Williston Basin Geologic Framework 5607 PRE PINE SALT UNCONFORMITY 5675 TOP CHARLES FORMATION 5958 5993 GREENPOINT MARKER BASE LAST SALT 6173 6219 TOP MISSION CANYON FORMATION STATE A MARKER
Williston Basin Geologic Framework The Williston Basin digital stratigraphic data files contain stratigraphic correlations including formation tops, lithologic picks, and significant intraformational markers for large areas or basins. These digital data files expedite the search for oil and gas by providing explorationists with a consistent regional geodigital (stratigraphic) framework necessary for the integration of other disparate subsurface data types such as drill stem tests, cores, perforations, stimulations, plugging methods, casing programs, mud programs, drill bit programs, production information, and many others. Explorationists need this depth-related information to begin detailed geologic analyses and mapping of hydrocarbon trends. Experience in regional stratigraphic studies, tested scientific methodologies, and commitment to superior quality have resulted in the largest commercial library of interpreted, regionally-correlated digital stratigraphic data files in the Williston Basin. These Williston Basin digital stratigraphic data files contain information on 16,413 wells. Forty-eight Paleozoic and Mesozoic intervals and markers were correlated in 15,043 of these wells which have the relevant geophysical logs necessary to make correlations. Locations and basic header information are also provided for the remaining wells. Overview Database INTERNALLY CONSISTENT CORRELATIONS - These Williston Basin digital stratigraphic data files were developed by a scientific team experienced in the regional stratigraphy of the Williston Basin to ensure an internally-consistent system of picking tops and markers. RIGOROUS ERROR CHECKING - The data have been subjected to rigorous errorchecking routines using computergenerated statistics and contour maps. Williston Basin experienced geologists also hand-contoured maps to check for regional consistency and compatibility with the stratigraphic models of the area. CORRECTED ELEVATION AND LOCATION DATA - All reported well locations were evaluated using the header data off well logs compared to vendor data. Elevation data from logs was cross-checked with vendor data and, where necessary, with 71/2 minute topographic maps. CLIENT TESTED FILES - The Williston Basin digital stratigraphic data have been client tested and designed for optimum quality and applicability. PERSONNEL INVESTED - A 17-member geologic team contributed a total of ten people-years worth of work to the Williston Basin digital stratigraphic data file. 15,043 Study Wells 48 Regional Stratigraphic Picks
12 Regional Stratigraphic Cross Sections Cross Sections Report Contents STRATIGRAPHIC DATA - This digital file contains the stratigraphic data, as well as information on well name, operator, location, API number, completion date, datum, and production status for 15,045 wells. CROSS SECTIONS - This appendix contains 12 regional cross sections documenting the geodigital framework in the Williston Basin DISC.
Williston Basin Geologic Framework HARDING BOWMAN ADAMS CORSON SIOUX DEWEY ZIEBACH POTTER WALWORTH EDMUNDS FAULK MCPHERSON CAMPBELL EMMONS MCINTOSH LOGAN MORTON BURLEIGH STUTSMAN LA OURE KIDDER WELLS SHERIDAN MCLEAN FOSTER ED Y RAMSEY BENSON PIERCE MCHENRY CAVALIER TOWNER ROLETTE WILLIAMS PERKINS DICKEY GRANT SLOPE HETTINGER BILLINGS GOLDEN VALLEY STARK DUNN MERCER McKENZIE WARD MOUNTRAIL OLIVER SHERIDAN DANIELS ROOSEVELT RICHARD McCONE DAWSON WIBAUX FALLON PRAIRIE CUSTER CARTER POWDER RIVER ROSEBUD GARFIELD VALLEY BUTTE SOUTH DAKOTA MONTANA CANADA NORTH DAKOTA MILES 50 0 N Study Boundary
Geologic Framework of the Williston Basin Study Table of Contents
TABLE OF CONTENTS TABLE OF CONTENTS... i ACKNOWLEDGMENTS... iii INTRODUCTION...... 1 THE WILLISTON BASIN... 1 METHODS..... 3 AN OVERVIEW OF THE STRATIGRAPHY... 4 STRATIGRAPHY...... 6 LOWER PALEOZOIC ERA... 6 PRECAMBRIAN... 6 DEADWOOD FORMATION... 6 WINNIPEG GROUP... 7 Black Island Formation... 7 Icebox and Roughlock Formations... 8 RED RIVER FORMATION... 9 STONY MOUNTAIN FORMATION... 10 Stoughton Member... 10 Gunton Member... 11 Stonewall Formation... 11 INTERLAKE FORMATION... 12 Lower Interlake Marker... 13 Interlake Formation... 13 MIDDLE PALEOZOIC ERA... 16 ASHERN FORMATION... 16 WINNIPEGOSIS FORMATION... 17 PRAIRIE FORMATION... 19 Prairie Salt... 21 Prairie Formation... 22 DAWSON BAY FORMATION... 23 SOURIS RIVER FORMATION... 24 DUPEROW FORMATION... 25 BIRDBEAR FORMATION... 27 THREE FORKS FORMATION... 28 UPPER PALEOZOIC ERA... 30 BAKKEN FORMATION... 30 MADISON GROUP... 31 Lodgepole Formation... 32 Mission Canyon Formation... 34 State A Marker... 34 Mission Canyon Formation... 35 Charles Formation... 36 Base of the Last Charles Salt... 37 Greenpoint Marker... 37 Charles Formation... 37 BIG SNOWY GROUP... 38 Kibbey Formation... 39 Otter Formation... 40 TYLER FORMATION... 41 AMSDEN FORMATION... 43 BROOM CREEK FORMATION... 45
OPECHE FORMATION... 46 Opeche Salt... 47 Opeche Formation... 47 MESOZOIC ERA... 48 SPEARFISH FORMATION... 48 Pre-Pine Salt Unconformity... 49 Pine Salt... 50 Pre-Jurassic Unconformity (and Saude Member)... 51 PIPER FORMATION... 53 Dunham Salt... 54 Kline Member... 55 Firemoon Member... 56 RIERDON FORMATION... 57 INYAN KARA FORMATION... 58 MOWRY SHALE... 60 GREENHORN LIMESTONE... 61 BIBLIOGRAPHY...... 63
Geologic Framework of the Williston Basin Selected Figures from the Study
FIGURE 1. Partial stratigraphic column of the Williston Basin. Oil-producing intervals are indicated by asterisks (modified from Bluemle et al., 1981). Return to Text
FIGURE 6. Gamma ray and resistivity log responses of the Red River Formation. Return to Text
Figure 14a. Core of the Oyloe No. 1 from 11,753 to 11,854 feet shows the lithologies of the Winnipegosis Formation on the shelf of the Elk Point Basin. The lithologies in this core represent a shallowing-upward sequence. Within the upper Winnipegosis, fossiliferous lime wackestone (11,833 to 11,854 feet), deposited in an open-marine environment, is gradationally overlain by dolomite mudstone and pelletal dolomite packstone (11,816 to 11,833 feet) deposited under more restricted conditions, possibly in an intertidal environment. These lithologies are overlain by lime mudstone, which contains anhydrite nodules and is interbedded with dolomite mudstone (11,800 to 11,816 feet). The rocks of the overlying lower Prairie Formation record further restriction. They grade upward from laminated dolomite mudstone (11,785 to 11,800 feet) to interbedded dolomite mudstone and halite (11,753 to 11,772 feet). Dolomite mudstone of the upper Winnipegosis Formation and lower Prairie Formation is productive. Depths shown on photograph correspond to well log. Continued on Next Page
Figure 30. Cross section across the Cedar Creek Anticline demonstrates thinning of the Charles Formation over Williston Basin structures. Up to 50% of the thickness of the Charles Formation is lost due to (1) a facies change from halite to carbonate on the structure, and (2) dissolution of uppermost Charles halite beds at the beginning of Kibbey deposition. Facies changes from halite to carbonates suggest that the Cedar Creek was a paleohigh during deposition of the Charles Formation. Dissolution of halite may have been due to regional uplift and to a "freshening" of Williston Basin water at the initiation of Kibbey deposition. Return to Text