1	Approaches to Cold Heavy Oil Production: Workover Practices and Strategies March 15^th, 2000 Tropical Inn – Lloydminster AB M. Dusseault, K. Hayes, M. Kremer, C. Wallin
2	Workshop Goals “Produce the MAXIMUM possible VOLUME at the MINIMUM possible OPEX resulting in the MAXIMUM possible NETBACK Understand the Problem Solving Process Develop the “Best” Workover Strategy How to effectively Implement and Evaluate
3	Format and Rules of Engagement Workshop not a Lecture Develop a “screening process” Form a basis for “Decision Tree/Grid” Workshop participants will be acknowledged in Paper
4	Workshop Outline Introduction to CHOP The Problem Solving Process Root Causes: Why does CHOP stop? Possible remedies – Discussion of Workover Methods Choosing and Implementing the “Right” Solution Monitoring and Evaluating
5	Introduction to CHOP World Scale: Heavy Oil Future Lloydminster Scale: CHOP Processes
6	Problem Solving Process Define The Problem Symptoms Define Potential Root Causes Analyze for the Particular Root Causes Possible Remedies/Solutions Choosing the Best Solution Execution of the Workover Monitor Post Workover Evaluation
7	Problem Definition Define problem in terms of $$$ Well is SI - not making any $$$ Well has lower oil production
8	Symptoms No Pressure Test No Inflow/Fluid Level Low Production High Torque Can’t reseat rotor after flush Increased Gas production Increased Water production Low Injectivity (High P/Low V) High Injectivity (Low P/High V) …more
9	Root Causes - Mechanical May be root causes but are often symptoms of reservoir type problems Surface Drives/VFDs Prime Movers SCADA alarms/controls Downhole Rod String Tubing String BHP Casing Problems
10	Root Causes - Reservoir/Near Wellbore Blockage of sand flow No sand, little oil Excessive sand production Energy Loss in the reservoir Depletion of drive mechanism “disconnection” Water influx Localized Regional Gas influx Phase separation Gas coning/fingering
11	Particular Root Causes Well Scale: CHOP Workovers “Why does CHOP stop”?
12	Possible Remedies or Solutions “Cookie cutter” approach not good Specific problems require specific solutions Mechanical Fixes “Quick” Fixes Sand Cleanouts Reservoir/Near Wellbore Problems Combined Methods “Staged” approach
13	Key - Describing Workover Methods
14	Key - Ranking
15	Remedies - Mechanical Easy to diagnose and fix – replace or change equipment Charge/Booster Pump Compression Pumps Downhole Gas Separators/Anchors Extended rotors Z-tools, Sliding Sleeves BHP landing Depth Lined tbg Downhole Water separator …others?
16	Remedies - “Quick Fix” Fluids are introduced into tubing or annulus to flush sand away from intake or perforations – Be Very Selective in workover fluid!!! Vary casing pressure, RPM or fluid level Flushby “SUPER” Flush CTU and Flushby Loading Continuous Load Swabbing …others??
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23	Remedies – Sand Cleanouts Often determined by: geometry, reservoir pressure and characteristics, sweet/sour Circulating Perforation wash Bailing Sand Line Sand Pump/Tubing Pump to Surface (PTS) Rig Portable Continuous Stable Foam Cleanouts CTU …others?
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33	Remedies - Low/No Inflow Often determined by proximity of damage Could spend a whole day discussing each method…. Reperforating Abrasi-Jet Proppant/Hydraulic Fracturing Chemical Stimulations Chemical Treatments Pulse Enhancement …others?
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40	Remedies – Combined Methods A combination of two or more methods producing enhanced results… Foam while perforating Perf wash w/foam, chemicals Pressure Pulse w/chemicals Foam Acid frac Pressure Pulse /CSE …others?
41	Remedies - Water Problems Not in the scope of this workshop Dye Testing Wax Squeeze/Placement Polymer Squeeze Cement Squeeze Gas Injection …others?
42	Choosing the Best Solution Engineering Assessment Short term “fix” vs long term “solution” Economic Assessment Corporate knowledge base Cost Ranking Adding in Risk External Advice Service Company help
43	Execution of the Workover Success Criteria Flexibility Bringing the well back on production
44	Monitoring Rates/cuts Sand cuts/volumes Fluid levels/Pressures GORs Surface Equipment/BHP parameters Fluid/debris analysis
45	Post Workover Evaluation Technical success – Shorter term Well back on production Economic success – Longer term Payout + Profit Documentation Lookbacks/Followup Reports Learn more from mistakes than successes!!!
46	Perhaps next workshop…. Disasters, Failures and Mistakes in CHOP : How We Learned to do Things Better!!! Continuous or long term applications of existing workover techniques
47	Acknowledgements The Lloydminster and District Heavy Oil Section of the Petroleum Society would like to thank the following people for their contribution to this workshop: M. Dusseault All workshop participants C. Wallin M. Kremer K. Hayes J. Bootsman C. Gall D. Pavka S. Reid