Patrick Draw Field was discovered in 1959 in Sweetwater County, Wyoming, in the Green River Basin. The sizeable, oil-filled stratigraphic trap created quite a stir in the Rockies when it was found. The reservoir was an Almond sandstone-the upper unit of the Lower Cretaceous Mesaverde Formation-that pinched out against the southern flank of the Wamsutter Arch. Patrick Draw has produced a total of 60 million barrels of oil and 130 billion cubic feet of gas from its two units, Arch and Monell. The Monell Unit, which encompasses the southern portion the field, was formed in 1964 as a secondary recovery unit after primary production by solution gas drive had begun to decline. Originally developed on 80-acre spacing, Monell was infilled to 40-acre spacing for waterflooding. Altogether, 150 wells were drilled for both the primary and secondary recovery phases, and Monell produced 24 million barrels of oil on primary and an additional 16 million barrels via waterflooding. When Monell was acquired in 2000 by Anadarko Petroleum Corp., as part of its merger with Union Pacific Resources, the old field's glory days seemed long past. It was producing just 10 barrels of oil per day from a handful of stripper wells. "Most of the wells had already been abandoned, and there wasn't much salvage value either," says Frank Lim, a reservoir engineer with Houston-based Anadarko. A lot of companies would have walked away from Monell. After all, in the merger Anadarko had just acquired the famed Union Pacific Land Grant, some 8 million acres of mineral rights that lay in a checkerboard pattern along the transcontinental railroad in Wyoming, Utah and Colorado. The company had plenty of lucrative opportunities on its new swath of lands from which to choose. For more on this, see the October issue of Oil and Gas Investor. For a subscription, call 713-993-9320, ext. 126.