Beyond CSS, SAGD and VAPEX. Zhangxin Chen

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1 Beyond CSS, SAGD and VAPEX Heavy Oil and Oil Sands Reservoir Modeling Zhangxin Chen University of Calgary, NSERC/AERI/CMG Chair Professor

2 Participants Synergia Polygen Ltd

3 Outline Why? Importance of the Research Enhanced Recovery Methods: - CSS (cyclic steam stimulation) - SAGD (steam assisted gravity drainage) - VAPEX (vapor extraction) Problems in Oil Recovery from Heavy Oil/Oil Sands Modeling Challenges

4 Importance of the research Reserves of unconventional oil are enormous worldwide and important to economy Conventional oil & gas in decline and must be replaced by unconventional resources New technology needed to reduce risk and costs and make environmentally sustainable Mathematical modeling important for process design & optimization

5 Importance of the research (cont d) About 10 trillion barrels of heavy oil resources worldwide Roughly triple the combined world reserves of conventional oil and gas

6 Global crude reserves by country Proven reserves (billions of barrels) Canada, with 174 billion barrels in Oil Sands reserves, ranks second only to Saudi Arabia in global oil reserves Saudi Canada Iraq Iran Kuwait Abu Dhabi Source: Canadian Heavy oil Association Venez. Russia Libya Nigeria USA

7 Oil classification Viscosity (cp) Density (kg/m3) Density (API) Conv. oil <100 <934 >10 Heavy oil , , Bitumen >10,000 >1,000 <10

8 Examples of heavy oil/bitumen Cold lake bitumen Peace river bitumen Athabasca bitumen 11 API 9-10 API 8-9 API 1-300,00 cp 200,000 cp 2-5 million cp

9 What is oil sands? Composition Inorganic material (75-80%, of which 90% quartz sand) Water (3-5%) Bitumen (10-12%) Unconsolidated, crumbles easily in hands

10 Canadian oil sands growth Currently about 1.5 million b/d of oil sands (out of total 2.5 million b/d of oil production) 2015=3.5 million b/d 2015=3.5 million b/d (out of total 4.5 million b/d of oil production)

11 In-situ represents a growing opportunity Open Pit Mine More than 80% of reserves too deep to mine Open Pit Mine Athabasca River Currently 65% of production is mined Oil Sands

12 Enhanced recovery methods of heavy oil reservoirs The principal obstacle in heavy oil (<20 API, >100 cp) recovery is the high viscosity. Any reduction in viscosity will increase the oil mobility. Thermal methods Non-thermal methods CSS Steamflooding Hot waterflooding In-situ combustion (THAI) SAGD Waterflooding (polymers) Chemical flooding Immiscible CO 2 flooding Solvents injection VAPEX

13 Enhanced recovery methods: CSS CSS was accidently discovered in 1957 when Shell Oil Company of Venezuela was testing a steam drive in the Mene Grande field.

14 Problems in oil recovery from oil sands In-place hydrocarbons (bitumen): too viscous and thus immobile. No communication between injection and production wells. Oil sands in shallow formations that do not contain superimposed injection pressures.

15 Partial solutions The viscosity can be lowered by application of heat in the form of: Steam injection In situ combustion Conduction heating Electrical heating

16 Steam Saturation Athabasca Bitumen Visco Pressure, Kpa Oil Viscosity,cP U o = 0.1 k μ o o Thermal Method Favorable zone Temperature, C ( P ρ gz) o o Oil phase effective permeability is a control on oil flow rate. Oil phase viscosity is the other. 1

17 Partial solutions (cont d) The lack of communication between injection and production wells can be rectified by: Fracturing Use of steam stimulation of individual wells Use of an existing bottom water zone linking the wells

18 Partial solutions (cont d) Insufficient overburden is related to injection pressure requirements: Reduction of well spacing to compensate for overburden Use of horizontal wells

19 Enhanced recovery methods: SAGD Low recovery rate: 30% of initial oil in place Relatively new thermal concept: SAGD (steam assisted gravity drainage) by Butler in

20 SAGD concept

21 SAGD (cont d) Uses heating for viscosity reduction Drive energy comes from gravity Process is driven by heat transfer between steam and cold oil Heat can pass through rock grains Thin shale layers are not a big barrier to heat transfer

22 SAGD (cont d) Up to 70% recovery Commercial steam/oil ratio under favorable conditions High operating costs and environmental impact

23 Enhanced recovery methods: VAPEX Similar to SAGD, VAPEX (vapor extraction) involves injection of light hydrocarbon vapors such as propane, butane, or mixture of them as solvent into a reservoir to dilate and recover bitumen (late Butler, 1989).

24 Enhanced recovery methods: VAPEX (cont d)

25 Unresolved issues & challenges of VAPEX Lower oil rate than SAGD Loss of solvent to untargeted zones Accumulation of non-condensable gas in the vapor chamber Formation damage by asphaltenes precipitation Hydrate formation

26 Examples of heavy oil/bitumen (cont d) Cold lake bitumen 11 API 1-300,00 cp CSS Peace river bitumen 9-10 API 200,000 cp CSS Athabasca bitumen 8-9 API 2-5 million cp Mining /SAGD

27 Modeling challenges Reservoir heterogeneities Heterogeneities in fluid properties Moving thermal fronts--thin For thermal-solvent processes, moving mobile solvent-rich oil layers are thin Phase behavior important (e.g., VAPEX) Presence of mud and shale layers, vertical flow barriers Geomechanics important (e.g., shearing of sand at chamber edges) Reactions (in situ combustion and upgrading) Thin diffusion

28 Modeling challenges (cont d) Reservoir NOT Homogeneous

29 Modeling challenges (cont d) Cold lake bitumen Peace river bitumen Athabasca bitumen 11 API 9-10 API 8-9 API 1-30,000 cp 200,000 cp 2-5 million cp

30 Modeling challenges (cont d) Current simulation models are too simple, homogeneous and does not have sufficient physics for heavy oil/bitumen. Need detailed simulation models and robust algorithms that can capture physics. Need fast tools because hundreds to thousands of simulations are run for process design and uncertainty analysis.

31 5-year program Foundation CMG $1 mil NSERC $1 mil CMG/SEGP/CFI/SYNERGIA Equipment $1 mil THE CHAIR RESEARCH PROGRAM U of C Infrastructure Oil industry $2 mil $50K x 5 yr AERI $1 mil

32 Collaborators Lab Research: Drs. J. Abedi, R. Heidemann, B. Maini, R. Mehta, G. Moore, and T. Okazawa Reservoir Characterization: Drs. J. Jensen and THE CHAIR RESEARCH PROGRAM Reservoir Simulation: Drs. M. Dong, I. Gates, L. Nghiem, T. Harding, and T. Settari S. Larter DR. MANI Students, PDFs, and RAs Reservoir Geomechanics: R. Chalaturnyk, T. Settari, and R. Wan LAB EXPERIMENTS MODELING

33 Research resources Simulation software Computing hardware (128 CPU Shared Memory) Computer server room CMG Simulation Laboratory Visualization Centre (i-centre) Tomographic Imaging/Porous Media Lab Advanced oil recovery laboratories Administrative and technical support staff and systems Graduate students and PDFs

34 Lab Experimental Set Up Modification Data Acquisition Model Temp Temp Steam Steam Oil/Water Production Water Load Cell Weight Cum Steam Inj. Modification

35 Applications

36 Applications (cont d) THAI Model Modelling Complex Layers & Slanted Wells Wells Complex Flow Due to Heterogeneous Geology Water Oil & Water Mixture Oil Modelling of a Reservoir

37 Applications (cont d) Tracer study Given a rock volume, where would the petroleum be found? Use fluid flow simulations to simulate reservoir filling, charging history. For well planning, field economics For quantification of mixing

38 Applications (cont d) Fluid mixing Unstable displacement Fingering, instability Advection, diffusion, gravity segregation, and viscosity Compositional variation

39 Applications (cont d) Demo 1 Assessing development projects Demo 2 Management of reservoirs Simulation with shales

40 Applications (cont d) Demo1 Well architecture Demo2 Adaptive grids Demo3 Conner point correction Demo4 Streamlines Demo5 Fault treatment

41 Conclusions Thermal/solvent processes for heavy oil/bitumen are difficult to simulate. With sufficient physics and good geological characterization, significant improvement in modeling and simulation will be made. With all the new tools (gridding, solvers, parallelization, and computer hardware) significant improvements in simulation robustness and speed and optimization algorithms will be made. All these mean significant savings in capital costs.

42 Three recent books Finite Element Methods and Their Applications Z. Chen Year 2005 Textbook & reference

43 Three recent books (cont d) Computational Methods for Multiphase Flows in Porous Media Year 2006 Z. Chen, G. Huan and Y. Ma Textbook and reference

44 Three recent books (cont d) Reservoir Simulation: Mathematical Techniques in Oil Recovery Year 2007 Z. Chen CBMS-NSF Regional Conference Series in Applied Mathematics

45 Acknowledgements

Oil Sands Development in Canada by SAGD - Further Challenges to Improve Efficiency -

Oil Sands Development in Canada by SAGD - Further Challenges to Improve Efficiency - Nov-29, 2017 JAPEX (Japan Petroleum Exploration Co., Ltd) Canada Oil Sands Project Dept. Tanetomo (Tom) Izumi Japan