Alaska

Mission

In fiscal year 1981, the U.S. Geological Survey completed the operational phase of the petroleum exploration program in the National Petroleum Reserve in Alaska, which was begun by the Department of the Navy in 1974 and transferred to the Department of the Interior in June 1977 under the Naval Petroleum Production Act of 1976. Under the Act, the Survey was assigned to explore and evaluate the petroleum resources of the Reserve by drilling and conducting geological investigations, to build an information base to assist Congress in determining the best use of land within the Reserve, to continue developing and producing natural gas in the Barrow area for the native village of Barrow and other communities and Federal Government installations in the vicinity, and to continue the environmental rehabilitation of parts of the Reserve disturbed by previous exploration and construction activities.

During fiscal year 1981, six exploration wells were completed, including one that had been started in the previous year and suspended during the summer months of 1980. At the completion of drilling, all contractor equipment, including drilling rigs, was demobilized from the Reserve, and all materials, equipment, and supplies were removed from the Reserve, surplused, or transferred to Barrow to be used in operating and maintaining the Barrow gasfields, a continuing responsibility of the Department. One geophysical party acquired 590 line-miles of seismic data under a geophysical program designed to study the shallow Cretaceous sandstones at Umiat, which are known to contain oil, and the deeper Jurassic sandstones penetrated by the North Inigok and Walakpa wells. Seismic data were collected in those areas of the Reserve where the petroleum industry had expressed interest in early leasing. The Survey continued to operate the South Barrow gasfield. Construction continued on surface facilities at the East Barrow gasfield, located approximately 7 miles east of the South Barrow field, in preparation for production from three East Barrow wells during the winter of 1981-82. Husky Oil NPR Operations,

Inc., continued as the contractor for drilling. Geophysical Services, Inc., was the contractor for the collection and processing of field seismic data, and Tetra Tech, Inc., provided technical services, including interpretation of seismic data.

Budget and Personnel

Obligations for drilling and related activities within the National Petroleum Reserve in Alaska in fiscal year 1981 totaled $107.0 million, all against the appropriation "Exploration of the National Petroleum Reserve in Alaska." Of this total, $105.5 million was devoted to continuing the evaluation and assessment of the Reserve, and $1.5 million went for operating the South Barrow gasfield. The Environmental Restoration Program, which consisted of the normal cleanup of current exploration drilling sites and the rehabilitation of areas of the Reserve disturbed during previous petroleum exploration and construction activities, was continued with funds included in the program termination costs.

The Office of the National Petroleum Reserve in Alaska ended fiscal year 1981 with 18 permanent full-time employees and 4 employees in other categories.

DIRECT APPROPRIATIONS

Status of Exploratory
Drilling

Awuna Test Well No. 1, located approximately
152 miles south-southwest of Barrow in the cen-
tral part of the Reserve, was started on March 1,
1980, to test for potential accumulations of oil
and gas on one of the highest structural positions
along the prominent Carbon Creek-Awuna an-
ticline, which extends across much of the
Reserve. The well, designed to test sands of the
Torok and Fortress Mountain formations of
Cretaceous age, was suspended for the summer
on May 8, 1980, at a depth of 5,300 feet before
the potential reservoir horizons were en-
countered. It was reentered on December 5, 1980,
and drilled to a total depth of 11,200 feet. The
Torok consisted mainly of shale and some thin,
nonporous sands, many of them with gas shows.
The upper part of the Fortress Mountain forma-
tion was more sandy than the Torok, but the

sands were fine grained and generally exhibited poor porosity. Gas shows were indicated in many of the sands. Very minor amounts of asphaltic material were found in the lower part of the well. Very high pressures and lost circulation slowed the penetration rate, and drilling was terminated well short of the projected total depth.

Walakpa Test Well No. 2, located 4 miles south-southwest of Walakpa Test Well No. 1, was drilled to a total depth of 4,360 feet and was temporarily abandoned on February 15, 1981, following testing. The well was designed to test the Jurassic "Simpson" sand near its updip truncation and Lower Cretaceous sand (the "Walakpa" sand), which tested gas in the Walakpa No. 1 well. The Lower Cretaceous "Walakpa" sand, found 536 feet lower than it was in the No. 1 well, was cored from 2,611 to 2,640 feet; fine-grained sand having poor to good porosity and a show of hydrocarbons was recovered. A drill-stem test of the sand recovered gas at the rate of 2.4 million cubic feet per day. The "Simpson" interval was siltstone, as it was in the Walakpa No. 1 well.

North Inigok Test Well No. 1 was completed as a dry hole on April 4, 1981. The well was spudded on February 13, 1981, at a location 20 miles north-northeast of the Inigok No. 1 well and drilled to a total depth of 10,170 feet in the Triassic Shublik Formation. Gas shows, as logged by the well-site geologist, were encountered only in the lowermost Torok formation; a single show was indicated in the Jurassic siltstone. Surprisingly, a drill-stem test of the Jurassic zone produced gas at an estimated rate of 30,000 cubic feet per day. The gas was quite rich and analyzed 73 percent methane, 12.8 percent ethane, 7.3 percent propane, 3.2 percent butane, and 3.7 percent pentanes and heavier hydrocarbons. Such an analysis has important implications for a possible oilcolumn downdip and for reservoirs elsewhere in the Kingak formation of Jurassic age.

Kuyanak Test Well No. 1 was spudded on February 13, 1981, and completed on March 31, 1981, to a total depth of 6,690 feet. Located 22 miles southeast of Walakpa No. 2, the Kuyanak well was drilled primarily to explore for the "Simpson" sandstone within the Jurassic Kingak shale. This sand had been found in wells having good reservoir characteristics to the southeast, south, and southwest. A secondary objective was the Sag River sandstone of Triassic age. Drilling was begun in rock of Cretaceous age and terminated in argillite basement. A sand correlated as the "Walakpa" sand was found at 5,092 feet and cored from 5,093 to 5,186 feet. There were no hydrocarbon shows in the sand, but good porosity and permeability were measured. The

"Walakpa" sand thus occurs more than 2,500 feet structurally low to the Walakpa No. 2 well and possibly indicates a continuous sand having good reservoir characteristics below a proven gas column. An equivalent of the "Simpson" sand occurs in the Kuyanak well from 5,378 to 5,656 feet and consists mostly of siltstone and minor gas shows near the top. The "Simpson" sand play lies to the south of this well. Equivalents of the Jurassic "Barrow" and Triassic Sag River sands of the East Barrow field were cored. The equivalent of the Sag River sand indicated a minor gas show. Tulageak Test Well No. 1, located on the Beaufort Sea coast 24 miles east-southeast of Barrow, was spudded on February 26, 1981, and completed to a total depth of 4,015 feet on March 23, 1981. The well was drilled to test a combination structural-stratigraphic prospect and encountered basement at 3,947 feet. Argillite was drilled and cored from this point to the total 4,015-foot depth. Only one hydrocarbon show was found.

Koluktak Test Well No. 1, located 39 miles southwest of the Inigok No. 1 well, was spudded on March 24, 1981, and completed as a dry hole on April 19, 1981, after a total depth of 5,882 feet had been reached. The primary objective of the well was the Nanushuk Group sands, which had good gas and oil shows in several of the older

wells drilled during the Pet-4 program. Koluktak
No. 1 drilled a Nanushuk sequence from the sur-
face to about 4,200 feet. The upper two-thirds of
this section was predominantly sandstone; some
thin shale, siltstone, limestone, and coal beds;
many minor gas shows; and a few oil shows. The
lower third was much more shaley and had only a
few gas shows. The top of the Torok was
estimated at about 4,200 feet, and, from this
point to total depth, shale and minor amounts of
sandstone and siltstone were drilled. Only one
minor gas show was indicated in this interval. The
imminence of spring breakup precluded any
testing.

Barrow Area Gas
Activities

The Geological Survey continued to operate and maintain the South Barrow gasfield, which supplies gas to the village of Barrow as well as to Federal installations in the Barrow area. Construction continued on production facilities at the newer East Barrow gasfield, which will double the amount of natural gas available to the Barrow

area.

No new gas wells were drilled during fiscal year 1981. The status of the Barrow gas wells is indicated on the accompanying table.