Much of the oil and gas produced within the Front Range Infrastructure Resources Project study area, and much of that used by people living in the Front Range, is extracted from sedimentary rocks that are deeply buried (up to 9000+ ft below the surface) just to the north of the Denver Metropolitan area. These rocks extend to the surface and are exposed in a ridge (hogback) along the western side of the study area. Rocks in which the oil and gas occurs are called "reservoir" rocks and rocks from which the oil and gas was generated are referred to as "source" rocks. We have the opportunity, at our first stop at the mouth of Turkey Creek Canyon along U.S. Highway 285, to see examples of both reservoir and source rocks. Here we will discuss some of the basic geologic features of the reservoir and source rocks and how this will affect new drilling activity in the near future.

Figure 1.  Oil & Gas Source (S) & Reservoir Rocks (R)    North side Hwy 285 Cut at Turkey Creek Canyon

How the rocks were originally deposited and what happened to them after they were deposited are studies that are ongoing or previously done by USGS scientists as well as others in private industry and at universities. These types of studies are necessary to identify where it might be possible to locate large accumulations of oil and gas. However, questions remain as to the role of faults in aiding or hindering oil and gas production, and accordingly, the volume of oil and gas that will ultimately be produced from the region. Further, the location of wells likely to be drilled in the future is of question and concern for many of the landowners in our study area. These are some of the fundamental questions that USGS scientists are currently attempting to answer as part of the energy-related research activities for the USGS Front Range Infrastructure Resources Project.

Much of the natural gas used in the Front Range is extracted locally, particularly from the Wattenberg field north of Denver, and it was in this area that a drilling frenzy took place not too long ago. For example, in 1994, 80% of the wells drilled in the State of Colorado were in the Wattenberg field, mostly in Weld County. In addition to drilling, the petroleum industry employs many people in the region to explore and exploit additional resources. Furthermore, new acreage for drilling was opened for exploration as recently as 1996 on the Denver International Airport grounds. Although there has been and will continue to be keen interest in oil and gas resources of the region, the urbanization occurring within the Front Range has already "sterilized" some of the petroleum resources from future development. This is especially apparent in Greeley, where the City of Greeley has banned drilling within its limits and as a result, production of some portion of the resources has been sterilized.

Although most of the USGS effort will be focused using information from the Wattenberg field itself, which we will be visiting later today, looking at some of the source and reservoir rocks will give you an appreciation for the how difficult it is to locate likely drilling sites and hunting for reservoirs that may exist in one place but not another. Furthermore, the search for oil and gas in rocks heretofore not drilled, or not previously exploited in past drilling, will keep oil and gas operators very busy in the next few years. We expect to see a renewal of drilling activities in Wattenberg for a variety of reasons, some of which we’ll explore during the day.

U.S. Department of the Interior, U.S. Geological Survey URL: http://rockyweb.cr.usgs.gov/frontrange/virtour/turkcr.htm Contact: Carol Mladinich  mailto:csmladinich@usgs.gov Updated: 05/16/2001