Bulletin Article
Diagenesis significantly impacts mudstone lithofacies. Processes operating to control diagenetic pathways in mudstones are poorly known compared to analogous processes occurring in other sedimentary rocks. Selected organic-carbon-rich mudstones, from the Kimmeridge Clay and Monterey Formations, have been investigated to determine how varying starting compositions influence diagenesis.
American Association of Petroleum Geologists (AAPG)
Added on 28 February, 2014
Bulletin Article
Umiat field in northern Alaska is a shallow, light-oil accumulation with an estimated original oil in place of more than 1.5 billion bbl and 99 bcf associated gas. The field, discovered in 1946, was never considered viable because it is shallow, in permafrost, and far from any infrastructure. Modern drilling and production techniques now make Umiat a more attractive target if the behavior of a rock, ice, and light oil system at low pressure can be understood and simulated.
The Umiat reservoir consists of shoreface and deltaic sandstones of the Cretaceous Nanushuk Formation deformed by a thrust-related anticline. Depositional environment imparts a strong vertical and horizontal permeability anisotropy to the reservoir that may be further complicated by diagenesis and open natural fractures.
Experimental and theoretical studies indicate that there is a significant reduction in the relative permeability of oil in the presence of ice, with a maximum reduction when connate water is fresh and less reduction when water is saline. A representative Umiat oil sample was reconstituted by comparing the composition of a severely weathered Umiat fluid to a theoretical Umiat fluid composition derived using the Pedersen method. This sample was then used to determine fluid properties at reservoir conditions such as bubble point pressure, viscosity, and density.
These geologic and engineering data were integrated into a simulation model that indicate recoveries of 12%–15% can be achieved over a 50-yr production period using cold gas injection from five well pads with a wagon-wheel configuration of multilateral wells.
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American Association of Petroleum Geologists (AAPG)
Added on 28 February, 2014
Bulletin Geologic Note
Offshore sequences of volcaniclastic rocks (such as hyaloclastite deposits) are poorly understood in terms of their rock properties and their response to compaction and burial. As petroleum exploration targets offshore volcanic rifted margins worldwide, understanding of volcanic rock properties becomes important both in terms of drilling and how the rocks may behave as seals, reservoirs, or permeability pathways. The Hawaiian Scientific Drilling Project phase II in 2001 obtained a 3 km-(2-mi)-long core of volcanic and volcaniclastic rocks that records the emergence of the largest of the Hawaiian islands. Core recovery of 2945 m (9662 ft) resulted in an unparalleled data set of volcanic and volcaniclastic rocks. Detailed logging, optical petrology, and major element analysis of two sections at depths 1831–1870 and 2530–2597 m (6007–6135 and 8300–8520 ft) are compared to recovered petrophysical logs (gamma ray, resistivity, and P-wave velocity). This study concludes deviation in petrophysical properties does not seem to correlate to changes in grain size or clast sorting, but instead correlates with alteration type (zeolite component) and bulk mineralogy (total olivine phenocryst percentage component). These data sets are important in helping to calibrate well-log responses through hyaloclastite intervals in areas of active petroleum exploration such as the North Atlantic (e.g., Faroe-Shetland Basin, United Kingdom, and Faroe Islands, the Norwegian margin and South Atlantic margins bordering Brazil and Angola).
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American Association of Petroleum Geologists (AAPG)
Added on 28 February, 2014
Explorer Division Column EMD
By Jeremy Boak
Every six months, chairs of the Energy Minerals Division committees convene and report on developments in the areas they cover. In this column, we highlight important observations from these recent reports.
American Association of Petroleum Geologists (AAPG)
Added on 01 February, 2014
Explorer Emphasis Article
By Brian Ervin
Icebreaking vessels are the key to navigating the Arctic, and so are in high demand as oil producers set their sights on the vast oil reserves at the top of the world.
American Association of Petroleum Geologists (AAPG)
Added on 01 February, 2014
Explorer Emphasis Article
By Louise Durham
Oil spills are a potential challenge in any corner of the world, but the Arctic brings its own set of challenges to oil production and transportation, and so it needs its own dedicated technologies for meeting them.
American Association of Petroleum Geologists (AAPG)
Added on 01 February, 2014
Explorer Emphasis Article
By David Brown
Arctic pioneers will relate their lessons and experiences from exploring and producing in the frozen north at the third annual Arctic Technology Conference this month in Houston.
American Association of Petroleum Geologists (AAPG)
Added on 01 February, 2014
Explorer Emphasis Article
By Louise Durham
The Final Frontier: The Arctic Circle’s vast, untapped treasures of oil and gas resources beckon explorers to boldly go, despite the daunting technical, political and environmental challenges.
American Association of Petroleum Geologists (AAPG)
Added on 01 February, 2014
Explorer Article
The Distinguished Lecture program, funded in part by the AAPG Foundation, is the Association’s flagship initiative for spreading the latest in science, technology and professional information.
American Association of Petroleum Geologists (AAPG)
Added on 01 November, 2013