ORIGIN ENERGY – 588-1 CONDAMINE RIVER GAS SEEP INVESTIGATION: TECHNICAL REPORT 1-1 1 INTRODUCTION 2 The Condamine River Gas Seep Investigation is a voluntary, integrated, multi-disciplinary project commissioned by Origin Energy (Origin), in collaboration with the Queensland CSG Compliance Unit (CSGCU) (formerly the LNG Enforcement Unit) to identify the source(s), mechanism(s), and pathway(s) of methane gas seeps observed in early 2012. The Strategic Plan for the Investigation was based on a list of tasks (Table A.1) that was developed jointly by Origin and CSGCU. This task list laid the foundation for a comprehensive and ongoing investigation of the Condamine River gas seeps. In addition the CSGCU has undertaken independent and comprehensive investigations and testing along the Condamine River and developed a process in which technical experts will verify the information received from Origin, including the results and recommendations of this report. Queensland Gas Company (QGC) also participated in the Condamine River Gas Seep Investigation by providing information about their coal seam gas (CSG) operations and baseline water bore sampling. In 2012, observations by landowners, Origin, independent consultants, and the CSGCU, identified visible gas seepage in four different segments of the Condamine River. The four gas seeps include one (Rock Hole) that has been observed by landowners for at least several decades and three (Pump Hole, Fenceline, and Camping Ground) that may not have been observed prior to 2012. Later information revealed that one of the latter three seeps (Camping Ground) had been observed in November 2011. Although there is a range of dates of when the seeps were first observed, in this report the key date will be taken as 17 May 2012 – the date when the seeps were first reported to the CSGCU by a landholder 3 . 1.1 PURPOSE The purpose of the Investigation was to develop an initial site conceptual model that identified potential gas source(s), pathway(s), and mechanism(s); to initiate desktop and field activities that would generate, compile, and verify information to test the validity of the model; to revise the model based upon the findings; to identify data gaps; to develop recommendations for collecting additional data to fill those gaps; to zero in on identifying the cause of the seeps; and to make recommendations for ongoing monitoring. 2 Sections 1 through 6 of this report are largely based, with modifications, on the Condamine River Gas Seep Investigation: Strategic Plan (Norwest, 2013), submitted to Origin on 22 January 2013. Readers that are already familiar with the background and strategy presented in the Strategic Plan, and that wish to move straight to the investigation results, should proceed directly to Section 7 of this report. 3 Queensland, Department of Natural Resources and Mines, 2012: Summary Technical Report – Part 1 Condamine River Gas Seep Investigation. Version 1.0. December 2012.
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ORIGIN ENERGY – 588-1 CONDAMINE RIVER GAS SEEP INVESTIGATION: TECHNICAL REPORT
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1 INTRODUCTION2
The Condamine River Gas Seep Investigation is a voluntary, integrated, multi-disciplinary project commissioned by Origin Energy (Origin), in collaboration with the Queensland CSG Compliance Unit (CSGCU) (formerly the LNG Enforcement Unit) to identify the source(s), mechanism(s), and pathway(s) of methane gas seeps observed in early 2012. The Strategic Plan for the Investigation was based on a list of tasks (Table A.1) that was developed jointly by Origin and CSGCU. This task list laid the foundation for a comprehensive and ongoing investigation of the Condamine River gas seeps. In addition the CSGCU has undertaken independent and comprehensive investigations and testing along the Condamine River and developed a process in which technical experts will verify the information received from Origin, including the results and recommendations of this report.
Queensland Gas Company (QGC) also participated in the Condamine River Gas Seep Investigation by providing information about their coal seam gas (CSG) operations and baseline water bore sampling.
In 2012, observations by landowners, Origin, independent consultants, and the CSGCU, identified visible gas seepage in four different segments of the Condamine River. The four gas seeps include one (Rock Hole) that has been observed by landowners for at least several decades and three (Pump Hole, Fenceline, and Camping Ground) that may not have been observed prior to 2012. Later information revealed that one of the latter three seeps (Camping Ground) had been observed in November 2011. Although there is a range of dates of when the seeps were first observed, in this report the key date will be taken as 17 May 2012 – the date when the seeps were first reported to the CSGCU by a landholder3.
1.1 PURPOSE
The purpose of the Investigation was to develop an initial site conceptual model that identified potential gas source(s), pathway(s), and mechanism(s); to initiate desktop and field activities that would generate, compile, and verify information to test the validity of the model; to revise the model based upon the findings; to identify data gaps; to develop recommendations for collecting additional data to fill those gaps; to zero in on identifying the cause of the seeps; and to make recommendations for ongoing monitoring.
2 Sections 1 through 6 of this report are largely based, with modifications, on the Condamine River Gas Seep Investigation: Strategic Plan (Norwest, 2013), submitted to Origin on 22 January 2013. Readers that are already familiar with the background and strategy presented in the Strategic Plan, and that wish to move straight to the investigation results, should proceed directly to Section 7 of this report. 3 Queensland, Department of Natural Resources and Mines, 2012: Summary Technical Report – Part 1 Condamine River Gas Seep Investigation. Version 1.0. December 2012.
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The four gas seeps in the Condamine River are located approximately 4 kilometres (km) downstream of the Chinchilla Weir in Queensland, Australia. They were observed by landowners in early 2012 shortly after the water levels subsided from the 2011-2012 flooding. For the purposes of the investigation and related surveys, there are four named seeps, from east to west (upstream to downstream), “Pump Hole”, “Fenceline”, “Camping Ground”, and “Rock Hole” (Figure 1-1).
The following were investigated:
• The extent and source(s) of the gas emanating from the four gas seeps.
• The potential impacts to groundwater and surface water quality, water supply bores, vegetation, and aquatic ecology
• The potential pathway(s) and mechanism(s) that enable gas migration.
• The potential contribution to the seeps from CSG activities, other industries in the area, water and coal exploration bores, and natural phenomena.
1.2 PHASED APPROACH
Origin and CSGCU jointly developed a list and schedule of tasks (Table A.1) to be accomplished in phases. This allows for the collection and evaluation of data and observations to refine the initial conceptual model and hypotheses that could explain why and how the gas seeps have occurred, and to revise the model and eliminate hypotheses that are not borne out by the scientific facts. These tasks were designed to provide a starting point for the investigation, but as new technical information is acquired, tasks will be modified or added. Briefly the three phases and the tasks they include are:
Phase 1 – Initial field and desktop investigations that include:
• Review existing area-specific information regarding CSG wells, water bores, coal mine related exploratory bores, government monitoring bores, and geology.
• Collect water and gas samples for field and laboratory analyses, measure field parameters, and run downhole videos in selected bores.
• Collect gas samples for composition and stable isotope analysis.
• Interview landowners regarding recent and previously known gas seepage in the Condamine River, occurrence of gas in water and coal exploration bores, and occurrence of unusual or suspected areas of stressed or dead vegetation.
• Inspect the Condamine River through the Origin and some neighbouring tenements to determine whether there are other areas of visible bubbling or other signs of gas discharge, such as stressed or dead vegetation.
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• Construct a preliminary geologic map and cross section.
• Review rainfall and Condamine River hydrographic data.
• Develop preliminary conceptual geologic and hydrogeologic models for the seep area.
Phase 2 - Focused investigations around the four Condamine River gas seep areas, the four Orana pilot wells, and in areas of stressed or dead vegetation identified by landowners that include:
• Conduct an aquatic ecology assessment of the seeps.
• Install temporary water level gauging stations.
• Map visible bubble locations, prepare individual maps, install soil gas monitoring probes, collect water and gas samples for laboratory analysis, and measure soil gas field parameters.
• Develop and test a method for measuring flux of methane at the four gas seeps and develop a monitoring protocol for subsequent application.
• Conduct a bathymetric survey and construct a three-dimensional (3D) model of the river profile.
• Review existing information regarding similar events and situations elsewhere in Australia and in other parts of the world.
• Refine the conceptual geologic and hydrologic models and hypotheses that explain the source(s), pathway(s), mechanism(s), and potential impacts of gas migration and seeps.
• Prepare a technical report that includes recommendations for additional technical studies that will form part of Phase 3 of the gas seep investigation.
Phase 3 – Identify, propose, and implement additional investigation and ongoing monitoring tasks that are needed to:
• Verify the conceptual geologic and hydrogeologic models and hypotheses that explain the source(s), pathway(s), mechanism(s), and impacts of gas migration and gas seeps.
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Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, and the GIS User Community
!( Orana Pilot Wells5 km10 kmCondamine River Basin 1
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1:25,000Date:1/8/2014 M.Dohnalová
FIGURE 1-1Condamine River
Gas Seeps
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Data Sources:1 Australian Water Resource Assessment Region Aerial Photography (ESRI Mapping Service: Digital Globe, 5-5-2010)
Coordinate System:Projection: Transverse Mercator
Datum: GDA 1994Units: Meter
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1.3 PRINCIPAL CONSULTANT
Norwest Energy Consultants Pty. Ltd. (Norwest) was engaged as an independent consultant (herein referred to as “Principal Consultant”) to assist in developing the strategy and scope for conducting this comprehensive investigation and to ensure that it is done in an open and transparent manner. Norwest was selected in part because of its previous experience with CSG development and production, and with investigating gas seeps in Colorado, USA.
Phase 2 field activities were undertaken by independent consultants, including: assessment of aquatic ecology, surveys of surface and shallow subsurface soil gas, development of methods to measure riverine gas flux, and survey of river bathymetry. Norwest observed and coordinated the shallow subsurface soil gas surveys and aquatic ecology assessment and provided input and technical review for the development of methods to measure riverine gas flux. Norwest has reviewed and compiled information from Phase 1 and Phase 2 activities and used it to refine the conceptual geologic and hydrogeologic model and hypotheses and to develop recommendations for future technical investigations and monitoring.
1.4 REPORT ORGANISATION
In summary the report presents:
• Background information about regional and site-specific geology, the occurrence of methane, and the approach to investigating methane seeps in the United States (USA).
• The initial site conceptual model. • Methods and findings from the Phase 1 and Phase 2 tasks. • The revised conceptual model, and hypotheses regarding the potential source(s),
mechanism(s), and migration pathway(s) of the gas seeps in the Condamine River. • Recommendations, with justification, for future technical investigations for Phase 3. • Recommendations for an ongoing monitoring program for Phase 3.
The report is organized into 12 sections, including this introduction (Section 1), which provides introductory material including the goals of developing a conceptual model that explains the source(s), pathways(s), and mechanism(s) of the Condamine River gas seeps and of implementing desktop and field activities to gather and compile scientific information to test, validate, refine, and revise the model. Section 2 presents the investigation objectives.
Section 3 describes the geographical location of the project area. Section 4 introduces regional factors that affect oil and gas exploration and gas and fluid flow; presents site-specific geologic information; introduces the concept of using geochemical analysis to differentiate between sources of methane gas; and provides a high-level review of investigations of methane gas seepage in the San Juan and Raton Basins of Colorado, USA.
Section 5 presents the initial geologic and hydrogeologic conceptual model of the project area.
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Section 6 presents the investigation rationale; introduces the activities carried out in Phase 1 and Phase 2 and how the information collected was used to evaluate environmental impacts, refine and revise the conceptual model, and to develop recommendations for ongoing investigations and monitoring.
Section 7 contains ten sub-sections that present methods used, data collected, and results of the initial response tasks carried out in Phase 1 including:
• investigating and gathering information from CSG wells and landowner water bores, government monitoring bores, and coal exploration bores.
• collecting and geochemical analysis of gas samples from seeps, water bores, and CSG wells.
• interviewing and gathering information from landowners about the occurrence of new and historic gas seeps.
• conducting reconnaissance inspections beyond the limits of the observed seeps to determine whether there were additional areas of seepage.
• collecting and reviewing additional information from landowners, published reports, and government records.
• collecting and reviewing regional and site-specific geologic information.
• examining water and coal exploration bores using a downhole video camera to record the condition of the bores and to look for gas bubbles and their source.
• reviewing hydrographic and rainfall records for the Condamine River.
Section 8 contains seven sub-Sections that present methods used, data collected, and results of the focused field investigations carried out in Phase 2, including:
• initial surface water quality sampling and assessing the aquatic ecology in the vicinity of the seeps.
• developing and deploying a method for measuring the gas flux from the seeps; installing and monitoring surface water level gauging stations.
• collecting and reviewing additional scientific information regarding gas seepage in Australia and elsewhere.
• conducting surface and shallow subsurface soil gas surveys in and around the seeps, areas of stressed and dead vegetation of concern to landowners, and the CSG pilot wells.
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• conducting a bathymetric survey of the Condamine River.
Section 9 contains a review and evaluation of the information provided by QGC about well drilling, completion, and production from CSG wells in its Argyle Field and associated baseline water bore monitoring.
Section 10 summarizes the results of all of the Phase 1 and Phase 2 tasks in a table format to facilitate review.
Section 11 presents the revised site conceptual model based upon the results of the investigation to date.
Section 12 presents the recommendations for future investigation and monitoring in a table format to facilitate review.
Appendix A and Appendix B contain selected Tables and Figures, respectively, and follow the text in separate sections.
1.5 CSG COMPLIANCE UNIT4 – CONDAMINE RIVER GAS SEEP INVESTIGATION
The CSGCU has undertaken its own independent and comprehensive investigations and testing in the vicinity of the Condamine River gas seeps. Queensland Department of Natural Resources and Mines (DNRM) published a technical report and a later update that summarize the results of the work5. A two phased approach has been used: one focused on ensuring public safety, assessing environmental harm, and determining the extent and locations of the gas seeps; and the other a long-term investigation that involves a process in which technical experts will verify the information received from Origin and its consultants.
Initially the focus of the government was to ensure public safety and to conduct an assessment of environmental harm. To assess gas safety risk in the immediate area of the seeps, the Petroleum and Gas Inspectorate inspected the area, collected samples, and evaluated the results. To assess environmental harm, Environmental Officers from the Department of Environment and Heritage Protection (DEHP) inspected the area and collected additional water samples at the Camping Ground seep. The results of these assessments indicated that, based on the data collected, there is no gas safety risk in the immediate area of the seeps, nor environmental harm at the Camping Ground seep when compared to background conditions. The Government report concluded with recommendations for further work and this comment:
4 Formerly LNG Enforcement Unit. 5 Queensland, Department of Natural Resources and Mines, (1) 2012: Summary Technical Report – Part 1 Condamine River Gas Seep Investigation. Version 1.0. December 2012; and (2) 2013: Condamine River Gas Seep Investigation, January 2013 update.
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“It is recognised that the source and cause of the Condamine River gas seeps is unlikely to be determined in the short-term, and that a long-term approach to find more science-based answers to the phenomenon is needed.”
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2 OBJECTIVES
The objectives of the Condamine River Gas Seep Investigation are to:
• Gather, review, and compile existing technical and anecdotal information.
• Collect new information and conduct focused seep-specific activities that were used to help determine the locations, source(s), pathway(s), and mechanism(s) for gas migration and seepage into the Condamine River and nearby land.
• Refine conceptual geologic and hydrogeologic models that attempt to explain the occurrence of the gas seeps.
• Determine whether the gas seeps have impacted groundwater and surface water quality, water bores, vegetation, aquatic ecology, and/or air quality.
• Identify additional technical data needed to test and to refine the conceptual geologic and hydrogeologic models or hypotheses, and propose plans for collecting the data.
• Develop a plan for ongoing monitoring of the gas seeps to determine whether changes in the rate or areal extent occur.
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3 PROJECT AREA
The investigation is focused primarily in an area southwest of the town of Chinchilla, Queensland. The project area is centred approximately 4 km downstream from the Chinchilla Weir, and extends from the weir, downstream along the valley of the Condamine River and the land adjacent to it, to approximately 500 m downstream of the Rock Hole seep (Figure 1-1). The seeps are located on properties which have not yet experienced CSG development (only exploration drilling). The area of investigation was agreed to by Origin and the CSGCU; however, based upon the results of the initial tasks, the investigation was extended into other areas.
As part of the initial response, Origin personnel visually inspected approximately 70 km of the Condamine River and 21 km of Charleys Creek, where they flow through the Origin and some neighbouring tenements (Figure 3-1). The initial inspections were conducted from the middle of June through the middle of July 2012. A summary of the observed features is included in Table A.2. One of the goals of the initial reconnaissance inspections was to determine whether there are other areas of gas seepage and vigorous bubbling. Based on the results of the field reconnaissance, it is generally agreed that currently visible gas seepage is occurring in four different segments of the Condamine River (Figure 1-1). From east to west (i.e., upstream to downstream) the gas seeps are referred to as:
• Pump Hole
• Fenceline
• Camping Ground
• Rock Hole
Information obtained from landowners and local residents indicated that the Rock Hole gas seep has been observed for at least several decades, but that the Pump Hole, Fenceline, and Camping Ground gas seeps had not been observed bubbling vigorously before late 2011 or early 2012.
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Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, and the GIS User Community
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LOCATION MAP
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(when printed at A1 paper size)Data Sources:
1 Occurances of Natural Gas in Brigalow Area, A.R.G. Gray, 19672 Queensland Globe (Groundwater database - Queensland)3 Australian Water Resource Assessment Region Aerial Photography (ESRI Mapping Service: Digital Globe, 5-5-2010)
