Wyniki wyszukiwania - BazTech

1

Time-dependent rheology of crude oils and effect of wax and asphaltene constituents

El-Gamal I. M., Schnabel R., Anton W.

International Journal of Applied Mechanics and Engineering

|

2003

|

Vol. 8, no spec.

25-32

EN

Time-dependent rheological behavior of four Egyptian crude oils was studied below, at and above pour point via rheometric measurements. The obtained hysteresis loops showed thixotropic pseudoplastic character for all crude oils at and below pour point. However, at 10°C above pour point, waxy and intermediate-base crude oils exhibited anti-thixotropic behavior. The thixotropic degree increases with the decrease of temperature. Time-effect at constant shearing showed a slight continuous decrease of viscosity for asphaltic crude oil, while displayed an increase for intermediate-base one. Further increase of wax content led to steep fall decrease of viscosity followed by gradual increase for the other crude oils according to the degradation-reformation competition of paraffin interparticles during shearing. Recovery of structure after shearing revealed a progressive viscosity increase with the increase of holding time periods and that viscosity after recovery exceeded the initial values in many cases. At the corresponding temperatures, high asphaltene constituent induces high viscosity of asphaltic crudes that equals orders of magnitude higher than that of waxy crude oil. Pseudoplasticity of crude oils increases with the decrease of temperature except for asphaltic crude oil and that this increase is correlated with the increase of wax/asphaltene ratio contained in the crude oils.

2

Polycyclic aromatic hydrocarbons in crude oils from Poland

Bojakowska I., Sokołowska G.

Geological Quarterly

|

2001

|

Vol. 45, No 1

81-86

EN

The content of 17 polycyclic aromatic hydrocarbons (PAHs) in oil samples derived from all three oil-bearing regions of Poland, i.e. from the Carpathians, the Carpathian Foredeep and the Polish Lowlands (the Fore-Sudetic-Wielkopolska, the Western Pomeranian and the Peribaltic areas), were determined. The concentrations of PAHs determined in these crude oils varied from 22.85 to 332.45 ppm. The average content of PAHs in crude oils from the Carpathians and the Carpathian Foredeep (191.18 ppm) was several times higher than that in crude oils from the Polish Lowlands (44.70 ppm); there was throughout, though, a relatively small variability in the content of perylene, varying from 0.50 to 0.80 ppm. Of PAH compounds determined, the largest share was occupied by 3-cyclic hydrocarbons (an average of 72%) and 4-cyclic (about 24%), whereas the content of 5- and 6-cyclic hydrocarbons did not exceed 3%. Phenanthrene and fluorene were prevailing PAH compounds. The diverse PAH composition in oil samples from the Polish Lowlands compared to those from the Carpathians and the Carpathian Foredeep seems to have resulted more from the composition of original organic matter than from the course of geochemical and biochemical processes (which occur during biomass decay) and the subsequent migration of these compounds in rock formations.

3

Charakter geochemiczny rop naftowych akumulowanych w złożach fałdu Potoka i ich związek z budową tektoniczno-strukturalną pułapek złożowych

Kruczek J., Matyasik I., Steczko A.

Prace Instytutu Górnictwa Naftowego i Gazownictwa

|

2000

|

nr 110 wyd. konferencyjne

61--65

EN

The results described in this study will centre on the geochemical characterisation of oils from the Outer Caipathian region of Poland which has been a major petroleum province for over one hundred years. Nineteen oil samples from Silesian Unit of the eastern Carpathian Overthrust have been characterised geochemically in order to determine source rocks and their maturity level. Geochemical correlation based on biomarker distributions showed a closed relationship between all oils (included biodegraded oils.