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Abstract Several investigations were perfor ed on six samples of crude oils ta en from different areas in Cg;pt; Ras Gharib, Ras El-Behar, Pas El-Fanar nd :’ar3 ·Jt fro eastern desert, !.. lamein from .,.·estern Cesert ar:cJ ·-:organ from the Gulf of Suez (off shore sarn;:-,lei. This six different saxples were distilled nto top- ped fract1on and residue a!Jove 350°C, tGe 3 G:rlc abEorp- tion, spectrophotometry, microprobe analysis a d x-ra; diffraction studies were corried out o cr0 0:.. ·t. results of the distillatio 1 dicate t at cr c G!-S cornffilng out frcJr, cil field ocQteG has the highest perce t ;e of t e li ht ra i· is Alamein next to it comes r:as El-Bei1ar ’”n’”’ ; higtest percentage and organ field. T!.c r csu.1..ts of set_J3 ra:. :r. of the oil fields, t! s as fou c -·· sever : 1:1 ttJ.iS v.·ork t!11s :rG;· :.”:: c..:..:•=-· u:.· c:.c: ·:..:. -· lead 1n this part1cular oil field. /Physico-chemical tests such as densities, .ean le- cular weight, API gravity, viscosity, pour po1nt, flash point, Sulphur content, asl1 content and car o r sid e were -2- determined and comparative studies has been carried out between these six oil fields and were correlated to the petroleum qualities.’ v, Ni, Fe, Cu, Co, and Zn are used as important evaluating parameters in petroleum crudes.’ Several tech niques are applied in this work in order to evaluate these elements. Graphite furnace atomic absorption spectrophoto meter was used in order to determine the percentage of these elements. Reproduceble results using this method were obtained for V, Ni, Fe, Cu, Co, and Zn in the samples prepared from the above six different crudes. The same above technique were used to determine the same trace elements in the asphaltene obtained from the above six crudes. The results were co pared and discussed in the light of the type of crude and its area as well. As the analysis by using atomic absorption was limited for certain elements only. It was essential to use another technique in order to evaluate as possible most of the trace elements present in the six crude oil samples and accordingly the sulphated ash of six petro leum crude oil samples were subjected to microprooe analysis in order to determine semiquantitatively the possible elements in these samples. The percentage of the analyzed elements showed that Ras Gl1arib , Ras 1-Fanar, -3- Ras El-Behar and Tarabot have the hig cst percentage of V (23-45%) and :;i(lB-34<), while tr<e other two samples have the least .1. rnount of \·’ ..::llid i.TLc rw.tic or t:.r ,.r C’ two elements were calculated for each sample and a cor relation was carried out which shows that the ratio dif fers from one oil field to another even those which are from the same area from which they were found. A high percent of Si was found in A amein which may comes as contamination from desert d ring the migration of crJje oil from source to reservoir rocks. Na and Cl elements were found in Morgan and Alamein due to its situation (off shore of Suez Gulf for organ and near to the Midi- tc·r..J.r:c.: n se 1 for I.L.J:r.€’ in), T cse ide tif ed 0le ents obtained by microprobe ;;ere t!.en c;sed as a <:;Jice for identuf ·ing the possible phases !oxide, si:icate,suJp atel c using the x-ray diffractio method. ·,-;i_ t:-. the help c[ t e JCPDS cards, it as poss ble to ide tif · all t e phases present in the sa ples. (These p ases ave not been indentified oefore in literature). showed that there are common phases among the samples anc most of these phases are compounds containing mainly V, Ni, Fe w!1ich are correlated to the orig1n of petroleum. The structure of asphaltene was also determined in this work by using x-rav diffraction. Prom this analysis it •·as possible to find the unit cell parameters of tr.c -4- cryst;:1l system, llie p:ackiiHJ dinl::>nr.:e of the uli[,hallc chains or the condensed saturated rings, the packing distance of the .JJ:Omutic r in<Js, the size of tre siuP chain and also the nuMber of the aromatic rings present in the structure. from Lll l these d.:.ta Ll rr.odel for ’che structure was performed. / rumaticity ”’-’hich is the number of aromatic carGon lo tut<:Jl carbons was .:.lso fou d for the five sarlrFles uy us1n · tr.e .i:ctces;ateu are<Js c·f so;ce im ,>ortant peaks. as it gives qualitatively the contents of the saturateci and aromatic structure. T!1e results of these str cture analysis when co pared wit!· s0 e syn hetic and na ral petr0leum rerorted in lj tcr:Iture, showed t!1c1t these samples tend to have some orcler ing in the structL:re, and larger number o[ .: rom::>tic r1ngs 1.e. l.: rger olecular structure, this was attri0uted to the prese ce cf a y heavy atoms in the uspl•.: lterre resi,lue <.’hie. ::-.ay iJCt us lletecoatoms in tile structL:re r.d help ir clustering thf> arowatic rings toyetller. |