Seismic assessment of maturity and richness in carbonate source rocks

Sengupta, Madhumita; Jacobi, David; Eichmann, Shannon L.; Wallet, Brad; Altowairqi, Yazeed; Alsinan, Salma

doi:10.1190/image2022-3736741.1

Cited by 2 publications

(2 citation statements)

References 17 publications

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“…and porosity [23]. The discrimination of each property that affects the seismic response is a big challenge and is usually achieved with rock physics numerical models (e.g., [26]).…”

Section: Introductionmentioning

confidence: 99%

Source Rock Evaluation from Rock to Seismic Data: An Integrated Machine-Learning-Based Work Flow and Application in the Brazilian Presalt (Santos Basin)

Reis,

Damasceno,

Roriz

et al. 2023

Minerals

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The capacity to predict the occurrence and quality of source rocks in a sedimentary basin is of great economic importance in the evaluation of conventional and non-conventional petroleum resources. Direct laboratory examinations of rock samples are the most accurate way to obtain their geochemical properties. However, rock information is usually sparse, and source rocks are often sampled at positions that may not be representative of the average organic content and quality of oil kitchens. This work proposes a work flow supported by machine learning methods (random forest, DBSCAN, and NGBoost) to automate the source rock characterization process to maximize the use of available data, expand data information, and reduce data analysis time. From the automated quality control of the input data through the extrapolation of laboratory measurements to continuous well logs of geochemical properties, culminating in the 3D estimation of these properties, we generate volumes of total organic carbon (TOC) by applying machine learning techniques. The proposed method provides more accurate predictions, reducing uncertainties in the characterization of source rocks and assisting in exploratory decision making. This methodology was applied in the presalt source rocks from Santos Basin (Brazil) and allowed us to quantify the TOC distribution, improving the interpretation of the main source rock interval top and base based only on seismic amplitude data. The result suggests higher TOC values in the northern and western grabens of the studied area and a higher charge risk in the eastern area.

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“…and porosity [23]. The discrimination of each property that affects the seismic response is a big challenge and is usually achieved with rock physics numerical models (e.g., [26]).…”

Section: Introductionmentioning

confidence: 99%

Source Rock Evaluation from Rock to Seismic Data: An Integrated Machine-Learning-Based Work Flow and Application in the Brazilian Presalt (Santos Basin)

Reis,

Damasceno,

Roriz

et al. 2023

Minerals

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“…The presence of kerogen in solid composition was described by a modified Backus average (Vernik and Landis, 1996), inclusions (Wang et al, 2018), and solid substitution (Zhao et al, 2016). The maturation also modifies the kerogen properties, which can be calculated from first principles (Ibrahim et al, 2020), modeled empirically (Sengupta et al, 2022), or defined a priori (Zhao et al, 2016). There are studies that model the porosity as inclusions (Zhao et al, 2016) and fractures (Liu et al, 2020), with fluid effects considered after using Gassmann equations (Zhao et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

On the evolution of artificially maturated hydrocarbon source rocks

Lacerda¹,

Mörschbächer²,

Justen³

et al. 2023

Front. Earth Sci.

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The elastic moduli are a function of properties that could vary between samples and change during maturation. Consequently, the effects of organic matter maturation on the elastic wave velocities of organic-rich rocks are challenging to describe. This work analyzes the isolated maturation effects on the organic content, pore volume, microstructure, and propagation velocities of elastic waves. To avoid any initial rock heterogeneity, we prepared a series of homogeneous samples from a unique outcrop block collected on the Eagle Ford formation with mineral composition initially determined using X-ray diffraction. From the initial set, four samples were held in their original condition and four were artificially maturated by hydropyrolysis until transformation rates were up to 95%. Then, the evolution of the sample properties was examined using an association of LECO TOC, Rock-Eval pyrolysis, vitrinite reflectance, mercury intrusion porosimetry (MIP), and ultrasonic pulse propagation. In addition, scanning electron microscopy images registered the microstructure evolution. To evaluate the effects of maturation on pore geometry and the organic matter elastic moduli, we analyze the relationship between the measured quantities using a rock physics inclusion model with the unmeasured properties taken as fitting parameters. The hydropyrolysis maturation increases the vitrinite reflectance from the initial 0.55% to 1.34% on the most matured sample. A total organic carbon reduction from 4.2% to 2.1% and a porosity increase from 9.2% to 21% are associated with observed maturation. The geochemical characterization on cleaned samples reveals an initial increment of soluble organic matter followed by a monotonical reduction related to oil migration out of bulk volume. The measurement of wave propagation velocities as a function of confining pressure displays an increasing pressure sensitivity with a downward trend in both velocity moduli. The petrophysical analysis indicates that the porosity increases through organic matter consumption and pore creation. The rock physics diagnoses indicate a decrease in the pore aspect ratio with an increase in the elastic modulus of the organic matter with maturation.

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Seismic assessment of maturity and richness in carbonate source rocks

Cited by 2 publications

References 17 publications

Source Rock Evaluation from Rock to Seismic Data: An Integrated Machine-Learning-Based Work Flow and Application in the Brazilian Presalt (Santos Basin)

Source Rock Evaluation from Rock to Seismic Data: An Integrated Machine-Learning-Based Work Flow and Application in the Brazilian Presalt (Santos Basin)

On the evolution of artificially maturated hydrocarbon source rocks

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