Print this pageAAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Heat Flow History in the Chukchi Sea – Mega-Regional Tectonics, Local Heat Flow and Charge Implications
(1) Chevron, Houston, TX.
The Chukchi region is part of the Arctic Alaska-Chukotka microplate which comprises northern Alaska, Chukotka, Wrangel Island, and part of the East Siberia Shelf (Klemperer et al., 2002; Natalin, 2004). The structural history of Chukchi Sea is associated with the formation of the Amerasian Basin through an opening by seafloor spreading and subsequent rotation of the Arctic Alaska-Chukotka microplate about a pole located near the McKenzie Delta (Grantz et al., 1990; Lawver et al., 2002). Granz et al. (1990) managed to restore the Alaskan North Slope to Arctic Canada by simple rotation; however, Chukotka couldn’t be restored to the Canadian Arctic margin without significant internal deformation of Chukotka and other parts of the Alaska-Chukotka microplate. This deformation can be clearly seen in the Herald Thrust area which is adjacent to our area of interest (Lawver et al., 2002; Klemperer et al., 2002). The complex tectonic history which includes rotation, extension, and compression, raises many questions related to heat flow history:
1. Is the deformation associated with significant extension and crustal thinning, causing higher heat flow at some point in the geologic history of the basin?
2. Is erosion in the Chukchi Sea caused by a thin-skin deformation associated with the collision of the Arctic Alaska-Chukotka microplate with the Siberian Plate, and not resulting in elevated heat flow?
3. Can a bowl-shaped erosional feature visible on some seismic lines across the Hanna Trough be explained by mega-regional deformation of Alaska and Chukchi Sea, i.e. heat flow history could be derived from local well data and heat flow trends extrapolated from the North Slope of Alaska?
4. Is local under-plating and subsequent thermal sagging required for explaining the bowl-shaped erosional feature, i.e. heat flow history should reflect a period of much higher heat flow in the past?
This paper discusses uncertainty and exploration risk related to charge, migration and preservation of hydrocarbons in the Chukchi Sea exploration area for different tectonic and structural scenarios. Our analysis led to selecting a thin-skin deformation scenario combined with erosion in the Hanna Trough area, and no associated (significant) heat flow spike. This scenario helped us to reproduce hydrocarbon types and volumes in the Klondike and Burger locations, and led to much more realistic predictions of generation, migration, and hydrocarbon volumes.