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Search results for: local area networks

2 Hydrocarbon Source Rocks of the Maragh Low

Authors: Elhadi Nasr, Ibrahim Ramadan

Abstract:

Biostratigraphical analyses of well sections from the Maragh Low in the Eastern Sirt Basin has allowed high resolution correlations to be undertaken. Full integration of this data with available palaeoenvironmental, lithological, gravity, seismic, aeromagnetic, igneous, radiometric and wireline log information and a geochemical analysis of source rock quality and distribution has led to a more detailed understanding of the geological and the structural history of this area. Pre Sirt Unconformity two superimposed rifting cycles have been identified. The oldest is represented by the Amal Group of sediments and is of Late Carboniferous, Kasimovian / Gzelian to Middle Triassic, Anisian age. Unconformably overlying is a younger rift cycle which is represented the Sarir Group of sediments and is of Early Cretaceous, late Neocomian to Aptian in age. Overlying the Sirt Unconformity is the marine Late Cretaceous section. An assessment of pyrolysis results and a palynofacies analysis has allowed hydrocarbon source facies and quality to be determined. There are a number of hydrocarbon source rock horizons in the Maragh Low, these are sometimes vertically stacked and they are of fair to excellent quality. The oldest identified source rock is the Triassic Shale, this unit is unconformably overlain by sandstones belonging to the Sarir Group and conformably overlies a Triassic Siltstone unit. Palynological dating of the Triassic Shale unit indicates a Middle Triassic, Anisian age. The Triassic Shale is interpreted to have been deposited in a lacustrine palaeoenvironment. This particularly is evidenced by the dark, fine grained, organic rich nature of the sediment and is supported by palynofacies analysis and by the recovery of fish fossils. Geochemical analysis of the Triassic Shale indicates total organic carbon varying between 1.37 and 3.53. S2 pyrolysate yields vary between 2.15 mg/g and 6.61 mg/g and hydrogen indices vary between 156.91 and 278.91. The source quality of the Triassic Shale varies from being of fair to very good / rich. Linked to thermal maturity it is now a very good source for light oil and gas. It was once a very good to rich oil source. The Early Barremian Shale was also deposited in a lacustrine palaeoenvironment. Recovered palynomorphs indicate an Early Cretaceous, late Neocomian to early Barremian age. The Early Barremian Shale is conformably underlain and overlain by sandstone units belonging to the Sarir Group of sediments which are also of Early Cretaceous age. Geochemical analysis of the Early Barremian Shale indicates that it is a good oil source and was originally very good. Total organic carbon varies between 3.59% and 7%. S2 varies between 6.30 mg/g and 10.39 mg/g and the hydrogen indices vary between 148.4 and 175.5. A Late Barremian Shale unit of this age has also been identified in the central Maragh Low. Geochemical analyses indicate that total organic carbon varies between 1.05 and 2.38%, S2 pyrolysate between 1.6 and 5.34 mg/g and the hydrogen index between 152.4 and 224.4. It is a good oil source rock which is now mature. In addition to the non marine hydrocarbon source rocks pre Sirt Unconformity, three formations in the overlying Late Cretaceous section also provide hydrocarbon quality source rocks. Interbedded shales within the Rachmat Formation of Late Cretaceous, early Campanian age have total organic carbon ranging between, 0.7 and 1.47%, S2 pyrolysate varying between 1.37 and 4.00 mg/g and hydrogen indices varying between 195.7 and 272.1. The indication is that this unit would provide a fair gas source to a good oil source. Geochemical analyses of the overlying Tagrifet Limestone indicate that total organic carbon varies between 0.26% and 1.01%. S2 pyrolysate varies between 1.21 and 2.16 mg/g and hydrogen indices vary between 195.7 and 465.4. For the overlying Sirt Shale Formation of Late Cretaceous, late Campanian age, total organic carbon varies between 1.04% and 1.51%, S2 pyrolysate varies between 4.65 mg/g and 6.99 mg/g and the hydrogen indices vary between 151 and 462.9. The study has proven that both the Sirt Shale Formation and the Tagrifet Limestone are good to very good and rich sources for oil in the Maragh Low. High resolution biostratigraphical interpretations have been integrated and calibrated with thermal maturity determinations (Vitrinite Reflectance (%Ro), Spore Colour Index (SCI) and Tmax (ºC) and the determined present day geothermal gradient of 25ºC / Km for the Maragh Low. Interpretation of generated basin modelling profiles allows a detailed prediction of timing of maturation development of these source horizons and leads to a determination of amounts of missing section at major unconformities. From the results the top of the oil window (0.72% Ro) is picked as high as 10,700’ and the base of the oil window (1.35% Ro) assuming a linear trend and by projection is picked as low as 18,000’ in the Maragh Low. For the Triassic Shale the early phase of oil generation was in the Late Palaeocene / Early to Middle Eocene and the main phase of oil generation was in the Middle to Late Eocene. The Early Barremian Shale reached the main phase of oil generation in the Early Oligocene with late generation being reached in the Middle Miocene. For the Rakb Group section (Rachmat Formation, Tagrifet Limestone and Sirt Shale Formation) the early phase of oil generation started in the Late Eocene with the main phase of generation being between the Early Oligocene and the Early Miocene. From studying maturity profiles and from regional considerations it can be predicted that up to 500’ of sediment may have been deposited and eroded by the Sirt Unconformity in the central Maragh Low while up to 2000’ of sediment may have been deposited and then eroded to the south of the trough.

Keywords: Geochemical analysis of the source rocks from wells in Eastern Sirt Basin.

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1 Longitudinal Psychological Impact of Psoriasis: A Comparative Study Between Adults and Children in Canada and the United States

Authors: Jenny Carpenter, Josh Chan, Persephone MacKinlay, Madeline Chiang, Devlyn Sun, Hiba Syed, Jana Lau, Mariam Arshad, Joy Xu

Abstract:

Introduction: Psoriasis is a chronic inflammatory skin condition that affects 1 million Canadians and over 8 million Americans. It is associated with psychosocial challenges exacerbated by the presence of visible lesions, which can lead to feelings of embarrassment and social discomfort. Children often experience bullying and lower self-esteem, while adults face workplace discrimination, impaired productivity, and higher rates of comorbid mental health conditions. Understanding these impacts across age groups is vital for tailored interventions. Objective: The main objective is to compare the longitudinal psychological impact of psoriasis between adults and children in Canada and the United States. Methods: This systematic review was conducted following PRISMA guidelines and a PROSPERO-registered protocol. Studies were identified from PubMed, Scopus, ProQuest, PsycINFO, Dermatology Online Journal, JMIR Dermatology, and Embase. The included studies were published between 2014 and 2024, measured standardized psychological outcomes, and had a longitudinal design with at least a one-year follow-up period. Methodological quality was assessed using the GRADE tool. Results: Fifteen studies encompassing 67,964 participants (mean age 49.1 years, 53.3% female) were included. Adults with moderate-to-severe psoriasis demonstrated significant impairments in Dermatology Life Quality Index (DLQI) scores, with a mean baseline score of 9.0 to 10.2 for severe cases, reflecting moderate-to-severe quality of life (QoL) impairments. Treatment with biologic therapies significantly improved outcomes, with DLQI scores decreasing by an average of 7 points (from 9.6 to 2.6; p < 0.001). Key areas of improvement included social functioning, reduced physical symptoms, and increased work productivity. In severe cases, DLQI scores were 7.95 points higher compared to mild cases (p < 0.05), indicating a disproportionate burden of disease severity. Anxiety and depression were common in adults, affecting 16-23% and 18-22%, respectively. These conditions were linked to visible lesions, social stigma, and comorbidities such as hypertension and metabolic syndrome. Children with psoriasis also exhibited similar impairments in QoL, as assessed by the Children’s Life Quality Index (CLDQI). Visible lesions negatively affected school participation and peer interactions, with bullying and stigma consistently reported as major contributors to social isolation and emotional distress. Although biological therapies improved CDLQI scores, children faced persistent challenges in psychological well-being, including lower self-esteem and stigma, which often persisted in adolescence. Disease severity was quantified using the Psoriasis Area and Severity Index (PASI). Among adults, severe cases had a mean baseline PASI score of 13.9, improving by 87.1% (to 1.8, p < 0001) following biologic therapy. Canadian cohorts showed greater PASI improvements, with biologic-naive adults achieving a 95.1% reduction (from 16.3 to 0.7, p < 0.0001). Canadian patients also had higher biologic continuation rates (89.9%). Conclusion: Psoriasis significantly impacts quality of life and psychological well-being across age groups, with notable differences in outcomes between adults and children. Regional differences further highlighted greater work-related impairments in U.S. adults and more pronounced psychological challenges in Canadian children, where bullying and stigma delayed recovery. These findings emphasize the need for age- and region-specific strategies to address both the physical and psychosocial dimensions of psoriasis and support long-term well-being.

Keywords: psoriasis, psychological impact, mental health, quality of life, self-esteem, autoimmune, chronic skin condition

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