THE Unlversity of CALGARY Cornpositional Variation In
Total Page：16
File Type：pdf, Size：1020Kb
THE UNlVERSITY OF CALGARY Cornpositional variation in formation fluids and their relation to fluîd flow and water-rock interaction in Devonian to Lower Cretaceous sedimentas, rocks of southem Alberta by Dirk Kirste A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES M PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF GEOLOGY AND GEOPHYSICS CALGARY, ALBERTA SEPTEMBER, 2000 O Dirk Kirste 2000 National library Bibliothèque nationale ml .,,da du Canada Acquisitions and Acquisitions ot Bibliographie Services services bibliographiques 395 Wdihgton Street 395, nie Wetlaim Otraw8ON K1AûN4 WONK1AûN4 canada Canada The author has granted a non- L'auteur a accordé une licence non exchive licence dowing the excIusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distniute or seli reproduire*prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic fonnats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propnéte du copyright in this thesis. Neither the droit d'auteur qui protège cette thése. thesis nor substantial extracts from it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Abstract Variations in the chernical composition of waters Ui six aquifers ranging in age fkom Uppa Devonian to Lower Cretaceous were examineci to determine the chernical and hydrologie controls on the evolution of formation tluids in southem Alberta. The principal factors affecthg fluid composition are mïxing, water-rock interaction, and bactaid sulfate redution. Mullng of chemically evolved formation waters with meteoric water has rdted in a complex regional distrriution of chernical constituents. Several episodes of meteoric Uinux are recognized based on isotopic and chernicd variations. ûverlain on the fluid mixing signature are a number of chdcal trends that are a product of water-rock interaction. Mineralogical control of the water chemistry is dominated by calcite-dolomite equilibrium in the carbonate and clastic reservoirs, aithough in the clastic reservoirs, calcium to magaesium activity ratios appear to be artifacts of earlia equilibria. The NiskdArcs formation waters are close to equilibrium with calcite, dolomite and anhydrite. Dissolved silica activities and pH of clastic-hosted waters are strongly infIuenced by the presence of clay minerals and srnectite-aqueous solution metastable equiïibrium. Bicarbonate and sulfate content and stable isotopes of SUE&and carbon are interpreted to refl ect bacterial sulfate reduction that has occurred in areas affected by meteoric influx. Fluid flow is dominated by south to north topography-driven flow with recharge in Alberta, Montana and Wyoming. Rapid changes in chernid composition and hydraulic head gradient indicate complex flow patterns that reflect changes in hydraulic conductivity adorcontinuity of aquifers, and structural features like the SweetgrasslBow Island Arch and the Vdcan Low. ... lll Acknowledgements Three have been numerous people who have provided me with the support and inspiration needed to cany me through this endeavor. First and foremost, thanks are extended to Ian Hutcheon who could always be relied on for insight and clanty and cash when confusion or disillusion or poverty threatened- Tmy Gordon, Lany Bentley, Ron Spencer, Dave Pattison, Ed Ghent all provided guidance and answen to questions only a grad student could ask. Graham Simpson, John Cody, Scott McLeUan and dl of the other grad students who entertainai and enlightened. In particular I want to express my thanks to Cindy Riediger, iMa.Fowler, Vern Stasiuk and Fari Goodarzi for encouraging me to return to research af€era long hiatus. The stable isotope laboratory of Dr. H.R. Krouse and its occupants Maria, Jesusa and Nenita need to be thanked profusely. Special thanks to Maurice Shevalier for keeping the analytical and computational side of the research machine running. 1 am gratefüi to the following who provided money or savices needed to conduct the research. Kaush Rakhit of Rakhit Petroleum Consulhg provided access to the AEUB database of water chemistry. Wayne Cox and PanCanadian Petroleum Ltd. provided money and a tremendous amount of logistic support. Lithoprobe for financial support. The AOSTRA COURSE funds also provided financial support. Ian Hutcheon's NSERC operating gant funded a substantial part of the sample collection and analyses. Financial assistance is gratefully acknowledged from the University of Calgary Faculty of Graduate Studies through scholarships, AAPG Grants-in-Aid Foundation, Geological Society of America, and SPWLA. 1 would also like to thank my parents and family for al1 that they have done. CHAPTER 3 FLUD FLOW INTRODUCTION................................................................................. ,135 FLOWMODE~S .................................................................................................................. 138 STABLEISOTOPES OF OXYGEN AND HYDRûGEN ........................................................................ 142 KYDROSTRAT~GRAPHY.................................................................................................... 143 RESULTS ..........................................................................................146 6'8~-m)COMPOSITION OF THE FORMATION WATER ................................................................... 146 REGIONALDfSTRIBüTfON OF FRESHWATER HYDRAULIC HEAD, CL COMPOSITION, AND 6"0 VALUES .. 150 NWArcs Aquger fluid frow paths ................................................................................... 154 Mksissippian Aqu$erfruidflow paths ............................................................................... 156 Jurassir Aqu1j2rfluidflowpaths ....................................................................................... 158 Lower Mannville Aqu~Jierfluidjlowpaths ........................................................................... 160 Upper Mannville AqrrgerJluidJav paths- .......................................................................... 162 VikingLBow Island Aquijierrfluidflow paths ......................................................................... 164 PRESSURE- DEPTHPLOTS ................................................................................................. 166 OXYGENISOTOPlC COMPOSlTlON AND WATER-ROCK INTtRACTION ............................................. 173 6"O-CL ........................................................................................................................... 180 GD-CL ......................................................................................................................... 186 DISCUSSION ...................................................................................... 187 CONCLUSIONS .................... ..., .......................................................... -2O O FUTURE WORK ................ ..............., ...... .,................. .......................... -202 GENERAL CONCLUSIONS..................................................................... 204 REFERENCES CITED ........................................................................... 2 05 LIST OF TABLES Table 2.1 Table 2.2 Table 2.3 Table 2.4 Table 2.5 Table 3.1 Table 3.2 vii List of Figures Figure 2. I General stratigraphy Figure 2.2 Map of the study ara Figure 2.3 NisWArcs Piper plot Figure 2.4 Missiçsippian Piper plot Figure 2.5 Sawtooth Piper plot Figure 2.6 Lower Mannville Piper plot Figure 2.7 Upper Maflllville Piper plot Figure 2.8 VikingBow Island Piper plot Figure 2.9 NisWArcs chlonde rnap Figure 2.10 NisWArcs bicarbonate rnap Figure 2.1 1 NisMArcs sulfate rnap Figure 2.12 Mississippian chloride rnap Figure 2.13 Mississippian bicarbonate rnap Figure 2.14 Mississippian sulfate rnap Figure 2.1 5 Sawtooth chloride rnap Figure 2.1 6 Sawtooth bicarbonate rnap Figure 2.17 Lower Mannville chloride rnap Figure 2.18 Lower Mannville bicarbonate map Figure 2.1 9 Lower Mannville sulfate rnap Figure 2.20 Lower Mannville latitude vs chloride plot Figure 2.21 Mississippian latitude vs chloride plot Figure 2.22 Upper Mannville chlonde rnap Figure 2.23 Upper Mannville bicarbonate rnap Figure 2.24 Upper Mannville sulfate map Figure 2.25 VikingBow Island chloride rnap Figure 2.26 VikingBow Island sulfate rnap Figure 2.27 NisWArcs major cations vs chloride plot Figure 2.28 NiskdArcs log a (HCO3/Hg)vs a (SO,) plot Figure 2.29 NisWArcs log a (M&-)vs a (s0,/ca2+)plot Figure 2.30 Calcitedolomite stability diagram Figure 2.3 1 Mississippian to Uppa Mannville sodium vs dnloride plots Figure 2.32 Mississippian to Upper Manndle calcium vs chloride plots Figure 2.33 Mississippian to Upper Mannville magnesium vs chloride plots .. VUI Figure 2.34 Mississippian to Upper Mannviile potassium vs chloride plots 89-90 Figure 2.35 Mississippian to Uppa MannviIle bicarbonate vs chloride plots 92-93 Figure 2.36 Mississippian to Upper Mannville sulfate vs chioride plots Figure 2.37 Smectite stability diagram Figure 2.38 Mississippian alimiinosiiicate stability diagrams Figure 2.39 Sawtooth duminosilicate stability diagrams Figure 2.40 Lower Mmville duminosilicate stability diagnuns Figure 2.41 Upper Mannville duminosilicate stability diagrams Figure 2.42 Lower Mannville log a (Na+M)