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Reports on a clinical audit of endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy at the Surgery Department of the Alice Ho Miu Ling Nethersole Hospital in Hong Kongk, China from 1997 to 1998. Review of the incidence of blood transfusion; Discontinuation of post-sphincterotomy bleeding with local adrenaline injection; Chart showing ERCP results.

Abstract: Based on quantitative modeling and experimental data on n-tetracosane cracking to generate gaseous hydrocarbons in a confined system, we calculated the generation kinetics and carbon isotope kinetics of methane, ethane and propane and determined the main controlling factors influencing the variation of δ 13C2 and δ 13C3. The carbon isotope of gaseous hydrocarbons from n-C24 cracking to gas are comparable to those from crude oil reported recently, and they can be used to investigate the geochemical characteristics of crude oil cracking to gas under geological conditions. The geological model of n-C24 cracking suggests it is stable at 150–160°C and its cracking temperature ranges from 180 to 200°C, consistent with geological models of crude oil cracking currently reported. With increasing degree of thermal stress, the changes in δ 13C2 and δ 13C3 are larger than that of δ 13C1. It is shown that isotope accumulation controlled by the recharging history of a reservoir has a considerable impact on the carbon isotope distribution of natural gas. Compared to that of cumulative gas, the carbon isotope ratio of partly accumulation gas is heavier and influences the fractionation of the δ 13C2 and δ 13C3 curves to a greater extent. The geological model of n-C24 cracking to gas has been used to interpret the origin of carbon isotopic variation of natural gas in some reservoirs in the Tarim Basin. [Copyright &y& Elsevier]

Abstract: The identification of a deeply-buried petroleum-source rock, owing to the difficulty in sample collection, has become a difficult task for establishing its relationship with discovered petroleum pools and evaluating its exploration potential in a petroleum-bearing basin. This paper proposes an approach to trace a deeply-buried source rock. The essential points include: determination of the petroleum-charging time of a reservoir, reconstruction of the petroleum generation history of its possible source rocks, establishment of the spatial connection between the source rocks and the reservoir over its geological history, identification of its effective source rock and the petroleum system from source to trap, and evaluation of petroleum potential from the deeply-buried source rock. A case study of the W9-2 petroleum pool in the Wenchang A sag of the Pearl River Mouth Basin, South China Sea was conducted using this approach. The W9-2 reservoir produces condensate oil and gas, sourced from deeply-buried source rocks. The reservoir consists of a few sets of sandstone in the Zhuhai Formation, and the possible source rocks include an early Oligocene Enping Formation mudstone and a late Eocene Wenchang Formation mudstone, with a current burial depth from 5000 to 9000m. The fluid inclusion data from the reservoir rock indicate the oil and the gas charged the reservoir about 18–3.5Ma and after 4.5Ma, respectively. The kinetic modeling results show that the main stages of oil generation of the Wenchang mudstone and the Enping mudstone occurred during 28–20Ma and 20–12Ma, respectively, and that the δ13C1 value of the gas generated from the Enping mudstone has a better match with that of the reservoir gas than the gas from the Wenchang mudstone. Results from a 2D basin modeling further indicate that the petroleum from the Enping mudstone migrated upward along the well-developed syn-sedimentary faults in the central area of the sag into the reservoir, but that the petroleum from the Wenchang mudstone migrated laterally first toward the marginal faults of the sag and then migrated upward along the faults into shallow strata. The present results suggest that the trap structure in the central area of the sag is a favorable place for the accumulation of the Enping mudstone-derived petroleum, and that the Wenchang mudstone-derived petroleum would have a contribution to the structures along the deep faults as well as in the uplifted area around the sag. [Copyright &y& Elsevier]