DOCSLIB.ORG

Faults and Associated Karst Collapse Suggest Conduits for Fluid Flow That Influence Hydraulic Fracturing-Induced Seismicity

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Faults and Associated Karst Collapse Suggest Conduits for Fluid Flow That Influence Hydraulic Fracturing-Induced Seismicity Faults and associated karst collapse suggest conduits for fluid flow that influence hydraulic fracturing- induced seismicity Elwyn Gallowaya, Tyler Haucka, Hilary Corlettb, Dinu Pana˘ a, and Ryan Schultza,1 aAlberta Geological Survey, Alberta Energy Regulator, Edmonton, AB T8N 3A3, Canada; and bDepartment of Physical Sciences, MacEwan University, Edmonton, AB T5J 4S2, Canada Edited by Paul Segall, Stanford University, Stanford, CA, and approved August 21, 2018 (received for review May 1, 2018) During December 2011, a swarm of moderate-magnitude earth- bore [up to hundreds of meters (18–21)]. Furthermore, geo- quakes was induced by hydraulic fracturing (HF) near Cardston, mechanical modeling reveals that poroelastic changes from HF Alberta. Despite seismological associations linking these two processes, are transmitted only locally (20). These results are in direct the hydrological and tectonic mechanisms involved remain unclear. In contradiction to HF-related earthquakes that are located kilo- this study, we interpret a 3D reflection-seismic survey to delve into the meters away from the closest well bore (e.g., refs. 2, 6, 11, 22, and geological factors related to these earthquakes. First, we document a 23). Specific to the Cardston case, earthquakes (located on re- basement-rooted fault on which the earthquake rupture occurred that gional arrays) were observed within the uppermost crystalline ∼ – extends above the targeted reservoir. Second, at the reservoir’s strati- basement, 1.5 km deeper than the target upper Stettler Big SI Appendix graphic level, anomalous subcircular features are recognized along the Valley Reservoir zone ( ,Fig.S1); this observation is fault and are interpreted as resulting from fault-associated karst pro- further complicated by the fact that the fault slip response oc- ∼ – cesses. These observations have implications for HF-induced seismicity, curred immediately (i.e., 1.5 3.0 h) after well stage stimulations as they suggest hydraulic communication over a large (vertical) dis- (11). Due to geological complexities/unknowns in the subsurface, tance, reconciling the discrepancy between the culprit well trajectory seismological and geomechanical approaches to explaining these and earthquake hypocenters. We speculate on how these newly iden- discrepancies remain speculative. tified geological factors could drive the sporadic appearance of induced Based on these complications, we instead look for geological indications of past fluid migration in a 3D reflection-seismic seismicity and thus be utilized to avoid earthquake hazards. survey that surrounds the Cardston earthquakes (Fig. 1). In this paper, we describe the methods by which we analyzed this dataset hydraulic fracturing | induced seismicity | hydraulically active faults | and then bolster our interpretation with additional earthquake, drill dissolution karst core, and well log data. Together, the intersection of these in- dependent datasets leads us to the conclusion that fault-associated nduced seismicity is a phenomenon by which stress accumu- fluid flow caused the dissolution of the Stettler Formation anhy- SCIENCES SI Appendix Ilating on a fault is suddenly released via an anthropogenically drites (Wabamun Group) ( ,Fig.S1) and resulted in ENVIRONMENTAL triggered shear slip. This phenomenon is well documented, with karst features that affected accommodation patterns in the overlying numerous cases related to mining, waste-water disposal, reser- upper Stettler/Big Valley/Exshaw interval near the Cardston hori- voir impoundment, and geothermal development activities (1). zontal well (CHW) location. This interpretation has implications for More recently, induced earthquakes have also been recognized understanding the induced seismicity caused by the CHW: The in- as the direct result of hydraulic fracturing (HF) stimulation of unconventional reservoirs (2–10). One such case occurred in Significance southern Alberta, Canada, near the town of Cardston (Fig. 1) (11). Starting in December, 2011, anomalous earthquakes oc- Induced earthquakes can be caused by hydraulic fracturing curred contemporaneously with the completion of a multistage (HF). However, the exact means by which stress changes are horizontal well in the uppermost Wabamun Group (also referred transferred to seismogenic faults are unknown. This paper “ ” to as the Exshaw play ). These induced events were of mod- provides evidence that a case of induced earthquakes in erate magnitude (up to moment magnitude 3), with hypocenters southern Alberta responded to increased pore pressure on a located in the shallow crystalline basement (11). fault in hydraulic communication with the HF operation. Induced earthquakes are thought to require three geo- Reflection-seismic and drill core data provide evidence that mechanical conditions: (i) the presence of a fault, (ii) nearly iii fluid flow along this fault caused strata underlying the target critical slip-orientation of the fault, and ( ) a means to perturb reservoir to dissolve, causing a karst collapse in the geo- stress on the fault past the critical condition (12). In general, the logical past. We suggest that seismogenic and hydraulically first two conditions are well-established requirements for fault active faults are geologically rare and that the injection rupture nucleation. However, the third point is contentious, since there are multiple anthropogenic means to communicate of fluid directly into them is even rarer, potentially explain- stress changes. For example, effective stress changes can be ing the small percentage of HF wells that cause induced communicated to the fault either through pore-pressure per- earthquakes. turbations transmitted along the damage zone of a mechanically active fault (13) or poroelastically through a (impermeable) rock Author contributions: R.S. designed research; E.G., T.H., H.C., D.P., and R.S. performed research; E.G., T.H., H.C., and R.S. analyzed data; and E.G., T.H., H.C., D.P., and R.S. wrote matrix (14). For disposal cases, pore-pressure diffusion is often the paper. the favorite speculative explanation, since continued injection The authors declare no conflict of interest. into permeable formations allows plausible communication over great distances until the intersection with a critically unstable This article is a PNAS Direct Submission. fault (e.g., refs. 15 and 16). However, for HF, this reasoning is Published under the PNAS license. complicated by additional conceptual hurdles. For example, HF 1To whom correspondence should be addressed. Email: [email protected]. wells inject into impermeable formations to stimulate reservoir This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. productivity (17); thus, reasonable pressure perturbations are 1073/pnas.1807549115/-/DCSupplemental. restricted to the stimulated reservoir zone proximal to the well Published online October 8, 2018. www.pnas.org/cgi/doi/10.1073/pnas.1807549115 PNAS | vol. 115 | no. 43 | E10003–E10012 Downloaded by guest on September 27, 2021 113.4° W 113.2° W 113.0° W 112.8° W Tectonic Setting The area under investigation is in the southern Alberta Plains, 49.6° N ∼10 km east of the triangle zone of the foothills, which repre- sents the approximate eastern limit of the Cordilleran defor- mation front. The sedimentary succession comprises Cambrian to Paleocene strata of the Western Canada Sedimentary Basin (WCSB), which overlie the Precambrian crystalline basement of St. Mary River the North American craton. The strata of the WCSB were de- SALTSALT 30 posited in three different general tectonic settings: a passive continental margin from the Neoproterozoic to Middle Devo- WSOF nian, a back-arc setting from the Late Devonian to Jurassic, and 49.4° N a foreland basin between the Jurassic and Eocene. Far-field stress related to the purported Late Devonian–Early Carbonif- Belly River 3D Seismic Study Area erous Antler and the Jurassic-to-Early Eocene Cordilleran CHW St.S Mary Reservoir contraction to the west may be responsible for faulting in the investigated area. Postorogenic isostatic reequilibration of the Cordilleran foreland system was accompanied by the removal of two kilometers of strata in the Alberta Plains (26), which may have triggered minor Late Cenozoic faulting or fault reactivation. 49.2° N Quaternary deposits cover the bedrock. Cardston First, we considered public 2D reflection-seismic transects from Canada’s LITHOPROBE study, thereby placing the study 0 5 10 15 km area into a regional context (Figs. 1 and 2). Specific to southern Alberta, the Southern Alberta Lithospheric Transect (SALT) Fig. 1. Map of the study area. The location of the HF well responsible for includes 290 km of reflection-seismic lines acquired in 1995 be- the induced earthquakes (yellow star), 3D reflection-seismic survey (black tween the Cordilleran deformation front and the western side of box), SALT 2D reflection-seismic line (black line), and a previously inferred the Sweetgrass Arch in southern Alberta and northern Montana fault (the WSOF) (red dashed line) are displayed alongside local municipal- (27). This portion of the SALT consists of two east–west lines: ities (gray areas), roads (gray lines), and waterbodies (blue). (Inset) Map line 30 (110 km) and line 31 (140 km), tied by the roughly north– shows the location of the study (white star) in North America. south line 29 (40 km). The SALT data revealed a subhorizontal layer-cake structure of the WCSB stratigraphy affected by ex- dication of fault-associated
Load more

Recommended publications
  • Soil Survey and Reclamation Suitability Evaluation of the Proposed Nova Gas Transmission Ltd
    NOVA Gas Transmission Ltd. Environmental and Socio-Economic Assessment Norma Transmission Pipeline Project February 2013/8660 APPENDIX 3 SOIL SURVEY AND RECLAMATION SUITABILITY EVALUATION OF THE PROPOSED NOVA GAS TRANSMISSION LTD. NORMA TRANSMISSION PIPELINE PROJECT Page A3-1 SOIL SURVEY AND RECLAMATION SUITABILITY EVALUATION of the PROPOSED NOVA GAS TRANSMISSION LTD. NORMA TRANSMISSION PIPELINE Prepared for: TERA ENVIRONMENTAL CONSULTANTS On behalf of: NOVA GAS TRANSMISSION LTD. Prepared by: MENTIGA PEDOLOGY CONSULTANTS LTD. A.G. Twardy, M.Sc., P.Ag. B. Chernipeski, B.Sc., P.Ag. February 2013 11037B.1 TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................. 1 2.0 THE STUDY AREA .......................................................................................................... 3 2.1 Location and Extent ............................................................................................ 3 2.2 Bedrock Geology ................................................................................................ 3 2.3 Surficial Materials and Landform ........................................................................ 3 2.4 General Soil Patterns .......................................................................................... 4 2.5 Present Land Use ............................................................................................... 4 3.0 SOILS ...................................................................................................................
    [Show full text]
  • Post-Carboniferous Stratigraphy, Northeastern Alaska by R
    Post-Carboniferous Stratigraphy, Northeastern Alaska By R. L. DETTERMAN, H. N. REISER, W. P. BROSGE,and]. T. DUTRO,JR. GEOLOGICAL SURVEY PROFESSIONAL PAPER 886 Sedirnentary rocks of Permian to Quaternary age are named, described, and correlated with standard stratigraphic sequences UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1975 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress Cataloging in Publication Data Detterman, Robert L. Post-Carboniferous stratigraphy, northeastern Alaska. (Geological Survey Professional Paper 886) Bibliography: p. 45-46. Supt. of Docs. No.: I 19.16:886 1. Geology-Alaska. I. Detterman, Robert L. II. Series: United States. Geological Survey. Professional Paper 886. QE84.N74P67 551.7'6'09798 74-28084 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-02687-2 CONTENTS Page Page Abstract __ _ _ _ _ __ __ _ _ _ _ _ _ _ _ _ _ _ _ __ __ _ _ _ _ _ _ __ __ _ _ __ __ __ _ _ _ _ __ 1 Stratigraphy__:_Continued Introduction __________ ----------____ ----------------____ __ 1 Kingak Shale ---------------------------------------- 18 Purpose and scope ----------------------~------------- 1 Ignek Formation (abandoned) -------------------------- 20 Geographic setting ------------------------------------ 1 Okpikruak Formation (geographically restricted) ________ 21 Previous work and acknowledgments ------------------ 1 Kongakut Formation ----------------------------------
    [Show full text]
  • Faults and Associated Karst Collapse Suggest Conduits for Fluid Flow That Influence Hydraulic Fracturing-Induced Seismicity
    Faults and associated karst collapse suggest conduits for fluid flow that influence hydraulic fracturing- induced seismicity Elwyn Gallowaya, Tyler Haucka, Hilary Corlettb, Dinu Pana˘ a, and Ryan Schultza,1 aAlberta Geological Survey, Alberta Energy Regulator, Edmonton, AB T8N 3A3, Canada; and bDepartment of Physical Sciences, MacEwan University, Edmonton, AB T5J 4S2, Canada Edited by Paul Segall, Stanford University, Stanford, CA, and approved August 21, 2018 (received for review May 1, 2018) During December 2011, a swarm of moderate-magnitude earth- bore [up to hundreds of meters (18–21)]. Furthermore, geo- quakes was induced by hydraulic fracturing (HF) near Cardston, mechanical modeling reveals that poroelastic changes from HF Alberta. Despite seismological associations linking these two processes, are transmitted only locally (20). These results are in direct the hydrological and tectonic mechanisms involved remain unclear. In contradiction to HF-related earthquakes that are located kilo- this study, we interpret a 3D reflection-seismic survey to delve into the meters away from the closest well bore (e.g., refs. 2, 6, 11, 22, and geological factors related to these earthquakes. First, we document a 23). Specific to the Cardston case, earthquakes (located on re- basement-rooted fault on which the earthquake rupture occurred that gional arrays) were observed within the uppermost crystalline ∼ – extends above the targeted reservoir. Second, at the reservoir’s strati- basement, 1.5 km deeper than the target upper Stettler Big SI Appendix graphic level, anomalous subcircular features are recognized along the Valley Reservoir zone ( ,Fig.S1); this observation is fault and are interpreted as resulting from fault-associated karst pro- further complicated by the fact that the fault slip response oc- ∼ – cesses.
    [Show full text]
  • Subsurface Characterization of the Pembina-Wabamun Acid-Gas Injection Area
    ERCB/AGS Special Report 093 Subsurface Characterization of the Pembina-Wabamun Acid-Gas Injection Area Subsurface Characterization of the Pembina-Wabamun Acid-Gas Injection Area Stefan Bachu Maja Buschkuehle Kristine Haug Karsten Michael Alberta Geological Survey Alberta Energy and Utilities Board ©Her Majesty the Queen in Right of Alberta, 2008 ISBN 978-0-7785-6950-3 The Energy Resources Conservation Board/Alberta Geological Survey (ERCB/AGS) and its employees and contractors make no warranty, guarantee or representation, express or implied, or assume any legal liability regarding the correctness, accuracy, completeness or reliability of this publication. Any digital data and software supplied with this publication are subject to the licence conditions. The data are supplied on the understanding that they are for the sole use of the licensee, and will not be redistributed in any form, in whole or in part, to third parties. Any references to proprietary software in the documentation, and/or any use of proprietary data formats in this release, do not constitute endorsement by the ERCB/AGS of any manufacturer's product. If this product is an ERCB/AGS Special Report, the information is provided as received from the author and has not been edited for conformity to ERCB/AGS standards. When using information from this publication in other publications or presentations, due acknowledgment should be given to the ERCB/AGS. The following reference format is recommended: Bachu, S., Buschkuehle, M., Haug, K., Michael, K. (2008): Subsurface characterization of the Pembina-Wabamun acid-gas injection area; Energy Resources Conservation Board, ERCB/AGS Special Report 093, 60 p.
    [Show full text]
  • Upper Devonian and Lower Mississippian Stratigraphy
    UPPER DEVONIAN AND LOWER MISSISSIPPIAN STRATIGRAPHY OF NORTHWESTERN MONTANA: A PETROLEUM SYSTEM APPROACH by Paul S. Schietinger A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Science (Geology). Golden, Colorado Date _____________ Signed: ____________________________ Paul S. Schietinger Signed: ____________________________ Dr. Stephen A. Sonnenberg Thesis Advisor Golden, Colorado Date _____________ Signed: ____________________________ Dr. John D. Humphrey Professor and Head Department of Geology and Geological Engineering ii ABSTRACT The Upper Devonian and Lower Mississippian stratigraphy in the Antler foreland basin of northwestern Montana is the current focus of exploration for several petroleum companies. Conodont zonation indicates that the Exshaw Formation of southern Alberta and northern Montana is Late Devonian and Early Mississippian in age, and is stratigraphically equivalent to the Bakken Formation in the Williston Basin and the Sappington Member of the Three Forks in southwestern Montana. The Exshaw, Bakken and Sappington are lithologically similar. Each formation is comprised of basal organic-rich shale, middle dolomitic siltstone and sandstone, and upper organic-rich shale. The Three Forks Formation in northwestern Montana consists of two members: the older Logan Gulch Member and the younger Trident Member. The Logan Gulch is 100 ft to over 450 ft thick and was subdivided in this study into three facies that were deposited in salina to sabkha environments. Locally, the Logan Gulch is termed the Potlatch Anhydrite. The Three Forks Formation in northwestern Montana is equivalent to the Stettler and Big Valley formations in southern Alberta. The younger Trident Member was subdivided into two facies that are transgressive, open marine deposits.
    [Show full text]
  • Interpretation of 3D Multicomponent Seismic Data for Investigating Natural Fractures in the Horn River Basin, Northeast British Columbia
    Natural fracture analysis from 3D-3C seismic data Interpretation of 3D multicomponent seismic data for investigating natural fractures in the Horn River Basin, northeast British Columbia Abdallah Al-Zahrani* and Don Lawton ABSTRACT A 3D multicomponent seismic dataset from the Horn River Basin was assessed for mapping fractures. The data had good fold, offset and azimuth distributions and several approaches were used to interpret the distribution of natural fractures. In addition to amplitude mapping, PP and PS curvature maps enhanced the structural interpretation of the data and enabled the lateral continuity of faults and fractures to be mapped across the area of the seismic survey. Both horizon and volume based most negative curvature were effective in mapping fault and fracture trends within both Exshaw and Muskwa shale gas targets. At the Exshaw level, the curvature shows two main fault trends: northwest- southeast trending normal faults that dip toward the southwest, as well as northeast- southwest strike-slip faults. At the Muskwa level, the curvature image shows different major fault trends, namely north, northeast-south, southwest (normal and reverse faults), and northwest-southeast faults. Fractures interpreted using curvature attributes are close to the major faults and their dominant trends are generally parallel to the major faults in the area. INTRODUCTION Shale gas is one of the three types of unconventional gas plays that are growing rapidly in North America (Kuuskraa and Stevens, 2009). What make this play attractive to the oil companies compared with conventional resources is that the shale gas formations are continuous over large areas, with giant reserves, and the gas is enclosed within microporosity of the shales, and the rocks, in this case act as source, reservoir and trap at the same time (Kuuskraa and Stevens, 2009).
    [Show full text]
  • Conodont Biofacies in a Ramp to Basin Setting (Latest Devonian and Earliest Carboniferous) in the Rocky Mountains of Southernmost Canada and Northern Montana
    U. S. DEPARTMENT OF THE INTERIOR U. S. GEOLOGICAL SURVEY Conodont biofacies in a ramp to basin setting (latest Devonian and earliest Carboniferous) in the Rocky Mountains of southernmost Canada and northern Montana by Lauret E. Savoy1 and Anita G. Harris 2 Open-File Report 93-184 This report is preliminary and has not been reviewed for conformity with Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. \ Department of Geology and Geography, Mount Holyoke College, South Hadley, MA 01075 2 U.S. Geological Survey, Reston, VA 22092 1993 TABLE OF CONTENTS ABSTRACT 1 INTRODUCTION 2 LITHOSTRATIGRAPHY AND DEPOSITIONAL SETTING 2 CONODONT BIOSTRATIGRAPHY AND BIOFACIES 8 Palliser Formation 8 Exshaw Formation 13 Banff Formation 13 Correlative units in the Lussier syncline 15 PALEOGEOGRAPfflC SETTING 17 CONCLUSION 23 ACKNOWLEDGMENTS 23 REFERENCES CITED 24 APPENDIX 1 38 FIGURES 1. Index map of sections examined and major structural features of the thrust and fold belt 3 2. Correlation chart of Upper Devonian and Lower Mississippian stratigraphic units. 4 3. Selected microfacies of the Palliser Formation. 5 4. Type section of Exshaw Formation, Jura Creek. 6 5. Lower part of Banff Formation, North Lost Creek. 7 6. Conodont distribution in Palliser and Exshaw formations, Inverted Ridge. 9 7. Conodont distribution in upper Palliser and lower Banff formations, Crowsnest Pass. 11 8. Conodont distribution in upper Palliser, Exshaw, and lower Banff formations, composite Jura Creek - Mount Buller section. 12 9.
    [Show full text]
  • Forensic Chemostratigraphy in Geosteering Multilateral Wells: an Example from Devonian to Carboniferous-Aged Sequences in Southe
    URTeC Control ID # 1579996 1 URTeC Control ID Number: 1579996 Forensic Chemostratigraphy in Geosteering Multilateral Wells: An example from Devonian to Carboniferous-aged sequences in Southern Alberta Heather Stilwell1*, Nahysa Martinez1, Gemma Hildred1, Brian Zaitlin2 1. Chemostrat, Houston, TX, United States. 2. Native American Resource Partners, Calgary, AB, Canada. Copyright 2013, Unconventional Resources Technology Conference (URTeC) This paper was prepared for presentation at the Unconventional Resources Technology Conference held in Denver, Colorado, USA, 12-14 August 2013. The URTeC Technical Program Committee accepted this presentation on the basis of information contained in an abstract submitted by the author(s). The contents of this paper have not been reviewed by URTeC and URTeC does not warrant the accuracy, reliability, or timeliness of any information herein. All information is the responsibility of, and, is subject to corrections by the author(s). Any person or entity that relies on any information obtained from this paper does so at their own risk. The information herein does not necessarily reflect any position of URTeC. Any reproduction, distribution, or storage of any part of this paper without the written consent of URTeC is prohibited. Summary The results presented in this study test the efficacy of using whole-rock elemental data to characterize the stratigraphy penetrated when drilling lateral wells and use this information along with comparisons to a vertical offset well to stay in zone. This approach is tested in the Alberta Bakken Petroleum System (ABPS) in Southwestern Alberta, Canada, focusing on the Banff, Exshaw, Big Valley, and Stettler formations (Hildred et al 2013, Zaitlin 2013).
    [Show full text]
  • Bedrock Geology of Alberta
    Alberta Geological Survey Map 600 Legend Bedrock Geology of Alberta Southwestern Plains Southeastern Plains Central Plains Northwestern Plains Northeastern Plains NEOGENE (± PALEOGENE) NEOGENE ND DEL BONITA GRAVELS: pebble gravel with some cobbles; minor thin beds and lenses NH HAND HILLS FORMATION: gravel and sand, locally cemented into conglomerate; gravel of sand; pebbles consist primarily of quartzite and argillite with minor amounts of sandstone, composed of mainly quartzite and sandstone with minor amounts of chert, arkose, and coal; fluvial amygdaloidal basalt, and diabase; age poorly constrained; fluvial PALEOGENE PALEOGENE PALEOGENE (± NEOGENE) PALEOGENE (± NEOGENE) UPLAND GRAVEL: gravel composed of mainly white quartzite cobbles and pebbles with lesser amounts of UPLAND GRAVEL: gravel capping the Clear Hills, Halverson Ridge, and Caribou Mountains; predominantly .C CYPRESS HILLS FORMATION: gravel and sand, locally cemented to conglomerate; mainly quartzite .G .G and sandstone clasts with minor chert and quartz component; fluvial black chert pebbles; sand matrix; minor thin beds and lenses of sand; includes gravel in the Swan Hills area; white quartzite cobbles and pebbles with lesser amounts of black chert pebbles; quartzite boulders occur in the age poorly constrained; fluvial Clear Hills and Halverson Ridge gravels; sand matrix; ages poorly constrained; extents poorly defined; fluvial .PH PORCUPINE HILLS FORMATION: olive-brown mudstone interbedded with fine- to coarse-grained, .R RAVENSCRAG FORMATION: grey to buff mudstone
    [Show full text]
  • Devonian Petroleum Systems and Exploration Potential, Southern Alberta, Part 3 Core Conference
    Devonian Petroleum Systems and Exploration Potential, Southern Alberta, Part 3 Core Conference Andy Mort (1), Leonard Stevens (2), Richard Wierzbicki (2) Abstract Part 1: Devonian Petroleum Systems Dr. Andy Mort (Presentation 1) The Devonian in Southern Alberta has many porous and permeable reservoirs but few major hydrocarbon traps and limited exploration drilling. Part of the concern with this stacked carbonate dominated system is questions about source rock presence, quality, maturity, migration and charge. Previous work has shown there is proven source rock and hydrocarbon being generated in the Winnipegosis, Nisku, and Exshaw/Lower Banff in Southern Alberta. There is associated hydrocarbon production in the Lower Banff to Big Valley (Alberta Bakken), in the Nisku, and in the Winnipegosis. There are oil shows and oil stain in the Leduc and in the Beaverhill Lake equivalents and minor production from a DST in the Cooking Lake. Figure 1: Summary Chart: Source, Reservoir, Seal Intervals, Southern Alberta In the last few years Andy Mort of the GSC has been doing source rock evaluation of selected samples from core in the Beaverhill Lake and Winnipegosis in the study area. These samples show the presence of oil prone source rocks within these intervals. The oils evaluated in the Nisku, Leduc, Beaverhill Lake and Winnipegosis all indicate an evaporite related source. This paper is a synthesis of existing data and the new information and an evaluation of the remaining exploration potential of known reservoirs in the Devonian of Southern Alberta in light of the current understanding of the petroleum system. Part 2: Reservoirs and Traps Len Stevens, Rick Wierzbicki (Presentation 2) Existing and potential reservoirs in the Devonian of Southern Alberta will be reviewed in relation to the identified source rock intervals.
    [Show full text]
  • Petroleum Systems and Quantitative Oil Chemometric Models for Heavy Oils in Alberta and Saskatchewan to Characterize Oil- Source Correlations Fay, M., Larter, S
    Petroleum Systems and Quantitative Oil Chemometric Models for Heavy Oils in Alberta and Saskatchewan to Characterize Oil- Source Correlations Fay, M., Larter, S. Bennett, B., Snowdon, L., Fowler, M. Produced oils from western Canada in the Kindersley, Lloydminster and Cold Lake heavy oil belt are commonly believed to be genetically sourced from the Type IIS Exshaw shales (south central Alberta) based on the quantitative molecular geochemistry of >100 produced oils from previous work (Obermajer et al., 2004), plus hundreds of produced oil samples from the surrounding basin (Deroo et al., 1977; Brooks et al., 1988; Allan and Creaney, 1991; Creaney and Allan, 1992; Riediger et al., 1993; Osadetz et al., 1994; Li et al., 1996, 1997; Karavas et al., 1998; Stevenson, 1998; Riediger et al., 1999; Manzano-Kareah et al., 2004). However, seven potential source rocks that are thermally mature exist in south central Alberta through the Lower Cretaceous and Paleozoic section, and this study shows that multiple oil families do in fact exist in the heavy oil belt. Oils sourced from rocks other than the Exshaw shale surrounding the heavy oil belt based on biomarker and molecular composition include Ostracode and Duvernay (Q and D) oils observed in the Provost region (Riediger et al., 1999). Also, the Banff/Madison (M) and Exshaw oils are observed in the Medicine Hat region (Manyberries) (Manzano- Kareah et al., 2004). The potential for oil charge from other source rocks in the region, may in part, explain some of the minor but outstanding differences in biomarker compositions, molecular concentrations (e.g. diamondoids; Fay, 2010) and isotope evidence (Marcano et al., 2011) that are observed in produced oils from the heavy oil belt (Obermajer et al., 2004).
    [Show full text]
  • Map 600: a New 1:1 000 000 Bedrock Geology Map of Alberta G.J
    Map 600: A New 1:1 000 000 Bedrock Geology Map of Alberta G.J. Prior*, Alberta Geological Survey, 402, 4999-98th Ave., Edmonton, Alberta [email protected] B. Hathway, Alberta Geological Survey, 402, 4999-98th Ave., Edmonton, Alberta P. Glombick, Alberta Geological Survey, 402, 4999-98th Ave., Edmonton, Alberta D.I. Pana, Alberta Geological Survey, 402, 4999-98th Ave., Edmonton, Alberta C.J. Banks, Alberta Geological Survey, 402, 4999-98th Ave., Edmonton, Alberta D.C. Hay, Neftex Petroleum Consultants, 97 Milton Park, Abingdon, Oxfordshire, England C.L. Schneider, University of Alberta, 116 St. and 85 Ave., Edmonton, Alberta M. Grobe, Alberta Geological Survey, 402, 4999-98th Ave, Edmonton, Alberta R. Elgr, Alberta Geological Survey, 402, 4999-98th Ave, Edmonton, Alberta J.A. Weiss, Alberta Geological Survey, 402, 4999-98th Ave, Edmonton, Alberta Summary Map 600 is the new 1:1 000 000 bedrock geology map of Alberta prepared by the Alberta Geological Survey (AGS). This map supersedes Map 236 (Hamilton et al., 1999) and Map 27 (Green, 1972). Map 600 represents the compilation of existing geological maps and new geological mapping by staff of the Alberta Geological Survey (AGS). The representation of the Canadian Shield and Athabasca Basin is based on compilation. The geology of the Rocky Mountains and the Rocky Mountain Foothills is also the product of compilation with rare instances of new geological interpretation (e.g. the interpretation of bedrock geology beneath drift-filled valleys). The Devonian geology of northeast Alberta is also largely a product of compilation with some reinterpretation based, in part, on field observations.
    [Show full text]