The productivity of natural gas wells in the Marcellus Shale and the neighboring Utica Shale is steadily increasing because of ongoing improvements in precision and efficiency of horizontal drilling and hydraulic fracturing occurring in those regions. Since January 2012, natural gas production in the Marcellus and Utica regions has accounted for 85% of the increase in natural gas production reported in EIA's Drilling Productivity Report (DPR) and has driven recent growth in total U.S. natural gas production.

The DPR provides a month-ahead projection of both oil and natural gas production for the seven most significant shale formations in the United States. Although the DPR regions are grouped according to the name of the predominant shale formation, the report analyzes all drilling and production within each geographic area. In practice, this means natural gas production activity in the Marcellus region, which includes Pennsylvania and West Virginia, encompasses not only the Marcellus formation, but also portions of the Utica shale and conventional formations that lay beneath those states. The Utica DPR region, which includes resources that lay beneath Ohio, includes production from the bulk of the Utica formation as well as production from the Point Pleasant shale formation and (to a lesser extent) conventional resources.

The DPR identifies trends in total production and rig productivity, expressed as new-well gas production per rig. The July edition of the DPR noted that average new-well gas production per rig in the Marcellus region was 3.2 million cubic feet of natural gas per day (MMcf/d) in January 2012. In July 2015, new-well gas production per rig increased to 8.3 MMcf/d. This trend corresponded with an overall increase in the amount of natural gas produced in the Marcellus region during the same period. The DPR also indicates that the Marcellus region produced an estimated 6.3 billion cubic feet of natural gas per day (Bcf/d) in January 2012, increasing to 16.5 Bcf/d in July 2015.

The Utica region also experienced significant gains in rig productivity and production. In January 2012, new-well gas production per rig in the Utica region averaged 0.31 MMcf/d. July 2015 new-well gas production per rig is 6.9 MMcf/d. The DPR also indicates that the region's total natural gas production increased rapidly over the same period: production in July 2015 was almost 18 times higher than in January 2013 (2.6 Bcf/d and 0.15 Bcf/d, respectively).

Increases in natural gas production from these regions occurred because of many factors, including:

• Greater use of advanced drilling techniques

• Increased number of stages used in hydraulic fracturing operations

• Increased use of techniques such as zipper fracturing (simultaneous fracturing of individual stages of two parallel horizontal wells)

• Use of specific components during well completion that aid in increasing fracture size and porosity of the geologic formation being targeted

EIA's latest data show that natural gas produced from U.S. shale basins now accounts for 56% of U.S. dry natural gas production. Collectively, shale gas production from the Marcellus and Utica regions increased by 12.6 Bcf/d from January 2012 to June 2015, making these regions the driving forces behind overall U.S. natural gas production growth.