Flashback: The Bakken Boom Began With Vertical Wells in Elm Coulee (Montana)

This article was published in 2007. It provides a bit of perspective to the current Bakken boom.

The first commercial Bakken well at Elm Coulee was completed in 1981 by Coastal Oil and Gas. Early wells were vertical completions and were often a fall-back position for an unsuccessful deeper well-test. After stimulation, vertical Bakken wells have historically exhibited a respectable initial production, but with high initial declines followed by long-term, low productivity. A typical economic vertical well would initially produce at more than 100 b/d of oil, but would soon decline to approximately 15 b/d to 20 b/d of oil.

Production thereafter exhibited a minimal decline and due to the low production rates, oil price was the major factor in economic operations. Gas/oil ratios were approximately 750 Mcf/bbl, however, no sales outlet was available, and casing-head gas was used on the lease. Superior productivity was dependent upon intersecting local fractures to double or triple the IP and the corresponding long-term productivity rates. The estimated ultimate recovery (EUR) of the typical economic vertical Bakken completion is estimated at 130,000 bbl of oil. Assuming a 30-year project life, however, that results in unfavorable project economics.

The first horizontal, Upper Bakken wells were drilled in Richland County in 1989 and 1990, but few were successful. The EUR rates for these horizontal wells were estimated at 21,000 boe. In 2000, Lyco Energy initiated the current horizontal activity by drilling the Burning Tree State 36-2H using an improved completion technique. The Lyco well’s IP was 196 b/d of oil, 85 Mcf/d of gas and 7 b/d of water, and the EUR is currently estimated at more than 300,000 bbl of oil. 

Although not addressed in this article, early on it was felt by some that horizontal drilling would obviate the need for fracture stimulation. How things have changed!

Enjoy!