NORX Project overview: The South Sun River Bak
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The South Sun River Bakken Prospect is an over-pressured Bakken shale resource play in Lewis & Clark County, Montana, in the developed Bakken Fairway that extends southwards from Alberta, Canada into northwest Montana. Potential oil production is estimated throughout the literature and publications at 10-15 MMBO per square mile in areas where the Bakken is thermally mature and where the critical middle Sappington Member is between 20’-30’ thick. It encompasses a superb land package of 10,097.99 mineral acres. It is where the western edge of the Bakken Fairway plunges into contact with the tectonically heated Thrust Zone and where we believe the resulting thermal maturity of the Bakken offers the highest potential for oil production.
Oil generation from organically rich shale units is considered to commence at Ro=0.65%, with peak oil generation occurring at Ro=1.00% and the end of oil generation occurring when Ro >1.3%. Ro values associated with the Bakken range from 0.6% in the east to >1.00% toward the west and south.
Reservoir quality in the middle member of the Bakken, known as the Sappington, is generally poor to fair, and is a calcite cemented siltstone. The porosity of the Sappington typically falls within the 3-10% range, but can reach as high as 15%. Permeability is also typically low in the 1-20 md range. However, resistivity readings in the Bakken have been recorded as high as 25,000 ohms. While oil generation has been recorded with resistivity as low as 35 ohms, this makes the Bakken formation an excellent candidate for horizontal completion techniques.
Specifically, the prospect lies within the key oil producing zone where thermal maturity (Ro) is between 0.7% and 1.5%. Oil production begins when Ro is above 0.65% and slows when Ro is over 1.3%.
The Total Oil Content (T.O.C.) readings in the prospect area are high as well, reading between 7% and 14%, and water content of the Bakken in the area is low.
There are excellent resistivity readings in the Upper and Lower Bakken members in key wells in the prospect area. The wells show excellent sections of the Bakken with resistivity readings over 400 ohms, well in excess of the minimum 35 ohms needed for possible oil production. The Middle Member of the Bakken, known as the Sappington Silt, is also well developed, with adequate porosity (3-15%) and permeability (1-20 md) for oil production.
Below are several wells in the prospect area and their Bakken section thickness and corresponding resistivity readings.
Sec.22 T17N-R6W ARCO/Steinbach # 1 Bakken: 76' Ohms: >2,000
Sec.32 T18N-R5W Shell/Krone 31-32 Bakken: 70' Ohms: 400
Sec.3-T14N-R6W Suncor/Flesher 14603 Bakken: 52' Ohms: 100- 300
Sec.9-T19N-R8W Sun Exploration/JB Long # 1-9 Ohms: >200
RESISTIVITY
Although resistivity values do not distinguish whether oil has been generated in situ within the shales at a given location, or has migrated into the shales, extensive Bakken core research by Schmoker and Hester (1990) has indicated that a resistivity value of greater than 35 ohm-m coincides with the onset of observable oil generation within Bakken shale.
Electric logs in the South Sun River Bakken Prospect area record resistivity readings in excess of 400 ohms, and over 2,000 ohms in certain wells. The Bakken is oil productive with as little as 35 Ohms. Currently, there is intense leasing activity in the area as many major companies are rapidly acquiring lease positions. Majors like Newfield Energy, Anschutz, Rosetta Resources and at least a dozen other companies have been extremely active in the area. Primary Petroleum and their major partner are just completing their last well of a 6 well drilling program in the South Sun River Bakken Prospect area.
Well control in the vicinity of the South Sun River Bakken Prospect displays excellent maturity in the Bakken that is superior to the above model. The Bakken is at a depth of 6,896’ feet in the key Krone # 31-32 well drilled by Shell. Resistivity in the Krone 31-32 well is in excess of 400 ohms, and throughout the South Sun River Bakken Prospect. All the reference wells can be found on this website under the tab “Reference Wells”.