StratigraphJc, Diagenetic and Geochemical Study of Cretaceous Strata in Central Saskatchewan A thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements For the Degree of Master of Science In Geology University of Regina by Autumn Q Wang Regina, Saskatchewan August, 2010 Copyright 2010: Autumn Q. Wang Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington OttawaONK1A0N4 OttawaONK1A0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-79906-2 Our file Notre reference ISBN: 978-0-494-79906-2 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'Internet, prefer, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. ••I Canada UNIVERSITY OF REGINA FACULTY OF GRADUATE STUDIES AND RESEARCH SUPERVISORY AND EXAMINING COMMITTEE Qiuxia (Autumn) Wang, candidate for the degree of Master of Science in Geology, has presented a thesis titled, Stratigraphic, Diagenetic and Geochemical Study of Cretaceous Strata in Central Saskatchewan, in an oral examination held on May 7, 2010. The following committee members have found the thesis acceptable in form and content, and that the candidate demonstrated satisfactory knowledge of the subject material. External Examiner: Ms. Melinda Yurowski, Subsurface Geological Lab Co-Supervisor: Dr. Guoxiang Chi, Department of Geology Co-Supervisor: *Dr. Per Kent Pedersen, Adjunct Professor, Department of Geology Committee Member: Dr. Hairuo Qing, Department of Geology Chair of Defense: Dr. Xue Dong Yang, Department of Computer Science *Not present at defense Abstract The poorly studied Cretaceous succession in central Saskatchewan is examined for vertical changes in sedimentary facies and diagenetic features in two continuous cores (3-28-33-23W2 and 6-18-36-6W3) in this study. The studied area includes Townships 28 to 41, Ranges 10 to 1 West of the Third Meridian and Ranges 28 to 20 West of the Second Meridian. Two hundred and four samples were collected and analyzed. Facies analysis shows that the Cretaceous was deposited in marginal marine to marine environments with facies changes closely related to sea-level variations. Four uncomformities were identified through core logging in between the Jurassic Success Formation and the Cantuar Formation, Cantuar and Pense Formations, the Second White Specks and First White Specks, and the Milk River and Lea Park Formations. A stratigraphic framework based on cores and well log correlations from southwestern Saskatchewan to southeastern Saskatchewan places the studied sections in a regional stratigraphic context. The regional cross section shows an eastern thinning trend over the Colorado Group, and indicates that the high topographic relief of the Cantuar Formation was scoured by Pense and Joli Fou transgression. The composition of the studied sandstones varies from quartzarenite, sublitharenite, subarkose, and litharenite to feldspathic litharenite. The diagenetic study of sandstones indicates that cementation, compaction, dissolution and I replacement were the main diagenetic processes. The porosity, estimated from point counting (n=200), ranges from 0% to 46%, and was mostly between 1% and 25%. The carbon and oxygen isotope analysis of calcite cements indicates that the significant depletion of 5180 values relates to the influence of meteoric water. The depleted 513C values may have been caused by meteoric water influx that 13 brought in low 5 C carbon isotope composition from soil-derived C02 or by the anaerobic microbial oxidation of organic carbon. The TOC analysis indicates that most of the shale of the Colorado Group in central Saskatchewan has a good to excellent source-rock potential. The organic matter of the Second White Specks and Carlile shale consists of a mixture of Type II and Type III kerogen, which is oil/gas prone. All of the other shales fall into the gas prone field, with mainly type III organic matter. The Tmax data and Ro value (<0.4%) indicates that the source rocks in central Saskatchewan are immature. These rocks are above the thermogenic oil and gas windows and gas production may be limited to bacterially-generated biogenic methane. II Acknowledgements This thesis is supported by an NSERC -CDR grant from Profico Energy and a Saskatchewan Industry and Resources grant to Drs. Guoxiang Chi and Per Kent Pedersen. I would like to thank my supervisors Dr. Guoxiang Chi and Dr. Per Kent Pedersen for their strong support, invaluable discussion, patience and encouragement. Particular thanks are due to Drs. J.E.Christopher and D.M. Kent for help in core logging and for stimulating discussions. Gratitude is also expressed to the staff of the Subsurface Geological Laboratory, and Saskatchewan Energy and Resources, for logistical support for core logging. A special thanks to my husband Jilu who always gives me encouragement, support and love. I extend my thanks to my colleague Michelle Hawke for support and assistance in the preparation of my thesis. Ill Table of Contents Abstract I Acknowledgements III Table of Contents IV List of Table VU List of figures VM Chapter 1 Introduction 1 1.1 Study area 1 1.2 General stratigraphy 3 1.3 Regional geology 11 1.4 Previous work 17 1.5 Objectives 21 1.6 Methods of Study 22 Chapter 2 Core Descriptions and Facies Analysis 27 2.1 Mannville Group 27 2.1.1 Cantuar Formation 27 2.1.2 Pense Formation 41 2.2 Colorado Group 48 2.2.1 Joli Fou Formation 48 2.2.2 Viking Formation 55 2.2.3 Westgate Formation 58 2.2.4 Fish Scale Formation 61 2.2.5 Belle Fourche Formation 65 IV 2.2.6 Second White Specks Formation 67 2.2.7 Carlile Formation 72 2.2.8 First White Specks Formation 73 2.3 Montana Group 76 2.3.1 Milk River Formation 76 2.3.2 Lea Park Formation 78 2.3.3 Belly River Formation 83 Chapter 3 Stratigraphic Correlation 89 3.1 Introduction 89 3.2 Structure and Isopach maps 91 3.3 Stratigraphic Correlation 100 3.3.1 Mannville Group 100 3.3.2 Colorado Group 102 3.3.3 Montana Group 108 3.4 Depositional Environments and Changes in Relative Sea-Level 111 Chapter 4 Diagenetic Studies 115 4.1 Introduction 115 4.2 Petrography of sandstones 115 4.2.1 Composition and texture 115 4.2.2 Diagenesis and paragenetic sequence 124 4.3 Organic matter study of shales 139 4.3.1 Rock-Eval analysis results 139 V 4.3.2 Source rock potential 142 4.3.3 Thermal maturity 148 4.4 Stable isotopes of carbonate components 155 4.4.1 Data description 155 4.4.2 Interpretation of the results 159 Chapter 5 Discussion 162 5.1 Sediment sources 162 5.2 Porosity 163 5.3 Implications for hydrocarbon exploration 164 5.4 Recommendation for future studies 166 Chapter 6 Conclusions 168 References 170 Appendix IPL well data retrieved from well tickets 182 VI List of Tables Table 1 Depth, porosity, and components of the sandstone samples from the well 3-28-33-23W2 and well 6-18-36-6W3 116 Table2 Rock-Eval analysis results of samples from Well 3-28-33-23W2 117 Table3 Rock-Eval analysis results of samples from Well 6-18-36-6W3 118 Table 4 Summary of Rock-Eval data from core samples of well 6-18-36-6W3 and 3-28-33-23W2 143 Table 5 Hydrocarbon source rock evaluation parameters for Rock-Eval pyrolysis data 144 Table 6 Results of Carbon and Oxygen Isotope analysis 156 VII List of Figures 1.1 A Map of the distribution of oil and gas fields in Saskatchewan showing the location of the study area 2 1.2 Location map showing the studied area 4 1.3 The facies belts of the interior Cretaceous sea 5 1.4 Stratigraphic correlation chart of Saskatchewan 7 1.5 Late Cretaceous Sea of North America 12 1.6 Tectonic elements of the Williston and Sweetgrass Arch region 16 1.7 Location of the two continuous corea studied 24 2.1 Lithofacies of the Mannville Group in well 6-18-36-6W3 28 2.2 Core photos showing various sedimentary structures of the lower lithofacies association of the Cantuar Formation in well 6-18-36-6W3 30 2.3 Core photos of the middle lithofacies association of the Cantuar Formation in well 6-18-36-6W3 31 2.4 Core photos showing various sedimentary structures of the upper lithofacies association of the Cantuar Formation in well 6-18-36-6W3 33 2.5 Lithofacies of the Mannville Group in well 3-28-33-23W2 35 2.6 Core photos of the middle lithofacies association of the Cantuar Formation in well 3-28-33-23W2 36 VIII 2.7 Core photos of the middle lithofacies association of the Cantuar Formation in well 3-28-33-23W2.