2009 Portland GSA Annual Meeting (18-21 October 2009)

Paper No. 5
Presentation Time: 9:00 AM-6:00 PM


ZENG, Zhengwen, HE, Jun, PEI, Peng and WANG, Yunyong, Geology and Geological Engineering, University of North Dakota, 81 Cornell St, Stop 8358, Grand Forks, ND 58202, zeng@und.nodak.edu

Bakken Formation is a rock unit occupying about 200,000 square miles of the subsurface of the Williston Basin, mainly in North Dakota, Montana, and Saskatchewan. The Bakken formation has three distinct members and therefore can be divided as upper, middle and lower Bakken. Shales that comprise the upper and lower members of the Bakken are world class source rocks. These shale members were deposited in marine conditions. The middle Bakken can be dolomite, limestone, or sandstone. The middle part is the main petroleum reservoir rock. The data used in this project is mainly obtained from the information provided by companies who once drilled production wells and wildcat wells in this area. There are 65 wells used in this project. Useful data and information include well logs, formation intervals, well location, production record, core analysis report, sample lithology descriptions, RQD measurement, and so on. Most of this information can be reached via the premium services on the website of North Dakota Department of Mineral Resource, and Core and Sample Library of the North Dakota Geologic Survey. Well logs from the DMR website include Gamma, Resistivity, Neutron, Sonic, and Density. However, it should be noticed that most of these 65 wells do not have all the above logs, and 45 wells’ logs are originally in the form of image instead of digit format. Interactive Petrophysics converts these log files into useful core parameters like clay volume, porosity, and saturation. The second way to get the core parameters is collecting data from the well reports submitted by commercial companies. Available core parameters in the well report were collected in ASC format, and imported into the database of Interactive Petrophysics. The core parameters obtained through the two approaches will be compared and provide reference for later analysis. This paper describes the development of a 3-D Bakken model.