The connections and possible interactions between coffee consumption, tobacco consumption, blood pressure (BP), age, and body mass index (BMI) were analysed in a cross-sectional epidemiologic study of 1098 men and 393 women of the Algiers district. Systolic blood pressure (SBP) was negatively and significatively correlated with cigarette smoking. Diastolic blood pressure (DBP) was positively and significantly associated with coffee consumption (P less than 0.001) and negatively and significantly with cigarette consumption (P less than 0.001). These associations remained significant after multivariate analysis including sex, age, BMI, physical exertion at work, athletic activity, rural versus urban residency, tobacco, tea and coffee consumption. Coffee consumption and cigarette smoking were positively associated (P less than 0.001). In the subgroup of men, the association between coffee consumption and DBP was significant only after adjustment for cigarette smoking. In the subgroup of women, containing a low percentage of smokers, this association was significant without such adjustment. This finding suggests that cigarette consumption might partly mask the association between coffee consumption and BP. The contradictory interactions observed between BP, cigarette consumption and coffee consumption might help to explain the conflicting reports concerning the association between coffee consumption and ischemic heart disease.
In field operations of volatile oil and gas condensate reservoirs, separator conditions often change because these volatile fluids are usually separated through three and more separation stages, when wellhead pressure allows. The well stream is usually rerouted to lower pressure separators at later stages of the field life.
Although the reservoir simulation is widely used for recoverable reserves calculations, material balance equation is still used as a fast and easy method for reserves and forecast calculations. The conventional material balance equation does not allow accurate calculations for hydrocarbons in-place when separator conditions change during the history of the field production, since PVT properties are usually calculated for specific separator conditions in black-oil and modified black-oil approaches.
In this work, a new material balance equation was developed. This equation can be easily used and will allow accurate calculations of hydrocarbons in-place when separator conditions change during the production history. The inputs to the equation can be easily obtained from the equation of state model (EOS) which is used to generate the black oil or modified black oil PVT tables. In some cases, PVT properties can be also calculated at different separator conditions using newly published correlations that take separator conditions into consideration.
To validate the new equation, many reservoir fluids covering a wide range of black and volatile oil reservoirs (and their associated PVT tables) were used. The new equation was applied to calculate oil in-place using the production and pressure data from many test cases generated by fully compositional simulation (note that compositional simulation takes into consideration the effects of changing separator conditions on production data during the simulation time). The new material balance was found to give results with close agreement to the compositional simulation model.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.