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The Prudhoe Bay field, located on the North Slope of Alaska, is the largest oil and gas field in North America. The main Permo-Triassic reservoir is a thick deltaic high-quality sandstone deposit about 500 ft thick with porosities of 15 to 30% BV and permeabilities ranging from 50 to 3,000 md. The field contains 20 109 bbl of oil overlain by a 35 Tcf gas cap. The oil averages 27.6 API gravity and has an original solution gas-oil ratio (GOR) of about 735 scf/STB. Under much of the oil column area, there is a 20- to 60-ft-thick tar mat located above the oil-water contact (OWC).
A new extended-release (ER) scale-inhibitor technology showing significantly increased lifetimes has been applied in the Permian Basin. Tomson Technologies and Group 2 Technologies, in partnership with Occidental Petroleum (Oxy), implemented a scale-squeeze program for this carrier system. It allows for fewer squeeze treatments, which results in lower chemical usage, decreased plugging risk, and reduced environmental impact. Squeeze programs are an effective field treatment strategy to prevent scale formation in wells for extended periods of time. However, in some cases, squeeze lifetimes can be short, leading to frequent re-squeezing and production decreases, lowering overall economic recoveries.
Var Energi has confirmed a discovery at its King and Prince exploration wells in the Balder area in the Southern North Sea. Success at the combined King and Prince exploration wells lifts preliminary estimates of recoverable oil equivalents between 60 and 135 million bbl. King/Prince was drilled in PL 027 by semisubmersible rig Scarabeo 8. The Prince well encountered an oil column of about 35 m in the Triassic Skagerrak formation within good to moderate reservoir sandstones, while the King well discovered a gas column of about 30 m and a light oil column of about 55 m with some thick Paleogene sandstone. An additional King appraisal sidetrack further confirmed a 40-m gas column and an oil column of about 55 m of which about 35 m are formed by thick and massive oil-bearing sandstone with excellent reservoir quality.
The study outlined in the complete paper focuses on developing models of the Upper Cretaceous Waha carbonate and Bahi sandstone reservoirs and the Cambrian-Ordovician Gargaf sandstone reservoir in the Meghil field, Sirte Basin, Libya. The objective of this study is to develop a representative geostatistically based 3D model that preserves geological elements and eliminates uncertainty of reservoir properties and volumetric estimates. This study demonstrates the potential for significant additional hydrocarbon production from the Meghil field and the effect of heterogeneity on well placement and spacing. The reservoir of interest consists of three stratigraphic layers of different ages: the Waha and Bahi Formations and the Gargaf Group intersecting the Meghil field. The Waha reservoir is a porous limestone that forms a single reservoir with underlying Upper Cretaceous Bahi sandstone and Cambro-Ordovician Gargaf Group quartzitic sandstone.
Flow assurance in ultradeep water is a major issue for production. The Atlanta field, which produces heavy oil in ultradeep water, is a project combining several challenges: hydrates formation, emulsion tendency, scale formation, foaming, and high viscosities. The complete paper discusses innovations and technologies applied to make Atlanta a successful case of ultradeepwater heavy-oil production. Discovered in 2001, the Atlanta field is in the presalt exclusion area in the north of the Santos Basin, 185 km southeast of Rio de Janeiro, at a water depth of 1550 m. The postsalt reservoir is contained in the Eocene interval and is characterized by high net-to-gross sands (82–94%) with a high average porosity of 36% and high permeabilities in the range of 4–6 Darcies.
Cyclic-gas-injection-based enhanced oil recovery (CGEOR) in the Eagle Ford was begun in late 2012 by EOG Resources and, at the time of writing, has expanded to more than 30 leases by six operators (266 wells). An extensive EOR evaluation was initiated to analyze the results recorded in these leases. The authors write that CGEOR in Eagle Ford volatile oil can yield substantial increases in estimated ultimate recovery (EUR) with robust economics, depending on compressor use and field life. The Eagle Ford shale represents some of the world's richest source rocks. The Upper Cretaceous seafloor received abundant organic debris and preserved it in an anoxic environment.
When the CEO of Occidental Petroleum described the company's future this week, it was clear the company will not be moving away from hydrocarbons. By 2050, Occidental expects to still be a big oil company, but producing oil and natural gas is not likely to be its biggest source of revenue. Several decades from now, Vicki Hollub, the president and chief executive officer of Occidental, predicted that income from carbon capture and storage "will be bigger than oil production revenue." During the plenary session for the Unconventional Resources Technology Conference (URTeC) she described how Occidental is scaling up its carbon-capture business, beginning with a facility in the Permian Basin with the capacity to capture 1 million tons of CO2 per year. First announced by Occidental in early 2019, design is in progress with construction expected in 2023. The planned capacity is 250 times greater than any such plant in existence and will be an early test of the economics of large-scale carbon capture.
This page provides a reservoir management case study for a sandstone field under strong waterdrive in which crestal gas injection techniques have been implemented. Production from this field is from several Upper Cretaceous sandstone formations. The producing zones are in pressure communication in the gas cap and aquifer but separate in the oil column. The structure is a complexly faulted anticline with a major fault separating the west and east flanks. There is minor communication across the fault.
This page provides a reservoir management case study for a low-permeability sandstone field in which waterflooding techniques have been implemented. The reservoir is a series of Cretaceous-age, prograding delta clastic sediments consisting of laminated fine-grained sands and shales that are trapped stratigraphically by overlying shales. The primary recovery mechanism was solution-gas drive. The field was converted to waterflood in 1961 with an inverted nine-spot injection pattern. Subsequently, a portion of the field was converted to line-drive water injection for improved sweep efficiency and increased water injection capacity.
This page provides several reservoir management case studies that illustrate carbonate reservoirs in which waterflooding and miscible gas injection techniques have been implemented. This field produces primarily from a Jurassic-age limestone-dolomite section that has a simple plunging anticline structure. The updip trap is formed by a combination of facies change from dolomite to dense limestone and a bounding fault. The formation is layered and has been divided into 18 correlative zones. The field was developed competitively by several operators.