Metagenetic methane generation in gas shales I. Screening protocols using immature samples

Impact of Inorganically Bound Sulfur on Late Shale Gas Generation

“…Various sources for late generation, such as kerogen cracking, secondary oil cracking (not in this study), wet gas cracking, decomposition of alkylaromatics at very high temperatures, etc., may provide some theoretical supports for the large yields of methane. 3,4,30,31,33 Our results in the control series imply the existence of a large late gas potential of methane as a resource from mature shales under high thermal pressures.…”

“…Roughly similar δ 13 C values for methane were obtained in the control, pyrite, and CaSO 4 series, whereas from 480°C onward δ 13 C values for the pyrite and CaSO 4 series are slightly but systematically less negative. A remarkable enrichment of 13 C occurs for CaSO 4 above 504°C. On the other hand, the δ 13 C values of methane in the MgSO 4 series are much higher than those in the control series below 480°C.…”

“…Related experiments demonstrate that late gas generation might come from the cracking of a stable moiety previously formed via recombination reactions between liquid hydrocarbons and kerogen. 3 The late gas precursor structures are thought to be associated with terrestrially influenced, aromatic marine organic matter types, 4 which may be phenolic or very heterogeneous.…”

Impact of high water pressure on oil generation and maturation in Kimmeridge Clay and Monterey source rocks: Implications for petroleum retention and gas generation in shale gas systems

“…The generated gas is stored as free gas in 120 either intergranular porosity and fractures in shales, nanoporosity in kerogens that developedM A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 6 during maturation, adsorbed onto the kerogen and clay particle surfaces, or absorbed in either 122 kerogen or bitumen (Bernard et Scotchman, 2015). 124 125 Unconventional shale gas resource systems are generally slightly to highly over-126 pressured (Jarvie, 2012), and the few published studies so far have used either open system 127 pyrolysis (Rock Eval and pyrolysis gas chromatography), or low pressure MSSV closed 128 system pyrolysis, to investigate gas generation and retention in shale gas resource systems 129 (Hartwig et al 2010;Mahlstedt and Horsfield, 2012;Slowakiewicz et al 2015). The 130 retention of gas in shales depends partly on the adsorption of the generated gas by the kerogen 131 and inorganic minerals (Williams, 2013).…”

Geofluids in Deep Sedimentary Basins and Their Significance for Petroleum Accumulation

“…With petroleum exploration entering into deep strata, the traditional hydrocarbon generation models seem to confront numerous challenges in explaining the deep hydrocarbon discoveries [1,2]. Hydrocarbon generation simulation and kinetics research suggested that gases from kerogen cracking could be extended to a relatively higher maturity stage [3,4]. It is indicated that although the abundance of long, fatly chains in high-to-over-mature kerogen decreases drastically, there is still certain amount of short branched aliphatic structures present, and the lower limit for gas from kerogen cracking can be extended to a maturity stage with Ro reaching 3.5% [5].…”