The document provides an overview of Enhanced Oil Recovery (EOR) methods, detailing their mechanisms, parameters for application, and various techniques such as gas flooding, chemical injection, steam injection, and microbial EOR. It emphasizes the importance of understanding reservoir characteristics and fluid properties for effective implementation, highlighting various case studies and their results. Ultimately, EOR aims to increase oil recovery rates significantly, revitalizing mature fields and extending their production life.

1. Francisco Bassano
Riccardo Pago/o
April 7, 2015
Enhanced Oil Recovery:
Engineering ideas for ge9ng the most
out of proven oil reserves
Kern River, California (US)

2. Enhanced Oil Recovery (EOR) 1/18
• What is EOR and how does it work?
• What parameters (reservoir and surface) must be taken into account
before applying EOR?
• Overview of the four main EOR methods:
! Gas flooding
! Chemical injecPon
! Steam injecPon
! Microbial enhanced oil recovery (MEOR)
• Field case examples
Aims

3. Enhanced Oil Recovery (EOR) 2/18
! Enhanced oil recovery (EOR)
methods provide addiPonal energy to
improve the recovery of the
remaining oil reserves
! Mechanical form, by injecPng a fluid
which displaces those already in place
! The efficiency of an EOR method will
depend on:
a) the reservoir characterisPcs
b) the nature of the displacing and
displaced fluids
c) the arrangement of producPon
and injecPon wells
hVps://ugmsc.wordpress.com/2010/09/15/eor-enhanced-oil-recovery/
Water or gas
injection
Natural Flow Artificial Lift
Primary
Secondary
Pressure maintenance
Chemical
Surfactant Polymer Caustic
What is EOR?

4. Injected CO2
meets trapped oil
CO2 and
oil mix
Oil expands and moves
towards producPon well
Drive
water
CO2 water CO2
Miscible
Zone
Oil
Bank
InjecPon well
ProducPon well
Enhanced Oil Recovery (EOR) 3/18
InjecPon of HC or non-HC components, usually vapors (gas phase) at atmospheric T-P
SupercriPcal fluids at reservoir T-P " liquid-like properPes
HC:
! methane
! propane
Non-HC:
! carbon dioxide (CO2)
! nitrogen (N)
! hydrogen sulfide (H2S)
! sulfur dioxide (SO2)
Gas Flooding
hVp://energy.gov/fe/science-innovaPon/oil-gas-research/enhanced-oil-recovery
Mass transfer of components between the
flowing gas and oil phases " increases when
gas-oil become more miscible (mix) due to IFT
reducPon between the fluids

5. Enhanced Oil Recovery (EOR) 4/18
Subsurface heterogeneity "Permeability contrast leads to a poor sweep efficiency (high
capillary pressure)
West Texas San Andres dolomite (miscible flood pilot)
! Primary + Secondary recovery
(waterflood) ≈ 50% OOIP
! TerPary recovery ≈ 19.6% OOIP, as a
result of good WAG management and
the use of H2S in the gas
! Total RF for the pilot is expected to be
around 70% OOIP, well above the
average for most fields
Stein et al. (1992). Slaughter estate unit CO2 flood: comparison between pilot and field-scale performance

6. Enhanced Oil Recovery (EOR) 5/18
CO2 (supercriPcal phase): high density & viscosity, so less gravity segrega?on and viscous fingering
Why inject CO2 as foams? " the presence of thin foam films improve both aerial and verPcal
sweep efficiencies by reducing gas mobility
CO2-foam SAG process compared to water- flooding
and CO2-water WAG process (EMU unit, Texas)
Hoefner and Evans (1995). CO2 foam: results from four developmental field trials
CO2-Foam Injec]on in the Rangely Weber
Sand Unit, NW Colorado
! OOIP in the field: 1.6 BBO /
~ 332 MMBO (21% OOIP) iniPally
produced from 1ry R.
! Waterflood (1958) added 789 MMBO
(50% OOIP)
! As 3ry R., a miscible CO2 flood on a 1:1
WAG (Oct 1986) "~9.2 MMBO of
incremental (through June 1989)

7. Frost & Sullivan
1
Chemical Injec]on • Polymers
o synthePc " hydrolyzed polyacrilamyde (HPAM)
o bio-polymer " xanthan
• Surfactants
o organic compounds "HC chains
• Mixtures
o Polymer flooding
o Surfactant-Polymer flooding
o Alkaline flooding
o Alkaline-Polymer flooding
o Alkaline-Surfactant flooding
Enhanced Oil Recovery (EOR) 6/18
Revenue % by chemical flooding - US and EU
hVp://www.chemanager-online.com/en/topics/chemicals-distribuPon/enhanced-oil-recovery-chemicals-market-trends

8. We/ability
• A drop of oil on H20 – wet surface " θ ≈ 0°
oil = non-wenng fluid, H20 = wenng fluid
• Oil – wet surface " θ ≈ 180°
oil = wenng fluid, H20 = non-wenng fluid
• Oil/H20/wet surface " 0° < θ < 180°
Enhanced Oil Recovery (EOR) 7/18
hVp://www.ramehart.com/glossary.htm
Balance of forces between liquids on a solid surface
hVp://www.slb.com
θ ≈ 180° θ = arccos [(γsv-γsl)/γlv]
Solid surface
Solid surface
Water wet
hVp://www.eor-alliance.com/soluPons/foam/
Oil Brine (water) Rock grains
Water-wet Oil-wet Mixed-wet
0° < θ < 180°

9. Sheng et al. (2013). Enhanced Oil Recovery Field Case Studies
Shear rate vs HPAM solu]on viscosity
Oil recovery vs oil viscosity
Chemical effects
Enhanced Oil Recovery (EOR) 8/18

10. • 1st phase: 27 wells installed. H20 treatment plant ≈ 80k m3/day,
polymer treatment + H20 ≈ 17,5k m3/day. ProducPon = + 8k b/day
• 2nd phase: added 19 wells, opPmizaPon of min. capital expenditure
• 3rd phase: currently working on the feasibility study
PDO – Marmul
Polymer Project
Enhanced Oil Recovery (EOR) 9/18 hVp://www.Porco.com/Po/products/asp-sp.htm hVp://www.2b1stconsulPng.com
Petroleum Development Oman (PDO) - $1 billion investment in chemical EOR
Alkali-surfactant-polymer (ASP/AP)
Marmul
OMAN
0 600
km

11. Enhanced Oil Recovery (EOR) 10/18
! ReducPon of oil viscosity (higher temperature)
! Increased reservoir pressure (energy)
! Physical displacement of oil in a similar manner to WF
• Steam Flooding (SF)
• Cyclic Steam InjecPon (CSI)
• Steam assisted gravity drainage (SAGD)
Steam Injec]on
Main mechanisms: www.ogj.com/

12. Enhanced Oil Recovery (EOR) 12/18
• oil gravity degree: 12 API
• oil viscosity: 700-1200 cp
• reservoir depth: 915 m
Bachaquero,
Western Venezuela
1. Steam injecPon " days to weeks
2. Well is shut in / soak " days
3. Well returns to producPon " weeks to months
Reservoir parameters for both SF and CSI:
! RelaPvely high Φ and K values (~ >0.2 and >100-200 mD)
! Shallow depths (not higher than ~1,000 m)
! Preferably no aquifer or gas cap
! Low shale content
Bachaquero Field, Western Venezuela
• RF: 16.2%
• 776 wells
• 1600 steam cycles
Cyclic Steam Injec]on (CSI)

13. ! Uninterrupted verPcal permeability is a must
! Understanding of the distribuPon of sedimentary facies
! RF can be as high as 70% - 80% of OOIP in suitable reservoirs
• Proven oil reserves have increased to 179 BBO
• Raised Canada's oil reserves to the 3rd highest in the world (azer Venezuela and Saudi Arabia)
• As of 2011, the oil sands reserves stand at around 169 BBO
www.energy.alberta.ca
Steam assisted gravity drainage (SAGD)
SAGD Development of Alberta oil sands - Canada
EOR method used for producing heavy crude oil and
bitumen, which flow down to the producPon well via gravity
Enhanced Oil Recovery (EOR) 13/18

14. Microbial Enhanced Oil Recovery
Sheng et al. (2013). Enhanced Oil Recovery Field Case Studies
Core samples from test produc]on well
Microbial Injec]on Scheme
• Geotoga suterranea
• Geotoga petraea
• Petrotoga miotherma
Enhanced Oil Recovery (EOR) 14/18
2,00µm
2,00µm

15. hVp://theenergycollecPve.com
Guoqiang Li et al., (2014). Microbial Abundance and Community Composi?on
Influence Produc?on Performance in a Low-Temperature Petroleum Reservoir
Karamay oil field, China
Enhanced Oil Recovery (EOR) 15/18
Selec]ve plugging and IFT reduc]on

16. Produc]on improvement due to MEOR - Upper Shaunavon sand reservoir (P. of Saskatchewan, Canada)
! oil producPon:
350% increase
! water-cut:
8% decrease
Enhanced Oil Recovery (EOR)

17. Conclusions
# Main mechanisms of EOR methods focus on a beVer displacement (sweep efficiency) of the oil towards
producPon wells, and they are based on:
! reducPon of oil viscosity
! reducPon of IFT between fluids for miscible results
! reducPon of gravity segregaPon and fingering
The ulPmate goal being increasing oil produc]on and/or reducing water-cuts
# In order to be successfully applied, a detailed geological-petrophysical (or even microbial) characteriza]on of
the field must be in place, as well as relevant informaPon on the exisPng fluids in the reservoir
# Some EOR methods really stand out, namely gas flooding (e.g. WAG using CO2) and steam injecPon (SF and
SAGD) " Mature oil fields around the world can reach RF as high as 70% OOIP
# EOR processes play a major role in revitalizing mature oil fields by extending their service life or even
generaPng new oil reserves, such as in the outstanding case of the Alberta oil sands in Canada
Enhanced Oil Recovery (EOR) 17/18

18. Enhanced Oil Recovery (EOR)
References
18/18
Chourio, G., Bracho, J., Mohtad, M., 2011. EvaluaPon and ApplicaPon of the Extended Cyclic Steam InjecPon as a New Concept for Bachaquero-01 Reservoir in West Venezuela. SPE
148083-MS.
Davey, M.E., Wood, W.A., Key, R., Nakamura, K., Stahl, D.A., 1993. IsolaPon of Three species of Geotoga and Petrotoga: Two New Genera, RepresenPng a New Lineage in the Bacterial Line
of Descent Distantly Related to the “Thermotogales”. System. Appl. Microbiol. 16, 191-200 (1993).
Guoqiang Li, Pei-Ke Gao, Hui-Mei Tian, Xue-Cheng Dai, Yan-Sen Wang , and Qing-Feng Cui, 2014. Microbial Abundance and Community Composi?on Influence Produc?on Performance in a
Low-Temperature Petroleum Reservoir. Environmental Science & Technology. 04/2014; 48(9). DOI: 10.1021/es500239w .
Hoefner, M.L., Evans, E.M., Buckles, J.J., Jones, T.A., 1995. CO2 foam: results from four developmental field trials. SPE Reserv. Eng. 10 (4), 273281.
LaPl, M., 1980. Enhanced Oil Recovery. InsPtut Francais du Petrole (IFP). Gulf Publishing Co, EdiPons Technip, 246 pages.
Sheng, James J.J., Herd, B., 2013. Enhanced Oil Recovery Field Case Studies. Department of Petroleum Engineering, Texas Tech University, Lubbock, TX 79409-3111 USA.
Stein, M.H., Frey, D.D., Walker, R.D., 1992. Slaughter estate unit CO2 flood: comparison between pilot and field-scale performance. JPT September.
Taber, J.J., MarPn, F.D., Seright, R.S., 1997. EOR screening criteria revisited—part 2: applicaPons and impact of oil prices. SPERE 12 (3), 199-206.
Web pages
h/p://www.]orco.com/]o/products/asp-sp.htm - Alkaline Surfactant Polymer / Surfactant Polymer Technologies.
h/p://www.energy.alberta.ca/OilSands/pdfs/FS_SAGD.pdf - Talk about SAGD (PDF), Energy Alberta, November 2013.
h/p://www.theenergycollec]ve.com - In a Low Oil Price Environment: Increasing Oil Field ProducPvity via Microbially Enhanced Oil Recovery (MEOR). Posted January 7, 2015.
h/p://www.chemanager-online.com/en/topics/chemicals-distribu]on/enhanced-oil-recovery-chemicals-market-trends - Pie graph from Frost & Sullivan
h/p://www.ogj.cougmsc.wordpress.com/2010/09/15/eor-enhanced-oil-recovery/ - AAPG Universitas Gadjah Mada – Student Chapter. Geological Engineering Dept. Gadjah Mada University Jl.
h/p://www.2b1stconsul]ng.com
h/p://www.eor-alliance.com/solu]ons/foamm/oil-drilling-and-produc]on/produc]on-opera]ons/ior-eor.html - Oil & Gas Journal. EOR 2012 Survey
h/p://www.ramehart.com/glossary.htm
h/p://www.slb.com

19. Enhanced Oil Recovery (EOR)