BC-NGA. Natural Gas Atlas. BC Natural Gas Atlas. Michael J. Whiticar and Curtis Evans School of Earth and Ocean Sciences University of Victoria

Transcription

1 BC-NGA Natural Gas Atlas BC Natural Gas Atlas Geochemical Characterization of our Energy Resources Michael J. Whiticar and Curtis Evans School of Earth and Ocean Sciences University of Victoria CSUR talk by Geoscience BC

2 Goals of BC-NGA. & Why? Create a thorough, searchable geochemical inventory and mapping of natural gases in BC (Phase I is NE BC) Develop an accessible geochemical database for a broad range of users, e.g., industry, government and non-government groups, and general public This atlas will inventory the molecular and stable isotope signatures of natural gas coming from the relevant geologic units and locations in BC. These natural gas fingerprints will: 1) Assemble a catalogue of unique natural gas compositional IDs for active gas operations around BC (Phase I is NE BC) 2) Characterize and map the geochemical conditions of BC s major ongoing and future regions of petroleum exploration and production. CSUR talk by Geoscience BC 2

3 Why? Goals of BC-NGA 3) Contribute to understanding the geologic framework of natural gas deposits at scales of fields to basin levels 4) Assist petroleum system models to de-risk plays by understanding and predicting generation occurrences, histories and potential productivity of natural gas in BC 5) Provide robust baseline of gas signatures to identify and track fugitive emissions of natural gas (groundwaters and atmosphere), e.g., distinguish microbial gas from thermogenic gases (associated, shale, CSG, etc.) 6) Offer a geochemical DNA catalogue for different gas sources for provenance work in production, well completions, processing and transport 7) Establish a database for fugitive emissions in surface waters and the atmosphere CSUR talk by Geoscience BC 3

4 What is Natural Gas Fingerprinting? Natural Gas compositions: 1. Molecular abundances C 1, C 2+, CO 2, N 2, H 2 S, etc. (based on maturity and kerogen) 2. Stable isotope ratios d 13 C 1, d 2 H C1, d 13 C 2+, d 13 CO 2, d 15 N 2, d 34 S H2S, etc. after Hunt, 1979 CSUR talk by Geoscience BC 4

5 12 6C 13 6C What are Stable Isotope Ratios? mass = 12 mass = 13 e.g., d 13 C CH4 The ratio R is: æ ç è 13 C 12 C ö ø CH 4 Relative to a standard (VPDB) æ R ö d 13 C CH4 ( ) = gas -1 ç èr 103 s tandard ø additional neutron CSUR talk by Geoscience BC 5

6 Stable Isotope Systematics Distinctive stable isotope signatures Diagnostic stable isotope fractionations (separations) Whiticar, 1996 Geoscience BC Day 08/10/15 6

7 Combination of Natural Gas Molecular and Isotope Composition Combination of molecular and isotope ratio compositions are characteristic of: 1. Gas Types - Thermogenic - Microbial - Geothermal, etc. Carbon isotope ratio ( ) Whiticar, Process and Pathways - migration - mixing - maturity - alteration, etc. CSUR talk by Geoscience BC 7

8 Combination of Carbon and Hydrogen Isotope Composition Combination of C- and H- isotope ratio compositions are also characteristic of: 1. Gas Types 2. Process and Pathways after Whiticar, 1993 CSUR talk by Geoscience BC 8

9 Basis for the Atlas Resource Development and Geoscience Branch of BC Ministry of Energy and Mines and Petroleum Resources (MEMPR) in partnership with National Energy Board (NEB) The final report is entitled Conventional Natural Gas Play Atlas, Northeast British Columbia CSUR talk by Geoscience BC 9

10 Areas of Study (Phase I) and impact BC OGC Area-based Analysis: Overview April 2013 CSUR talk by Geoscience BC 10

11 Stratigraphic Control CSUR talk by Geoscience BC 11

12 Examples of Map Types for BC-NGA Our goal is to obtain gas compositional data (molecular and isotope) for all producing horizons in NE BC and map them according on a formation by formation basis Based on a searchable inventory of natural gas geochemistry ftp.bcogc.ca/outgoing/ogc_datageology_and_engineering/ Maps link to a web-hosted geochemical database CSUR talk by Geoscience BC 12

13 BC-NGA Project Summary BC-NGA Natural Gas Atlas Important geochemical inventory and assessment of natural gas occurrences in BC Establish comprehensive, legacy regional/play natural gas character framework, e.g., baselines, stratigraphic control, source rocks Critical multi-user participation by industry, Geosciences BC, OGC, MEMPR, UVic, UBC, NGO and public Open access (with restrictions) for database query, mapping and graphical tools Integration into existing petroleum database Incorporation of groundwater and fugitive emissions studies, e.g., FLNR CSUR talk by Geoscience BC