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This natural gas atlas creates an inventory of the molecular
and stable isotope signatures of natural gases from the relevant geologic units
and locations in BC.
These natural gas fingerprints will:
- Assemble a catalogue of unique natural gas compositional IDs for active gas operations in BC with a focus on northeast BC;
- Characterize the geochemical conditions of BC’s major ongoing and future regions of petroleum exploration and production;
- Contribute to understanding the geologic framework of natural gas deposits at scales of fields to basin levels;
- Assist petroleum system models to de-risk plays;
- understanding and predicting generation occurrences, histories and potential productivity of natural gas in BC;
- 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 gas, shale gas, coal seam gas and coal bed methane, etc.);
- Offer a “geochemical DNA” catalogue for different gas sources for provenance work in production, well completions, processing and transport;
- Establish the database of fugitive emissions in surface waters and the atmosphere
Detailed goal description
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Natural gas development in northeast British Columbia has a
history of over 60 years. With the advent of new drilling and completion
techniques to access previously uneconomic deposits, British Columbia is
experiencing somewhat of a natural gas development renaissance. The nascent LNG
industry on the west coast of British Columbia, which will be sourced primarily
from NE B.C., will require extensive new exploration, drilling and production
to realize any of the projected goals.
As these new (and previous) wells and oil and gas reservoirs
are drilled and tested, natural gas samples are collected. By routinely
measuring the molecular and isotopic composition of these gases, we learn
important details about the character of the gases present, their habitat,
origin (e.g., microbial or thermogenic), type of organic source material
(kerogen), maturity or rank levels. We can also identify secondary processes,
such as degradation, oxidation, mixing and commingling.
This detailed geochemical characterization of natural gases,
which must include the stable isotope information of the gases, has
exploitation benefits to the operator, potentially allowing them to optimize
the gas revenue stream by understanding where certain gas-types occur. The
systematic cataloguing of B.C. natural gases in this BC-NGA project will reveal
information about the development, migration, segregation and
compartmentalization within petroleum systems. It will also define the
distribution of natural gas liquids, which help gas producers target higher
value targets and natural gas streams.
Additional information may be gained on the effectiveness of
regional seals and the impact of geologic structuring on seal integrity. This
information is critical to ensure shallow aquifers are not being compromised
during hydraulic fracturing operations. Also, communication between wells,
e.g., during hydraulic fracturing, can be tested with gas geochemical tracers.
Although new wells are generally drilled with state-of-the-art
completion methods and production equipment, there are concerns that the
associated drilling, production and transmission activities allow gases to
fugitively escape into the atmosphere or shallow groundwaters. This includes
release of natural gas from poor well completions, compromised surface casing
cements and from pressure cycling during hydraulic fracturing. There are also
additional concerns regarding fugitive gas emissions from older, sometimes
abandoned, well bores where cementing practices were less rigorous than today.
The ability to identify a leaking gas source has many
benefits for the public and industry. In the case of a leaking wellbore,
operators can lower remediation costs, by having a higher level of certainty as
to the gas source (e.g., depth and location), thereby allowing the operator to
quickly and efficiently plan remediation of leaking wellbore. This same
methodology can remediate old and abandoned wellbores – the methodology would
allow the service company to pinpoint the horizon(s) which is (are) leaking,
thereby reducing fugitive gas emissions (and lost product).
The detection of fugitive emissions from natural gas upstream
activities (exploration, production and transmission) is critical for the
responsible development of the resource, and for the health and safety of the
adjacent communities, including the First Nations. Cataloguing the fingerprint
of the different types and sources of natural gas in the subsurface is a
critical first step in the development of this comprehensive air monitoring
network for air quality.
Rationale and value
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This study has value for public, local communities, First Nations, the BCOGC, the natural gas sector, and Governments.
Some of the value-adds include:
- Identification of thermogenic vs. biogenic natural gas sources
- Provide initial critical step in the evaluation of potential fugitive gas emissions
- Identification of fugitive gas sources in abandoned and producing wellbores
- Optimization of gas revenue stream by predicting and mapping gas content and quality
- Lower remediation costs by providing a high level of certainty as to the location in the subsurface of the gas release
- Provide the technical framework for air monitoring programs
- Provide information that aids regulatory agencies with aquifer protection
- integrates with ongoing activities to monitor groundwater and analyze dissolved hydrocarbons in B.C.
- Increase understanding of petroleum systems, seal integrity, NGL distribution, to help natural gas producers target higher value gas reservoirs
- Petition for access to legacy isotope data and archived gas samples, (Produced Gas Samples and Gas Samples from Exploratory Wildcat (EW) and Exploratory Outpost (EO) wells).
In order for this initiative to be successful, the project
requires representative natural gas samples from all producing pools/fields
throughout the geological column in BC, focusing on N.E. BC. In addition,
temporal gas samples from the same well/pool/field can provide important
information with respect to the gas stream and optimization of production
The needed data for the project will come from three
- Legacy isotope data (and standard molecular analyses) from older archived conventional gas production and mud gas analyses;
- Produced gas samples from existing producing wells will help infill data gaps from the legacy isotope data;
- New gas samples from Exploratory Wildcat (EW) and Exploratory Outpost (EO) wells will update knowledge in new exploration regions and fairways.
Tasks of BC-NGA
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- Acquire and catalogue existing and ongoing data;
- Complete compilation and integration of existing and new geochemical and metadata from exploration and production wells in northeast British Columbia;
- Identify and catalogue all available molecular and isotope compositional data from previous petroleum wells in northeast British Columbia that are available from regulatory agencies (e.g., BCOGC, Minister of Energy and Mines), service companies and industry;
- Collate molecular and isotope compositional data from new and ongoing petroleum wells in northeast British Columbia;
- Request and collect proprietary gas data from the energy sector;
- Gas geochemical analyses on archived well samples;
- Make routine measurements on gas samples from past petroleum wells in northeast B.C. (e.g., shut-in or abandoned wells);
- Measure molecular and isotope compositions of gas on archived samples from petroleum wells in northeast British Columbia, e.g., gas composition of hydrocarbon and permanent gases, e.g., methane - pentane, δ13CH4, δ13C2H6, δ13C3H8, δ13CO2 and δ2H-CH4;
- Assemble geochemical data with related metadata from exploration and production wells from NEBC;
- Extend the archived sample study to other exploration regions in B.C. e.g., Netchako basin, Elk Valley and Crowsnest, Hat Creek, Comox and Nanaimo, etc.;
- Explore using archived cuttings samples to make ‘sorbed gas’ compositional measurements instead of traditional ‘free gas’ data, when the latter are unavailable;
- Gas geochemical analyses on current well samples;
- Make routine measurements on gas samples from current petroleum wells in NEBC;
- Measure molecular and isotope compositional data from new and ongoing petroleum exploration and production wells in NEBC at the Biogeochemistry Facility (SEOS, UVic), e.g., gas composition of hydrocarbon and permanent gases;
- Assemble geochemical data with metadata from exploration and production wells from NEBC;
- Extend the study to current unconventional exploration in other regions of B.C., e.g., Netchako basin, Elk Valley and Crowsnest, Hat Creek, and Comox and Nanaimo, etc.;
- Identify critical gaps in data and seek to obtain infill samples;
- Water geochemical analyses on current well samples Northeast BC Aquifer Characterization Study;
- Make complimentary gas geochemical measurements on fluid (water) samples collected from current petroleum wells in northeast British Columbia;
- Sampling and analyses in conjunction with joint water project ‘Northeast BC Aquifer Characterization Study’ with OGC, BCMFLNRO, BCMoE, and SFU (contacts: C. van Geloven D. Wilford and D. Kirste);
- Measure dissolve gas molecular and isotope compositions, i.e., hydrocarbon and permanent gas concentrations;
- Currently the NE B.C. water sampling program coordinated through D. Wilford and C van Geloven (OGC) has access to over 95 water and monitor wells in the region for measurement and cross referencing in the BC-NGA;
- Approximately 100 water gas samples will be collected and analysed during the project for detailed lab-based gasmolecular ad isotope measurements at the Biogeochemistry Facility (UVic).
- Gas geochemical measurements on fugitive emissions from well sites in NEBC - Fugitive Gas Emission Characterization Study - Collaboration in the joint OGC/UBC project (PI: U. Mayer) to analyze surface gas samples collected from oil and gas well sites in NEBC
- Our part in this project analyses the stable carbon and hydrogen isotope compositions of free gases fluxing out the soil at well sites and dissolved gases in the waters in the well bores;
- Similar to the NBCACS, this study will interpret the origin of the gases, i.e., allochthonous vs. autochthonous, or microbial vs. thermogenic, etc.
- In the case of thermogenic gases, the project will establish any links of shallow gas occurrences with potential sources in the subsurface using the detailed BC-NGA signature inventory;
- At the outset of the project approximately 25 well sites in NE B.C. will be visited by the team. Flux measurements will be made on site at ca. 20 - 30 locations on and around wellsites by optical spectroscopy. Gas samples will be collected for detailed lab-based gas molecular and isotope measurements at the Biogeochemistry Facility (UVic).
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