The Bureau of Indian Affairs (BIA) has been stepping up its efforts to aid native American tribes-which number more than 500 and own 56 million acres of land-in drumming up oil and gas industry interest in their land assets. The BIA's job is to provide services to the tribes to help them maximize their resource potential, to whatever extent they desire, says the staff at the BIA's Division of Energy and Mineral Resources Management (DEMRM). The division, headquartered in Lakewood, Colorado, is a liaison between industry and the tribes, assisting both tribal and individual native American landowners. The agency has been adding staffers with petroleum experience, so the people advising the tribes can communicate in industry terms. The DEMRM helps the tribes market their interests: it performs geologic studies, purchases and interprets seismic, performs economic analyses and generates prospects. The BIA also advises the tribes on how to structure and negotiate oil and gas agreements. And, it manages the tremendous amount of data that has been acquired on native American lands. In Lakewood, the BIA has its own seismic-processing center and climate-controlled data storeroom. DEMRM wants industry to know that it has staffed up and has the ability to be more proactive. A recent project-the first of a new generation that features an integrated geologic and geophysical package-has been completed on Fort Berthold Reservation, in the heart of North Dakota's fruitful Williston Basin. Here, the Three Affiliated Tribes-Mandan, Hidatsa and Arikara-have almost 600,000 acres of land available for lease, 360,000 acres of which are allotted (individually owned) and 200,000 acres of which are tribal. Although the reservation lands lie close to the prolific Nesson Anticline and are surrounded by production, they are only lightly explored. Only about 100 wells have been drilled on native American lands in the reservation; of those, approximately half were producers. Structurally controlled Antelope Field, a 40-million-barrel-plus accumulation in the Madison, Duperow, Interlake and Sanish zones, is within reservation boundaries. The real hook to the story, however, is the 150,000 acres of tribal lands that lie beneath Lake Sakakawea, a reservoir created when the Missouri River was dammed in 1951. No wells have been drilled on this acreage, which was returned to the tribes by the federal government within the last 10 years. Advanced Resources International (ARI), an Arlington, Virginia-based consulting firm, undertook a study of the lands under the lake through the Department of Energy's (DOE) Native American Initiatives program, says Scott R. Reeves, ARI's Houston-based executive vice president. "The Fort Berthold reservation offers a unique exploration opportunity. The Lake Sakakawea lands are a huge, contiguous block that has one owner in a very prospective part of a prime oil-producing basin." The DOE program provided the funds to purchase 200 miles of seismic, Landsat and aeromagnetic data covering the area around and beneath the lake. ARI, in cooperation with the BIA division, integrated and interpreted the data and generated prospect leads. In the western portion of the reservation, they came up with numerous attractive seismic structures, bigger than the typical Red River bumps. Compared with the rest of the Williston, this area is highly structured. Indeed, 10 structural leads that are accessible by horizontal wellbores lie beneath the narrow, sinuous lake. The eastern portion of the Lake Sakakawea area also features an attractive stratigraphic prospect. Over a broad swath of the Williston, oil is produced from several shoreline trends in the Mission Canyon formation. Altogether, the study identified 11 exploration leads that have expected recoveries ranging from 283,000 to 1.7 million barrels of oil apiece, says Reeves. "Horizontal dryhole costs are estimated at between $450,000 and $1 million per well, with finding and development costs of below $10 per barrel for the top five prospects." To further enhance interest, the state of North Dakota is providing special tax relief for the reservation. "There is a high likelihood of finding significant reserves," says Reeves.