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GEOS4 staff has (co)authored several new research papers relevant to the petroleum upstream sector.

Intraformational migration of petroleum: insights into the development of sweet spot in the Cretaceous Niobrara shale-oil system, Denver Basin

Using a combined analytical approach, petroleum has been shown to migrate from the organic-rich marls into juxtaposed chalks, and that this has fractionated oils into higher quality liquids. Extremely high OSI values are characteristic of Niobrara chalks, and therefore, the chalk intervals represent primary sweet spots.

Han, Y., Horsfield, B., LaReau, H., Mahlstedt, N. (2019), Marine and Petroleum Geology, https://doi.org/10.1016/j.marpetgeo.2019.05.026

 

On the release of acidic NSO compounds from the oil-mature Barnett Shale using different solvents

This study compares the selectivity with which DM (dichloromethane: methanol) and an azeotropic solvent mixture ACM (acetone: chloroform: methanol) release NSO-compounds from the oil-mature Barnett Shale of the Fort Worth Basin (USA). DM extracted less polar and smaller NSO compounds in comparison with ACM, in line with its relatively low polarity. Therefore, ACM is recommended for extracting oil-mature shale for future FT-ICR-MS analysis.

Han, Y., Poetz, S., Mahlstedt, N., Horsfield, B. (2020), Journal of Petroleum Geoscience and Engineering https://doi.org/10.1016/j.petrol.2019.106605

 

Geological alteration of organic macromolecules by irradiation: Implications for organic matter occurrence on Mars

Organic matter from Kolm nodules in the Upper Cambrian Alum Shale Formation of middle Sweden shows similar alteration pathways in response to ionizing radiation compared to mudstones from Mars: cross-linking, dealkylation and aromatization processes are responsible for the changing extractability and composition of pyrolysates. Results suggest that the newly discovered organic matter on Mars could be the irradiated residues of ancient lake biota.

Yang, S., Schulz, H.-M., Horsfield, B., Schovsbo, N. H., Grice, K., Zhang, J. (2020), Geology, accepted manuscript, https://doi.org/10.1130/G47171.1

 

Geochemical factors controlling the phase behavior of Eagle Ford Shale petroleum fluids

Applying GEOS4´s “PhaseSnapShot” approach results in a forward model showing that phase behavior and bulk compositional properties of hydrocarbons can be quickly and effectively predicted using mature shale samples as long as calibration data from PVT reports are available.

Kuske, S., Horsfield, B., Jweda, J., Michael, G. E., Song, Y. (2019), AAPG Bulletin, https://doi.org/10.1306/09051817227

 

Solid bitumen in shales: Petrographic characteristics and implications for reservoir characterization

Different solid bitumen types and transformation stages over a broad maturity interval and for varying primary kerogen compositions were characterized using combined optical and scanning electron microscopy applied to 35 Cambrian to Triassic solid bitumen-rich shales. Solid bitumen shows complex textural features at microscale. A pore evolution model was established for oil- and gas-prone organofacies. Mineral authigenesis is strongly influenced by solid bitumen transformation.

Misch, D., Gross, D., Hawranek, G., Horsfield, B., Klaver, J., Mendez-Martin, F., Urai, J. L., Vranjes-Wessely, S., Sachsenhofer, R. F., Schmatz, J., Li, J., Zou, C. (2019), International Journal of Coal Geology, https://doi.org/10.1016/j.coal.2019.02.012