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*Winter Talk by Mike Lovell.. *We need to talk about shale gas…*
Wednesday October 14, 2015 | 7:30 pm to 9:00 pm
We need to talk about shale gas…
Attention has turned away from conventional gas reservoirs, characterised by static density stratification and a hydrocarbon-water contact, to formations that act as both source and reservoir (shale gas and coal bed methane) or where gas is a solid component (gas hydrates). These unconventional resources may contain free or dissolved gas, augmented by adsorbed gas (shale and coal bed methane) or caged gas (gas hydrates).
“Shale gas” refers to fine grained formations, or mudstones, consisting primarily of clay and silt sized particles, where free gas occupies the pores and adsorbed gas is fixed on organic surfaces. The permeability is so low that the methane cannot easily migrate through the rock; complex hydraulic fracturing is generally required to produce significant quantities. The relative proportions of the two separate components of gas in the reservoir – free and adsorbed – vary considerably from one play to another. The free gas component is similar in concept to a conventional reservoir. The adsorbed gas component is trapped under pressure, adsorbed onto surfaces from which it yields only on depressurisation.
The objectives when characterizing a shale gas resource are quite different from those in conventional formation evaluation; and the main interest is in organic content, its maturity, and the amount of gas that can be moved as the pressure varies. Thus we are concerned far more with the dynamics of the system and the reservoir’s potential behaviour.
Detailed petrophysical models are required that honour the underlying geology, and respect the physical properties not only of the solid-fluid system, but also of the dynamics of the system as it changes during production. Increased understanding of these complex systems has enabled considerable progress, but significant challenges remain.
This talk takes a detailed look at why shale gas resources are scientifically so intriguing and fascinating. Questions we can ask include: How and where is the gas located? Are the estimates of volumes of gas realistic? Why is it necessary to hydraulically fracture the rock? And what exactly do we mean by the phrase “shale gas”?
Mike is Professor of Petrophysics in the Department of Geology at the University of Leicester. His interest in petrophysics – the study of rock properties and their interactions with fluids – started through studies of ocean floor sediments in connection with radioactive waste management, before leading in 1984 to involvement in ocean drilling. Mike’s research increasingly focusses on the petrophysics of conventional and unconventional reservoirs taking a geological-based approach to the characterization of rocks
Costs for entry are as follows :
Entry is free for Members of the SDGS.
Students in full time education and for non-members for single meetings are £3.
You can also apply for Membership on the night.