Reservoir rock typing and zonation in sequence stratigraphic framework of the Cretaceous Dariyan Formation, Persian Gulf

Mehrabi, Hamzeh; Ranjbar-Karami, Rasoul; Roshani-Nejad, Maryam

doi:10.1007/s13146-019-00530-2

Cited by 25 publications

(2 citation statements)

References 18 publications

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“…In general, the cut-off porosity for most carbonate reservoirs is 3%, compared to 8% for sandstones (e.g., Tiab and Donaldson 2015;Mehrabi et al 2019). Based on this assumption and the observed porosity ranges, we define porosity evaluation levels for estimation of reservoir quality as follows: 0 to 3% are negligible, 3 to 6% is poor reservoir quality, 6 to 9% is moderate, 9 to 12% is defined as a good reservoir, and > 12% is a very good reservoir quality.…”

Section: Reservoir Qualitymentioning

confidence: 99%

Porosity estimation of a geothermal carbonate reservoir in the German Molasse Basin based on seismic amplitude inversion

Wadas

Hartmann

2022

Geotherm Energy

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The Molasse Basin is one of the most promising areas for deep geothermal exploitation in Germany and the target horizon is the aquifer in the Upper Jurassic carbonates. Carbonate deposits can be very heterogeneous even over a small area due to diagenetic processes and varying depositional environments. The preferential targets for geothermal exploitation in carbonate deposits are fault zones, reef facies and karstified areas, since they are expected to act as hydraulically permeable zones due to high porosity and high permeability. Therefore, identifying these structures and characterizing, e.g., their internal porosity distribution are of high importance. This can be accomplished using 3D reflection seismic data. Besides structural information, 3D seismic surveys provide important reservoir properties, such as acoustic impedance, from which a porosity model can be derived. In our study area in Munich we carried out a seismic amplitude inversion to get an acoustic impedance model of the Upper Jurassic carbonate reservoir using a 3D seismic data set, a corresponding structural geological model, and logging data from six wells at the ‘Schäftlarnstraße’ geothermal site. The impedance model and porosity logs were than used to calculate a porosity model. The model shows a wide porosity range from 0 to 20% for the entire reservoir zone and the lithology along the wells reveals that dolomitic limestone has the highest porosities and calcareous dolomite has the lowest porosities. The study area is cut by a large W–E striking fault, the Munich Fault, and the footwall north of it shows higher porosities and more intense karstification than the hanging wall to the south. Considering the entire study area, an increase in porosity from east to west is observed. Furthermore, we identified a complex porosity distribution in reef buildups and pinnacle reefs. The reef cores have mostly low porosities of, e.g., < 3% and the highest porosities of up to 7 to 14% are observed at the reef caps and on the reef slopes. The reef slopes show a characteristic interfingering of the reef facies with the surrounding bedded facies, which indicates a syn-sedimentary reef development with slightly varying build up growth rates. We also assessed the reservoir quality with regard to porosity distribution and determined areas with moderate to good quality for geothermal exploitation by defining porosity evaluation levels. The porosity evaluation maps show that the carbonate rocks of Berriasian to Malm $$\zeta$$ ζ 1 are preferential targets for exploitation, especially in the footwall of the Munich Fault and to the west of the hanging wall, because these areas are characterized by high porosities due to intense karstification of bedded and massive facies, although the latter is mainly restricted to reef caps and reef slopes.

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Section: Reservoir Qualitymentioning

confidence: 99%

Porosity estimation of a geothermal carbonate reservoir in the German Molasse Basin based on seismic amplitude inversion

Wadas

Hartmann

2022

Geotherm Energy

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“…It creates a continuous stratigraphic of core porosity (Ø) and permeability (K) with unique K/Ø ratios, known as reservoir process speed (RPS). Reservoir storage capacity (Øh) and flow capacity (Kh) are calculated using the following Equations ( 2) and (3) [46][47][48]:…”

Section: Methodsmentioning

confidence: 99%

Pore-Type Characterization and Reservoir Zonation of the Sarvak Formation in the Abadan Plain, Zagros Basin, Iran

Mehrabi,

Karami,

Fakhar-Shahreza

et al. 2023

Minerals

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Carbonate reservoirs are characterized by their complex depositional–diagenetic history and, consequently, intricate pore networks. In this study, pore types and reservoir zones of the Sarvak Formation, which is the second most important oil reservoir in Iran, are investigated by integrating core, thin-section, porosity–permeability, scanning electron microscopy (SEM), and mercury injection capillary pressure (MICP) data. Depositional, diagenetic, and fracture pores are identified in macroscopic to microscopic scales. Frequency analysis of pore types revealed that diagenetic pores, including vuggy, moldic, intercrystalline, and fracture pores, formed the majority of pore spaces of the Sarvak Formation. They are dominantly recorded in the regressive systems tracts of both the Cenomanian and Turonian sequences, just below the paleoexposure surfaces. Away from the disconformities, there are two general trends regarding the pore-types distribution: (a) grain-supported facies of shoal and talus settings with dominant primary (depositional) pores including interparticle, intra-skeletal, and growth-framework pores, which are concentrated in the middle part of the formation, and (b) microporous mud-dominated facies with various types of primary and secondary pore types in the TSTs of third-order sequences, especially in the lower part of the Sarvak Formation. Stratigraphic modified Lorenz plot differentiated reservoir, speed, barrier, and baffle zones in this formation. Depositional–diagenetic characters, petrophysical properties, and dominant pore types are defined for each zone in a sequence stratigraphic framework.

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Coated grain petrography and geochemistry as palaeoenvironmental proxies for the Aptian strata of the southern Neo-Tethys Ocean, Persian Gulf, Iran

Bahrehvar

Mehrabi

Rahimpour‐Bonab

2019

Facies

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Reservoir rock typing and zonation in sequence stratigraphic framework of the Cretaceous Dariyan Formation, Persian Gulf

Cited by 25 publications

References 18 publications

Porosity estimation of a geothermal carbonate reservoir in the German Molasse Basin based on seismic amplitude inversion

Porosity estimation of a geothermal carbonate reservoir in the German Molasse Basin based on seismic amplitude inversion

Pore-Type Characterization and Reservoir Zonation of the Sarvak Formation in the Abadan Plain, Zagros Basin, Iran

Coated grain petrography and geochemistry as palaeoenvironmental proxies for the Aptian strata of the southern Neo-Tethys Ocean, Persian Gulf, Iran

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