The link between petroleum emplacement and sandstone cementation

Abstract

When a reservoir fills with petroleum, the process commonly takes about 10 Ma. Cementation of a sandstone reservoir can occur in a similarly short time. There is much direct evidence that these two processes can occur at about the same time. In petroleum-bearing sandstone reservoirs it is common to find inclusions of petroleum trapped in diagenetic minerals. The effect on reservoir porosity and permeability caused by the interaction of these two processes is dramatic. Fields with a relatively early petroleum charge, earlier that is than cementation, can be saved from the ravages of reservoir quality destruction. Fields in which the two processes were acting at the same time commonly display porositydepth gradients which are twice the regional average. If cementation beats petroleum in this 'race for space' there may be no field to produce, as the petroleum may not be recoverable from the low quality reservoir.We believe that the processes of petroleum generation/migration and cementation may share a common cause. Both processes are commonly associated with major changes within a basin: rapid burial/heating of the sediment pile and/or major faulting which changes the basin 'plumbing'.

Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities

“…Some have concluded that petroleum emplacement has no influence on sandstone diagenesis (Taylor et al 2010). Some have concluded that petroleum emplacement stops sandstone diagenesis (Gluyas et al 1993), while others have concluded that sandstone diagenesis can be inhibited (slowed down) by petroleum emplacement (Worden et al 1998;Marchand et al 2001;Worden et al 2018).…”

Pore water evolution in oilfield sandstones: constraints from oxygen isotope microanalyses of quartz cement

“…The precipitation of quartz overgrowths in many sedimentary basins commonly occurs during deep burial diagenesis (>2.5 km) at elevated temperatures, typically 70 -130 jC (e.g. Giles et al, 1992;Gluyas et al, 1993;Walderhaug, 1994;Bjørkum et al, 1998). Small amounts of quartz cement may, however, develop slowly at lower temperatures ( < 70 jC) given enough time (Bjørkum et al, 1998).…”

Dynamics of cementation in response to oil charge: Evidence from a Cretaceous carbonate field, U.A.E.

“…Cementation and oil migration are thought to occur synchronously (Gluyas et al, 1993), but the oil-filling of reservoirs is a gradual process where pores in the crest are filled first (Marchand et al, 2001). Cement growth will therefore cease or slow initially in the crest and continue down the structure until the final oil/water contact is reached.…”