G. Alan Petzet
Exploration Editor
Potential Williston Lodgepole Trends
The Williston basin Mississippian Lodgepole oil play is swelling the rig count and oil production in North Dakota.
As much as 200 sq miles of 3D seismic surveys have been acquired in southwestern North Dakota, and at least as much more is expected to be gathered through next year.
Exploratory drilling so far has moved south and east from Conoco Inc.'s 1993 Lodgepole discovery in Dickinson oil field.
The play also seems destined to become active in Montana in light of Vastar Resources Inc.'s recent agreement with Collins & Ware Inc., Midland, Tex., on 105,000 acres in Dawson and Richland counties, Mont.
OGJ estimates North Dakota's oil production at about 84,000 b/d, up from 75,000 b/d at the same time a year ago. State restrictions pending field unitization have reined production.
Baker Hughes Inc. shows 19 rigs running in the state, compared with only five at this time in 1994. About one third are dedicated to Lodgepole drilling, the others to successes in other, more established plays.
Trend rims basin
Based on current patterns of discovery, step-out, and well stakings based on 3D seismic data, a trend can be postulated along a battery of roughly parallel northwest-southeast striking faults, writes Scott Montgomery in the latest issue of Petroleum Information's Petroleum Frontiers quarterly.
The faults, spaced every 2-4 miles east-northeastward from the Dickinson area, helped localize mound growth.
"Given appropriate structural and depositional settings, mound growth could conceivably have rimmed much of the basin depocenter, in a trend that would extend for over 150 miles, linking up the current play area with noted mound occurrences in southeastern Saskatchewan."
North Dakota recently leased acreage northeast of Dickinson in Mercer, McLean, and Mountrail counties.
"Moreover, mound growth could also have occurred along portions of the Central Montana trough, both its north and south flanks," Montgomery writes.
The map shows the relatively small number of deep penetrations which PI counts as about one well in 37 sq miles-within Lodgepole facies trends interpreted as favorable for growth of Waulsortian type mounds.
The 110 page quarterly notes that workers do not expect the Lodgepole play to extend beyond the limits of the Bakken shale, thought to be the main source interval.
Field summary
The largest of five announced Lodgepole discoveries is Eland field, in northeastern 139n-97w. Previously referred to as Knopik-Klein and Hondl, it covers parts of 11 sq miles.
Eland has at least 12 wells capable of Lodgepole production, the most widely separated being 3-4 miles apart. The field's southeastern reaches are still being defined.
The other discoveries are: a mound informally named Hondl-Gress in 14- and 15-139n-96w; one well Versippi field, in 29-139n-96w; Conoco's Dickinson Lodgepole field just northwest of the town of Dickinson; and Duck Creek field consisting of two producing wells in 35-140n-97w and 2-139n-97w.
