Pore typing using nuclear magnetic resonance, an example with samples from cretaceous pre-salt lacustrine carbonates in the Santos Basin, Brazil

Belila, Aline Maria Poças; Basso, Mateus; Chinelatto, Guilherme Furlan; Kuroda, Michelle Chaves; Vidal, Alexandre Campane

doi:10.1016/j.petrol.2020.107079

Cited by 18 publications

(5 citation statements)

References 15 publications

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“…It should be emphasized that the pre‐salt lacustrine carbonate reservoirs in the Santos Basin are characterized by strong heterogeneity, so it is necessary to calibrate the carbonate samples of different strata to obtain suitable T 2 cut‐off values. In addition, NMR logging is not sensitive to pore throat, so diagenesis can greatly affect the estimation of porosity and permeability (Belila et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

Prediction of lithology in lacustrine carbonates using well logs: The Cretaceous Barra Velha Formation in Santos Basin, offshore Brazil

Wang¹,

Zhang

Fan³

et al. 2023

Geological Journal

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Abundant hydrocarbons have been produced from the pre‐salt lacustrine carbonates of the Cretaceous Barra Velha Formation in the Santos Basin of offshore Brazil. The highly heterogeneous lithology and pore systems make it difficult to predict the reservoir quality via petrophysical well logs. Core description, computed tomography (CT) scanning, thin sections and wireline well logs are utilized to characterize the lithology, pore spaces are reservoir quality of the Cretaceous Barra Velha Formation pre‐salt lacustrine carbonates in the Santos Basin. The results show that the lithology mainly includes shrubstone, grainstone, laminated micrite and massive micrite. The pore systems are dominated by secondary pores, such as intergranular pores, dissolution pores and intercrystalline pores as well as modified primary pores. Geological well logs (conventional well logs, electrical and sonic image logs and nuclear magnetic resonance [NMR] logs) are integrated to build the predictable models of the carbonate reservoirs. The shrubstone, which is dominated by intergranular pores, has the highest reservoir quality, which can be derived from NMR logs. Grainstone contains both primary intergranular pores and abundant secondary dissolution pores. The laminated and massive micrite contain only micropores and therefore have the lowest reservoir quality. Lastly, conventional well logs integrated with electrical and sonic image logs are utilized to predict the distribution of lithology and reservoir quality in single wells, and the results are testified by the NMR log data. The shrubstone and grainstone are future exploration targets of the Cretaceous Barra Velha Formation in the Santos Basin. The results are hoped to give insights into the petrophysical behaviours of various lithologies, and provide theoretical and technical guidance for reservoir evaluation and prediction.

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Section: Discussionmentioning

confidence: 99%

Prediction of lithology in lacustrine carbonates using well logs: The Cretaceous Barra Velha Formation in Santos Basin, offshore Brazil

Wang¹,

Zhang

Fan³

et al. 2023

Geological Journal

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“…The SDR model was applied to calculate permeability based on the obtained T 2(lm) data, but the model did not provide good permeability predictions. As an alternative, Belila et al (2020) demonstrated that performing irreducible water saturation experiments is useful to define the Free‐Fluid Index (FFI) and the bulk volume irreducible (BVI) and consequently a FFI/BVI T 2 cut‐off of the pore network. This T 2 cut‐off can in turn be used to calculate permeability using the Timur–Coates equations.…”

Section: Discussionmentioning

confidence: 99%

“…Nuclear magnetic resonance (NMR) logging is one of the preferred methods for porosity measurement in reservoirs due to the techniques relative insensitivity to changes in mineralogy and its reliability in estimating permeability (Boyd et al, 2015). Nuclear magnetic resonance, after calibration with laboratory measurements, consequently plays a central role in addressing complex pore geometries and other heterogeneities, certainly in combination with X‐ray computed tomography (XCT; Alabi et al, 2014; Belila et al, 2020; Chitale et al, 2014; Diniz‐Ferreira & Torres‐Verdín, 2012). In this paper, an integrated methodology for characterising the pore network, including petrography, XCT, mercury injection capillary pressure (MICP) and laboratory NMR is tested.…”

Section: Introductionmentioning

confidence: 99%

Unravelling the pore network and its behaviour: An integrated NMR, MICP, XCT and petrographical study of continental spring carbonates from the Ballık area, SW Turkey

Soete

Claes

et al. 2021

The Depositional Record

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Applying an integrated methodology, including petrography, mercury injection capillary pressure, laboratory nuclear magnetic resonance and X‐ray computed tomography, on continental spring carbonate reservoir analogue samples is a prerequisite to understand plug scale porosity and permeability heterogeneities. Depending on the dominant pore type in a sample, the orientation and distribution of the pores, pore network connectivity varies from poor to excellent in these continental spring carbonates. The latter exhibit large‐scale ranges for both porosity (3%–25%) and permeability (0.004–3,675 mD). Facies classification alone proved insufficient to link porosity and permeability, due to intrafacies pore network variability. Better assessment of reservoir properties can be achieved by subdividing facies into lithotype and pore type classes. Obtained pore network data addresses the pore types, pore (throat) sizes, number of pore compartments, and allow a subdivision of the pore size distributions into unimodal, bimodal and atypical types. There is no micropore compartment present in samples with unimodal mercury injection capillary pressure and nuclear magnetic resonance distributions. Decoupled micropore compartments are observed in samples with bimodal mercury injection capillary pressure and nuclear magnetic resonance distributions, which show isolating calcite rims, and have limited permeabilities. The cement rims decrease the macropore connectivity and decouple the micropore compartments, which reside in micritic dendrites. The micropore compartment (r < 1 µm) is coupled with the mesopore (r = 1–15 µm) and macropore compartment (r > 15 µm) for atypical samples which lack pore‐lining calcite rims.

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“…NMR T 2 method provides a fast, easy, and non-destructive way of detecting hydrogenbearing fluids [33][34][35][36]. The NMR T 2 method is used to determine the petrophysical characteristics of conventional and unconventional porous media in oil and gas fields, such as porosity, pore geometry, pore connectivity, permeability, and even the fluid saturation in reservoirs [37][38][39][40][41][42][43][44]. Therefore, the NMR T 2 method is also widely used for monitoring the pore structure and the formation process of gas hydrate in sediments [45][46][47][48][49][50][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

Advances in Characterizing Gas Hydrate Formation in Sediments with NMR Transverse Relaxation Time

Liu

Zhan

et al. 2022

Water

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The formation process, structure, and distribution of gas hydrate in sediments have become focal points in exploring and exploiting natural gas hydrate. To better understand the dynamic behavior of gas hydrate formation in sediments, transverse relaxation time (T2) of nuclear magnetic resonance (NMR) is widely used to quantitatively characterize the formation process of gas hydrate and the change in pore characteristics of sediments. NMR T2 has been considered as a rapid and non-destructive method to distinguish the phase states of water, gas, and gas hydrate, estimate the saturations of water and gas hydrate, and analyze the kinetics of gas hydrate formation in sediments. NMR T2 is also widely employed to specify the pore structure in sediments in terms of pore size distribution, porosity, and permeability. For the recognition of the advantages and shortage of NMR T2 method, comparisons with other methods as X-ray CT, cryo-SEM, etc., are made regarding the application characteristics including resolution, phase recognition, and scanning time. As a future perspective, combining NMR T2 with other techniques can more effectively characterize the dynamic behavior of gas hydrate formation and pore structure in sediments.

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Pore typing using nuclear magnetic resonance, an example with samples from cretaceous pre-salt lacustrine carbonates in the Santos Basin, Brazil

Cited by 18 publications

References 15 publications

Prediction of lithology in lacustrine carbonates using well logs: The Cretaceous Barra Velha Formation in Santos Basin, offshore Brazil

Prediction of lithology in lacustrine carbonates using well logs: The Cretaceous Barra Velha Formation in Santos Basin, offshore Brazil

Unravelling the pore network and its behaviour: An integrated NMR, MICP, XCT and petrographical study of continental spring carbonates from the Ballık area, SW Turkey

Advances in Characterizing Gas Hydrate Formation in Sediments with NMR Transverse Relaxation Time

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