DGGS again working foothills this summer

Agency looking for industry sponsors to help fund research; rocks along Colville, Kavik rivers object of this year’s work

Alan Bailey

Petroleum News

Alaska’s Division of Geological and Geophysical Surveys has issued a proposal for its 2006 summer field season in the Brooks Range foothills of Northern Alaska. A DGGS-led team of geologists has been conducting a multi-year research program in the area and each year seeks industry sponsors to help fund the work.

Rock exposures in the foothills provide opportunities to investigate strata that are deeply buried in the petroleum province of the North Slope. And the foothills are of considerable interest for natural gas exploration. The DGGS-led research results in publicly available geological data that supports oil and gas exploration.

DGGS geologic mapping in the foothills has also received U.S. federal funding under the U.S. Geological Survey’s StateMap program for the production of detailed maps in conjunction with state agencies.

During the summer 2006 field season DGGS proposes to continue its investigations of the early Cretaceous evolution of the Colville basin in the central foothills — the geologists are assembling detailed information about the structure of the area and the reservoir potential of the rocks. Fieldwork this year will focus on rock exposures along the Colville River and the nearby Tuktu escarpment, near the southeastern boundary of the National Petroleum Reserve-Alaska. The geologists expect to obtain detailed measured sections in rock strata that should correlate with rocks found in nearby wells. The studies will also enable a better understanding of the variations in reservoir quality in the area.

Kavik River area

The Ellesmerian sequence includes the reservoir rocks of North Slope fields such as Prudhoe Bay, Lisburne and Endicott. Surface outcrops of these rocks should provide insights into the early formation of the sequence. The stratigraphy of the Lisburne group that includes the reservoir rock for the Lisburne field (and is also an exploration target in the Jacob’s Ladder unit to the north of the study area) will also be a research focus.

Beaufortian research will particularly focus on the major unconformity at the base of the Cretaceous sequence and an important sandstone known as the Kemik sandstone that lies over that unconformity. The studies should enable a better understanding of how the Kemik formed. The fieldwork will also enable surface investigations of the Pebble Shale and Gamma Ray Zone, two prolific North Slope oil source rocks.

The Brookian sequence in the area of study includes another important source rock, the Hue shale, as well as potential reservoir sands. The team of geologists will use surface outcrops to study the Brookian sequence in detail and to obtain information about the rock stratigraphy and the environments in which the rocks were deposited. The use of microscope slides and other techniques will enable an assessment of reservoir quality in the sandstones.

This year’s StateMap mapping will cover more than 500 square miles in the Kavik area. This mapping will tie into previous detailed DGGS mapping in the western part of ANWR and in the area of the Kemik gas field to the southwest of Kavik.

DGGS plans to publish a comprehensive geologic map and cross-sections of the Kavik area in the second half of 2007.

The division says that fieldwork costs have increased by about 20 percent in the past few years, mainly as a result of increasing helicopter costs. This year’s field season and associated analytical work will cost about $400,000.

The fieldwork proposal is available on the DGGS Web site at http://wwwdggs.dnr.state.ak.us/download/2006_Sponsors_Proposal.pdf.