Document Type: Original Article
Young Researchers and Elite Club, Omidiyeh Branch, Islamic Azad University, Omidiyeh, Iran
Petroleum Engineering Department, Petroleum University of Technology, Ahwaz, Iran
Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
National Iranian South Oil Company (NISOC), Ahvaz, Iran
One of the most important properties of reservoir fluids is bubble point pressure which helps
the reservoir engineer to estimate reservoir oil in place, inflow performance and to design
In this study, 65 tested data, related to 10 wells located in the one Southwest fields in Iran have
been used which data in this field for 0API<=30 and 0API>30 includes: 1) oil formation volume
factor (1.2-1.6) and (1.3-1.58) bbl/STB, 2) oil sample temperature (110-150) and (130-170)0F,
3) stock tank oil gravity (14.47-26.20) and (32.19-71.09)0API, 4) solution gas-oil ratio (707-
1146) and (654-1066) SCF/STB, 5) gas specific gravity (0.898-1.085) and (0.881-1.187) and
6) bubble point pressure (2962-4196) and (2078-4149) psi.
According to the different 0API range and to researchers carried out on this field, it has been
determined that out a model for data range with 0API>30 and one estimating the model for
0API<=30 is required.
These equations respectively are applicable for crude oil of 0API ranging between
The results have shown that for the equation with range of 0API>30 the minimum error is 0.009
and maximum error is 0.28 and for the equation with range of 0API<=30 the minimum error is
0.0082 and maximum error is 0.25 which it shows the high accuracy of the equation proposed
in this study than other researchers.