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.

Sarir Oil Field, Libya--Desert Surprise

Abstract: The Bunker Hunt-British Petroleum Sarir oil field of Libya appears to be one of the 10 to 12 super-giants of the world. Credited with 11-13 billion bbl of oil in place, it is a water-drive field that could, and probably will, recover nearly 50 percent of its total oil. The maximum oil column is 300 ft and the area of surface closure is 155 mi2. The field was discovered in November 1961 on a seismically defined structure. Development drilling was continuous through the next 4 years; a pipeline and loading terminal were completed and production was begun in late 1966. The oil reservoir is Cretaceous sandstone on basement, the probable oil source being the several hundred feet of overlying Cretaceous marine shale. Structurally, the field is a combination anticline and high fault-block complex within a broad structural low. There appears to be good fluid communication throughout the reservoir. Average porosity values are 18-19 percent, and permeability values average several hundred millidarcys, with a few 2-3-darcy streaks. All production is water free. The oil is sweet and sulfur free, though of high paraffin content. More than 100 wells have been drilled, of which about 60 are on production and 12-14 are awaiting gathering lines; most of the others are observation wells for pressure or fluid control. There was a decline of reservoir pressure during the first year of production; however, in most of the field a sustained water drive is developing. Producing capacities of individual wells range from a few thousand barrels daily to maximum estimated open flow of 28,000-30,000 bbl/day. The field went on production at 100,000 bbl/day, which rose to 300,000 bbl within the first year. Additional field facilities, when installed, will permit even greater increases.

Hydrocarbon Potential of Aleutian Basin, Bering Sea

Abstract: The Aleutian basin is the deep-water (more than 3,000 m) basin that lies north of the Aleutian Islands adjacent to the Bering Sea continental shelf. The basin, about the size of Texas, is underlain by a flat-lying sequence of mostly Cenozoic sediment 2 to 9 km thick that rests on an igneous oceanic crustal section. Prior to 1974, marine investigations in the Aleutian basin were directed at understanding the basin's regional geologic and geophysical framework; more recent investigations by the U.S. Geological Survey have been aimed at assessing the basin's hydrocarbon potential. Preliminary results suggest that the four major requirements for hydrocarbon accumulations may be present--structural and stratigraphic traps, source rocks, reservoir beds, and an adequate thermal nd sedimentation history. The recent energy-resource studies indicate that: (1) numerous structural features (gentle folds, diapirs, basement ridges) are present in the central and eastern parts of the basin; (2) acoustic features called VAMPs (velocity amplitude features) are common (over 350 identified) in the central basin; these features may be caused by pockets of gases and possibly other hydrocarbons that have been trapped in the sedimentary section; (3) the sedimentary section consists of diatomaceous sediment overlying indurated mudstones; high porosities (58 to 85%) and good permeabilities (10 to 35 md) in the diatomaceous sediment suggest that it is a potential reservoir unit and the thick section of underlying mudstone may contain the source beds; (4) concentrations of organic gases, primarily metha e, in the upper 1 to 3 m beneath the seafloor are very small, increase with depth, and are highest in areas near VAMPs; (5) the thermal gradient and the sediment thickness are sufficiently large to allow hydrocarbon maturation at depth, if suitable organic material is present. Our initial results suggest that the Aleutian basin deserves further exploration as a site for possible hydrocarbon accumulations.

Volumes, Types, and Distribution of Clay Minerals in Reservoir Rocks Based on Well Logs

Abstract: Discussed in this paper, is an innovative digital shaly sand evaluation approach which provides information on total and effective reservoir porosity, total and effective fluid distribution based on the Waxman-Smits equation, reservoir productivity, silt volume, and volumes, types and distribution modes of clay minerals present in subsurface ford. 52 refs.

Effective flow properties of heterolithic, cross-bedded tidal sandstones: Part 1. Surface-based modeling

Abstract: Tidal heterolithic sandstones are commonly characterized by millimeter- to centimeter-scale intercalations of mudstone and sandstone. Consequently, their effective flow properties are poorly predicted by (1) data that do not sample a representative volume or (2) models that fail to capture the complex three-dimensional architecture of sandstone and mudstone layers. We present a modeling approach in which surfaces are used to represent all geologic heterogeneities that control the spatial distribution of reservoir rock properties (surface-based modeling). The workflow uses template surfaces to represent heterogeneities classified by geometry instead of length scale. The topology of the template surfaces is described mathematically by a small number of geometric input parameters, and models are constructed stochastically. The methodology has been applied to generate generic, three-dimensional minimodels (9 m3 [∼318 ft3] volume) of cross-bedded heterolithic sandstones representing trough and tabular cross bedding with differing proportions of sandstone and mudstone, using conditioning data from two outcrop analogs from a tide-dominated deltaic deposit. The minimodels capture the cross-stratified architectures observed in outcrop and are suitable for flow simulation, allowing computation of effective permeability values for use in larger-scale models. We show that mudstone drapes in cross-bedded heterolithic sandstones significantly reduce effective permeability and also impart permeability anisotropy in the horizontal as well as vertical flow directions. The workflow can be used with subsurface data, supplemented by outcrop analog observations, to generate effective permeability values to be derived for use in larger-scale reservoir models. The methodology could be applied to the characterization and modeling of heterogeneities in other types of sandstone reservoirs.

A Process for Primary Migration of Petroleum

Abstract: Experimental data support a model migration process in which carbon dioxide and hydrocarbon gases are produced in source rocks and are dissolved in pore water concurrently with oil generation. The dissolved gases mobilize the liquid hydrocarbons so that they can leave the source rock with any water expelled during compaction. In noncompacting situations the liquid hydrocarbons can diffuse over reasonable distances from their source rocks into adjacent permeable beds. They later phase-separate by removal of carbon dioxide from the water in or near a reservoir or en route to a reservoir. Removal of carbon dioxide is accomplished by reaction with "carbon dioxide-starved" or unconditioned sedimentary rocks as the oil-bearing water moves up faults and permeable strata, or by e solution due to low pressure at shallow depths.