Wattenberg Gas Field

The Wattenberg Gas Field is a large producing area of natural gas and condensate in the Denver Basin of central Colorado, USA. Discovered in 1970, the field was one of the first places where massive hydraulic fracturing was performed routinely and successfully on thousands of wells. The field now covers more than 2,000 square miles between the cities of Denver and Greeley, and includes more than 20,000 wells producing from a number of Cretaceous formations. The bulk of the field is in Weld County, but it extends into Adams, Boulder, Broomfield, Denver, and Larimer Counties.

The reservoir rocks are Cretaceous sandstones, shales, and limestones deposited under marine conditions in the Western Interior Seaway.

The gas and condensate is contained within Cretaceous formations in the deepest part of the Denver Basin, where the rocks were subject to enough heat and pressure to generate oil and gas from organic material in the rock. The field is a stratigraphic trap, basin-centered gas field. Most of the gas-producing formations are considered tight gas, having low natural permeability. Although the field today is in the deepest part of the basin, an unconformity at the base of the Pierre Shale shows that the field is on an early paleohigh active in the Middle Cretaceous.

Although numerous wells had drilled through the Wattenberg Field over the decades, and many drillers and wellsite geologists noticed gas “shows” (indications) in the J Sandstone and other strata, the J Sandstone and other gas-bearing formations had permeability too low to yield gas in commercial quantities, and all the wells were dry holes.

Amoco geologist Pete Matuszczak noticed that all the wells drilled over a large area recorded noncommercial gas shows, with no water, through the J Sandsone (also called the Muddy Sandstone) on the mudlogs, cores, and drillstem tests. He suggested that the area might be made to produce large economic quantities if the wells were treated with the new method of massive hydraulic fracturing, which Amoco was using successfully in the San Juan Basin of New Mexico.

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