A comprehensive review on characterization and modeling of thick capillary transition zones in carbonate reservoirs

Bera, Achinta; Belhaj, Hadi

doi:10.1016/j.juogr.2016.10.001

Cited by 25 publications

(10 citation statements)

References 76 publications

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“…The capillary transition zone is referred to a reservoir interval from the oil-water contact (OWC) up straight to the height where water saturation reaches its irreducible condition, Swir (Bera and Belhaj 2016;Masalmeh et al 2007;Nono et al 2014). The thickness of a capillary transition zone may vary from a few feet in high-permeability reservoirs to more than 300 feet in low-permeability reservoirs such as carbonate reservoirs, due to its extreme heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

Capillary pressure and relative permeability correlations for transition zones of carbonate reservoirs

Shi

Belhaj

Bera

2017

J Petrol Explor Prod Technol

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A sizable oil reserves are held in a thick oil/ water capillary transition zones in the carbonate reservoirs, but it is an ongoing challenge to accurately describe the relationship between capillary pressure, relative permeability and oil/water saturation due to the complex wettability variation, pore geometry and heterogeneity throughout the reservoir column. It has been shown that a proper interpretation of relative permeability and capillary pressure including hysteresis has a substantial influence on the prediction and optimization of field production, especially for a heterogeneous carbonate reservoir with a thick transition zone. The conventional models, such as Corey method and Leverett J-function, cannot precisely present the behaviors of capillary pressure and relative permeability of transition zones in carbonate reservoirs. In the present work, a study has been conducted to provide an improved understanding of capillary pressure and relative permeability of the transition zones in carbonate reservoirs by implementing and optimizing recently developed models considering mixed-wet property and geological heterogeneity. For single core plug and each reservoir rock typing classified on the basis of petrophysical properties, the applicability to generate bounding drainage and imbibition curves of the models was tested with fitting parameters by comparing with experimental data. Also, a comprehensive assessment was provided about the feasibility and efficiency of the models along with an evaluation of the hysteresis between bounding drainage and imbibition curves. The results showed excellent matches in the case of Masalmeh model (SPE Reserv Eval Eng 10(02):191-204, 2007) with a correlation coefficient value of 0.95, in which mixed-wet and pore size distribution are taken into account. Therefore, it can be stated that the work conducted in this study could be used as a guide for further investigation and understanding of transition zones in carbonate reservoirs.

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Section: Introductionmentioning

confidence: 99%

Capillary pressure and relative permeability correlations for transition zones of carbonate reservoirs

Shi

Belhaj

Bera

2017

J Petrol Explor Prod Technol

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“…Based on our earlier study, it can be stated that cementation is a very important factor for controlling porosity and permeability in rock (Bera and Belhaj, 2016). Figure 5A and B shows drusy and blocky calcite in the present sample analysis.…”

Section: Cementationmentioning

confidence: 51%

Petrographic and diagenetic studies of thick transition zone of a middle-east carbonate reservoir

Mohamed¹,

Belhaj²,

Gomes³

et al. 2017

J. Petroleum Gas Eng.

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This work aims to characterize petrographically some of the transition zone plug samples in order to understand the impact of diagenetic processes on the transition zone rock quality. Three carbonate samples were collected from the same well which cuts through a thick transition zone of a heterogeneous cyclic carbonate reservoir of Abu Dhabi with respect to depth. The petrographic analysis was conducted by the thin sections study and scanning electron microscope (SEM) imaging in order to interpret the main depositional facies, diagenetic features and how the poro-perm characteristics were affected by them. SEM analysis is utilized in order to observe and recognize in detail the diagenetic relationships between different mineral phases or cement types and to help in identifying the pore geometry. Diagenesis in the transition zone is very extensive especially affected by micritization and cementation. The diagenetic features are increasing with depth as the zone is having higher water saturations. The importance of this analysis is to better understand the rock fabric heterogeneity and capillary pressure behavior as a function of depth of thick carbonate transition zones.

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“…The oil-water transition zone (OWTZ) in a petroleum reservoir is the zone below the main oil leg where the saturation of water progressively increases from an irreducible value to 100% (Adegbite et al, 2021). The thickness of this transition zone is dependent on several properties including the hydrocarbon density, the reservoir pore sizes and distribution etc., and can range from a few metres to several hundreds of metres (Bera and Belhaj, 2016;Adegbite et al, 2021). In the main oil leg, only immovable water exists.…”

Section: Introductionmentioning

confidence: 99%

High temperature susceptibility measurements: A potential tool for the identification of oil-water transition zone in petroleum reservoirs

2022

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Determining the position and thickness of the oil-water transition zone (OWTZ) in hydrocarbon reservoirs is important to reserve estimation and production planning. This paper describes a magnetic method of identifying this zone. High temperature susceptibility (HT-χ) measurements on core samples from Paleogene reservoirs of the UK Central North Sea revealed distinct signatures around the oil water interface. Rapid increases in susceptibilities at temperatures <250°C were observed for samples around the oil water interface unlike the main oil leg where alteration involving increase in susceptibility occurred at significantly slower rates and higher temperatures. The HT-χ data together with Mössbauer measurements revealed that the variation in alteration characteristics is due to the increasing concentration of hexagonal pyrrhotite and/or lepidocrocite around the oil water interface. Hexagonal pyrrhotite was identified in reservoirs existing at temperatures of <80°C, while lepidocrocite dominated the signature around the contact of deeper reservoirs. These observations suggest that the precipitation of hexagonal pyrrhotite is related to OWTZ centred biogenic activities i.e., biodegradation. The dominance of lepidocrocite in deeper diagenetic settings has been related to hydrolysis of hydrocarbon at the oil water interface, together with cessation of biogenic activities.

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A comprehensive review on characterization and modeling of thick capillary transition zones in carbonate reservoirs

Cited by 25 publications

References 76 publications

Capillary pressure and relative permeability correlations for transition zones of carbonate reservoirs

Capillary pressure and relative permeability correlations for transition zones of carbonate reservoirs

Petrographic and diagenetic studies of thick transition zone of a middle-east carbonate reservoir

High temperature susceptibility measurements: A potential tool for the identification of oil-water transition zone in petroleum reservoirs

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