Integrating geochemical and reservoir engineering approach to evaluate reservoir continuity: A case study from Foroozan field, Offshore Iran

Abstract

The purpose of this study was to identify intra-reservoir compartmentalisation using geochemical and reservoir engineering evidences. On the basis of this approach, 11 gaseous samples, which belong to different wells producing from the Burgan reservoir of Foroozan field, were selected. Gas composition, gas isotopes and associated oil bulk properties were tested to determine the reservoir continuity through the Burgan reservoir. In addition, fluid contacts and properties are also used to investigate reservoir continuity. Regarding clear differences in gas composition such as hydrogen sulphide concentrations, at least two separate segments in the north and south of the reservoir were detected. Moreover, the percentages of the different gas components indicated two separate compartments. Other evidences such as C 1-C 4 alkane isotopic compositions and sulphur and nitrogen isotopic signatures confirmed the Burgan reservoir compartmentalisation. A number of petroleum bulk properties confirmed gradual variations that provide supplementary evidence on the reservoir-filling direction, signifying that fluids equilibrium had not been extended through the Burgan reservoir, laterally. Initial reservoir condition, different original water-oil contacts, solution gas-oil ratio at original pressure and bubble point pressure are other reservoir engineering evidences that support the Burgan reservoir compartmentalisation.

Petroleum Systems Analysis of the Eastern Arabian Plate: Chemometrics Based on a Review of the Geochemical Characteristics of Oils in Jurassic – Cenozoic Reservoirs

“…Evaporative fractionation caused by pressure release around active faults (Gürgey, 2003), such as those around Binak, can lead to the loss of light fractions from the original oil, and the remaining oil then becomes heavier with low API gravity. A similar process may explain the presence of a condensate accumulation in the Albian reservoir in the Foroozan oil field located to the south (Hassanzadeh et al, 2019). In fact, migration pathways are more complex than those shown in the map in Fig.…”

“…LMW hydrocarbon data for samples from the Azadegan and Foroozan oil fields (AZ and FR, Fig. 1; Hassanzadeh et al, 2018;Alizadeh et al, 2020b) point to even higher thermal maturities.…”

“…Publications by Alizadeh et al (2016) and Alizadeh et al (2020b) as well as Kobraei et al (2019aand 2019b) and Asadi Mehmandoosti et al (2022 were used to compile a dataset for oils from the Abadan Plain, SW Iran. The dataset for oils from the Iranian sector of the Persian Gulf was from Rabbani et al (2014), Alizadeh et al (2017), Baniasad et al (2017), Hosseiny et al (2017) and Hassanzadeh et al (2018); and that for the Summan area in northeastern Saudi Arabia was from Arouri et al (2018). This dataset was complemented by new bulk and molecular geochemical data for 49 oil samples from the Kirkuk Embayment (16 samples), Bahrain (three samples), the Abadan Plain (three samples) and the Dezful Embayment (27 samples).…”

“…Petroleum generation and expulsion from these source rocks at different levels of thermal maturity (Aqrawi and Badics, 2015;Sfidari et al, 2016;Baniasad et al, 2021a), together with complexities of charge history and petroleum mixing (e.g. Baniasad et al, 2017;Hassanzadeh et al, 2018) and often complex migration pathways (Ahlbrandt, 2014;Bordenave, 2014;Baniasad et al, 2021b), make geochemical characterization of the petroleum systems in this area challenging. Although numerous geochemical studies have been made at different scales in different sub-basins (e.g.…”

“…Rabbani et al, 2014;El Diasty et al, 2016;Arouri et al, 2018) and at different oil fields (e.g. Al-Khafaji, 2015;Hassanzadeh et al, 2018;Alizadeh et al, 2020b), no regional study has previously been published at the scale of the entire eastern Arabian Plate. Such a regional geochemical study may help to elucidate the relationships between the discovered oils in different parts of this area and migration pathways from kitchen areas to reservoirs and traps.…”