Criteria for a Multi-Disciplined Approach for Exploration, Exploitation, and Development Drilling in the Morrow Oil Trend of Colorado and Kansas: The 3-G Method

LeBlanc, Rufus J., Victor T. Jones
Exploration Technologies, Inc, Houston, TX

March, 2004 marked the 25th anniversary of the discovery of Sorrento and SW Stockholm Morrow oil fields in Cheyenne County, Colorado and Greeley County, Kansas respectively. The discovery of oil-bearing Morrow sandstones in these two fields was the result of serendipity associated with exploration for Mississippian structural anomalies. The extremely profitable Morrow oil reserves associated with these fields kept exploration efforts very active in these areas from 1979 through 1995 even during the drastic oil price decline in 1986. Twenty-six Morrow oil fields were discovered which will result in recoverable reserves of 110,000,000 BO.

Over the past 25 years, new exploration techniques and concepts involving geology, geophysics, and geochemistry (3-G Method) have evolved which can greatly enhance the success rate in this stratigraphic oil play which is well known for its elusiveness in locating reservoir quality, oil-bearing sandstones in the incised-valley trends.

Case histories involving three different companies using different combinations of subsurface geology, seismic, and soil gas geochemistry are discussed with the corresponding resultant success rates. All three examples are within the same general area of the southern Stateline trend.

Morrow sequence stratigraphy concepts, 3-D seismic surveys, and high-density grids for soil gas surveys are now being used in tandem as an integrated approach in current drilling ventures in the Morrow oil play. Drilling statistics document that solely using 2-D or even 3-D seismic is not sufficient. The 3-G method is a superior method whereby advantages in one of the three disciplines overcome and complement the shortcomings of another.