Experimental evidence for formation water promoting crude oil cracking to gas

Abstract

Crude oil cracking to gas is the key to determining the exploration potential and strategy for deep hydrocarbon resources. Identifying the factors that affect the threshold and potential of crude oil cracking to gas as well as other possible influencing factors will provide the scientific basis for deep hydrocarbon exploration. A comparison of pyrolysis simulation experiments of crude oil, hydrous crude oil, and various water media under a constant temperature (350°C) and pressure (50 MPa) shows that water plays a large role in crude oil cracking to gas. (1) When water is added, the gas yields increase significantly, including those of alkane gases and non-hydrocarbon gases: the yield of alkane gases increases 1.8-3 times; the yields of H 2 and CO 2 also increase significantly. This means that water takes part in the process of crude oil cracking to gas, and supplies hydrogen. Therefore, the presence of water will dramatically enhance the potential of crude oil cracking to gas. (2) Mg 2+ ions in the formation water promote the crude oil + water reaction to some extent and increase the total yield of alkane gases and the yields of both H 2 and CO 2 ; more interestingly, the i-C 4 /n-C 4 and i-C 5 /n-C 5 ratios increase significantly. This indicates that Mg 2+ ions in formation water act as a catalyst, and a disproportionation reaction is involved in the crude oil + water reaction. This study helps us to understand the factors influencing crude oil cracked gas and to evaluate the hydrocarbon resources in deep sedimentary basins.

Coupled mineral alteration and oil degradation in thermal oil-water-feldspar systems and implications for organic-inorganic interactions in hydrocarbon reservoirs

“…9) in the hydrous system suggest that water promoted the oil (eicosane) degradation reactions in the present study. This result is in agreement with some previous studies (Shuai et al, 2012;Wang et al, 2015), although some other researchers claimed that water retards oil degradation (Hesp and Rigby, 1973;Lewan, 1997;Price, 1993;Uguna et al, 2016) or has little impact on oil degradation (Xie et al, 2016). The oil-NaCl water systems generate even more gases, liquid hydrocarbons, and organic acids than the oil-D water systems (Fig.…”

Thermal simulation experiment and research on the system of coal/coal and water/coal and water and MgSO4/coal and water and CaSO4

“…(1) Water plays a huge role in the cracking of coal into gas [14]. With the participation of water, the production of H 2 S and CO 2 increased significantly, indicating that water participates in the coal pyrolysis and gasification process.…”

The Effects of High Pressure on Oil‐to‐gas Cracking During Laboratory Simulation Experiments

“…Increased gas yields from oil-to-gas cracking reactions occur in aqueous conditions at high temperatures (Hoering, 1984;Price and Wenger, 1992;Andersen et al, 1994;Stalker et al, 1994;Lewan, 1997;Shuai et al, 2012). The cracking of hydrocarbon macromolecules increases in aqueous conditions because at high pressures water provides hydrogen which in turn promotes cracking (Lewan, 1997;Lewan and Roy, 2010).…”

“…Furthermore, isotope tracer experiments indicate that the H 2 and oxygen in liquid water can react with saturated alkanes and alkyl phenols to form CO 2 (Hoering, 1984;Price and Wenger, 1992;Andersen et al, 1994;Stalker et al, 1994;Lewan, 1997;Shuai et al, 2012).…”

“…Oil cracking to gas is accelerated in the presence of water (Lewan, 2010). Experiments simulating the pyrolysis of crude oil under constant temperatures (350 °C) and pressures (50 MPa) show that the addition of water results in an increaed gas yield, including yields of gaseous alkanes and nonhydrocarbons such as H 2 and CO 2 (Shuai et al, 2012).…”