Pollutant migration behavior in slurry ponds at Ordos Basin gas well sites
With an acceleration in the rate of gas exploration in Ordos Basin, more and more waste drilling mud has been discharged. After a series of treatment, the waste mud had been buried in some slurry ponds. So a significant number of ponds are scattered in the basin, which give more harm to the fragile ecological environment. But until now, there is little research focusing on real environmental effects of pollutants in slurry ponds. This research chose five slurry ponds used in succession during 2005 and 2009 as targets. The migration behavior of organics, oil and sulfide was studied, and their possible effects on shallow groundwater were forecasted. The results showed that the order of these three pollutants' effects on environment was sulfide>;oil>;organics. According to the migration behavior of mentioned pollutants, it came to conclusion that the sulfide and oil in the slurry ponds used over two years should have brought much influence on shallow groundwater.
Asphaltene structure in reservoir affected by discharge of secondary condensate oil: laboratory simulation
The oil accumulated probably changed in chemical characters due to discharge of natural gas and condensate oil generated later. This process has been simulated by the adding of petroleum ether to crude oil instead of condensate oil, and the structure of asphaltenes from the Well Lunnan 1, Tarim Basin precipitated under various petroleum ether: crude oil ratio was investigated by flash pyrolysis-GC-MS. It is found that the chemical structure of asphaltene precipitated from oil have not been changed yet when petroleum ether was added continuously. The pyrolysate of asphaltenes can be used as the substituent of low molecular compounds for oil-source rock correlation and also for identification of oil source whatever the oil reservoir in superposition basin was discharged by secondary gas or condensate oil. The major contributors to these alkyl components might be non-saponifiable and aliphatic biopolymers in the cell walls of some algae species. The high abundance of 1,2,3,4-tetramethylbenzene in the pyrolysate of the asphalting may derived from photosynthetic green sulphur bacteria, which indicated the precursor of the oil from the Well Lunnan1 were formed under strongly reducing conditions.
Characterization of Polycyclic Aromatic Hydrocarbons in Motor Vehicle Fuels and Exhaust Emissions
Motor vehicles are a significant source of polycyclic aromatic hydrocarbon (PAH) emissions. Improved understanding of the relationship between fuel composition and PAH emissions is needed to determine whether fuel reformulation is a viable approach for reducing PAH emissions. PAH concentrations were quantified in gasoline and diesel fuel samples collected in summer 1997 in northern California. Naphthalene was the predominant PAH in both fuels, with concentrations of up to 2600 mg L-1 in gasoline and 1600 mg L-1 in diesel fuel. Particle-phase PAH size distributions and exhaust emission factors were measured in two bores of a roadway tunnel. Emission factors were determined separately for light-duty vehicles and for heavy-duty diesel trucks, based on measurements of PAHs, CO, and CO2. Particle-phase emission factors, expressed per unit mass of fuel burned, ranged up to 21 μg kg-1 for benzo[ghi]perylene for light-duty vehicles and up to ∼1000 μg kg-1 for pyrene for heavy-duty diesel vehicles. Light-duty vehi...