Modelling source rock production potentials for short-chain organic acids and CO2 — a multivariate approach

Barth, Tanja; Andresen, Bjørg; Iden, K.; Johansen, H.

doi:10.1016/s0146-6380(96)00147-7

Cited by 20 publications

(8 citation statements)

References 12 publications

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“…Therefore, the LMWOA transport by advection from the far end to the root area may explain the commonly reported high LMWOA concentrations in formation waters in areas away from major shale intervals. Moreover, it is expected that the produced LMWOA would initially react with undersaturated minerals within the shales (Barth et al, 1996;Barth & Bjørlykke, 1993), which is supported by the observed dissolution pores within shales (Adeyilola et al, 2022;Baruch et al, 2015). This process may consume LMWOA and result in the near neutral to slightly alkaline pH commonly observed in shale waters (Figure S4a).…”

Section: Early and Late Carbonate Cementsmentioning

confidence: 72%

“…However, due to the thin thicknesses of the top and bottom shales observed in the samples (Figure 3a), the LMWOA yield in these shales is expected to be limited. Barth et al (1996) determined the yield of LMWOA in shale samples collected from the North Sea continental shelf using hydrous pyrolysis experiments. They utilized a multivariate approach to construct a quantitative equation for predicting the yield of LMWOA.…”

Section: Early and Late Carbonate Cementsmentioning

confidence: 99%

“…They utilized a multivariate approach to construct a quantitative equation for predicting the yield of LMWOA. The yield of acetic acid was found to correlate with shale maturity (represented by depth) and total organic carbon (TOC) according to the following equation (Barth et al, 1996).…”

Section: Early and Late Carbonate Cementsmentioning

confidence: 99%

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Modelling diagenetic reactions and secondary porosity generation in sandstones controlled by the advection of low‐molecular‐weight organic acids

Li,

Black,

Hao

et al. 2024

Basin Research

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Higher secondary porosity was observed in the centre of a sandstone unit in the Eocene Shahejie Formation fan delta front sandstones from the Bozhong Depression, Bohai Bay Basin. This differs from past studies showing secondary porosity mainly in the marginal parts of sandstones adjacent to shales. This study utilized reactive transport models involving low‐molecular‐weight organic acids (LMWOA) to discuss potential processes resulting in the contrary distribution of secondary porosity. An interface model simulating LMWOA diffusion from adjacent shales to the sandstone resulted in secondary porosity in sandstones adjacent to shales. In contrast, an advection model simulating advective transport of LMWOA parallel to the sandstone bedding successfully generated higher secondary porosity in the central part. The central part of the sandstone exhibited better grain sorting (greater depositional porosity) and significantly less early carbonate cements compared to the marginal sandstone parts. Consequently, the central part had greater porosity prior to the dissolution through LMWOA. The initially higher porosity in the central part allowed for a higher advective flux of LMWOA‐rich water and associated lower pH, resulting in decreased oligoclase saturation, higher oligoclase dissolution rates and ultimately higher secondary porosity. This study indicates that grain sorting during sediment deposition, early carbonate cementation, LMWOA production in adjacent shales, and advection processes collectively control the diagenetic reactions and the distribution of secondary porosity in sandstones.

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Section: Early and Late Carbonate Cementsmentioning

confidence: 72%

Section: Early and Late Carbonate Cementsmentioning

confidence: 99%

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Modelling diagenetic reactions and secondary porosity generation in sandstones controlled by the advection of low‐molecular‐weight organic acids

Li,

Black,

Hao

et al. 2024

Basin Research

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“…Hydrous and anhydrous pyrolysis experiments with pure kerogen or source rocks have been used to investigate the maturation of organic matter in source rocks with respect to the generation of organic acids and CO 2 (Barth et al 1988; Barth et al 1996;Barth and Bjørlykke 1993). acids and CO 2 during kerogen maturation (Table 2) (Barth et al 1988;Barth et al 1996; Barth and Bjørlykke 1993;Chen et al 1994;Kawamura et al 1986;Kawamura and Kaplan 1987;Meng et al 2008;Zeng et al 2007;Zhang et al 2009). The results of the experiments demonstrate that the maximum yield of acetic acids and total organic acids (TOA) is 0.685 × 10 −3 mol/g TOC and 1.34 × 10 −3 mol/g TOC, respectively.…”

Section: Pyrolysis Experiments Of Kerogenmentioning

confidence: 99%

“…(data from Kawamura et al 1986;Kawamura and Kaplan 1987;Barth et al 1988; Barth and Bjørlykke 1993;Chen et al 1994;Barth et al 1996;Zeng et al 2007;Meng et al 2008;Zhang et al 2009 Fisher 1987;Surdam and Crossey 1987;MacGowan and Surdam 1988;Surdam et al 1989;Wang et al 1995;Cai et al 1997;Xiao et al 2005;Meng et al 2006;Wang et al 2007;Meng et al 2011) volume that can be dissolved in the reservoirs is reduced significantly. In addition, most source rocks contain considerable carbonate minerals and silicate minerals (Ehrenberg et al 2012;Giles and Marshall 1986;Taylor et al 2010); these minerals first consume some of the organic acids generated in the mudstones, which also decreases the volume of acids expelled to the reservoirs and the leaching ability of the organic acids in the reservoirs (Barth et al 1996;Barth and Bjørlykke 1993).…”

Section: Acids In Pore Watermentioning

confidence: 99%

How important is carbonate dissolution in buried sandstones: evidences from petrography, porosity, experiments, and geochemical calculations

et al. 2019

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Burial dissolution of feldspar and carbonate minerals has been proposed to generate large volumes of secondary pores in subsurface reservoirs. Secondary porosity due to feldspar dissolution is ubiquitous in buried sandstones; however, extensive burial dissolution of carbonate minerals in subsurface sandstones is still debatable. In this paper, we first present four types of typical selective dissolution assemblages of feldspars and carbonate minerals developed in different sandstones. Under the constraints of porosity data, water-rock experiments, geochemical calculations of aggressive fluids, diagenetic mass transfer, and a review of publications on mineral dissolution in sandstone reservoirs, we argue that the hypothesis for the creation of significant volumes of secondary porosity by mesodiagenetic carbonate dissolution in subsurface sandstones is in conflict with the limited volume of aggressive fluids in rocks. In addition, no transfer mechanism supports removal of the dissolution products due to the small water volume in the subsurface reservoirs and the low mass concentration gradients in the pore water. Convincing petrographic evidence supports the view that the extensive dissolution of carbonate cements in sandstone rocks is usually associated with a high flux of deep hot fluids provided via fault systems or with meteoric freshwater during the eodiagenesis and telodiagenesis stages. The presumption of extensive mesogenetic dissolution of carbonate cements producing a significant net increase in secondary porosity should be used with careful consideration of the geological background in prediction of sandstone quality.

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Natural Product Molecular Fossils

Falk

Wolkenstein

2017

Progress in the Chemistry of Organic Natural Products

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The natural products synthesized by organisms that were living a long time ago gave rise to their molecular fossils. These can consist of either the original unchanged compounds or they may undergo peripheral transformations in which their skeletons remain intact. In cases when molecular fossils can be traced to their organismic source, they are termed "geological biomarkers".This contribution describes apolar and polar molecular fossils and, in particular biomarkers, along the lines usually followed in organic chemistry textbooks, and points to their bioprecursors when available. Thus, the apolar compounds are divided in linear and branched alkanes followed by alicyclic compounds and aromatic and heterocyclic molecules, and, in particular, the geoporphyrins. The polar molecular fossils contain as functional groups or constituent units ethers, alcohols, phenols, carbonyl groups, flavonoids, quinones, and acids, or are polymers like kerogen, amber, melanin, proteins, or nucleic acids. The final sections discuss the methodology used and the fundamental processes encountered by the biomolecules described, including diagenesis, catagenesis, and metagenesis.

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Modelling source rock production potentials for short-chain organic acids and CO2 — a multivariate approach

Cited by 20 publications

References 12 publications

Modelling diagenetic reactions and secondary porosity generation in sandstones controlled by the advection of low‐molecular‐weight organic acids

Modelling diagenetic reactions and secondary porosity generation in sandstones controlled by the advection of low‐molecular‐weight organic acids

How important is carbonate dissolution in buried sandstones: evidences from petrography, porosity, experiments, and geochemical calculations

Natural Product Molecular Fossils

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