ERCB/AGS Special Report 090 Subsurface Characterization of Acid-Gas Injection Operations in the Peace River Arch Area Subsurface Characterization of Acid-Gas Injection Operations in the Peace River Arch Area K. Michael and M. Buschkuehle Alberta Energy and Utilities Board Alberta Geological Survey ©Her Majesty the Queen in Right of Alberta, 2008 ISBN 978-0-7785-6947-3 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: Michael, K. and Buschkuehle, M. (2008): Subsurface characterization of the acid-gas injection operations in the Peace River Arch area; Energy Resources Conservation Board, ERCB/AGS Special Report 090, 186 p. Published March 2008 by: Energy Resources Conservation Board Alberta Geological Survey 4th Floor, Twin Atria Building 4999 – 98th Avenue Edmonton, Alberta T6B 2X3 Canada Tel: (780) 422-1927 Fax: (780) 422-1918 E-mail: [email protected] Website: www.ags.gov.ab.ca This report is the AGS release of a 2007 client report prepared for the Acid Gas Management Committee, a consortium of provincial and federal agencies and industry partners. ERCB/AGS Special Report 090 (March 2008) i Executive Summary Injection of acid gas in the Peace River Arch area occurs at eleven operations in three major stratigraphic units, the Upper Devonian Leduc Formation and Wabamun Group, the Permo-Mississippian Belloy and Kiskatinaw formations, and the Triassic Halfway Formation. By the end of 2006, approximately 340 million cubic metres of acid gas were injected into deep geological formations in the Peace River Arch area. If only the natural setting is considered, including geology and flow of formation waters, the regional- and local-scale hydrogeological analyses indicate that injecting acid gas into these deep geological units in the Peace River Arch area is a safe operation with no potential for acid-gas migration to shallower strata, potable groundwater and the surface. At Dunvegan, Eaglesham, Gordondale (Halfway), Mirage, Normandville, Parkland, and Puskwaskua, injection occurs or took place into depleted hydrocarbon reservoirs. By regulation, downhole pressures will not exceed the respective initial reservoir pressures and the injected gas will remain within the respective pool outlines. At Mirage and Gordondale-Halfway, acid gas was injected into currently producing Halfway reservoirs, which will partly be recycled in the injection/production cycle. In the cases of acid-gas injection into deep saline aquifers (Gordondale- Belloy, Mulligan, Pouce Coupe, Rycroft and Wembley), the extent and migration of the acid-gas plume will likely be limited by dissolution, dispersion, residual gas saturation and trapping along the migration pathway and therefore not reach the overlying aquifers. The entire stratigraphic interval from the Leduc Formation to the Halfway Formation is overlain by at least one contiguous thick shale sequence, the Smoky Group. Other aquitards (i.e., Wilrich, Fernie, Charlie Lake, Montney, Banff-Exshaw) form additional barriers to acid-gas migration from the various injection zones into other strata, and the flow process, if it will ever happen, would take an extremely long time, on a geological time scale. Any acid gas plume would disperse and dissolve in formation water during flow on such large time and spatial scales. Tectonics greatly affected the sedimentary framework, particularly the Paleozoic succession, in the Peace River Arch area. The main tectonic activity occurred during the late Carboniferous, resulting in thick Mississippian to Permian sediment accumulation in the area of the Dawson Creek Graben Complex. Under the present-day stress regime, faults that are present in the various local-scale study areas do not appear to act as fluid conduits through aquitards overlying the respective injection horizons. However, the displacement of strata along faults that are present near injection wells results in a partial lateral confinement of acid-gas within injection intervals. Based on available data, it seems that there is no potential for acid gas leakage through faults and fractures. However, the possibility for upward leakage of acid gas exists along wells that were improperly completed and/or abandoned, or along wells whose cement and/or tubing has degraded or may degrade in the future as a result of chemical reactions with formation brine and/or acid gas. The Peace River Arch area has a high well density and the wells penetrate hydrocarbon-bearing strata down to the Granite Wash overlying the Precambrian basement. Wells in the Peace River Arch area were drilled, and successively abandoned, as early as the late 1950s and, considering the old age, damage to or improper well completion is very likely in some cases. No leakage has been detected and reported to date, however, the potential for this occurring in the future should be considered by both operators and regulatory agencies. These conclusions are based on a qualitative hydrogeological analysis in the sense that the geological and hydrogeological data were interpreted within the framework of the most current knowledge about the Alberta Basin and its contained fluids. No quantitative analysis based on numerical modeling was ERCB/AGS Special Report 090 (March 2008) ii performed. However, recent modelling results published in the literature suggest that after 10,000 years the maximum radius of an acid-gas plume is in the order of 5 km. Predictive numerical models of acid- gas injection and flow should be used in the future to validate the qualitative hydrogeological analysis presented in this report. Geochemical and geomechanical effects on reservoir rock, caprock and faults should be assessed to confirm integrity. The potential for and risk of leakage through existing wells and faults should be better assessed. In addition, a monitoring program would support and provide feedback to the analysis and modelling, and greatly enhance the confidence in the safety of the operation. ERCB/AGS Special Report 090 (March 2008) iii Acknowledgements The work presented in this report was supported and contains contributions from various colleagues at the Alberta Geological Survey to whom the authors would like to extend their thanks. Dr. Dong Chen constructed the majority of the local-scale cross-sections by interpreting geophysical well logs and created a set of six downhole stratigraphic models. Her extensive knowledge of the stratigraphy in the Peace River Arch area was a great benefit for understanding the geology of the Triassic to Mississippian succession in this area. Dr. Nigel Atkinson contributed in the setup of databases and in the modelling of the stratigraphic framework. Dr. Dinu Pana provided scientific advice in the interpretation of faults and their affect on fluid flow. Dr. Shilong Mei offered assistance in understanding the history of the Peace River Arch and the nomenclature of regional tectonic elements. Dr. Matt Grobe reviewed the manuscript and provided helpful suggestions to improve the contents and structure of this report. Dan Magee provided graphic support and Maryanne Protz was in charge of the final assemblage and layout of the manuscript Financial support to conduct this study was received from Natural Resources Canada, Alberta Environment, Climate Change Central, Alberta Energy Research Institute, Western Economic Development, British Columbia Ministry of Energy, Mines and Petroleum Resources, Saskatchewan Industry and Resources, Keyera Energy, and Total. ERCB/AGS Special Report 090 (March 2008) iv Contents Executive Summary ....................................................................................................................................ii Acknowledgements .....................................................................................................................................iv 1 Introduction ....................................................................................................................................1 2 Selection of an Acid-Gas Injection Site .......................................................................................3 2.1 Acid Gas Properties ................................................................................................................3 2.2 Criteria for Site Selection ........................................................................................................5 2.3 Issues .......................................................................................................................................6 3 Basin-Scale Setting of Acid-Gas Injection Sites in the Peace River Arch Area ......................7 3.1 Basin Geology and Hydrostratigraphy ...................................................................................7 3.2 Basin-Scale Flow of Formation Water ..................................................................................18 4 Regional-Scale Setting of Acid-Gas Injection Sites in the Peace River Arch Area ..............22 4.1 Evolution of the Peace River Arch ........................................................................................23 4.2 Geology of the Upper Devonian to Triassic..........................................................................24 4.2.1 Devonian Woodbend Group ....................................................................................25 4.2.2 Devonian Wabamun Group .......................................................................................28 4.2.3 Carboniferous ............................................................................................................32 4.2.4 Permian (Belloy Formation) .....................................................................................32 4.2.5 Triassic ......................................................................................................................33 4.3 Hydrogeology of the Upper Devonian to Bullhead Group Strata .......................................39 4.3.1 Hydrostratigraphy .....................................................................................................39 4.3.2 Hydrogeological Observations ..................................................................................40 4.3.3 Flow Interpretation ...................................................................................................54 4.4 Stress Regime and Rock Geomechanical Properties ............................................................54 5 Local-Scale Setting Of the Acid-Gas Injection Sites in the Peace River Arch Area ............59 5.1 Puskwaskua...........................................................................................................................61 5.1.1 Geology ....................................................................................................................61 5.1.2 Hydrogeological Characteristics and Rock Properties .............................................64 5.2 Normandville ........................................................................................................................68 5.2.1 Geology ....................................................................................................................68 5.2.2 Hydrogeological Characteristics and Rock Properties .............................................68 5.3 Rycoft ....................................................................................................................................75 5.3.1 Geology ....................................................................................................................75 5.3.2 Hydrogeological Characteristics and Rock Properties .............................................78 5.4 Dunvegan ..............................................................................................................................83 5.4.1 Geology ....................................................................................................................83 5.4.2 Hydrogeological Characteristics and Rock Properties .............................................83 5.5 Pouce Coupe ..........................................................................................................................89 5.5.1 Geology ....................................................................................................................89 5.5.2 Hydrogeological Characteristics and Rock Properties .............................................96 5.6 Wembley ..............................................................................................................................101 5.6.1 Geology ..................................................................................................................101 5.6.2 Hydrogeological Characteristics and Rock Properties ...........................................101 5.7 Mulligan ..............................................................................................................................106 5.7.1 Geology ..................................................................................................................106 5.7.2 Hydrogeological Characteristics and Rock Properties ...........................................109 5.8 Gordondale ..........................................................................................................................112 5.8.1 Geology ..................................................................................................................113 ERCB/AGS Special Report 090 (March 2008) v 5.8.2 Hydrogeological Characteristics and Rock Properties............................................115 5.9 Summary of the Local-Scale Hydrogeological Analysis ...................................................121 5.10 Site Specific Characteristics of the Acid-Gas Operations..................................................121 6 Discussion...................................................................................................................................124 6.1 Injection of Acid-Gas into Reservoirs................................................................................125 6.1.1 Sour Water Injection at Mirage...............................................................................125 6.1.2 Dunvegan................................................................................................................127 6.1.3 Parkland..................................................................................................................127 6.1.4 Eaglesham and Normandville ................................................................................130 6.1.5 Puskwaskua.............................................................................................................131 6.1.6 Gordondale-Halfway...............................................................................................133 6.2 Injection of Acid Gas into Regional Aquifers ....................................................................136 6.2.1 Mathematical Expression for the Lateral Migration of Separate-Phase Acid Gas.136 6.2.2 Near-Field Acid-Gas Migration During Injection..................................................138 6.2.3 Gordondale – Belloy...............................................................................................139 6.2.4 Mulligan .................................................................................................................140 6.2.5 Rycroft.....................................................................................................................144 6.2.6 Wembley..................................................................................................................145 6.2.7 Pouce Coupe............................................................................................................149 6.3 Comments on Well Abandonment and Potential Leakage through Wells..........................151 6.4 Comments on the Potential of Leakage along and across Faults........................................151 7 Conclusions and Recommendations.........................................................................................152 8 References...................................................................................................................................155 Appendix 1 - Downhole Stratigraphic Models 1-1 Downhole stratigraphic model for the Dunvegan acid-gas injection site, Alberta.....................164 1-2 Downhole stratigraphic model for the Gordondale area, Alberta...............................................165 1-3 Downhole stratigraphic model for the Mirage acid-gas injection site, Alberta..........................166 1-4 Downhole stratigraphic model for the Mulligan acid-gas injection site, Alberta.......................167 1-5 Downhole stratigraphic model for the Normandville area, Alberta...........................................168 1-6 Downhole stratigraphic model for the Pouce Coupe area, Alberta-BC......................................169 1-7 Downhole stratigraphic model for the Puskwaskua area, Alberta..............................................170 1-8 Downhole stratigraphic model for the Rycroft area, Alberta......................................................171 1-9 Downhole stratigraphic model for the Wembley area, Alberta...................................................172 ERCB/AGS Special Report 090 (March 2008) vi Tables Table 1 Ranges of salinity (TDS) and hydraulic-head values in the various aquifers in the Peace River Arch area................................................................................................................41 Table 2 Gradients of the minimum horizontal stress, S , determined from tests Hmin performed in wells in the Peace River regional-scale study area.............................................56 Table 3 Orientations of the minimum and maximum horizontal stresses determined from breakouts in wells in the Peace River Arch regional-scale study area.....................................58 Table 4 Geomechanical properties of rocks of interest from the Alberta Basin...................................59 Table 5 Location of acid-gas injection wells in the local-scale study areas..........................................60 Table 6 Major ion chemistry of Leduc brines in the Puskwaskua area.................................................64 Table 7 Well-scale porosity and permeability values obtained from measurements in core plugs from the Leduc (9 wells) and Ireton (2 wells) formations, and permeability values calculated from 7 drillstem test analyses in the Puskwaskua area................................67 Table 8 Major ion chemistry of Wabamun brines in the Normandville area........................................72 Table 9 Well-scale porosity and permeability values obtained from measurements in core plugs from the Wabamun (107 wells) and Exshaw (18 wells) formations, and permeability values calculated from 30 drillstem test analyses in the Normandville area......75 Table 10 Major ion chemistry of brines from the Belloy and Kiskatinaw formations in the Rycoft area................................................................................................................................79 Table 11 Well-scale porosity and permeability values obtained from measurements in core plugs from the Belloy (13 wells) and Kiskatinaw (2 wells) formations, and permeability values calculated from 10 drillstem test analyses in the Rycroft area................82 Table 12 Major ion chemistry of brines from the Belloy-Stoddart aquifer in the Dunvegan area............................................................................................................................................86 Table 13 Well-scale porosity and permeability values obtained from measurements in core plugs from the Kiskatinaw (6 wells) and Belloy (1 well) formations in the Dunvegan area....89 Table 14 Major ion chemistry of brines from the Kiskatinaw and Belloy aquifers in the Pouce Coupe area......................................................................................................................96 Table 15 Well-scale porosity and permeability values obtained from measurements in core plugs from the Kiskatinaw (39 wells) and Belloy (1 well) formations in the Pouce Coupe area...............................................................................................................................100 Table 16 Major ion chemistry of brines from the Belloy aquifer in the Wembley area ........................101 Table 17 Well-scale porosity and permeability values obtained from measurements in core plugs in two wells from the Belloy Formation in the Wembley area.......................................105 Table 18 Major ion chemistry of brines from the Belloy-Stoddart aquifer in the Mulligan area..........................................................................................................................................109 Table 19 Well-scale porosity and permeability values obtained from measurements in core plugs from the Kiskatinaw (20 wells) and Belloy (1 well) formations in the Mulligan area.....................................................................................................................112 Table 20 Major ion chemistry of brines from the Belloy-Stoddart and Halfway aquifers in the Gordondale area.............................................................................................................118 Table 21 Well-scale porosity and permeability values obtained from measurements in core plugs from the Kiskatinaw (14 wells), Belloy (2 wells), Doig (44 wells), and Halfway (98 wells) formations in the Gordondale area..........................................................120 Table 22 Characteristics of acid-gas injection operations in the Peace River Arch area......................122 Table 23 Properties of native fluids and injected acid gas at in-situ conditions at the six operations in the Peace River Arch area where acid-gas is or was injected into hydrocarbon reservoirs....................................................................................................127 ERCB/AGS Special Report 090 (March 2008) vii Table 24 Properties of native fluids and injected acid gas at in-situ conditions at the five operations in the Peace River Arch area where acid gas is injected into aquifers..................136 Table 25 Injection characteristics of acid-gas injection operations in aquifers......................................139 Figures Figure 1 Location of acid-gas injection operations in the Alberta Basin, Canada, at the end of 2006...................................................................................................................2 Figure 2 Phase diagrams for methane (CH4), carbon dioxide (CO2), hydrogen sulphide (H2S) and a 50%-50% acid gas mixture; hydrate conditions for CO2 and H2S..............................3 Figure 3 Solubility of water in acid gas as a function of pressure for: a) different acid-gas compositions (CO2 and H2S) at30° C, and b) different temperatures for an acid gas with a composition of 49% CO2, 49% H2S and 2% CH4.....................................................4 Figure 4 Basin-scale stratigraphic and hydrostratigraphic delineation and nomenclature as well as general lithology for the Peace River Arch area................................................................8 Figure 5 Depositional and erosional boundaries of the Woodbend Group, and outlines of Cooking Lake platform carbonates, Leduc Formation reefs and Grosmont Formation platform carbonates..............................................................................................................10 Figure 6 Physiography and tectonic elements of the Wabamun Group in the Alberta Basin............12 Figure 7 Tectonic elements and Carboniferous lithofacies assemblages in the Alberta Basin..........13 Figure 8 Tectonic elements and lithofacies distribution of Permian strata in the Alberta Basin........14 Figure 9 Depositional setting of Triassic sediments in the Alberta Basin.........................................15 Figure 10 Structure map of the sub-Cretaceous unconformity surface................................................17 Figure 11 Diagrammatic representation of flow systems and hydrostratigraphy in the Alberta Basin: a) in plan view and b) in cross-section......................................................................19 Figure 12 Location of acid-gas injection operations within the limits of the name-giving major oil and gas fields, and local-scale study areas in the Peace River Arch area.......................22 Figure 13 Topographic map of the regional-scale study area showing the location of the acid-gas injection operations in the Peace River Arch area...............................................................23 Figure 14 Diagrammatic summary of the history of the Peace River Arch.........................................24 Figure 15 Structural features of the Dawson Creek Graben Complex superimposed on the residual map for the top of the Debolt Formation (after Mei, 2006)....................................25 Figure 16 Stratigraphy, general lithology and hydrostratigraphy of the Mississippian to Lower Cretaceous (Spirit River Group) succession in the study area.............................................26 Figure 17 Stratigraphic SW-NE cross-section through the regional-scale study area showing the relative position of some of the target horizons in the Devonian to Triassic succession for acid-gas injection in the Peace River Arch area...........................................27 Figure 18 Stratigraphic WNW-ESE cross-section through the regional-scale study area showing the relative position of some of the target horizons in the Devonian to Triassic succession for acid-gas injectiton in the Peace River Arch area..........................................27 Figure 19 General lithofacies distribution in the Woodbend Group in the regional-scale study area.28 Figure 20 Main gelogocial features of the Leduc carbonate platform in the regional-scale study area: a) depth to top and b) structure elevation..........................................................29 Figure 21 General lithofacies distribution in the Wabamun Group in the regional-scale area............30 Figure 22 Main geological features of the Wabamun Group in the regional-scale study area: a) depth to top and b) structure elevation and Mississippian faults......................................31 Figure 23 General lithofacies distribution in the Stoddard Group in the regional-scale study area....33 Figure 24 Main geological features of the Stoddart Group in the regional-scale study area: a) depth to top and b) structure elevation and Mississippian faults.....................................34 ERCB/AGS Special Report 090 (March 2008) viii