An investigation of the in-reservoir conversion of oil to gas: compositional and kinetic findings from closed-system programmed-temperature pyrolysis

Transition metal catalysis in the generation of petroleum and natural gas. Final report, September 1, 1992--October 31, 1995

“…of Interior database (Hamak and Sigler, 1991). The horizontal lines indicate the compositional regions for gas products from the indicated processes: Oil & SR Pyrolysis: taken from reported products of oil and kerogen pyrolysis experiments (Horsfield et al, 1991;Espitalie et al, 1987;Saxby and Riley, 1984;Evans and Felbeck, 1983;McNab et ai., 1952). SR Catalysis: from experiments using a Monterey source rock (Miocene) described in Mango et al,(1 994).…”

“…Disturbing contradictions exist, however: oil is found at great depth, at temperatures where only gas should exist (Price, 1993) and oil and gas deposits show no evidence of the thermolytic debris indicative of oil decomposing to gas (Mango, 1987). Moreover, oil and kerogen pyrolysis typically produces between 10 and 60% wt methane (in C&) (Horsfield et al, 1991;Hikita et al, 1989;Espitalie et al, 1987;Saxby and Riley, 1984;Evens and Felbeck, 1983;McNab et al, 1952) while natural gas contains between 60 and 95+ 'YO methane (Hamak and Sigler, 1991). n-Alkanes give 6 and 13 % methane at 600 and 7OO0C, respectively (Fabuss et al, 1962;Appleby et al, 1947).…”

“…n-Alkanes give 6 and 13 % methane at 600 and 7OO0C, respectively (Fabuss et al, 1962;Appleby et al, 1947). Continued cracking of C2 -Cq hydrocarbons produces drier gas (Horsfield et al, 1991), but the relevance of these results to geologic conditions is unclear given the extraordinary stability of these light hydrocarbons. Propane, for example, has a half-life of -8 x lo8 years at 200°C (Laidler et al, 1962).…”

HPHT reservoir evolution: a case study from Jade and Judy fields, Central Graben, UK North Sea

“…While bulk kinetics and compositional predictions from primary cracking have proven their applicability (Schenk, et al, 1997, Schenk andHorsfield, 1993), demonstrating the correctness of secondary cracking predictions has been problematic (Vandenbroucke, et al, 1999). For example the stability of liquid petroleum in reservoirs seems to be relatively high (Horsfield, et al, 1992, Schenk, et al, 1997, indicating that it can withstand temperatures close to 200°C under geologic heating rates, whereas in source rocks residual oil is converted to gas at lower levels of thermal stress (Dieckmann, et al, 1998). As stated above, compositional predictions from kinetic models in combination with basin models have as yet large difficulties in correctly predicting the fluid composition and phase in deep, hot reservoirs (Vandenbroucke, et al, 1999), although newer models calibrated to observed fluid properties indicate that good predictions regarding the gas to oil ratio (GOR) and even phase properties are possible for the realm of primary cracking (di Horsfield, 2006, di Primio and.…”

Transition metal catalysis in the generation of petroleum and natural gas. Final report

“…Disturbing contradictions exist, however: oil is found at great depth, at temperatures where only gas should exist (Price, 1993) and oil and gas deposits show no evidence of the thermolytic debris indicative of oil decomposing to gas (Mango, 1987). Moreover, oil and kerogen pyrolysis typically produces between 10 and 60% wt methane (in C&) (Horsfield et al, 1991;Hikita et al, 1989;Espitalie et al, 1987;Saxby and Riley, 1984;Evens and Felbeck, 1983;McNab et al, 1952) while natural gas contains between 60 and 95+ % methane (Hamak and Sigler, 1991). n-Alkanes give 6 and 13 % methane at 600 and 7OO0C, respectively (Fabuss et al, 1962;Appleby et al, 1947).…”