Western Desert represents a major oil and gas province in Egypt producing more than 50%of the country’s oil production.Oil and gas blend occurs in most producing fields,however,the genetic link between gas and liquid...Western Desert represents a major oil and gas province in Egypt producing more than 50%of the country’s oil production.Oil and gas blend occurs in most producing fields,however,the genetic link between gas and liquid hydrocarbon phases are not well-constrained.Obayied sub-basin in the Western Desert where oil and gas phases coexist in the Middle Jurassic sandstones of the Khatatba Formation provides an ideal place to investigate the link between oil and gas generation.Geochemical analyses on rock samples(Rock–Eval pyrolysis,vitrinite reflectance,R_(o))and gases(molecular and isotopic composition)were conducted in order to identify the genetic characteristics of the hydrocarbon phases produced.Maturity-relevant parameters(Rock–Eval T_(max),vitrinite reflectance R_(o))elucidate that only Middle Jurassic Khatatba organofacies capable of generating wet and dry hydrocarbon gases.Additionally,the enrichment of C_(7)normal alkanes,mono-branched alkanes relative to polybranched components in the Obayied gases reflect their generation via cracking of oil.Basin modelling results confirm gas generation through both primary and secondary cracking.However,secondary cracking of liquid hydrocarbon phases is volumetrically more significant.Primary cracking of the Khatatba organofacies likely predate and catalyze the secondary cracking of the liquid phases and therefore the volume of generated gas increases incrementally eastward where both processes coexist.The present study highlights the significant role of secondary cracking in the generation and accumulation of huge gas accumulations in the basins containing oil-prone source intervals.展开更多
Background and aim: In patients infected with chronic hepatitis C virus, liver biopsy is the gold standard method of staging fibrosis. Different combinations of serum markers attempted to correlate with hepatic fibros...Background and aim: In patients infected with chronic hepatitis C virus, liver biopsy is the gold standard method of staging fibrosis. Different combinations of serum markers attempted to correlate with hepatic fibrosis in place of liver biopsy and have shown encouraging results. The aim of our study is to evaluate the diagnostic value of endoglin and FIB-4 as non-invasive markers of hepatic fibrosis in HCV patients. Methods: We estimated serum endoglin & FIB-4 index in 40 infected chronic hepatitis C patients. Histological staging of hepatic fibrosis was done according to the METAVIR scoring system. Results: Both endoglin and FIB-4 index showed positive correlation with age and aspartate transaminase and inverse correlation with albumin. The diagnostic performance determined by AUROCs for early fibrosis (≤F2), was 0.868 for endoglin and 0.887 for FIB-4, at cut off va- lues of 5.5 & 0.98 with sensitivity of 64.3% & 82.1%, and specificity of 100% & 85% respectively. For ad-vanced fibrosis (>F2), the AUROC was 0.98 for endoglin and 0.967 for FIB-4, obtained at cut off values of 6.29 & 1.6, with sensitivity of 100% & 91.7%, and specificity of 89.3% & 92.9%, respectively. Conclusion: Both serum endoglin and FIB-4 index are fairly accurate in differentiating stages of hepatic fibrosis;their combination in a single equation enhanced the accuracy of fibrosis detection in chronic HCV patients.展开更多
文摘Western Desert represents a major oil and gas province in Egypt producing more than 50%of the country’s oil production.Oil and gas blend occurs in most producing fields,however,the genetic link between gas and liquid hydrocarbon phases are not well-constrained.Obayied sub-basin in the Western Desert where oil and gas phases coexist in the Middle Jurassic sandstones of the Khatatba Formation provides an ideal place to investigate the link between oil and gas generation.Geochemical analyses on rock samples(Rock–Eval pyrolysis,vitrinite reflectance,R_(o))and gases(molecular and isotopic composition)were conducted in order to identify the genetic characteristics of the hydrocarbon phases produced.Maturity-relevant parameters(Rock–Eval T_(max),vitrinite reflectance R_(o))elucidate that only Middle Jurassic Khatatba organofacies capable of generating wet and dry hydrocarbon gases.Additionally,the enrichment of C_(7)normal alkanes,mono-branched alkanes relative to polybranched components in the Obayied gases reflect their generation via cracking of oil.Basin modelling results confirm gas generation through both primary and secondary cracking.However,secondary cracking of liquid hydrocarbon phases is volumetrically more significant.Primary cracking of the Khatatba organofacies likely predate and catalyze the secondary cracking of the liquid phases and therefore the volume of generated gas increases incrementally eastward where both processes coexist.The present study highlights the significant role of secondary cracking in the generation and accumulation of huge gas accumulations in the basins containing oil-prone source intervals.
文摘Background and aim: In patients infected with chronic hepatitis C virus, liver biopsy is the gold standard method of staging fibrosis. Different combinations of serum markers attempted to correlate with hepatic fibrosis in place of liver biopsy and have shown encouraging results. The aim of our study is to evaluate the diagnostic value of endoglin and FIB-4 as non-invasive markers of hepatic fibrosis in HCV patients. Methods: We estimated serum endoglin & FIB-4 index in 40 infected chronic hepatitis C patients. Histological staging of hepatic fibrosis was done according to the METAVIR scoring system. Results: Both endoglin and FIB-4 index showed positive correlation with age and aspartate transaminase and inverse correlation with albumin. The diagnostic performance determined by AUROCs for early fibrosis (≤F2), was 0.868 for endoglin and 0.887 for FIB-4, at cut off va- lues of 5.5 & 0.98 with sensitivity of 64.3% & 82.1%, and specificity of 100% & 85% respectively. For ad-vanced fibrosis (>F2), the AUROC was 0.98 for endoglin and 0.967 for FIB-4, obtained at cut off values of 6.29 & 1.6, with sensitivity of 100% & 91.7%, and specificity of 89.3% & 92.9%, respectively. Conclusion: Both serum endoglin and FIB-4 index are fairly accurate in differentiating stages of hepatic fibrosis;their combination in a single equation enhanced the accuracy of fibrosis detection in chronic HCV patients.
