Abstract
As exploratory work in Alaska moves beyond the known petroleum basins, new remote areas will be explored, where little sub surface data is available. This paper examines the overburden of Alaska, and develops a general relationship for determining overburden pressures based on the general geographic location in this region.
To develop such relationships, well logs available to the Public are used. To characterize the overburden on a large scale, three major sedimentary basins of the Alaska, the North Slope, Nenana Basin, and Cook Inlet Basin, are studied. Overburden is estimated by integrating density of the deposits, from using density log data, and using MATLAB to filter false readings. From this data, a regionalized relationship is developed for pressure vs depth, based on geographical location.
The collision of the Pacific Plate and North American Plate has resulted in thrust tectonics, associated with shortening and thickening of the crust at southern part of the Alaska Microplate. The studied basins are located along different locations in this deformation zone and evident with different lithological patterns across a north-south direction. Depending on tectonics and diagenesis of sediments, rocks undergo different compaction processes which make overburden various across this region. As a result of plate tectonics and variation in depositional environments, an increasing trend is observed across the entire Alaska region. Such trend can be used in further exploration work in this region to approximate overburden stress at any location in the state.
