Map data:
Montana
http://www.bogc.dnrc.mt.gov:4899/website/mtcbm/viewer.htm
http://bogc.dnrc.mt.gov/web_mapper.asp
ND
https://www.dmr.nd.gov/OaGIMS/viewer.htm
https://www.dmr.nd.gov/oilgas/
older data but gives well locations
http://www.eser.org/
My favorite ,,good luck
http://dnrc.mt.gov/EnvironmentalDocuments/November/GretelII12KA3.pdf