A laboratory pyrolysis study to investigate the effect of water pressure on hydrocarbon generation and maturation of coals in geological basins

► Gas yields from two coals are significantly retarded by increasing water pressure. ► Bitumen yield and VR for coals were reduced at 500 and 900 bar compared to 175 bar. ► Residual Rock-Eval S2 and HI for coals decreased at 175 bar compared to 500 and 900 bar. ► If pressure was insignificant results should be similar at 175, 500 and 900 bar.