SAGD Water Disposal Options, Associated Impacts, and Strategies to Improve Environmental Footprint. Basil Perdicakis, January 27, 2011

Transcription

1 SAGD Water Disposal Options, Associated Impacts, and Strategies to Improve Environmental Footprint Basil Perdicakis, January 27, 2011

2 Statoil Canada Kai Kos Dehseh (KKD) Lease Leismer site currently producing bitumen with wells on circulation and semi SAGD mode. Leismer Project -> ERCB approval for 40,000 BPD. Corner Project -> ERCB approval for 40,000 BPD. Full field KKD development -> AENV regional EIA deemed complete for 220,000 BPD. Leismer CPF is about a 2 hour drive SE of Fort McMurray. Thornbury Hangingstone Corner Leismer

3 Outline 1. Discussion of options for SAGD disposal water handling. 2. Impacts associated with different disposal water recovery schemes. 3. Strategies for improving the environmental footprint associated with SAGD water recycling systems. Improving ZLD operation: Organics mitigation in waste waters. Improved waste management (solidification/encapsulation). Reducing environmental impacts of Make-Up Water Processing.

4 Generic Water Use for SAGD Typical layout for a generic WLS based SAGD water plant illustrated below. Basis is 100 bbl of SOR = 3.0 with 90% recovery on a PW basis. 30 bbls of water lost to reservoir (10% reservoir retention). Requires facilities coordination with reservoir groups to reduce going forward (~ 50% of overall water losses). 27 bbls of blowdown from the steam separator are used to purge soluble salts and organics extracted from the reservoir. 57 bbl of water required to produce 100 bbl of bitumen. 30 bbl Retention OTSG Steam Separator 300 bbl Steam Reservoir Production Treatment 100 bbl Bitumen WLS Sludge 57 bbl Make-up Water Produced Water Treatment 400 bbl SG Feedwater 343 bbl Recycled Water 73 bbl Water 27 bbl Blowdown 270 bbl Produced Water What are the options and trade-offs involved in processing and reducing the blowdown volumes? Basis: Steam:Oil Ratio 3:1 Reservoir Retention 10% % Recycle (Steam & BD Basis) = 84%

5 Process Options to Reduce Make Up Water Demand PW MUW OTSG Steam Legend PW/BFW/Steam make up water disposal water solid waste to landfill disposal well OTSG Steam Drum Boiler Steam BFW/PW Tank Typically multiple options available in early design phases often with limited hydrogeological data. BFW/PW Tank truck-out (RLD) Different chemistries between WLS and PW evaporator blowdown. settled solids Salt cavern Dryer (ZLD) DWT Disposal well

6 SAGD Disposal Water and Waste Handling Disposal Wells Typically Class 1b (ERCB Directive 51) for SAGD PW liquid wastes. Disposal Pipelines > 50 km likely to be cost prohibitive. Balance between costs of matching chemistry of disposal water with formation water to minimize plugging and lifecycle costs of drilling for new disposal wells. Landfills Currently used for long term disposal of dewatered WLS sludge and ZLD solids. Land area to dispose of 1 m 3 of waste is about 0.16 m ,000 m3 landfill cell can take ~ 1 year to construct at a cost of ~ 1 million CAD. ~ 50 year life for a 20,000 BPD SAGD Plant using WLS. Class II landfills typically used for disposal of non-hazardous waste. Cost impact for disposal in third party class I landfill due to waste contamination is significant. ~ 0.5 m 3 of leachate per m 2 of uncapped landfill area per year. Risks: liner failure, trucking accidents and impacts, public perception, long-term liability.

7 SAGD Disposal Water and Waste Handling Disposal Water Treatment (DWT) Typically neutralization with HCl or H 2 SO 4 followed by solid-liquid separation (centrifuge, filter press). Have had reliability issues in SAGD application. Similar technologies could also be used to replace dryer operations in a ZLD operation to recover additional water as opposed to vapourizing water. Drying Many types of industrial dryers (gas fired rotary, drum, spray, vacuum). Challenging application in SAGD due to unique nature of feed slurry. Trucking High OPEX, low CAPEX. Typically short term solution for start-up or smaller facilities.

8 SAGD Disposal Water and Waste Handling Salt Caverns Man made sub-surface cavities created in salt formations. ~ 25 in operation in AB. Used to replace disposal water treatment facilities in SAGD applications. Gravity separation of concentrated slurry effected, typically with downstream disposal of treated water. Typically require > 100 m thick formations allowing for ~ 250,000 m 3 of storage. 1 cavern can take several years to construct at a cost of several million CAD. ~ 10 m 3 of water required for every 1 m 3 of cavern storage. For economic considerations only, typically want salt caverns within 5 to 10 km of source water and disposal zones and within 50 km of CPF.

9 Outline 1. Discussion of options for SAGD disposal water handling. 2. Impacts associated with different disposal water recovery schemes. 3. Strategies for improving the environmental footprint associated with SAGD water recycling systems.

10 Balancing Competing Objectives As produced water recycling technology evolves it is expected to help reduce the environmental footprint of in-situ thermal recovery of heavy oil. This means reducing: Make-up water usage Wastewater disposal Energy Consumption (GHG emissions) Landfill volumes Land disturbance associated with MUW and disposal water pipelines Production of difficult-to-manage residues Key Points with existing technologies: With existing technologies, increased reuse of PW and decreased use of fresh make-up water are at the expense of increased energy consumption and/or landfill volumes. Lack of disposal well availability results in increased energy consumption and landfill volumes. Local hydrogeology plays critical role in determining best option for specific projects (no single magic bullet for all projects).

11 Environmental Impacts of Make-up Water Sourcing 30 bbl Retention OTSG 400 bbl SG Feedwater Steam Separator 300 bbl Steam Reservoir Production Treatment 100 bbl Bitumen Solids ZLD System (evap-crystdryer) 270 bbl Produced Water 30 bbl Make-up Water RO Make-up Water Basis: Steam:Oil Ratio 3:1 Reservoir Retention 10% Disposal well PW = 3500 TDS Environmental Impact Fresh Water Use Brackish Water Use % Recycle Solids (relative basis) RO % Recovery RO Energy (kw-h/m 3 ) MUW TDS (ppm) 0 5,000 50,000 w RO w/o RO w RO w/o RO w RO w/o RO % - 87% 90% 80% 90% % - 50% ZLD water losses neglected for simplicity

12 Summary of Statoil Waste Management Study Relative Impacts of 7 Water Treatment Schemes (Normalized Scale: 0 to 1) Scheme PW Disposal Disposal Water Processing Solids Treatment Water 1 Pipelines Energy Reliability 1 WLS/AF/IX disposal well WLS/AF/IX Evap 2 + DWT 3 + disposal well WLS/AF/IX Evap + salt cavern + disposal well WLS/AF/IX Evap + Xtal 4 + Dryer (ZLD) Evap DWT + disposal well Evap Xtal + salt cavern + disposal well Evap Xtal + dryer (ZLD) Includes water used for salt cavern washing. 2 Evap = Evaporator 3 DWT = Disposal water treatment 4 Xtal = Crystallizer Notes: - Pipeline impact subject to hydrogeological conditions for each project. - Economics also impacted by project hydrogeological conditions.

13 Environmental Trade-Offs in a ZLD System Relative Water Use and Environmental Impacts WLS/AF/IX +Evap 82% 87% 88% 88% Produced Water Recycle % Makeup Water Disposal Water Landfill Energy GHG - GHG emissions for ZLD case are ~ 5% of overall SAGD facility GHG emissions. - Basis: 12% reservoir loss, SOR = 3.0, MUW > 5,000 ppm TDS, Lime and MgO derived from carbonate sources, lifecycle GHG emissions shown (power from Alberta grid). +Xtal +Dryer (ZLD)

14 Outline 1. Discussion of options for SAGD disposal water handling. 2. Impacts associated with different disposal water recovery schemes. 3. Strategies for improving the environmental footprint associated with SAGD water recycling systems. Improving ZLD operation. Organics mitigation in waste waters Improved waste management (solidification/encapsulation) Reducing environmental impacts of Make-Up Water Processing.

15 OSLI Vision: Achieving world-class environmental, social and economic performance in developing this world-scale oil sands resource. Mandate - what we re committed to do Improve oil sands industry reputation by demonstrating and communicating environmental and social and economic performance and technological advancements Vision what success looks like Achieving world class environmental, social and economic performance in developing this world scale resource Mission our reason for being OSLI is complementary to industry groups such as CAPP and the Oil Sands Developers Group. We are a leadership group with a laser focus on performance improvement. Lead the oil sands industry in the responsible development of Alberta s bitumen resource by taking demonstrable action to improve the environmental, social and economic performance

16 OSLI Structure Steering Committee Coordinating Committee Four active working groups: Land Stewardship Water Management Improved Waste Management Desalination 6 other projects Technology Breakthrough Sustainable Communities Supported by: Intellectual Property Working Group Communications Working Group Stakeholder Engagement Working Group The member companies allocated $10 million to OSLI in

17 Improved Waste Management Trend is towards higher produced water recycle rates to conserve water and comply with ERCB directives. This implies waste stream changes (more concentrated brine and/or dry salt). Lessons learned in industry with regards to first generation ZLD technology: high energy consumption/ghg production mechanical issues with solids handling Viscosity issues arising from high levels of dissolved organics Perpetual care of a highly soluble residue in a landfill Goal: To improve reliability of ZLD operations while also reducing waste liability Approach: Seek and evaluate alternative methods of managing evaporator/ crystallizer wastes to mitigate adverse impacts of ZLD technology

18 Improved Waste Management Current industry standard for treating OTSG blowdown from WLS PW Treatment Return Condensate Crystallizer Steam 2.) Develop alternatives ZLD Feed to drying. TOC ~ X ppm Saturated brine Evaporator TOC ~ 5X ppm Gas Dryer Feed TOC ~ 10X ppm Gas fired rotary dryer Exhaust Dry Salt 1.) Develop processes to reduce build-up of dissolved organics in waste.

19 Improved Waste Management ph adjustment for organics precipitation followed by suitable solid liquid separation process Return Condensate Crystallizer ZLD Feed TOC ~ X ppm Steam Saturated brine Evaporator TOC ~ 5X ppm Also studying ph adjustment in other parts of the SAGD process. ph Adjustment Salty Solids Organic Rich Solids

20 Improved Waste Management ph Adjustment

21 Improved Waste Management ph Adjustment

22 Improved Waste Management ph Adjustment

23 Improved Waste Management Alternatives to Drying solidification/encapsulation of waste Return Condensate Crystallizer ZLD Feed TOC ~ X ppm Steam Saturated brine Evaporator TOC ~ 5X ppm Also studying solidification options in other parts of the SAGD process. Solid Waste Solidification agents

24 Improved Waste Management Alternatives to Drying solidification/encapsulation of waste Return Condensate Crystallizer ZLD Feed TOC ~ 3,200 ppm Evaporator Saturated brine TOC Steam ~ 16,000 ppm Also studying solidification options in other parts of the SAGD process. ph Adjustment (SAs) (SAs) Solid Waste Solid Waste

25 Improved Waste Management Develop alternatives to drying: Degrees of success: Achieve landfill criteria (pass paint filter test; no free liquid). Achieve physical strength properties (bearing strength). Resist leaching (TCLP, salt dissolution). Produce a beneficial product. Solidification testing program initiated with technology vendor: Work commenced on water originating from OTSG blowdown. Different additives and ratios of additives tested. If sufficient bearing strength achieved, leaching tests performed.

26 Improved Waste Management Solidification of waste: ZLD waste + solidification agents = improved waste Mixing Dried Block Strength Testing

27 Improved Waste Management Example of leaching test. - Test below is a control performed on 60% NaCl solution. - Solidified waste of sufficient bearing strength is submerged in deionized water. - Conductivity of water monitored versus time. Conductivity For this set of additives tested significant leaching occurred. Samples lost 2-3% of weight after 5 days of submersion.

28 Improved Waste Management Next Steps Dissolved organics removal: Develop better understanding of high concentrations of simple organic acids in comparison to naphthenic acids in feed. Test different technologies for effecting liquid solids separation. Determine possible destinations for waste streams. Test blowdown from PW evaporators. Solidification/encapsulation: Optimize solidification parameters and test new solidification agents. Develop better understanding of the role of organics. Further reduce long term leachability of final end product. Process development. Refine processing schemes with and without ph adjustment. Determine overall economic and environmental benefits.

29 Desalination Technologies Reverse Osmosis 100% 6.00 Maximum Theoretical Recovery (%) 75% 50% 25% 0% P_RO = 82 atm, TDS_max=105,000 ppm P_RO = 82 atm, TDS_max=80,000 ppm P_RO = 27 atm, TDS_max=52,000 ppm P_RO = 7 atm, TDS_max= 9,000 ppm Theoretical Power/Flow (kw-h/m3) MRT % R 1 TDS TDS F R Power P Flow 3600 Feed TDS (mg/l) Solid lines refer to LHS axis. Dashed lines refer to RHS axis.

30 New Desalination Technologies Use exclusively or in combination with RO to reduce environmental impacts of make-up water sourcing. Reduced energy consumption. Note: Make-up water sourcing for high salinity water at 25% recycle begins to approach HP BFW pump energy requirements. Some new technologies claim up to 80% reduction in energy compared to RO. Use of low grade waste heat from SAGD facility. Increased water recovery as opposed to standalone RO, or use in place of MVC to treat RO reject. Potential for reduced capital costs. OSLI Desalination Project Consultant has completed Emerging Desalination Technologies Report. 2-3 new technologies currently being evaluated in greater detail.

31 QUESTIONS?