LARAMIE — Just under 600 oil and natural gas wells were produced statewide in 2018, according to the Wyoming State Geological Survey’s 2019 update to the Interactive Oil and Gas Map of Wyoming.
The map contains many layers, including fields; all wells from the Wyoming Oil and Gas Conservation Commission; the subset of wells used to create the fields; bottom hole locations for horizontal and directional wells; in addition to pipelines, surface and mineral management, and base layers including statewide geology, according to a WSGS press release.
The map can be found at wsgs.maps.arcgis.com/apps/webappviewer/index.html?id=3f7ab99343c34bd3ac5ae6ac8c04d95a.
Wells completed a year ago contributed more than 21% of the state’s 88 million barrels of oil produced in 2018, an annual total not reached since 1993, according to the Wyoming State Geological Survey.
Although information shown in the 2019 Interactive Oil and Gas Map of Wyoming may not look different from the outset, a closer look highlights significant activity statewide.
In 2018, 599 wells were completed in the state. Of these, 235 are in the Jonah and Pinedale fields in Sublette County, where operators are testing the field boundaries with nearly 2-mile-long laterals. The two fields produced 38% of Wyoming’s 2018 natural gas, a WSGS press release states.
In Sweetwater County, 25 natural gas wells were completed a year ago, down from 40 in 2017, WSGS Outreach and Publications Manger Christina George told the Rocket-Miner.
Overall, natural gas production in 2018 slightly increased from the previous year to more than 1.81 trillion cubic feet with the new wells accounting for more than 8% of total production. More than 970 billion cubic feet of natural gas, or 53% of the state total, was produced from Sublette County, according to the WSGS.
Converse and Campbell counties topped the state in oil production, contributing 23.4 and 17.3 million barrels of oil, respectively.
Six oil wells were completed in Sweetwater County in 2018; none in 2017, George said.
More than 46% of the wells completed in 2018 were horizontal wells, with the majority producing from Upper Cretaceous-age reservoirs in Campbell, Converse and Laramie counties. The Frontier Formation, Turner Sandstone, and Codell Sandstone continue to be operators’ primary targets in the Powder River and Denver basins. In 2018, the Frontier Formation and the Turner Sandstone accounted for 41% of the Powder River Basin and 23% of all Wyoming oil production. The Turner Sandstone was also the Powder River Basin’s highest noncoal gas-producing reservoir a year ago, accounting for 27% of all natural gas produced from the basin, the release states.
In Wyoming, wells are permitted either within a defined field, such as the Salt Creek field, or as a wildcat. Until recently, most traditional oil and gas fields were spatially defined by structural or stratigraphic traps that physically hold the oil or natural gas in place. Fields in the Big Horn Basin are good examples of these traps, where most fields are anticlines, or arch-shaped folds, that trap oil. Operators typically use vertical wells to produce from these fields.
“These days, especially in Wyoming’s Powder River and Denver basins, production is from tight sand and shale reservoirs where the oil and gas is widely distributed throughout the pore spaces of the rock,” said Rachel Toner, WSGS oil and gas geologist. “When the WSGS first published the Oil and Gas Map of Wyoming in 1943, all oil and gas wells were in traditional, named fields. Over the last decade the trend in eastern Wyoming is that wells are increasingly drilled as wildcats. Wildcat well locations and their target reservoirs are so variable that they cannot be combined into a single field.”
Wildcat wells are defined by the Wyoming Oil and Gas Conservation Commission as “wells outside known fields or new wells which are determined by the Commission to have discovered oil or gas in a pool not previously proven productive.” Modern drilling technologies, including lengthy horizontal wells and hydraulic fracturing techniques, are now allowing operators to explore for oil and natural gas in previously uneconomic unconventional reservoirs without well-defined spatial extents.
“The fact that we are not capturing wildcat wells as existing within documented fields makes them more challenging to study, since these wells need to be reviewed individually to understand new drilling areas and targets,” WSGS Director Erin Campbell said. “On the other hand, wildcat wells are prompting the energy community to rethink the definition of fields and what is important to hydrocarbon production in the state. We want to know where production is occurring and from what formations, so we need to start thinking of new ways to show production spatially and summarize it statistically. Fortunately, in the end, Wyoming is receiving revenue from these new wells, regardless of their field designation.”