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Quantifying Vent Gas Footprints Bruce Peachey, P.Eng. PTAC’s Green Toolbox September 29-30th, 2003.

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Presentation on theme: "Quantifying Vent Gas Footprints Bruce Peachey, P.Eng. PTAC’s Green Toolbox September 29-30th, 2003."— Presentation transcript:


2 Quantifying Vent Gas Footprints Bruce Peachey, P.Eng. PTAC’s Green Toolbox September 29-30th, 2003

3 Heavy Oil Vent Quantification Project  Project Background  Summary of Project Objectives  Key Issues and Quantification Factors  What Standards are Being Developed?  Where we are now?  Where we go from here?

4 Background  Nexen Sponsored JIP: Launched through PTAC  Target is to Economically Reduce Methane Vents First need to understand how much methane there is  Current Participants: Nexen; Husky; ExxonMobil; Petrovera; CNRL Budget $75k  Invited Participation by AEUB and SIR  Intended that results be made public through Industry Standards

5 Methane is Important in Both Alta and Sask 230 Mt 16Mt 48 Mt 23Mt 160 Mt 69 Mt Kyoto Target for Canada? Emissions? Population? 69Mt 23Mt Alta Upstream* Oil&Gas Total & Methane* Methane reduction is important - No matter what the target 18Mt 9Mt Sask Upstream* Oil&Gas Total & Methane* *Oil &Gas Sector based on NRCan 1997-2020 Emission’s Projection for 2000 Alberta’s Share Of National Target? Based on…….?

6 Vent Quantification Project  Main result is to improve quality and consistency of heavy oil vent gas numbers in use Both Produced and Vented  Better understand variability observed in vent measurements and reasons for it To help understand the numbers and to reduce variability  Increase ability to forecast vent volumes to facilitate mitigation Economically manage the opportunities and the risks

7 Standards Needed to Improve Data

8 Key Findings - Factor #1  Well Profile Types (24-hour tests) Type A - Best Results - Repeatable GOR’s Type B - Pumped-off wells (Assumed) Type C - Gas Well Behaviour Type D - Mix of Behaviours - Operational Impacts? Type F - Difficult to Explain at this Point

9 Type A - Avg 694 m3/d (720- 684) Est. 75-80% of wells

10 Type B - Avg 708 m3/d (1944-288) Well Pumped Off?

11 Type C - Gas Well Behaviour Wells on Same Lease; Tested at the Same Time; Diverted from Compression Rates (m3/d) Well #1 Avg 25,635 (31,680-23,400) Well #2 Avg 3,409 (11,664 - 1,728) Well #3 Avg 2,997 (10,080 - 1,944) Well #1 Well #2 Well #3

12 Type D - Operational Changes? Example 1 - Type C? Vent Valve Adjustment? Avg 225 m3/d (540-108) Pump Speed Change? Example 2 - Type A? or B? Avg 557 m3/d (1,296-288)

13 Type F - Avg 1,253 m3/d (6,264-0) Older wells? - Pumping Problems? Trapped Flow? Vent on Another Well Shut-in?

14 Key Findings - Factor #2  Impacts of Well Phases (Working Theory) Early Production - Near well oil being produced, fine foam (Dream Whip) Established Cold Heavy Oil Production (CHOP) - Sand production causes flow channels or wormholes, coarse foam (Beer suds) Late Production - Oil and gas separate in the reservoir, slug flow, trapped flow, interwell communication (End of the shaving foam can)

15 Well #2 - Early Phase & Established Summer 2001 No gas venting from annulus All from tank? Summer 2002 Gas venting from annulus Relatively Stable GOR

16 Well #3 - Established CHOP Production Summer 2001 Stable GOR Summer 2002 Higher oil and gas rates Same stable GOR

17 Well #4 - Instability due to Pump Summer 2001 Stable GOR Summer 2002 Pump Failing then Replaced Causes Type D/F Behaviour

18 Well #5 - Transition Between Phases Summer 2001 Transition from Early Phase Balance of Gas to Tank? Summer 2002 Production Stabilizing GOR Becoming more Stable

19 Well #6 and #7 - Late Phase CHOP Lost? Oil = 0.44 m3/d GOR = 1193 m3/m3 WOR=0.8 m3/m3 Oil = 0.82 m3/d GOR = 1495 m3/m3 WOR=2.1 m3/m3

20 Key Findings - Factors #3- 6  Obtaining a Well GOR Accounting for Fuel Use - Should be proportional to production and single source Tank Vents - Suggested add 5% to Type A for Established CHOP Phase. Others????? Meters Used - Standardized methods and configurations for various types of meters used. Oil Rate Used - Ensure rate is stable and matches conditions during the period of gas measurement.

21 Suggested Format for Standards  Basic Content for each Key Area Why – The standard is necessary When – Is the standard applied Who – Is responsible for what; who is affected What – Should be done in what order Where – Should the standard be used How – Should the work be done  Clear Language – Minimum length to do the job  Adjust based on end-user targeted Operators, technical staff, management, admin

22 Key Area – Regulations and Assessment  Separate Standards for each Province  Target – Those who manage operations  Content: Minimum spec for triggers to require a test Measurement accuracy required Frequency of testing Royalty rules Any mandated assessment requirements for conservation or license impacts

23 Key Area – Criteria for a Successful Test  Should be the same independent of province  Target – Field Technical, Operators, 3 rd Party Testers  Content: Description of flow types and causes Description of allowable Type A »Deviation from average Data collected to document test and allow adjustment for fuel use etc. Checklist What to do if test not acceptable

24 Key Area – Testing Non-A Type  Independent of Province  Target – Technical staff controlling testing  Type C – Gas Well Behaviour Initial test procedure with imposed step change in pressure (up or down) Standards for continuous testing  Type F – Sporadic Gas Flow Needs more work to define Assess by grouping wells in an area? Simultaneous testing of wells thought to be linked?

25 Key Area - Metering Equipment  By type of meter being used  Target – Technical staff controlling testing  Content: Basic properties of meter Minimum features meter should have Minimum specs for test set-up Set-up based on flow ranges and stream being measured – Tank, total or vent to atmosphere Calculations and factors to be used specific to heavy oil and low pressures

26 Key Area – Maintaining Revising Standards  Separate for H.O. Producers or Integrate with other Standards Groups?  Target – Industry group of knowledgeable people  Content: Reference to available information on each issue area Triggers to revise standards Issues to investigate further Consensus process for setting and rolling-out revisions

27 Example - Photon Control – New Atmospheric Gas Flow Meters 1” pipe optical gas flow meterTCPL & Daniel 4” optical plate Based on technology developed by NOVA Being developed by Photon Control - Vancouver Project supported by Husky for Vents

28 Where are we now?  Working on drafts of standards  Investigating some issues that are still unresolved  Documenting observations to date  Defining potential follow-up projects to improve quality of information and analysis  Planning for roll out of standards once they are completed and reviewed by participants.

29 Where do we go from here?  Producers need to assess use of vent gas measurement to: Produce more oil - Improved understanding of CHOP Mechanism Reduce operating costs - Use gas to monitor pump operation and extend run life  Move the standards into widespread use  Once initial standards are implemented monitor results and revise standards if necessary

30 Vent Gas Footprints - Summary  Defining the footprint of an emission stream can lead to insights and understanding  Collaboration provides insights by bringing in data and opinions from a number of sources.  Results should lead to increased vent gas conservation and improve the economics of heavy oil production  Similar methods might be applied to other vent streams (Dehydrators and Tanks)

31 Acknowledgements  Nexen (Garry Mann et al) for initiating the project  CNRL, ExxonMobil, Husky and Petrovera for seeing the benefits of collaboration  AEUB and SIR contacts for participating  Support from PTAC to launch  Support from ADOA Consulting

32 Contact Information New Paradigm Engineering Ltd. 10444 - 20 Avenue Edmonton, Alberta Canada T6J 5A2 tel: 780.448.9195 fax: 780.462.7297 email: or web:

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