The Wyoming State Geological Survey (WSGS) completed another update to its online Oil and Gas Map of Wyoming, the second since the map launched nearly two years ago.

This most recent update highlights the fact that more than 580 oil or gas wells were completed in Wyoming in 2017 and more than 80 have been completed so far this year. This is up from the more than 360 wells completed in 2016. Of the new oil or gas wells, around 200 are in the Powder River Basin in northeastern Wyoming, primarily targeting the basin’s stacked reservoirs. The bulk of these stacked reservoirs are Late Cretaceous in age, meaning the rocks that currently hold the hydrocarbons were deposited between 100 million and 66 million years ago. In 2017, these reservoirs in the Powder River Basin alone contributed more than 60 percent of Wyoming’s total crude oil production, with the Wall Creek-Turner sandstones accounting for about one-quarter of the total oil produced.

More than 50 of the new wells were completed in the Denver Basin in southeastern Wyoming, primarily targeting the Codell Sandstone.

“Approximately eight percent of Wyoming’s 2017 crude oil production was from the Codell Sandstone in the Denver Basin,” says WSGS oil and gas geologist, Dr. Jesse Pisel.

WSGS geologists note operators in the Greater Green River Basin are starting to drill successful horizontal gas wells on the flank of the Pinedale Anticline. Nearly 400 wells were completed in the Greater Green River Basin, mostly in the large Jonah and Pinedale natural gas fields. In March, a horizontal well in the Pinedale field produced 54.5 MMcfe/d (million cubic feet equivalent per day) during a 24-hour initial production period.

“The average initial production from new horizontal wells on the flank of the Pinedale Anticline is about 7.8 MMcfe/d. This means the new horizontal wells have the potential to produce up to seven times more gas per day than a normal Pinedale directional well,” says Pisel.

“As oil prices have risen over the past year, we’ve seen drilling start to pick up across the state,” says WSGS Director, Dr. Erin Campbell. “We are interested to follow production over time from the new wells in the Pinedale field. But the big play, right now in Wyoming, is the Upper Cretaceous stacked oil reservoirs in the Powder River Basin.”

The web-based interactive map displays oil and gas fields, their producing reservoirs, horizontal wells, pipelines, oil refineries, gas plants, hydrocarbon products, and well production status. The map went live in July 2016 and was first updated in April 2017. The map complements the WSGS’ traditional and popular paper Oil and Gas Map of Wyoming(updated in 2016), which was first published in 1943. The online platform allows WSGS staff to update the interactive map more frequently as new data become available.

The online Oil and Gas Map of Wyoming is free to use and can be accessed at: http://www.wsgs.wyo.gov/energy/oil-gas-maps-publications. The WSGS welcomes comments and suggestions on how to make the map an even more useful tool going forward. Feedback and comments can be addressed to WSGS oil and gas geologist Rachel Toner at rachel.toner@wyo.gov.

More information about Wyoming’s oil and gas resources, basins, maps, and publications can be found on the WSGS website.