Oil retention and porosity evolution in organic-rich shales

Han, Yuanjia; Horsfield, Brian; Wirth, Richard; Mahlstedt, Nicolaj; Bernard, Sylvain

doi:10.1306/09221616069

Cited by 124 publications

(87 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unsurprisingly, samples that initially contained higher TOC and more oil-prone orange AOM produced a slightly higher quantity of oil and thus exhibit a lower number of meso and macropores in the 10-100 nm pore size range and thus, lower remaining pore volumes after the early conversion of OM (Figs.7, 12E-F, 13C, D). This phenomenon was commonly observed in mudstones at thermal maturity up to Ro=0.90% (DiStefano et al, 2016;Furmann et al, 2016;Han et al, 2017;Katz and Arango, 2018;Ko et al, 2018;Löhr et al, 2015). These results…”

Section: Porosity Evolution Related To Oil and Gas Generation And Expsupporting

confidence: 77%

“…Löhr et al (2015) showed that primary organic porosity may influence the development of secondary organic pores during thermal maturation, leading to inhomogeneity in the OM-hosted pore distribution at more elevated maturities. The presence of primary pores in originally deposited amorphous and structured OM of algal and terrestrial origin was, indeed, previously noted in various thermally immature mudstones (Han et al, 2017;Löhr et al, 2015;Mastalerz et al, 2013;Reed, 2017) including the KCF (Fishman et al, 2012;Katz and Arango, 2018). These pores, which are markedly variable even in OM of the same class, appear to be mainly derived from the original biological cell structure of particular sedimentary organic compounds or inherited from primary depositional features (Fishman et al, 2012;Löhr et al, 2015;Reed, 2017).…”

Section: Preservation Of the Primary Pore Network In Thermally Immatusupporting

confidence: 56%

“…at this low level of maturity, Tab.3). The available literature suggests that these processes may reach a significant level at slightly higher thermal maturity levels (~0.80-0.85% Ro), where OM-hosted pores are known to develop further (Bernard et al, 2012a;Han et al, 2017;Loucks et al, 2009). Many irregular-shaped OM pores are, however, not associated with clay minerals (Fig.11C).…”

Section: Porosity Evolution Related To Oil and Gas Generation And Expmentioning

confidence: 99%

See 2 more Smart Citations

Effect of organic matter composition on source rock porosity during confined anhydrous thermal maturation: Example of Kimmeridge-clay mudstones

Cavelan

Boussafir

Milbeau

et al. 2019

International Journal of Coal Geology

View full text Add to dashboard Cite

To investigate how slight differences in the total particulate organic matter (OM) assemblage and maceral types of marine mudstones influence the development and the evolution of OM porosity throughout the same formation, laboratory gold-tube anhydrous confined thermal maturation was applied on low-mature organic-rich marine Kimmeridge clay mudstones (Yorkshire, UK). Organic petrography (palynofacies and maceral analysis), SEM observations, global and molecular geochemical characterization and low-pressure nitrogen adsorption measurements were performed to examine, to our knowledge for the first time, the role of the OM composition and properties on the evolution of porosity during thermal maturation. Evidence from organic petrography and geochemical analyses showed that organic-rich Kimmeridge clay samples containing a higher relative proportion of brown amorphous organic matter (AOM), known to be derived essentially from the cell walls of microalgae, exhibit a different pore evolution compared to samples containing a higher proportion of oil-prone orange AOM derived primarily from preservation by natural sulfurization of phytoplanktonic organic components naturally rich in lipidic compounds. OM conversion of orange AOM-rich samples has led to the production of higher amounts of low viscous oil and abundant gaseous hydrocarbon that are more 2 favorable to the formation of abundant but small OM micropores and mesopores in the condensate/wet gas zone and less abundant large modified mineral pores in the dry gas zone. The secondary cracking of the heavier oil produced by brown-AOM-rich OM has led to the formation of a greater quantity of CO2 and an abundant organic-rich residue more favorable to the formation of larger mesopores. Moreover, the more abundant thick laminar bituminite macerals forming a continuous ductile network particularly prone to compaction and the higher amounts of oil/bitumen generated during their conversion may have led to a higher pore collapse after oil/gas generation and migration, responsible for the destruction of part of the secondary pore network observed on some samples. Despite their slightly lower oil-prone potential, brown AOM-rich samples have thus developed larger mesopores during thermal maturation, resulting in higher pore volumes in the dry gas zone. Thus, the ability of marine mudstones to develop pores during maturation do not increase proportionally with the OM oil prone quality. These results show that variations in the individual particulate OM assemblage of a similar type II kerogen can significantly influence the amount of oil and gas generated during thermal maturation throughout the same formation, resulting in different pore evolution models. This reveals the importance of clearly identifying the composition of the original particulate OM assemblage to better predict the amount of bitumen, oil and gas generated during thermal maturation and the associated pore development.

show abstract

Section: Porosity Evolution Related To Oil and Gas Generation And Expsupporting

confidence: 77%

Section: Preservation Of the Primary Pore Network In Thermally Immatusupporting

confidence: 56%

Section: Porosity Evolution Related To Oil and Gas Generation And Expmentioning

confidence: 99%

See 1 more Smart Citation

Effect of organic matter composition on source rock porosity during confined anhydrous thermal maturation: Example of Kimmeridge-clay mudstones

Cavelan

Boussafir

Milbeau

et al. 2019

International Journal of Coal Geology

View full text Add to dashboard Cite

show abstract

“…Numerous studies have actually revealed that organic pores can develop over a wide range of maturities (Loucks et al, 2009;Curtis et al, 2011Curtis et al, , 2012Bernard et al, 2012a, b;Brian et al, 2013;Jennings and Antia, 2013;Milliken et al, 2013;Loucks and Reed, 2014;Pommer and Milliken, 2015;Reed and Loucks, 2015;Ko et al, 2016Ko et al, , 2017Mathia et al, 2016;Han et al, 2017), but it is still unclear how exactly organic pores are developed in the Niobrara shale oil play and whether they play a role in the along a north-to-south profile ( Figure 1A) prepared using focused ion beam (FIB) following the 203 procedure described in previous reports (Wirth, 204 2004(Wirth, 204 , 2009. Rock chips were first mechanically 205 polished and coated with a conducting material (e.g.,…”

Section: A T a S H A R E X Xmentioning

confidence: 99%

“…For instance, and for a given OM richness (TOC), the most aliphatic source rock samples from the B-chalk interval retain much less oil (S 1 ) through sorption than samples from the other intervals. With increasing maturity, the oil retention capacity (expressed in OSI = S 1 /TOC • 100) of Niobrara source rock samples first increases until a T max of approximately 445°C (~833°F) and then decreases.Organic Pores in Source RocksIt is widely accepted that organic pores owe their origin to the thermal cracking of kerogen and bitumen in the sense of extractable OM(Loucks et al, 2009;Bernard et al, 2012b Bernard et al, , 2013Curtis et al, 2012; Mastalerz et al, 2013;Romero-Sarmiento et al, 2013; Pommer and Milliken, 2015;Ko et al, 2016;Han et al, 2017). Clearly, the maturity level does not vary significantly in the least mature well 1 (T max 437°C-444°C [819-831°C]) (Figure 6A).However, nano-size pores are well developed within OM from the B chalk of this well but not common in other intervals(Figure 12).…”

mentioning

confidence: 99%