Mendeley
TY  _  JOUR
ID  -  13980903193615
TI  -  Occurrence  of  heavy   crude  oil  in the  Persian  Gulf
JO  -  Iranian Journal of  Petroleum Geology
JA  -  ES
LA  -  fa
SN  -  2251-8738
AU  -  Bashari Alireza
AD  -  شرکت ملی نفت ایران 
Y1  -  2020
PY  -  2020
VL  -  16
IS  -  
SP  -  66
EP  -  77
KW  -  Persian Gulf
 Heavy Crude Oil
 Qatar Arch
 Fracturing
Facies change
 Ferdows and farzad fields
DO  -  
N2  -  Some of the most  prolific  petroleum  reservoirs with  high  gravities  of  oil  in the world  occured  in the Upper Jurassic  and Cretaceous  carbonate  formations  in the Persian Gulf area .Most  of the reservoirs are composed of pelletal,oolitic ,or bioclastic  grainstones and reefal  limestone that  have high primary  porosity and permeability .These reservoirs  are sealed  either  by tight limestone ,massive anhydrite, or  by impermeable rocks. The seals  are effective throughout  most of the Persian Gulf  and surrounding  areas, Accumulations of heavy oil  and natural  asphalts on the Iranian  side  of the Persian  Gulf extend NE to SW along  the Qatar  arch. some of the geological structures  which  are located  along this  trend contain  heavy oil  and natural  asphalts   within  post- Jurassic  formations. The major  geologic  factor  which  caused accumulations  of heavy  oil within  some geological  structures  is the Qatar  arch. As a result ,some differences  appear   in lithologic    units  in two sub-basins  northwest   and southeast of the Qatar  Arch. In  general , the  occurrence  of heavy  oil  in this  trend  can be  explained  as follows;

•	Fracturing  and  joints  within  formation ;
•	Reduction  of  thickness  of  post- Jurassic  sediments;
•	Facies change  of Arab  reservoirs, cap rock (Hith anhydrite), in some  structures  from anhydrite  to  dolomite  and also pinchout;

The absence of proper  environment  for the generation of high  gravity oil may also  be of importance .It should  be mentioned that "F" structure (Ferdows), with  huge  amount of oil in Ratawi  and Sulaiy  carbonate reservoirs(Lower Cretaceous), is one of the  largest heavy  oil fields along  this trend .The Farsi "B" structure, ( Farzad),  with  a thick Jahrum formation (Eocene) which  has excellent  reservoir  properties, is filled with  natural  asphalts. 

UR  - rimag.ir/en/Article/33900
L1  - rimag.ir/en/Article/Download/33900
ER  -  
