Petroleum reservoir

About: Petroleum reservoir is a research topic. Over the lifetime, 5403 publications have been published within this topic receiving 83535 citations. The topic is also known as: petroleum deposit.

Carbon dioxide dissolution in structural and stratigraphic traps

Abstract: The geologic sequestration of carbon dioxide ( CO2) in structural and stratigraphic traps is a viable option to reduce anthropogenic emissions. While dissolution of the CO2 stored in these traps reduces the long-term leakage risk, the dissolution process remains poorly understood in systems that reflect the appropriate subsurface geometry. Here, we study dissolution in a porous layer that exhibits a feature relevant for CO2 storage in structural and stratigraphic traps: a finite CO2 source along the top boundary that extends only part way into the layer. This feature represents the finite extent of the interface between free-phase CO2 pooled in a trap and the underlying brine. Using theory and simulations, we describe the dissolution mechanisms in this system for a wide range of times and Rayleigh numbers, and classify the behaviour into seven regimes. For each regime, we quantify the dissolution flux numerically and model it analytically, with the goal of providing simple expressions to estimate the dissolution rate in real systems. We find that, at late times, the dissolution flux decreases relative to early times as the flow of unsaturated water to the CO2 source becomes constrained by a lateral exchange flow though the reservoir. Application of the models to several representative reservoirs indicates that dissolution is strongly affected by the reservoir properties; however, we find that reservoirs with high permeabilities ( Darcy) that are tens of metres thick and several kilometres wide could potentially dissolve hundreds of megatons of CO2 in tens of years.

Oil and gas data from Paleozoic rocks in the Appalachian Basin; maps for assessing hydrocarbon potential and thermal maturity (conodont color alteration isograds and overburden isopachs)

Abstract: Maps are presented which show indices of organic diagenesis, and form part of a data base which includes previously published stratigraphic and structural data for assessing hydrocarbon potential in the Appalachian and structural data for assessing hydrocarbon potential in the Appalachian basin (de Witt, 1975; de Witt and others, 1975; Harris, 1975; Miller, 1975). The potential for oil and gas production in any basin depends on the presence of source beds, favorable hydrocarbon channelways, and structural and stratigraphic traps. Crucial to these factors is the level of organic diagenesis or thermal maturity within the basin. Numererous studies have shown that depth and duration of burial and geothermal gradient (time and temperature) are the chief elements producing organic diagenesis.

Framework of Hydrocarbon Generation and Destruction in Eastern Smackover Trend

Abstract: Laminated lime mudstones of the lower member of the Jurassic Smackover Formation are significant source rocks for crude oil across Mississippi, Alabama, and Florida. The source facies was deposited in an anoxic and perhaps hypersaline environment that preserved algal-derived kerogen. The distribution of kerogen along laminations of depositional origin and along stylolites of diagenetic origin resulted in efficient expulsion of crude oil. With increasing thermal maturity, crude oil initially emplaced in reservoirs was cracked to yield gas condensate and then methane rich in nonhydrocarbon gases such as hydrogen sulfide, carbon dioxide, and nitrogen. Early destruction of methane was driven by thermochemical sulfate reduction. The thermal maturity framework of the Smackover rend explains the distribution of hydrocarbon discoveries and suggests areas previously overlooked by exploration.

Secondary Migration of Oil: Experiments Supporting Efficient Movement of Separate, Buoyant Oil Phase Along Limited Conduits: GEOLOGIC NOTE

Abstract: Experimental data suggest that the secondary migration of oil in porous, permeable sediments probably occurs, in most circumstances, along restricted pathways or conduits. These conduits are formed after the oil has reached a high enough saturation in the reservoir rock for the buoyancy of the oil to overcome the capillary pressure in the pore throats. The oil probably moves vertically until it reaches the top of the reservoir interval. The oil then moves updip along the top of the reservoir interval via a narrow, restricted pathway until it reaches the trap and begins to accumulate. Depending on the area of the original oil saturation at the bottom of the reservoir unit and the structural geometry, multiple conduits may form, along which the oil may flow. Because these conduits are limited in diameter, the amount of oil lost during secondary migration could be limited to the irreducible oil saturation left behind in the conduit, provided no small-scale traps exist along the path to the main trap. Rates of oil movement are very rapid in a geologic context, suggesting that the timing of primary migration is a good indicator of the timing of secondary migration.