Pattern drilling, based on the hypothesis that any field with dimensions larger than the area between pattern wells certainly would be discovered, is tested in a sample area on the east flank of the Denver basin ("fairway" trend area) and compared with effectiveness of actual drilling. This test might be described as a combination of random and geologic-lead drilling. The pattern selected "discovers" 1.16 × 10⁸ bbl of oil actually produced as of January 1, 1969. This quantity includes produced oil only and does not include estimates of reserves or total ultimate production. The pattern-drilling system yields 123,400 bbl/well of oil actually produced in the sample area (including dry holes). Actual drilling in the area has led to production of 1.53 × 1 ⁸ bbl of oil or 66,500 bbl/well.

It is concluded that, in the sample area at least, pattern drilling could have been more economical than drilling according to geologic leads, promotional deals, and leasing arrangements, as has occurred in the area.

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