The Niobrara Shale, an emerging play since 2009, lies beneath the surface of Northeast Colorado, Northwest Kansas, Southwest Nebraska and Southeast Wyoming. While the Niobrara extends from Canada to New Mexico, the most productive zones are in the rock formation located in the Denver-Julesburg Basin. The rock can be from 150 to 1,500 feet (46 to 451 meters) thick with organic content ranging from 1 to 5 percent.4 Core zones are in Weld and Yuma Counties in Colorado and Cheyenne County in Kansas. In 2009, EOG Resources drilled and completed its first wells. The most successful, Jake, was drilled horizontally and completed using hydraulic fracturing. It produced about 1,750 barrels per day (bpd) for the first few days and 50,000 barrels over a 90-day period.2 This success helped fuel the increasing interest in this formation.
Colorado’s fossil fuel resources include the Niobrara, with possible estimated ultimate recovery as high as 2 billion barrels of oil. According to the U.S. Energy Information Administration (EIA), Wyoming is ranked eighth and Colorado ninth in U.S. crude oil production (see Table 1).
Challenges & Benefits
Environmental, social and logistical concerns are similar in this formation as in past liquids-rich plays discussed in Upstream Pumping Solutions—such as the Bakken and Eagle Ford. Over the decades, the Niobrara has produced from select areas that are naturally fractured. However, its brittle, calcareous chalk benches make the formation highly suitable for fracturing, and operators are increasingly using techniques developed for shale reservoirs.4 The rock that makes up the area is shale, but it is not only shale. The formation changes from limestone and chalk in the eastern portion to calcareous shale in the middle and then changes to sandstone in the west.5 Both permeability and porosity in the Niobrara chalk are relatively low. Production—which follows, in most instances, multistage hydraulic fracturing—should be enhanced by “natural fractures related to: horst and graben structures, dissolution of evaporite beds, wrench faulting, listric faulting, regional stresses, and pore pressure.”1 As in any play requiring the use of hydraulic fracturing for hydrocarbon extraction, water is a critical prerequisite to operations. Sourcing, injecting, treating and reusing the produced and flowback water in all areas is crucial to safeguarding the environment and conserving water. In Weld County, Colorado, new sewer and water treatment infrastructure was added with the help of Halliburton. These upgrades along with other oil and gas industry jobs in the county have increased by about 1,500.3
Drilling and Production
The 2013 numbers from the EIA (projected through December) are in. The play has increased oil production while, as in other plays, slightly decreasing its gas production during 2013. Since 2007, legacy oil production has decreased while new well production has increased, resulting in a net increase of about 7,000 barrels per day. Net natural gas production has decreased 57 million cubic feet per day even though new well production has increased by 95 million cubic feet per day. Figures 1 and 2 indicate the production changes since 2007.
- “Advanced LWD Imaging Technology in the Niobrara: Abstract,” Schlumberger, http://www.slb.com/resources/technical_papers/drilling/143828.aspx.
- "Fast Facts: The Niobrara,” www.coga.org.
- “How the Niobrara Changed Fort Lupton: Part 2,” Nov. 14, 2011, www.coga.org.
- “Niobrara Shale,” www.halliburton.com.
- “Sprawling Niobrara Has Multiple Models,” AAPG Explorer, http://www.aapg.org/explorer/2011/06jun/niobrara0611.cfm.