there was no analogy for the concept. Finally, Halliburton agreed with Lyco's assessment of the potential, including the potential boon for its stimulation business, and agreed to support Lyco's operations financially through its commercial services division. Lyco drilled the first horizontal well in the field, the Burning Tree State #36-10 in late 1999, as the oil price moved upwards toward $20 per barrel. Although designed as a 3,000 foot lateral, the well was terminated early due to hole stability issues. Production casing was run to bottom and cemented, then perforated in three intervals over the roughly 1,000 foot lateral; at the toe, the middle and the heel. The well flowed oil immediately, at 196 barrels per day, and continued flowing for several months. Finally, the well was fracced, with a substantial increase in production. Lyco then began a continuous drilling program, progressing to 3 rigs and beyond. Headington, another oil company in the area that happened to own leases, began a drilling program also, followed by Continental and others who rushed in to take lease positions on this new, hot play. At Elm Coulee, the Middle Bakken is a dolomite sandwiched between the Upper and Lower Shales. The shales are very rich in organic material, and the oil generated from them expanded from the shales upon reaching thermal maturity, migrating into this Middle Bakken zone. The field is exploited via horizontal drilling technology by perforating the productive rocks parallel to the beds, rather than through a vertical well perpendicular to the relatively thin Bakken formation. At Elm Coulee Field, the Bakken is only about 45 feet (15 m) thick and lies at depths of 8,500 to 10,500 feet (2,600–3,200 m), but horizontal wells penetrate 3,000 to 10,000 feet (900–3,000 m) of the reservoir rock, a porous dolomite of Devonian age that probably originated as a large carbonate bank on the western flank of the basin. The field is a stratigraphic trap. In 2006, Elm Coulee was producing about of oil per day from more than 350 wells. Ultimate production is expected to exceed , with some estimates as high as . Production at Elm Coulee has more than doubled the oil output of the state of Montana, from around in 2000 to almost in 2006. However, Montana production fell again starting in 2007, down to some in mid-2009. References Geology of Montana Oil fields in Montana Geography of Richland County,