanian/Turonian), whilst the reservoirs are ranging in age from Lower/Upper Cretaceous to the Eocene. Sandstones predominate in the Cretaceous and carbonates are the main reservoirs in the Tertiary.Several different play types have been described from the study area of the western part of the Sirt Basin dominated by the structural traps, which range from simple normal faults to more complex faults and fold structures associated with wrench faults. Structural traps are dominant in the Zallah Trough and are mainly related to Eocene deformation on the heavily faulted western side of the basin.In addition several types of stratigraphic traps are present in the study area and essentially they are characterized by facies changes from carbonates to argillaceous carbonates to shales in the Beda and Dahra Formations. The top seal for most of the Paleocene reservoirs consists of shale to shaly-carbonates with Paleocene shales forming the main seal. Oil migration in the study area has both vertical and lateral components while in general the Sirt Basin is considered as one of the best examples of a dominantly vertically migrated petroleum system.The greatest thickness of this prime source rock (Sirte shales) in the study area is in the Zallah Trough which varies from 152 m to 305 m present adjacent to the western edge of the Az Zahrah-Al Hufrah Platform whereas depth to the top of the Sirte Shale varies from about 1646 m to 3048 m below sea-level.Although most oil pools discovered in Sirt Basin are located on horst structures at relatively shallow depths, the grabens, remain almost unexplored and thus can be considered a new exploration frontier within this area. © 2015 Elsevier Ltd. Source

Abunowara M.,Libyan Petroleum Institute | Elgarni M.,INC Research
Energy Procedia | Year: 2013

An electro balance reactor (thermo gravimetric analyzer) was used to study the reaction rate and achievable sorbent capacity as a function of carbonation temperature, carbonation gas composition, and calcination temperature and atmosphere. The first precursor (calcium carbonate) was calcined to calcium oxide and then converted at temperature ranges (550 °C ∼ 750 °C) to calcium carbonate (CaCO3) and final absorption capacity of calcium oxide at 700 °C is 65%. The second precursor (caustic soda) at temperature ranges (75 °C ∼ 225 °C) was directly carbonated to sodium carbonate and found that 77% sodium carbonate hydrate and sodium carbonate 23% at 150 °C. The final absorption capacity is 25 % and also caustic soda was directly carbonated to sodium carbonate at 225oC and final absorption capacity is 19.2 %. Lithium orthosilicate at temperature ranges (550 °C ∼ 750 °C) was directly carbonated to lithium metasilicate and lithium carbonate and found that the final absorption capacity at 700oC is 35%. Sorbent reproducibility and durability were studied in multi-cycle tests for calcium oxide and lithium orthosilicate. Electro balance tests show that lithium orthosilicate sample had better performance than calcium oxide sample for multi-cycle tests. © 2013 The Author. Source

Edreder E.A.,Libyan Petroleum Institute | Mujtaba I.M.,University of Bradford | Emtir M.,Academy of Graduate Studies
Chemical Engineering Journal | Year: 2011

Hydrolysis of methyl lactate to lactic acid in a reactive distillation column is widely used in the purification of lactic acid. In this work, optimal operations of conventional and inverted batch reactive distillation columns undergoing the hydrolysis reaction are presented. Minimum time optimisation problem is formulated incorporating a process model within gPROMS software and is solved for different range of lactic acid purity and the amount of product using both columns. For a given column type and configuration the minimum operation time is obtained by optimising the reflux ratio profile. For conventional column, the lactic acid being the heaviest in the reaction mixture, reflux ratio policy plays an important role in removing the light product methanol from the top of the column while ensuring the presence of both reactants in the reaction zone to maximise the conversion to lactic acid. For inverted column, reboil ratio policy plays an important role in removing the lactic acid from the bottom of the column while ensuring the presence of both reactants in the reaction zone to maximise the conversion to lactic acid. For some cases (although limited) it is observed that for low lactic acid product purity the conventional column outperforms the inverted column while for high product purity the inverted column outperforms the conventional column in terms of batch time. © 2011 Elsevier B.V. Source

Abdunaser K.M.,Libyan Petroleum Institute | McCaffrey K.J.W.,Durham University
Journal of African Earth Sciences | Year: 2014

The Cretaceous-Tertiary northwest-trending Sirt Basin system, Libya, is a rift/sag basin formed on Pan-African to Paleozoic-aged basement of North Africa. In this study, we investigate the rift-basin architecture and tectonic framework of the western Sirt Basin. Using remote sensed data, supported by borehole data from about 300 deep wells and surface geologic maps, we constructed geological cross sections and surface geology maps. Indication of the relative timing of structures and movement along faults has been determined where possible. Direction statistics for all the interpreted linear features acquired in the study area were calculated and given as a total distribution and then the totals are broken down by the major basin elements of the area. Hundreds of lineaments were recognized. Their lengths, range between a hundred meters up to hundreds of kilometers and the longest of the dominant trends are between N35W-N55W and between N55E-N65E which coincides with Sirt Basin structures. The produced rose diagrams reveal that the majority of the surface linear features in the region have four preferred orientations: N40-50W in the Zallah Trough, N45-55W in the Dur al Abd Trough, N35-55W in the Az Zahrah-Al Hufrah Platform, and in contrast in the Waddan Uplift a N55-65E trend. We recognize six lithostratigraphic sequences (phases) in the area's stratigraphic framework. A Pre-graben (Pre-rift) initiation stage involved the Pre-Cretaceous sediments formed before the main Sirt Basin subsidence. Then followed a Cretaceous to Eocene graben-fill stage that can divided into four structurally-active and structurally-inactive periods, and finally a terminal continental siliciclastics-rich package representing the post-rift stage of the development in post-Eocene time. In general five major fault systems dissect and divide the study area into geomorphological elevated blocks and depressions. Most of the oil fields present in the study area are associated with structural hinge zones and adjoining highs. Late Eocene rocks exposed in the western part of the basin exhibit a complex network of branching segmented normal and strike-slip faults, generally with a NNW-SSE structural orientations. Many surface structural features have been interpreted from satellite images which confirm sinistral strike-slip kinematics. Relay ramp structures, numerous elongate asymmetric synclines associated with shallow west limbs and steeper dipping east limbs are developed in the hangingwalls adjacent to west downthrowing normal faults. These structural patterns reflect Cretaceous/Tertiary extensional tectonics with additional control by underlying pre-existing Pan-African basement fabrics and ENE-WSW trending Hercynian structures. We relate the Sirt Basin rift development as exemplified in our study area to the break-up of Gondwana represented by the structural evolution of the West-Central African rift system, and the South and Central Atlantic, the Tethys and the Indian Oceans. © 2014 Elsevier Ltd. Source

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