b II N mm Milli”! THEQYS 3 1293 100 MIMI" l 3182 This is to certify that the thesis entitled A Study of the Dolomite/Calcite Ratios Relative to the Structures and Producing Zones of the Kawkawlin Oil Field, Bay County, Michigan presented by Michael Kevin Hyde has been accepted towards fulfillment of the requirements for Sc1ence Master 01’ degree in_Genlo.g¥_ W Major professor Date November 7, 1979 0-7839 A STUDY OF THE DOLOMITE/CALCITE RATIOS RELATIVE TO THE STRUCTURES AND PRODUCING ZONES OF THE KAWKAWLIN OIL FIELD BAY COUNTY, MICHIGAN BY Michael Kevin Hyde A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Geology 1979 ABSTRACT A STUDY OF THE DOLOMITE/CALCITE RATIOS RELATIVE TO THE STRUCTURES AND PRODUCING ZONES OF THE KAWKAWLIN OIL FIELD, BAY COUNTY, MICHIGAN BY Michael K. Hyde The middle Devonian carbonates are major producing zones in Michigan, much of the production being from dolomitic reservoir rocks. To obtain a better under- standing about the origin of dolomite and its relation- ship to the structural configuration, carbonate samples from Dundee formation wells were analyzed by the powdered x-ray diffraction technique to determine percentages from the various depth intervals and a petrographic analysis was performed on a core from the field. The highest degree of dolomitization from the Dundee formation was found at the top of the formation followed by a barren spot with increasing percentages of dolomite toward the bottom of the formation. All dolomite in the field was found to be epigenetic and showed a general correlation with the structural contour map. The geometry of folds and distribution of dolomite percentages suggest relat- ionships to faulting. Solution activity and fault breccia are the major causes of porosity in the Kawkawlin pay zone. ACKNOWLEDGEMENTS The writer wishes to express his sincere thanks to Dr. C. E. Prouty, Chairman of the Guidance Committee, for his devotion of time and interest in this problem and for his helpful suggestions and constructive criticism in reviewing this manuscript. Thanks are also extended to Dr. James W. Trow and Dr. Duncan Sibley for their helpful advice and review of the thesis text and illustrations. Foremost appreciation must go to my wife, Jane, for completing the typing of this work and for her patience, understanding, and encouragement. ii TABLE OF CONTENTS Page LIST OF TABLES . . . . . . . . . . . . . . . . . v LIST OF FIGURES . . . . . . . . . . . . . . . . . vi INTRODUCTION . . . . . . . . . . . . . . . . . . . 1 Purpose and Scope 3 Previous Work 4 STRATIGRAPHY L . . . . . . . . . . . . . . . . . . 7 General Framework . . . . . . . . . . . . . . 7 STRUCTURAL FRAMEWORK OF THE MICHIGAN BASIN . . . . 9 THE KAWKAWLIN OIL FIELD . . . . . . . . . . . . . 13 General . . . . . . . . . . . . . . . . . . . 13 Structure . . . . . . . . . . . 15 Structure Contour Map-Top of the Pay Zone . . 20 Porosity and Production of Hydrocarbons . . . 25 Lithology . . . . . . . . . 28 Analysis of Dolomite in the Kawkawlin Oil Field . . . . . . . . . . . . . . . . . 28 LIMESTONE AND DOLOMITE X-RAY ANALYSIS . . . . . . 30 Experimental Procedures . . . . . . . . . . . 30 Source of Samples . . . . . . . . . . . 30 Sample Selection . . . . . . . . 30 X- -ray Diffraction Procedures . . . . . . 31 The Method . . . . . . . . . . . . . . . 32 Procedure . . . . . . . . . 33 Standard Sample Preparation . . . . . . 34 Data Collection . . . . . . . . . . . . 36 Data Interpretation . . . . . . . . . . 39 Vertical Dolomite Variations . . . . . . 39 Lateral Dolomite Variations . . . . . . 42 U: \I General Correlations iii TABLE OF CONTENTS ISOPACHS General (Continued) Isopach of the Traverse Group Isopach of the Interval Between the Top of the Dundee and the Top of the Pay Zone PETROGENETIC ANALYSIS . . . . . . . . . . . . . General Relative Diagenetic Events . . . . . . . CONCLUSIONS APPENDICES . Appendix 1. Appendix 2. Appendix 3. Appendix 4. Appendix 5. BIBLIOGRAPHY List of Wells Used in Analysis List of Wells Used in Study Data for Cross Sections Lithologic Descriptions . Dolomite Percent from Dundee Formation iv 58 58 63 65 65 65 71 73 86 88 LIST OF TABLES Table Page 1. Different Components Used for Stan- 35 dardization LIST OF FIGURES Figure Page 1. Regional Structure Map of Michigan and Environs . . . . . . . . . . . . . . . 10 2. Major Structural Trends in the Michigan Basin . . . . . . . . . . . . . . . . . . 12 3. Location Map of Kawkawlin Field . . . . . . . 14 4. Well Location Map . . . . . . . . . . . . . . 17 5. Structure - Top of Dundee . . . . . . . . . . 19 6. Structure - Top of Pay Zone . . . . . . . . . 22 7a. Cross Sections. . . . . . . . . . . . . . . . 24 7b. Cross Section . . . . . . . . . . . . . . . . 24 8. Cross Section . . . . . . . . . . . . . . . . 27 9. Calibration Curve of Dolomite Percent . . . . 37 10a. Average Values for Kawkawlin Field . . . . . 40 10b. Average Values - Top 20 Feet - Less than 3% . 40 10c. Average Values - Top 20 Feet - 3% or more . . 4O lla. Vertical Dolomitization Patterns . . . . . . 41 11b. -Vertical Dolomitization Patterns . . . . . . 41 llc. High Dolomite Per cent - Top 20 Feet . . . . 41 11d. Low Dolomite Per cent - Top 20 Feet . . . . . 41 12. Dolomite Ratio Map; 0 - 20 Feet Below the Top of the Traverse Limestone . . . . . . . 45 vi LIST OF FIGURES (Continued) Figure Page 13. Dolomite Ratio Map; 20 - 40 Feet Below the Top of the Traverse Limestone . . . . 47 14. Dolomite Ratio Map; 40 - 60 Feet Below the Top of the Traverse Limestone . . . . 49 15. Dolomite Ratio Map; 60 - 80 Feet Below the Top of the Traverse Limestone . . . . 51 16. Dolomite Ratio Map; 80 - 100 Feet Below the Top of the Traverse Limestone . . . . 54 17. Dolomite Ratio Map; 100 - 120 Feet Below the Top of the Traverse Limestone . . . . S6 18. Isopach-Traverse Group . . . . . . . . . . . 6O 19. Isopach-Top of Dundee to Top of Pay Zone . . 62 20. Fossil Porosity - Top Pay . . . . . . . . . 65 21. Calcite Cement - Pore Space - Lower Pay. . . 65 22. Dolomite Growth Around Calcite Spar Lower Pay . . . . . . . . . . . . . . . . 66 23. Stylolite Through Calcite Spar Below Lower Pay . . . . . . . . . . . . . 66 24. Dolomite Rhombohedrons in Stylolite . Bottom of Lower Pay . . . . . . . . . . . 69 vii INTRODUCTION Some of the major reservoir rocks in Michigan oil and gas production are those of the Middle Devonian car- bonates: the Traverse Group; the Rogers City-Dundee Formations; and the Detroit River Group. Much of the production from these zones is located in roughly northwest-southeast or northeast-southwest trending anticlinal structures. It has been recognized for a number of years that linear structures in Michigan produce oil and gas from dolomite reservoir rock. Large portions of the porosity in these fields are thought to occur because of dolomitization of the host limestone, either early (diagenetic) or post consolidation (epigenet- ic) introduced by fluids, possibly hydrothermal, along faults and fractures within the field stone. Several geologists have noted that dolomitic limestone will tend to develop along joints, fractures, faults, and bedding planes within various limestone formations (Landes, 1946; Powell, 1950; Jodry, 1954; Tinklepuagh, 1957; Goodrich; 1957; Egleston, 1958; Paris, 1977; Newhart, 1976; Dastanpour, 1977; Hamrick, 1978). Widespread dolomitic facies have developed along structural highs and shallow epicontinental shelves (Prouty, 1948; Coney, 1948; Osmond, 1954; Adams and Rhodes, 1960; Deffeyes, et a1, 1965; Bathurst, 1971). Thus, it is appropriate to test the dolomite dis- tribution as related to Michigan producing structures as well as regional distributions. This has become a line of investigation within the Geology Department which could add information of a geologic and possibly economic nature, as well as test the wrenching deformation model (Prouty, 1972; 1976a, 1976b). Purpose and Scope The Kawkawlin Oil Field, Dundee Formation, in Bay County, Michigan, was selected as the subject of this study because of its prominence as a Middle Devonian Dundee producer with over 15,298,130 barrels of oil produced through the end of 1978. The availability of samples, density of wells, and location of this field to other studies of this type were taken into consideration in choosing this field. The purpose of the study will be to determine if there is dolomite present in the field; if so, to determine the ratio of dolomite to calcite, the relation- ship of the ratio to the structure; the relationship of the dolomite to production of oil and gas both as to horizontal and vertical relationships; attempt to deter- mine the origin of the dolomite - epigenetic and/or diagenetic; and other mechanisms relating to the porosity and production of oil from this field. All interpretations of the structure will be made from maps based on contacts confirmed by a microscopic study of samples selected from the wells. A comparative quantitative x-ray diffraction analysis of well samples 4 will be used to determine dolomite percentages. These percentages will then be displayed both on isodol maps and vertical bar graphs. An isopach map of the Traverse Group along with a structure contour map on top of the producing zone in the Dundee will be constructed as an aid in analyzing the relationships found between the isodolic maps and bar graphs compared to the structural map. There will also be an attempt to determine the relationship of the dolomitization to the porosity in the oil produc- tion capacity of the field. A petrogenetic analysis of selected core samples from the producing zone in the field will be done as an aid in determining the history of the dolomitization and porosity development in the field. It is the intent of the writer that the results of the study will provide helpful information on the characteristics of linear producing fields and aid in future oil and gas explora- tion in Michigan. Previous Work This study will be a continuation of a number of studies starting with Powell (1950) who used a titration- method of chemical analysis to determine the dolomite- S calcite ratio of the Dundee formation, Pinconning field. Jodry (1954) used the same method in showing dolomite trends related to producing oil fields in Mecosta County. Tinklepaugh (1957) studied some structures in central Michigan in the Dundee formation using the titration method and demonstrated the relationship between dolomite and fold axes. Dastanpour (1977), in the Dundee and Traverse of the Reynolds Oil Field, Montcalm County, and Hamrick (1978) in the Traverse Group of the Walker Oil Field, Kent and Ottawa Counties, used an x-ray diffraction method of determining the dolomite/calcite ratio. The last two showed not only relationships of dolomite distribution to the anticlinal forms but apparently detected some faults along and across the structure. Other studies by Young (1955) and Egleston (1958) compared their magnesium/calcium ratios with the struc- tural maps of the Stoney Lake Field and Winfield Fields but did not see a correlation between the dolomite and the structural maps. A regional study of the Dundee by Bloomer (1969) and the aforementioned studies by Hamrick and Dastanpour indicated the presence of two types of dolomite - epigene- tic and diagenetic. Other studies include the lithology and thickness of the Dundee formation (Cohee and Underwood, 1945) and a mechanical and statistical analysis of the Dundee by Bernardon (1957). Gardner (1974) made a comprehen- sive study of the Middle Devonian stratigraphy and depositional environments of the Michigan Basin. STRAT IGRAP HY General Framework The Kawkawlin Oil Field produces from a formation in the Middle Devonian rocks in the Michigan Basin. These rocks are represented by the Traverse Group, the Rogers City—Dundee formation, and the Detroit River Group. Only the Traverse Group and the Rogers City-Dundee for- mations were utilized in this study. The Traverse Group with the Bell Shale as the basil formation, probably lies disconformably on top of the Rogers City formation. Gardner (1974) described this as a subtle unconformity and Bloomer refers to this as Diastem Horizon with local zones of transition reflecting lower areas with a maximum relief probably never over a few feet. Baltrusaitis (1948) described the Traverse Group as being three separate divisions: the upper part being the Traverse formation; middle, the Traverse lime- stone; and the lower being the Bell Shale. The lithology of the Traverse Group has been described by Cohee (1947) in the Michigan Basin as argillaceous limestone with some pure limestone in Eastern Michigan, grading westward into calcareous shale with the limestone becoming more pure. In western Michigan, relatively pure limestone and some dolomite and dolomitic and argillaceous limestone. The 7 8 Bell Shale, the lower formation of the Traverse group, rests on tOp of the Rogers City-Dundee formation. The Bell Shale is described as fossiliferous gray shale which thins and is absent in the southwestern part of the Michigan Basin. The Rogers City formation beneath the Bell Shale rests on top of the Dundee formation. In the west central and western side of the Michigan Basin the Dundee formation and the Rogers City formation are collectively known as the Dundee due to the relatively indistinguishable characteristics in the subsurface, where they are described by Gardner (1974) as brown-gray limestone, anhydrite and porous secondary dolomite. STRUCTURAL FRAMEWORK OF THE MICHIGAN BASIN Michigan Basin is surrounded by various structural elements. To the north, northeast, and east is the North American Shield, on the west the Wisconsin Arch; in northern Indiana, the Kankakee Arch; and to the south- east and east, the thin Algonquin and Findlay arches. The Michigan Basin is an oblate and symmetrical structural and sedimentary basin on the interior platform of the United States. The Basin contains all the southern peninsula and includes the eastern part of the northern peninsula of Michigan, the northeast corner of Illinois, northwest Ohio, portions of Ontario, northern Indiana, and eastern Wisconsin (Figure 1). Of the several theories that have been developed about the origin of the Michigan Basin, Newcombe (1930) and Pirtle (1932) concluded that the Basin originated in Pre-Cambrian time with the present sedimetary structures folded by compression in Mississippian time. Lockett (1947) attributed the basin formation to differen- tial sedimentary loading with blockfaulting in the base- ment complex to create the structure seen today. Hinze and Merritt (1969) and Fowler and Kuenzi (1978) believed that a major rift zone played a dominant role in the subsidance of the Michigan Basin due to the added l l l 1 AM RICAN l \ 1'5: MCCNIGA l i l l ‘l l l l I 8A5! I f ‘7 (I g \ OOMF‘ \l' 1'0 . \N I I \" * x! r \. ‘ '4’ 1 AK“. ‘ /-"" " Figure 1 Regional Structure Map of Michigan and Environs 11 mass of mafic materials and then cooling and subsidence of these materials. Prouty (1976a) using LANDSAT imagery, has shown that lineaments are faults which fit a wrenching defor- mation model for the structures of the Michigan Basin. Some of the major fold axes, probably shear folds related to the wrenching system, are shown in Figure 2. Using the lineaments gathered by this process, Prouty has shown that many of the oil and gas fields in Michigan are at the intersection of these fault systems. Prouty believes that the shearing stresses came from a general eastward direction with the major deformation in post Osagean-Mississippean time. ’ ‘ ' “ltd-I1" 4" '~ “'4 I-z E I v .—----".r-T-.' 7 3 // f" I”? 1 3am}; H J Wu“ ‘ip'nuo (In K; I 9 / \ :T2V I /~f§ <1. : : ‘- . Q ' '. '-‘ ‘ *‘mimu "(swan “‘ '. I” ‘ . mm ; r _ 2 \ ". ‘ l . , .__--" I ._ "' ' , Winnings"? \\¢ .ii “ofii‘u’T‘ "' ‘ .‘.' ' ' ' ‘ % N... : ,1 m . . - . \ . -.| . " ‘ ‘ . fl, ' I ‘ ..... , ..’ I. —‘ .hlrillul‘.:’-,_II‘GIIVI--— IT'II"\5‘_Y III—ILT‘ 1 € \ / 5/ , I ‘ , -' “mu: " .-/ ," 1 ’ . . '/ I ‘ ! ‘ ~- Q l3." qpaj" /:":‘// fj,Fahn—IL-—-' W" . ‘ , , l 1 urn-Mann» ’ ‘ I cuouu .. —_:\: /’ I, _ ___."/'._ ,.V l otvo-u- .' » .-' ._ I - ‘ " / ./ ' I -' . J! ' "" \ ri' '/\ /" /" /' "-a'.‘/ L— \\ ‘l 3.. ~10. — /. "u _‘ /"' /- ./ L- \ \ . \/ SI.‘JII‘I / \ / l/ /7 .\ in... _. -' ‘ \ g -- ./ . ., .. ./ VJ HuLV VIA“ v...- V ./\ " ._.. _\\--eon\ urn uncut: --- \' “buf‘f: . \SD on .— \ \ ,. .. . _/' // - 'l L / ‘ \\ g—“"'K-- 671,3 ,2/ . \« J" “Ill \ (It! earn" ' "— ‘x\ ' \ /-‘ / /. TC ,V— 2:421 pp‘uo- [fin/(C , \!\ V-‘Ynfi. ~ I-“"'Ir Figure 2 Major Structural Trends in the Michigan BaSin (compiled by C. E., Prouty, 1971) THE KAWKAWLIN OIL FIELD General The Kawkawlin Oil Field is located in sections 1, 22, 3, 11, 12, T14N-R4E, Monitor Township and 4, 5, 6, 7, 8, 9, of T14-R5E Bangor Township; Sections 26, 27, 28, 29, 33, 34, 35, and 36, of TlSN-RSE, Kawkawlin Township; and Sec- tion 31, TlSN-RSE, Bangor Township, Bay County, Michigan. The Kawkawlin Oil Field is a northwest-southeast trending field with the strike of the main axis approxi- mately north 55 degrees west. The field is approximately 7 miles long and 1% miles wide. The Kawkawlin Oil Field was discovered on January 8, 1938, with the Martin #1 well located in the SE-SW-NE -section 1, T14N-R4E, Monitor Township, Bay County (Figure 3). This well produced from the Dundee. The field in- cludes a total of 286 wells producing from the Dundee with 4 wells producing from the Berea formation and 8 wells from the Detroit River. In 1978, the field produced a total of 114,307 barrels of oil for a production of 383.6 barrels of oil per well per year. There have been a total of 320 wells producing from the Dundee and it is these wells that are used in this study. The total production of the Kawkawlin Oil Field to the end of 1978 was 15,298,130 barrels of oil (Michigan Geological Survey, 1978). 13 l4 - I 3" .nt Nod-125:! -r..l:z » icwi ! _‘ 'gl_ “'1 M 1r}... 1- , Y: ‘ "if pgptll ._ I ll 'i. I . | ’01 . ' l ' 0.....- ‘ -.-;—1:-‘: -‘—'P—T--ii~- L’ ' 7" 411T >003).‘|-""1--]' - A § | , “ A .' s . -_- 5,7“! L" nun: ‘ ‘ t '_ 19.532133. E z 1 f l l } LOfilr-J—L-ILO-Lo'r—I o-LfiFL-E-o F ' ‘ i ' [nosed-mp: \ van-inhit‘J‘ 9 itlffll—‘Tulssluitt' f —L-T—A———.-—o-L—aq-.._' ‘ ' I k _L| l.l.l J-J. -;_.' 1. 1:1... / 11'? I: F! T T“ ! A L— _.—_'T—'r-- u E i I 1. T I i 1 I 1: ; ' l 4 ’“u‘iTn'n i Ll‘C_ l osctoLl f CL"! I i l i "‘ 34 l ‘ lr‘ : i ' I i l " i l l \ P.h4.1-T-€-_-f-4..--r-t Orr-{O‘T‘fi i l fr; ' I L ’ l *— § JSE‘_P‘.J-.3 . i I lutgglfn ISAlwlilaLkg-D. i : “'*' l I I , l I ‘ 0 : ’ : ‘ l ~4— L i 2 aw—Le- J—L+~ . i l I i ' i | 1 | .q LL..l--.:.a°t~.'.°:~L‘ ‘- " nus-Imam : L i '; i i 1' . “"‘9' __ g -L '5 ' - 3 LI_E_J-L--1 ‘ l- .. i l ("uu . j 1 '. 'l l 1 ‘pl 5 'l ctn¢_s.;__t_l ' fawn l ' h I or": . c'unroél '1 i 9 w --~—;—r—-—.--—+ l (74' J i l_l l l l l l l .‘ “ ?-J-i-alrolo—L-‘b-lo‘¥—1940L4.]J3“ ‘ ' 5 .' ‘ ‘ ‘ ' l l . ‘M‘ ' can 1LL‘CJ'. I ' IiRR7 ‘ if (.70. i ‘4‘.': 5 lith'Yfl‘Aw‘fiw Ifi'Tleléletal ..Lz 3?.“ ’ ' ‘ K . .EJ’Jl-‘z.’ u. GLii‘nlJuLJLkLJ.LLlAJ 31.3%.? 39-1.}.114341‘11-‘4; . . . l i . . I . l l "l - ' 1,_.__.;__...'-—-o—- ‘— ° 2 ‘ iLYII JAI‘IUI; (I sng’nalzoo 15:10:20! I J—ipquiqT-pa' | VASN' “fut-sit? . l . I 'T—i ; [-1 .. 9—. T13 'sl ‘ A . : ‘7? cue-nu 't""‘!“—i c-vsag Israel": l Luau Lang‘s-1:343 ‘U’M' . .- . LAX! (Nil 1 | I I ’ . . . ‘ i 0 l I I I, l l l l - T . p V 1 t Lfi I ' g ‘ 1 . AfirA—L A —'IjL1&—n—L" _ Willi: J 0 O '8 C“ Figure 3 Location Map of Kawkawlin Field Structure Structural interpretation of the Kawkawlin Field was based on drillers contacts confirmed by a microscopic study of samples selected from the wells to check the drillers tops; along with the 46 wells used in the x-ray portion of the study (Appendix 1). The well locations are shown in Figure 4 and well locations, ground elevations and depth corrected to sea level are located in Appendix 2. The structure contour map based on the contact of the Bell Shale, and the top of the Dundee (Figure 5) shows an assymmetrical anticlinal structure trending to the northwest-southeast with the dip on the southwest flank (basinward) of approximately 1.4 degrees and the dip on the northeast flank of approximately .78 degrees. This structural alignment fits well with other mid-basin Dundee-producing oil fields (Bloomer, 1969). There are cross structures evident within the major portions of the field. One is located in Section 34, Tl4N, 4E and another is located through approximately Section 2, T14N, R53 and to the eastern part of the field in sections 4, 5, 8, and 9 of Tl4N-R5E. The geometry suggests an en echelon folding along a shear couple having left lateral movement. The assymetrical aspect of the field with the 15 16 Figure 4 Well Location Map BAY Ga 1 Q 223 C C \43 232 12 233 224 ' o o g 0 29 28 27 26 25 3O 2114\218 223 225 C 15 ' 2'9 I C 256 24 26 217 (6 ' ' 21.20 c a 20 2:0 2.05 235 229 \222 227 2’3 215 2.. 209 I) I u . o g 0 o . 2V 231 226 “NW 2 212 203 214 202/ 293 . 204 3.4 I . . l 246 238 23 \234 274 275 2.5 280 302 287 300 3.03 21 ' 263 24s 242 273 255 251 266 223 293 30' 289 (b | ' ' O ' 0—. O 24! 245 249 \3/ 42 255 296 3 5 a a a 22' 2.50 o 0 a j 247 240 272 36/;B\ 292 262 a 38 31o 2;” - . - . . 233 - o . 238 - . 32 33 34 I 36 31 243 L3 270 267 260 304 ' 0 O o /n 09 237 257 261 266 308 306 3’. 313 . O O O U . 307 . C 239 4 265 269 29 3 I 0 . I / 311 312 v 3.’ ' Karin-Inn Twp, _— > _ _ _. ~ Bangor T'p ___... W L _ _ —_ .— _ fl.“ _ _..,Z. ____. w. A— _ _ _ . 1: 117 5‘ ’—\ ~ \ Monitor TID. .2 . ‘05 . 67 a ' I57 I68 Bangor Tip, 112 62 I 167 9 . 104 ._\ . . \ 4e 5 '53 C 4.9 \6. '66 I56 IIG II} 0 a \ a7 .7 63 7o . . o . 155 '46 '42 4 3 | 6 5 l T 5 36 69 ‘9 6‘ 5' 160 152 4 . o 0 0 13° .4 C .4 N 5 es 164 165 5. use, 5.0 66 o n '62 45 153 ‘ [54 [47 o 140 I'M 144 46 54 52 . o ' 0 l3? 8 I6I |§O I36 I4 5.8.4 59 53 22 -\59 0 I58 1:8 1::11/. 5 0 57-‘ ' .’___————0P"" \15 . x 20 127 I 1.2_ . 1.34 0170 172 174 189 13 4° KAWKAWLIN OIL FIELD 1 53 ' - 26 121 I71 7 1 ' a .54 . 1.0 . . . ,94 128 ‘33 131 Bay County, M1chlgan , , , we .36 82 ‘28 ‘86 I o ' n . . '25 ‘52 132 '69 179 178 190 192 ,9a _ l E ‘ I ' a ' n 0 WELL LOCATI N 10 .1 ,2 '26 . .8 7 a 135 I I75 177 193 of CROSS SECTION . . . . . 3.9 . 9 Drawn by MHyde . producer Scale: I1n.=.5mIIe 0 dry hole RQE R55 18 Figure 5 Structure - Top of Dundee L i. 16> D m L mm mm 91 F.9 E9wh .mME my Lm pm IMMD .o O N 1EU NWRD Imu Momw C e A U Wm KYRPHi wamoMm B T :. A .Wm. K 3n? __w1 I00 CWR I ,lfl! LII 20 sharper flank being basinward is a common characteristic of middle Devonian producing oil fields (Newcombe, 1933). The northwest-southeast trend of the Kawkawlin field coincides closely with one of the major fault trends gleaned from LANDSAT imagery (Prouty, l976a and b) (Fig- ure 2). The general geometry of the field (northwest to southeast), with cross structural highs and lows trending to the northeast-southwest along with inferred faults suggests a fault related folding episode in the Kawkawlin Oil Field. The relationships of the folds to the inferred faults can be related to a wrench fault system (see Moody, 1973, for an illustration). Prouty (1976) considers that the shear faulting occurs episodically through renewed activity of Pre~Cambrian fault patterns and that the major movement creating related en echelon shear folds probably occurred for the most part in the middle Mississippean time. Structure Contour Map - Top of the Pay Zone In interpreting the pay zone structure contour (Figure 6) in relation to the Dundee structure contour (Figure 5) one finds that the pay zone has related stratigraphic highs over the main axial highs in an asym- metrical linear figure trending northeast—southwest (see 21 Figure 6 Structure Top of Pay Zone 2.2. Kawkawlin Twp L o Bangor Twp. Monitor Two _._____..__ __ ___ __.__._. __..__.__-__________'——1 T /\/ 14 j N O KAWKAWLIN OIL FIELD Boy County, Michigan I STRUCTURE .0 9 TOP OF PAY ZONE Confourlniervol=10ft DOIum=S.L. Drawn by M. Hyde 9—1979 i Scole=1in2 .Smile 23 Figures 7a and 7b Cross Sections Upper Pay / Lower Fay V 24 KAWKAWLIN OIL FIELD Bay County, Michigan CROSS SECTIONS Doiui’iie’ot 92I97o 0 g Weii numbe' /\ PAY ZONE Drawn by M Hyde Top of Dundee m g I\) U! section 35-15N-4E, section 2-l4N-4E). Comparing the structure contour of the pay zone to the isopach map of the intervals between the Dundee structure top and the pay structure (Figure 18) we again see remarkable similarities indicating that a stratigraphic relation- ship to the porosity (for example, an axial high trending from section 2-14N-4E through section 12-l3N-4E). The closure in section 4-14N-4E is similar in each of the structure maps. A cross structural high is seen in section 2—14N-4E to Section 35-14N-4E. Porosity and Production of Hydrocarbons The drillers log for the Gulf Schweitzer #1 indicates two distinct pay zones within the core interval present. One occurred at 2271 to 2293 and the second at 2801 to 2853. Construction of three cross sections shows these two zones to be more or less continuous throughout the entire field. Looking at these cross sections (Figures 7a, 7b and Figure 8) the close correl- ation between the top of the Dundee and the pay zones indicates this field is a stratigraphic reservoir rather than indiscriminate dolomitization along fracture zones (see Appendix 3 for cross section data). 26 Figure 8 Cross Section C —2140' Top a( Dundee 2|8 Uppev Pay Lowey Pay 28 Lithology In a previous study by Gardner (1974) of a core, the Gulf Schweitzer #l, l-l4N-4E, Bay County, from the Kawkawlin Oil Field describes the general lithology of the field as a brown biocalcarenite crinoidal wacky- stone and packstone. There is a fossil hash of crinoid columnals with abundant brachiopods, tabulate corals with black carbonaceous partings. There is a good intercrystalline interfragmental and pinpoint vugular porosity with prominent brown oil stains. As one goes to the bottom of the core it is increasingly carbonaceous with tight microcrystalline limestone interbedded with a biocalcaronitic packstone. Gardner (1974) calls this assemblage quite typical of the biostromal type of limestone. The writer, after studying the core through thin section analysis, concurs in general with Gardner's description, with the additional comments that stylolites and microstylolite swarms are common throughout the intervals studied. See Appendix 4 for a description of the Dundee Formation, from two wells. Analysis of Dolomitization in the Kawkawlin Oil Field After detailed study by thin section, staining for calcite with alazarin red and potassium ferrocyanide, it 29 was noted that discrete dolomite rhombohedrons were located in and associated with stylolite and microstyl- olite swarms. None of the rhombehedrons were distorted by the stylolitization process indicating either dolomitization contemporaneous with or post stylolitiz- ation. Also, no dolomite other than these rhombehedrons were located with the exception of some pore filling dolomite spar (see Petrogenetic Analysis). LIMESTONE AND DOLOMITE X-RAY ANALYSIS Experimental Procedures Source of Samples Among the best specimens for analytical research in the subsurface are well core samples of known depth. Rotary drill samples are generally unsuitable for this type of analysis because of down-hole caving, contamina- tion, and lack of control as to depth. Cable tool samples have been found to be suitable (Krumbein and Sloss, 1963) because of the comparatively pure condition of the sample and the control available for depth location. The well samples used in this study were cable tool samples from the Kawkawlin Oil Field. Sample Selection After careful consideration of the samples available, 46 wells were chosen to be analyzed. Careful consideration was given to the spacing of the wells to assure good representation throughout the field. Those samples that had not been previously washed were cleaned in distilled water and dried thoroughly. Samples were chosen for 20 foot intervals from the top of the Dundee to the bottom of 30 31 the hole. Each sample consisted of approximately 4 grams with some variation of sample size because of the quantity and availability of samples. The average depth in this study penetrated approximately 120 feet into the Dundee. X-Ray Diffraction Procedures Before the x-ray diffraction method was developed, previous chemical methods utilized in the determination of dolomite and limestone percentages were generally very tedious and time consuming. The new technique of x-ray diffraction can offer speed without sacrificing the accuracy and precision that was found in chemical procedures. Determination of dolomite percent based on x-ray diffraction uses the crystal phases of calcite and dolomite to determine the percentage and is therefore independent of other Ca and Mg carbonate minerals (Tenet and Berge, 1957). This technique has been utilized by many people in their pursuit of geological research (Tenet and Berger, 1956; Weber, 1967; Gunatilaaka and Till, 1971; Badiozamani, 1973; Folk and Lynton, 1975; and Dastanpour, 1977). This 32 technique has the advantage of speed with accuracy and precision comparable with chemical procedures (Kutsykovich, 1971; Gunatilaaka and Till, 1971;). However, Lumson (1979) points out systematical errors in the use of x-ray diffraction in determining dolomite percentages. These possible sources of errors should be considered whenever the x-ray diffraction technique is utilized. Lundstrom found that the precision with samples of 5% or less dolomite could be 3%. However, this precision increased to 1.5% for samples with 10% or more dolomite. Ten random samples from the sample suite were split. Each split was analyzed utilizing the x-ray technique described above and the precision utilizing these samples was found to be 1% or better. The Method The relationship between peak intensities and absorp- tive properties of minerals is the basis for determining the relative quantities of multi-component mixtures utili— zing the x-ray diffraction technique. The method followed in this study consists of measur- ing the relative peak heights of the strongest powder x-ray diffraction line of calcite and dolomite using a series of samples of known proportions. Then a comparison 33 is made utilizing a series of samples of unknown relative quantities (Tenet, 1956). This method is suitable for determining the quantitative ratios for the minerals present in a specimen. When an accurate quantitative measurement of a single mineral phase is required, a Spiking Internal Standard System has been suggested by Guanatilaaka and Till (1971). Diffraction peak intensities are influenced by grain size, sample packing and mineral orientation (Jenkins and DeVries, 1968). In order to reduce varia- bility and improve reproducability of the results, all samples x-rayed were crushed and ground by an electric grinder for approximately 10 minutes to less than 256 mesh fractions. All powdered samples were packed consistently tight into the sample holders and efforts were made to make sure the sample surface was smooth as practical. Procedure The powdered samples were packed into a sample holder and placed in a General Electric x-ray diffraction goni- meter and irradiated using Nickle filtration, copper K alpha radiation, SOKV, 10MA, rate meter 16 and a time 34 constant of 2. The readings were taken with a 1 degree, 0.10 degree slit system. Also, linear-amplifi- cation and pulse discrimination were utilized. A calcite intensity of 3.03 angstroms and a dolomite intensity of 2.88 angstroms at the 2 theta position were determined by utilizing the rate meter to position the counter over the most intense peak. Each position was then counted per 100 seconds and each sample was scanned twice (the sample rotated 180 degrees) and the average intensity for each mineral present was found. This method differs from previous studies of Dastanpour (1977) and Hamrick (1978) in that, rather than measuring peak intensity from a chart, the peak intensity was directly counted and calculated on a scaler counter. Utilizing the standards previously pre- pared by Dastanpour (1977) it was determined that this method gave results agreeable and compatible with calcul- ating the peak intensities from a rate chart, but requiring less time. Standard Sample Preparation In the study, previously prepared Dolomite calibrat- ion standards were used. These standards were prepared by 35 Dastanpour for a recently completed investigation (1977). In the following paragraphs and Table l is a description by Dastanpour of the methods he used in preparation of calibration standards. Both dolomite and calcium carbonate were used for standardization from selected grains from purchased specimens. Dolomite grains were left in five per cent hydrochloric acid for several hours to dissolve the very fine calcite minerals that might have grown in between the dolomite crystal. The grains were then thoroughly washed with distilled water and dried. Different prOportions of dolomite and calcite were weighed to an accuracy of l/lOth of 1 mg. Table 1 shows the different mixtures used. Table 1. Different components used for Standardization Weight percent Grams Grams dolomite Mass dolomite Mass dolomite 15 0.3000 1.7000 25 0.5000 1.5000 30 0.6000 1.4000 50 1.0000 1.0000 60 1.2000 0.8000 75 1.5000 0.5000 90 1.8000 0.2000 100 2.0000 0.0000 w .3» Each component was then mixed completely. Three samples of each concentration were scanned twice (sample rotated 180 degrees). Therefore each point on the curve represents the average results from 6 points. The cali- bration curve was established by plotting the dolomite (dolomite plus calcite) times 100 intensity ratio as measured versus the weight percent dolomite in the mixture (Figure 9). It should be mentioned that the meaning of dolomite percent as used here is percent of total mag- nesium calcium carbonate (MgC03 CaCO3) plus calcite (CaCo3) which is present as dolomite in a rock specimen. The dolomite described in this study is an ideal dolomite. Goldsmith and Graf (1958) identified ideal mineral dolomite as a rhombehedral carbonate containing equal molar proportions of calcium carbonate and magnesium carbonate. The characteristic spacing of atomic planes parallel to the (211) crystallographic plane is 2.88 angstroms in ideal dolomite. This characteristic is seen in x-ray diffraction patterns as symmetrical and sharp peak intensity. Data Collection Correlation coefficient between peak intensities and mass of dolomite percents from the standard samples is 100 hC . :19..- hD 37 100- 90fi 80‘ 50‘ 40‘ 30-1 20~ 10‘ ‘ -?.:r.o--L 9 :uo- ' nD — neisn. O; Dolomite Pear at 2 .fi '0 0 . no = height ofCa1c1te_ Peac at 3 Calibration Curve of Dolomite Percent C) 00 (1) :DO :l:-0 \A) 38 0.998 (r = 0.998) indicating a high correlation between the two variables. As the correlation curve (Figure 8) shows, a calculated peak intensity value hD x 100 hD + hC represents the amount of dolomite percent concentrated in that sample. Expressed another way: Dolomite = Dolomite mass x 100 = Dolomite peak x 100 percent (Dolomite + Calcite) mass (Dolomite + Calcite peak) The 327 samples from the 46 wells studied were scan- ned twice and the average intensity peaks for both calcite and dolomite were found. The dolomite percent of each sample was then calculated by using Dolomite percent 3 Dolomite average peak x 100 (Dolomite + Calcite) average peak See Appendix 4 for the permit numbers and the corres- ponding dolomite percentage derived from the x-ray analy- sis. Utilizing these data both vertical and lateral variations in the dolomite percent were drafted and inter- pretations were based on these drawings. 39 Data Interpretation The interval of study in the Kawkawlin Oil Field is the Dundee formation. This formation was divided into a series of 20 foot intervals in each well. All wells penetrated the Dundee to 120 feet with some to deeper depths. These data were incorporated in the bar graphs. Percent dolomite for the intervals was calculated from the results of the x-ray analysis (Appendix 5). Vertical and horizontal variations of dolomite percent is discussed below. Vertical Dolomite Variation Dolomite percent values of each well were plotted against their depth below the top of the formation. Various vertical dolomitization patterns within the Dundee Formation are shown in Figures 10 and 11. Figure 10a shows the average of all the wells in the study area. This figure shows that the top 20 feet averages the high- est dolomite percent of the wells studied. This is follow- ed downward by a relatively barren zone. The next zone increases in dolomite with the fourth zone again showing a relatively barren area of dolomite. From here there is a general increase of dolomite to the bottom of the hole. Figures 10a, 10b, and 10c represent a breakdown Depth Below Top of Dundee Formation 4O 0‘- 20 20 -40 40-60 I 50-80 80-100 100—- 120 120-140, 140-160 D l l l Average Values for Kawkawlin Field Figure 10a Dolomite 2 3 4 s s 7 a A A L l % 1 0-20 [ 20-40 I 40-60 60- 00 00-100 100-120 120—140 140-160 l l Average Values - Top 20 Feet - Less than 3% Figure lOb .% Dolomite 1 3 4 s 6 7 a 0 PM L 0- 20 20 - 40‘ 40- 60 60- 80 80- 100 100-120 i I I 120-140} 140-160 Average Values - Top 20 Feet - 3% or More Figure 10c Average Vertical Dolomitization Patterns Depth Below Top of Dundee Formation 41 % Dolomite % Dolomite # 0 1 2 3 4 s 7 43 1 1 l l 1 L l #41 0 1L 2 3 4 5 6 7 0-20 0-20 * ' ‘ L L 4 20-40 2°_40 40-50 “23'3“ £5.33. 60—60 L 80—100 _ _____fi 80100 ‘°°“2° 100-120 -140 """“ Figure l a Figure 11b Selected Wells % Dolomite ’14 . o 1 2 3 4 s s 7 8 9 10 11 12 13 14 1s 0-20 20-4 40- 60- so 80~100 100-12 120-14 140— 160 High Dolomite % - Top 20 Feet Figure 11c % Dolomite #40 0 1 2 a 4 5 e 7 a 9 10 11 12 13 14 1s 0" 20- 40-60 60-80 80-100 100-120 120—140 Low Dolomite % - Top 20 Feet Figure 11d Vertical Dolomitization Patterns 42 of the total average by using the top 20 foot zone - those with less than 3% dolomite and those with 3% or more dolomite. These figures, except for the top 20 feet, follow the general trend established in the total field average. Figure 10a, a dry hole, follows the same general trend established by less than 3% from the top twenty foot interval figure. Figure 11b, a producer, follows the same general trend established by the figure of greater than 3% in the top 20 feet. The next two figures (11c and 11d) represent the high value and the low value of the top 20 feet. Both of these show the same trend of increasing dolomite. Interval 40 - 60 shows an increase again, with interval 60 - 80 a decrease and then a general increase to the bottom of the hole. Lateral Variations The data derived from the analysis of the 46 wells were utilized in making dolomite ratio maps which indicate the relative degree of dolomitization along the Kawkawlin structure. Percent values for each interval were plotted on the base map of the Kawkawlin Oil Field. Lines of equal dolomite percent (isodols) were drawn. The values range between 1% and 18%. 43 Isodols: 0-20 feet (Figure 12) Pronounced axial trends can be located in section 5-14N-5E and in sections 2 and 3 of l4N-4E; also trends in section 33-15N-4E and sections 11-12 l4N-4E are seen. Cross structure can be seen in sections 34 and 25-15N-4E. 20-40 feet (Figure 13) There is an axially oriented high, section 12-14N-4E. In section 8-14N-SE a high has a similar orientation (E-W) as the strike of the south limb of the major en echelon fold and the intersection of the cross fault (Figure 5). Section 28-15N-4E shows a cross structure not readily observed in Figure 5. 40-60 feet (Figure 14) The isodols generally follow NW structures in this interval. The curved high in SW SW section 28-15N-4E appears to follow the curved crossfold shown on the structure map. Also, the high (8%) in the north half of section 2-14N-4E may be the result of an intersection of several faults shown on the structure map. 60-80 feet (Figure 15) The high in section 2-14N-4E (4.5%) is located on the intersection of a crossfault and the axis of an en Figure 12 Dolomite Ratio Map 0 - 20 Feet Below the Top of the Traverse Limestone 45 {Monifor Twp. fiawkawlin Twp_ ( KAWKAWLlN OIL FIELD Bay County, Michigan DOLOMITE RATIO MAP, 0'—20' lsodol Contour Interval = 2% Drawn by M. Hyde 9—l979 Scale: tin.= .5mile 46 Figure 13 Dolomite Ratio Map 20 - 40 Feet Below the Top of the Traverse Limestone A Bay 00. 29 Liawkawlin Twp_ Monilor Twp. T L____° l Bangor Twp. Bangor Twp. KAWKAWLIN Bay County, DOLOMlTE RATIO MAP, 20'—4o' lsodol Conlour Interval = 2% Drawn by M. Hyde Scale: lin.= .5 mile OIL FlELD Michigan 9—l979 R4E R5E 48 Figure 14 Dolomite Ratio Map 40 - 60 Feet Below the Top of the Traverse Limestone Iiowkowlin Twp_ Monitor Twp. Bay 60. ‘1‘? KAWKAWLIN OIL FIELD Bay County, Michigan DOLOMITE RATIO MAP, 4o'-60' Isodol Contour Interval = 2% Drawn by M. Hyde 9—I979 Scale? lin.=.5m1le I R4E [m SO Figure 15 Dolomite Ratio Map 60 - 80 Feet Below the Top of the Traverse Limestone '29 3') ,,.,-.'E°“°"_“",lip- _ . MonHor Twp. I KAWKAWLIN OIL FIELD Bay County, Michigan DOLOMITE RATIO MAP, 60'—80‘ Isodol Contour Interval = 2% [flown by M.Hydo 9—l979 I Scale I1n=.51nfle II) 32 \\ Bangor Twp. Bangor Twp. 4 a 53/- 52 echelon fold; cross-structures in sections 1, 3-14N-4E, Section 6—14N-5E and 3S-lSN-4F are evident. 80-100 feet (Figure 16) Salients of isodols appear to be oriented E-W and across axial trends of the field and are offset as if along en echelon fault trends. The 6% isodol in section l-l4N-4E seems to follow an en echelon fold. The 4% isodol in section 1 follows the axis and appears to be cross faulted also. In section 33-15N-4E the 6% isodol may be located at an intersection of fault and en echelon fold. 100-120 feet (Figure 17) This interval contains the highest concentration of dolomite found. The dolomite follows the general struc- ture trend and the high dolomite percents again are loca- ted on or near inferred faults, i.e., Section 9 l4N-SE; and Sections 1 and 2 l4N-R4E. A cross structural trend can be located in Section 2 l4N-4E. A NW‘SE dolomite high located in Sections 25 and 26 of 14N-4E may indicate faults that have no structural expression. 53 Figure 16 Dolomite Ratio Map 80 - 100 Feet Below the Top of the Traverse Limestone Bay 00. 29 |_Kawkawlin Twp_ ~I_ Bangor Twp. Monitor Twp. ‘I -I Bangor Twp. 9 5 4 4 O O KAWKAWLIN OIL FIELD Bay County, Michigan DOLOMITE RATIO MAP, 80'—IOO Isodol Contour Interval = 2% Drawn by M. Hyde 9—1979 Scale: lin.= .Smile U1 U1 Figure 17 Dolomite Ratio Map 100 - 120 Feet Below the Top of the Traverse Limestone KAWKAWLIN OIL FIELD Bay County, Michigan DOLOMITE RATIO MAP, IOO'—120' |=2°/o Contour lnterva Isodol 57 General Correlations General correlations between the isodolic maps include high concentrations of dolomite in section l-14N-4E on the 0-20, 40-60, 60—80, and the 100-120 intervals; also in section 9-14N-4E of the 60—80 and the 100-120 intervals. The dolomitization patterns of each isodolic map (Figures 12 through 17) roughly correlate with the general structural alignment of the Kawkawlin Field. However, individual dolomitization patterns tend to coincide with inferred faults rather than structural highs. Increased areas of high dolomite percent tend to be along the intersection of faults. The general correl— ation of the dolomitization patterns with the major axis of the field would indicate that the avenues along which dolomitization occurred are related in some way to the major folding and origin of the field. This could infer faulting and fracturing. The increase in dolomite at the intersection of inferred faults and not necessarily on the axis of the fold may be related to the non-axial position of some of the channel paths controlling the circulation of the fluids that brought about dolomitiz- ation. Isopachs General The isopach maps of Cohee (1945) and again of Gardner (1974) of the Rogers City-Dundee formation indicate that the formation thins to the south and southwest part of the Basin. The thinning of the interval is due to nondeposition rather than erosion. The Saginaw Bay area is considered the center of deposition during Dundee time (Gardner, 1974) and has been a depocenter intermittently from the Cambrian to the Devonian time (Fisher, 1969) or Middle Mississippean time (Prouty, 1970). Isopach of the Traverse Group There is a general lack of correlation between the Traverse Group isopach (Figure 18) and the Dundee struc- ture contour map (Figure 5), indicating that the folded structure was not present during Traverse time. However, there is some indication of thickening along lines of faults and fault intersections (i.e., the northwest corner of section 26-15N-4E and the center of section 1-14N-4E) indicating the fault system which later devel— Oped the anticline as a shear fold. An earlier episode of faulting might have occurred in Dundee time, with karsting along the faults active at that time. These 58 59 Figure 18 Isopach-Traverse Group 60 BAV Cu. KAWKAWLIN OIL FIELD Bay County, Michigan ISOPACH-TRAVERSE GROUP C_I.=5ft. Drawn by MHyde Scale: Iin=5mile 9 —1979 . producer 0 dry hole 61 Figure 19 Isopach-Top of Dundee to top of Pay Zone 32 (Monitor Twp. 5 Ijawkawlin Twp 68/ . Bangor Twp. .___—..______ Bangor Twp. 6° KAWKAWLIN OIL FIELD Bay County, Michigan ISOPACH—TOP OF DUNDEE to TOP OF PAY ZONE Contour Interval = loft. Drawn by M. Hyde 9—l979 Scale= I in.= .5mile 63 and other faults may have been reactivated at the time of the post-Traverse folding, which, along with other major basin folds are considered drag folds under a wrenching system (Prouty, 1976). Isopach of the Interval Between the Top of the Dundee and the Top of the Pay Zone Figure 19 was constructed as an aid in interpret- ing the origin(s) of the pay zone. Three factors were considered in constructing this isopach map: 1) the pay zone utilized in constructing the map might be stratigraphic; 2) there should be porosity due to fracture and faulting and if so, this map should reveal it; 3) if this porosity is related to stratigraphic considerations there should be a relationship to the major axis of the field. This isopach map shows two general trends: 1) a general thinning of the interval along the main axis of the field (see sections 2, l-l4N-4E and Section 6-14N-RSE); 2) if porosity is related to faulting and fracturing, one would expect porosity throughout most of the interval. This should show as extreme thinning in the isopach. This is seen in section 35 lSN-SE, Sections 28 15N-5E. The anomalous situation seen in 64 section 33 of a thick isopach could be the result of at least two considerations: 1) the upper porosity did not develop in this particular area; 2) a horizon was missed for potential production of hydrocarbons. If this latter consideration is valid, this type of a map might prove a valuable tool in the development of this type of field. It should be noted, however, that the possibility exists that there was a failure to record the pay zone on the drillers' log, which is the basis for displaying the pay zone. PET ROGEN ET IC ANALYS I S A petrographic analysis of the Gulf-Schweitzer #1 Core, located in section 1, 14N-4E, of Bay County was performed. This core included the interval between 2772' and 2925' with the top of the Dundee at 2713'. First, a visual examination of the core was performed to determine the intervals to be examined microscopically. Seventeen intervals were chosen for the section prepara- tion, generally at each change in lithology. Both producing and non-producing zones were sampled. Each slide was then classified according to Dunham's (1962) classification. These slides were then utilized to determine the relative time of dolomite genesis, types of porosity and types of cement. Six more slides were prepared from the producing zones. To enhance the porosity visibility, a red dye was utilized in the mounting medium A point count of at least 500 points per slide was then performed to determine percentage porosity of the zones. The producing zones totaled an average of 14.3% with a high of 24.2% and a low of 8.3%. Relative Diagenetic Events A petrogenetic analysis of the cored section from the Gulf Schweitzer #1 shows porosity in the field . J as 63 66 Fossil Porosity - Top Pay x 6.3 Figure 20 2nd gen. cement ' 1 . rs. ,h Calcite Cement - Pore Space - Lower Pay - x 10 Figure 21 67 Dolomite Growth Around Calcite Spar - Lower Pay x Figure 22 Stylolite Through Calcite Spar - Below Lower Pay x 6.3 Figure 23 68 been developed through: 1) dissolution of fossils and fossil fragments (Figure 20) and an incomplete cemen- tation of either calcite or dolomite; or 2) dissolution and recrystallization of the original matrix with an pore filling carbonate l'h incomplete precipitation 0 (Figure 21). Relative events of diagenesis that can be recognized from this study include: a) at least a partial lithif- ication before dissolution or recrystallization as eviden- ced by a lack of fossil pore fractures which would be expected if the fossil had been dissolved before lithifi- cation (Figure 20); b) part lithification and crystalli- zation of calcite spar (Figure 21); c) a subsequent remov— al of the matrix with pure calcite spar being deposited either after or during this process. The writer believes the creation of most of the dissolution pore space (versus fault porosity) occurred at this time with latter events including pore reduction with precipitation of calcite and dolomite spar; d) during the preceding period, relatively large vugular porosity was developed (1-4cm.). A period of pore filling calcite spar (red) growth follow- ed (Figure 22). This calcite growth preceded at least some of the stylolitization and can be seen by stylolites cutting throagh a partially filled vug by spar calcite 1?) I" 1Q r H (l) N LA) b.) rt” :3. ‘4 U) *4 'J (L F“ I) a: (T (Li (J) I r DJ (I U) l l' f a O H .4 r r P N (U (1 H O .3 69 follows at least some of the pore filling spar calcite; f) much of the dolomitization occurs during stylolitiza- tion and most dolomite seems to be associated with the stylolites. Figure 34 shows the dolomite in discrete rhombehedrons associated with but not disrupted by the stylolitization process and indicates a secondary origin of the dolomite; g) what pore filling dolomite is found can be seen to be post calcite spar in the pore spaces by growth around the calcite spar and may be contempera- neous with the stylolites-related dolomite (Figure 22). 70 Dolomite Rhombohedrons in Stylolite - Bottom of Lower Pay x Figure 24 71 CONCLUSIONS From the analytical data obtained and the petro- graphical analysis done on the middle Devonian Dundee formation, certain conclusions may be drawn: 1. The highest values of dolomite percent were found at the top of the Dundee formation and close to the base of the lower producing zone in the Dundee formation. 2. There is a general correlation between the dolomiti- zation patterns and the structural configuration of the Dundee formation in the Kawkawlin Oil Field. 3. Petrographical analysis of a core from the Kawkawlin Oil Field indicates a post diagenetic type of dolo- mitization. 4. The analytical data obtained showing the percentage of dolomite in lateral variations indicates that the dolomitization is related to fault and intersection 72 A petrographical analysis indicates the porosity in the pay zone is caused by: a) dissolution of ; 2) incomplete cementation of U) fossil fragment secondary porosity; 3) fault and fold related breccia. There appears to be a good relationship between faults and folds as in a wrenching deformation model. The intersection of faults appeared to be the foci of higher dolomite percentages where it is believed the dolomitization fluids circulated. Analysis of maps indicates a stratigrap'i control of porosity rather than an indiscriminate dolomitiz- ation along fractures. 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' Ln I.\ 1,) U: (I) '-J Pay Zone('s) S.L.Datum 2292-2297, 2302-2327 2255-2279, 2284-2334 2253-2259 2239-2259, 2265-2318 2229-2249, 2256-2318 2232-2252,2264-2304 2266-2285 2275-2309 2253 2273 7786-2293 2281-2286, 2309-2314 2172- -2194, 2201-2265 2200-2212 2244-2250 2190-2207 2232-2242 2251-2254 2192-2208, 2228-2278 2230-2237 2262-2268 2225- 2248, 2256-2309 224 2- 2257, 2286-2291 2252- -2276, 2294-2317 2331-2333 2265 -2291, 2298 2351 2270- 2292, 2300-2333 2264- 2287, 2298-2335 2235- 2255, 2260-2334 2235- 2256, 2266-2334 2229- 2252, 2256-2318 2234-2256, 2267-2327 2230-2251, 2265-2321 2237-2251, 2254-2324 2220-2231, 2256-2276 2207- 2231, 2237-2248 2200-2207, 2238-2242 2213-2231, 2238-2295 2290-2335 2203-2223, 2237-2288 2245-2265 2231-2243 2259-2269 2265-2272 2276-2286 2253-2264 2295-2306 APPENDIX 4 LITHOLOGIC DESCRIPTIONS Well Name: Location: Permit No. Elevation: 84 APPENDIX 4 J. and H. Swantek #1 .W-SE-SE, Section 35, T15N-R4E 4821 596 feet above sea level Dundee Formation 2758-66 2766-78 2778-93 2793-2812 2812-20 2810-41 2841-58 2858-69 2869-73 Limestone, dark grayish-brown, dense, fossiliforous and some gray shale Limestone, dark brown to buff, dense Limestone, light brown and buff, dense; some secondary calcite Limestone, dark brown and light brown, dense; and some secondary calcite Limestone, light brown, dense; some secondary calcite Dolomite, light brown, very fine to coarsely crystalline, porous: and some buff limestone; some secondary calcite Limestone, buff, dense: dolomitic - drills up very fine Dolomite, light brown, porous; and buff, dolomitic limestone (Pay 2858-64) Limestone, buff, dolomitic APPENDIX 4 Well Name: Location: Permit No. Elevation: (Continued) J. H. and S. Kircher #1 SW-SW-VE, Section 2, T14N-R4E 7900 594 feet above sea level Dundee Formation 2706-10 2710-35 2735-55 2755-2813 2813-50 Limestone, dark brown, dolomitic; a little buff limestone, a little shale Limestone, light brown, dense Limestone, dark brown and buff, dense Limestone, light brown, dense to crystal- line; a little dolomite? (Pay 2771-84) Limestone, buff, dense to broken crystal- line - Pay 2818-24; 2824-32; 2846-50 APPENDIX 5 DOLOMITE PERCENT FROM DUNDEE FORMATION 06 96661 96021 2'8 6'6 0'6 7'2 6'2 6'0 6'6 9'7 2'6 2'2 6'2 6'6 6'2 6'6 9'6 9'2 6'6 8'8 1'6 6'0 0'9 7'6 1'2 9'6 62 6'2 82 8626 69961 12161 62161 2'1 22 92 62 92 9'0 2'9 1'2 0'6 8'1 6'6 L\ 6'9 6'2 9'2 2 2'9 2'6 6'6 v". 1'2 9'7 9'6 191 90961 09601 Ln 9'2 62 22 9'1 9'2 6'9 2'6 8'2 6'1 0'6 1'2 2'6 9'2 6'1 9'2 8'9 9'2 9'7 12 9686 02671 96861 9’9 2'0 8'7 6'2 7'2 0‘) I 6 6'6 9'9 9'1 6'6 0'9 «1'9 2'9 6'1 61 81 1'8 0'61 9'91 6'0 6'6 6'9 6'9 2'8 96661 9'6 6“? 6'9 7'8 8'9 6'6 9'6 21 91 6286 1'2 6'1 6'0 7'2 1'5' 6'6 61 6028 6 6'2 8'8 2'6 2 61 2666 9'6 2'1 2'1 \JI ‘\ ‘3 an 0 9'6 61 21 66661 6966 21661 1'6 2'2 1'9 6'2 1'2 6'6 0'81 6'6 98 01 2'6 0'1 ‘Q 2'9 9'2 6'2 6‘1 2'9 7'? 92861 09261 'C .1 1'8 9'6 9'2 0'1 Ca) 9 LI 6:61 Li! H 9\ 6'2 6'1 8'8 2'6 8'8 9'2 6'9 9’9 1'6 6'2 9 60861 29601 2'9 0'2 9‘5 9'2 IV A.) u'l 9'11 8'6 8'2 8'1 9'9 8‘2 9'1 (.41 2‘11 19'9 612 66861 6'2 6'6 9'9 9'9 9'6 6 2 1 1'1 v1 9'6 16691 28061 8'1 6'1 2'1 6'2 v’l 6'9 '2 6 9‘9 6'2 6'6 4} A ‘1‘ 8’9 IOZI“OOI ° 0N 119M 0 (,N JImJBJ .02“0 .08’09 .09‘07 .09“02 IOOI’OQ 091“021 .091‘091 I J.\ NOIlVNHOJ HHGNDG N088 lNHOBfld HlIHO1OG g XIflNHddV DOLOMITE PERCENT FROM DUNDEE FORMATION (CONTENUED) Permit 1 0-20' Well NO. 80-100' 100-120‘ 120~140' 140—160' 40~60' 60~80' 20~40' No. 5.8 3.3 8.8 3.7 3.9 2.1 4.5 0.4 3.9 5.9 1.8 1.5 0.5 1.8 0.5 4.2 4.2 9640 31 4 10085 13942 32 2.6 9.1 2.5 1.7 0.2 NOS. 4.7 33 34 1.7 1.9 7.8 2.2 11177 3.8 2.0 8.6 5.4 8.2 10190 9824 9137 35 7.3 2.3 4 3.5 1.6 1.3 0.7 4.4 0.9 36 7 2.0 2.4 2.2 4.0 4.0 37 5.4 1.2 13.3 0.6 0.3 2.0 9098 38 3.5 1.3 10.8 1.2 1.3 8.8 5.3 0.5 14833 8655 1.9 3.2 0.9 0.9 2.2 40 41 6.5 3.5 5.6 4.0 \T 9682 9594 2.9 1.0 3.0 1.0 1.0 0.9 2 4 42 87 4_ 5.6 1.6 4 1.7 2.8 3.1 5.9 10.6 13486 43 \O 3.9 11703 15801 44 ‘1' A! 45 40 8.9 8.5 7.4 8.0 1.9 9.3 I" In) 1 BIBLIOGRAPHY 88 BIBLIOGRAPHY Adams, J.E., and Rhodes, M. 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E., 1976, Michigan Basin - A Wrenching Defor- mation Model? Geol. Soc. of Amer. Abst. with Programs, v. 8, no. 4, pp. 505. , 1976, Implications of Imagery Studies to Time and Origin of Michigan Basin Linear Structures: Abst., Am. Assoc. Petroleum Geologists Glst Ann. Meeting, pp. 102. Runyon, S. L., 1976, A Stratigraphic Analysis of the Traverse Group of Michigan: Unpublished Master's Thesis, Michigan State University. Suoko, P. R., 1977, Subsurface Dolomites, San Salvador, Bahamas: Jour. of Sed. Petrology, v. 43, no. 3, pp. 1063-1077. Syrjamaki, R., 1977, Stratigraphy of the Prairie du Chien Group of the Michigan Basin: Unpublished Master's Thesis, Michigan State University. Tennant, C. B., and Berger, R. W., 1956, X-Ray Deter- mination of Dolomite-Calcite Ratio of a Carbonate Rock: Am. Mineralogist, v. 42, pp. 23-29. Tinklepaugh, B. M., 1957, A Chemical, Statistical, and Structural Analysis of Secondary Dolomitization in the Rogers City-Dundee Formation of Central Michigan Basin: Unpublished Ph.D., Thesis, Michigan State University. Wanless, J.R., 1979, Limestone Response to Stress: Measure Solution and Dolomitization, Journal of Sed. Petrology, Vol. 49, No. 2, pp. 437-462. Young, R. T., 1955, Relationship of the Magnesium/ Calcium Ratio as Related to Structure in the Stony Lake Field, Michigan: Unpublished Master's Thesis, Michigan State University "7'111117"11111111111