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Reserve Growth & Higher Recovery Using Nitrogen Gas Injection
Reserve Growth & Higher Recovery Using Nitrogen Gas Injection
Joe Shine & Mark Holtz Praxair, Inc. 2008 Wyoming EOR/IOR Conference September 15, 2008
Joe Shine & Mark Holtz Praxair, Inc. 2008 Wyoming EOR/IOR Conference September 15, 2008
2
Business ConfidentialBenefits from Nitrogen Gas Injection
Proven hydrocarbon recovery method
Cost effective
A nitrogen plant can be located anywhere
Nitrogen:Can replace hydrocarbon recycle gasIs InertIs non-corrosiveIs dryIs oxygen free
3
Business ConfidentialNitrogen – A Proven Recovery Method in Wyoming Overthrust
4
Business ConfidentialNitrogen - A Proven Recovery Method
Gravity Drainage Miscible Displacement
5
Business ConfidentialNitrogen - A Proven Recovery Method
Gas Cap Displacement Pressure Maintenance –Gas Condensate
6
Business ConfidentialPraxair At A Glance
A Fortune 500 company with 2007 sales of $ 9.4 billion
One of the largest industrial gases companies worldwide and the largest in North and South America
Operations in more than 40 countries
27,000 employees
One million customers worldwide
7
Business ConfidentialSales by Markets Served
Energy 11% Manufacturing 23%
Metals 16%
Food and Beverage 7%
Other 11%
Electronics 8%
Aerospace 3%
Chemicals 10%
Healthcare 11%
8
Business Confidential
Nitrogen, oxygen, hydrogen15 + year supply contractsDesigned & operated for reliability
On-Site/Pipeline Supply
Liquid Supply
Nitrogen, oxygen, argon, CO2, helium, H2Specialized cryogenic distribution equipment
Packaged Gases
Welding, medical, specialty gasesCylinders for the retail market
Praxair At A Glance
9
Business ConfidentialCore Technologies
Cryogenic air separation
Non-cryogenic air separation
Hydrogen production
Carbon dioxide capture and purification
Atmosphere control
Gas dissolution
Gas-liquid separations
Oxidation technology (combustion)
Refrigeration
10
Business Confidential
NorthAmerica
SouthAmerica
EuropeAsia
Praxair Industrial Gases Reach World-Wide
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Business Confidential
Enhanced Oil RecoveryOver 30 years experience with Gas Displacement Recovery (GDR)
– Nitrogen– Carbon Dioxide– Methane
More than 25 projects
Well Stimulation Services
CO2 EOR Services
CO2 Capture & Purification
Exploration & Production
Hawkins 65 MMcfd / 2000 psigBinger 15 MMcfd / 5000 psig / NRU
Elk Hills 30 MMcfd / 1000 psig
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Business ConfidentialPraxair’s Portfolio of GDR Projects
Miscible DisplacementBlock 31, TX, USAPainter Field, WY, USA East Binger Unit, OK, USAFlomaton, AL, USAVealmoor Field, TX USAHeadlee North, TX USADouglas, WY, USASand Dunes Muddy WY, USA
Gravity DrainageHawkins Field, TX, USA
Pressure MaintenanceSamaria, MexicoAnschutz Ranch East, WY, USAElk Hills CA, USAYates Field, TX, USAPowell Field, WY, USATatums, OK, USAColorado, USA(2) Kansas, USA
ECBMTrinidad, CO, USAFarmington, NM, USA Anschutz 50 MMcfd / 6000 psig
Samaria 190 MMcfd / 3000 psig
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Business ConfidentialMany Types of Projects
Full field floodsCryogenic nitrogen plant
Single reservoir compartment Small cryogenic nitrogen plant Non-cryogenic membrane plant
Pilot projectsSmall cryogenic plantMembrane plantLiquid transport vessels
Offshore gas lift applicationsMembrane plant for platformLiquid transport vessels for platform/ship
Huff ‘n’ Puff applicationsPumping equipmentLiquid transport vessels
Elk Hills 3 MMcfd / 1000 psigPainter 50 MMcfd / 5000 psig
Offshore unit 2.5 MMcfd
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Business ConfidentialPraxair EOR Services
Identification of potential fields for GDR
Assist & facilitate with project development effortsReservoir engineering servicesSelection of gas injectantRecovery process simulationOptimization of gas supply system
Partner on GDR pilot projects
Provide gas injectant requirements for full scale operations
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Business ConfidentialRecoveries – Sample N2 GDR ProjectsField EOR Application Recovery (fraction OHIP)Hawkins Gravity drainage 0.20
Chunchula Pressure maintenance 0.31
Block 31 Miscible displacement 0.6 (total) no secondary
Szeged Moravaros Pressure maintenance 0.12
Jay/(LEC) Miscible displacement 0.13
Lake Barre Pressure maintenance 0.19
Fordoche Wilcox 8 & 12 Miscible displacement 0.195
Fordoche Wilcox 5 Pressure maintenance 0.19 – 0.46
Field B* Immiscible displacement 0.36
Anschutz Ranch East Pressure maintenance 0.45-.53
* From Clancy
*Carlson -ExxonMobil
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Business ConfidentialGDR’s Place in the Market
0
50000
100000
150000
200000
250000
300000
350000
400000
450000
500000
1985 1990 1995 2000 2005 2010
Years
Oil
prod
uctio
n (S
TB/D
)
Thermal (STB/D)Chemical (STB/D)Gas (STB/D)
# 1 EOR method to add light oil reserves.
“in the US chemical and thermal EOR projects have been in constant decline since the mid 1980s”*
Historical US EOR Production
*(Dr. Leonid Surguchev et al. World Petroleum Congress 2006)
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Business ConfidentialReserve Growth – From Two Sources
Increased sweep efficiency of moveable oil (contacting more oil)
Infill drillingFracingHorizontal wellsWaterflood realignmentGas displacement recovery (GDR)
Increased displacement efficiency from residual oil (displacing more oil out of each pore)
Steam floodingChemical floodingGas displacement recovery (GDR)
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Business ConfidentialN2 Reserve Growth Applications
Pressure maintenanceCondensate and retrograde condensate reservoirs
Miscible displacement
Gravity drainage
Immiscible displacementOilGas cap gas
Driving agent for slug/buffer
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Business ConfidentialGas Condensate Pressure Maintenance
Screening criteria:1) Dew point pressure near the original reservoir
pressure, under saturated by 150 to 300 psi, 2) High condensate yield typically >
175 bbl/MMSCF produced, 3) High liquid dropout rate with liquid
condensation from 20 to 40 % of the hydrocarbon pore space.
Pressure depletion effects cause;Reduction in gas permeability and well productivityAquifer encroachmentLower ultimate hydrocarbon recovery by 10 to 40 %
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Business ConfidentialRelative Permeability Effects in Gas Condensate Reservoirs
Near-wellbore Where saturation hysteresis is severe
Main reservoir away from wells Liquid mobility is near zeroGas flows at reduced permeability
Reservoir edge Water encroachment traps gas and condensateHydrocarbons trapped at 10- 40 % saturations
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Business ConfidentialPermeability Reduction from Condensate Dropout
From Al-Honi and Abdulrazag, 2004
Dew point pressure
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Business ConfidentialLaboratory and Simulation Studies
Methane used as buffer gas
Slightly greater revaporization occurred with buffer gas.
Test 12 run below dew point
Renner, et al., 1989
Test101112
TestPressure
(psia)
5,5655,565
5,565 to 4,500
Drive GasNitrogen
Buffer gasNitrogen
IrreducibleWater
Saturation(% PV)
28.127.828.0
LiquidRecovery at
1.5 HCPV Injected(% STLOIP)
87.891.964.0
99.798.699.0
MaterialBalance(vol%)
23
Business ConfidentialAnschutz Ranch E. Gas Condensate Pressure Maintenance Example
From Kleinsteiber et al., 1983
1) Dew point pressure is near the original reservoir pressure, under saturated by 150 to 300 psi,
2) High condensate yield of 175 bbl/MMSCF produced, 3) High liquid dropout rate with liquid condensation
from 20 to 40 % of the hydrocarbon pore space.
Nugget ss, WY
10 % porosity
3 md perm
5,600 psi injection pressure
N2 & CH4
Pi = 5,310 psi
Pdew= 5,080 psi
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Business ConfidentialAnschutz Ranch E. Gas Condensate Pressure Maintenance Example
Injection scheme1) Inject 0.1 HCPV of 35% N2
and 65% wet gas
2) Chases with pure N2
80-acre inverted 9 spot pattern
Amoco 1982, 50 MMscf/day
6,200 psi injection pressure
Wendschlag et al., 1983 From Kleinsteiber et al., 1983
9 COMP17 COMP
Cum N2 Injected, HCPV
Fig. 3-Recovery comparison from 1-D nitrogen displacement simulations
0.0 0.5 1.0 1.5 2.0
Cum
. Oil
Rec
over
y, %
OIP
0
10
20
30
40
50
60
70
80
90
100
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Business ConfidentialN2 Miscibility Displacement
There are three types of miscibility including;First-contact miscibility
Multi-contact miscibility
Vaporizing mass-transfer miscibility
Results in high displacement efficiency at the pore level
ProducerInjector
Prax
air
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Business ConfidentialMiscible N2 Flood East Binger, Oklahoma
K = 0.2 md
Phi = 0.075
Swi=0.25
60 ft net pay
Primary recovery 10.7 % of OOIP
Tr= 190 F
Pi = 5,800 psi
MMP =4,200 psi Depth 10,000 ft
42 API gravity
1.798 FVF
1,320 SCF/STB GOR
Miscibility lab results
27
Business ConfidentialEast Binger Miscible N2 FloodInjection began 23 wells drilled
Plugging from combination of compressor lube oil, CO, CO2, dust.
Primary recovery 11%*
GDR reserve growth 16 % to 27% ultimate recovery *
*Cornelius, 1983
28
Business ConfidentialMiscible WAG Jay Field, Florida
N2 miscible WAG 3:1 ratio
Line drive pattern
Pi = 7,850 psi, Tr = 285 F
51 API gravity oil
Phi= 0.14, K= 20 md
Reserve growth of 10 -13% OOIP (80MMSTB)
Lawrence et al., 2003
Figure 2. Jay Field wells and patterns.
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Business ConfidentialGravity Drainage
The most common Gravity drainage processes are:Gas assisted gravity drainage ( no water present)Double displacement process ( water present)
N2 injectorProducer
Double Displacement Process (DDP). The process of gas displacement of a water invaded oil column has been termed.
The double displacement process consists of injecting gas up-dip and producing oil down-dip
30
Business ConfidentialGravity Drainage Double Displacement Process (DDP)
Up dip gas injection into a dipping reservoir is one of the most efficient recovery methods.
Recovery efficiencies of 85 % to 95 %
Increases sweep efficiency
Increases displacement efficiencyOil film flow is an important recovery mechanism– Film flow connects the isolated blobs of residual oil in the
presence of gasStrong water wetPositive spreading coefficient
Modified from Ren et al., 2000)
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Business ConfidentialGravity Drainage – General Design
Obtain piston like displacement (no gas fingering) Horizontal gas-oil contactHave gravity dominate the gas flow
Optimize the time between gas injection and oil production.As fast as possible without gas fingering
The greater the dip angle the higher the injection & production rates w/o gas fingering
The greater the dip the more effective the gravity drainage
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Business ConfidentialGravity Drainage – General Design
Critical velocity analytical model
Simulation model dependent on 3 Phase relative permeability
Effected by film flowEffected by saturation historyTypically from 2 phase correlationsDepend on the direction of flow (i.e., be directionally anisotropic)
Vc is critical velocity rate (ft/day)Δρ
is density differencek is permeability (darcies)θ
is dip angleφ
is porosity (fraction)Δμ
is viscosity difference
μφθρ
ΔΔ
=sin741.2 kVc
Where
(Hill 1952)
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Business ConfidentialHawkins Field Double Displacement Process
Lawrence et al., 2003
Double Displacement Process Schematic
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Business ConfidentialN2 as Driving Agent for slug/buffer (chase gas)
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Business ConfidentialSt Elaine Pilot Gravity stable N2 after CO2
84.4 metric tons/D CO2 injected or 1/3 Pore volume
9 month pilot
N2 slug after CO2
From Palmer et al., 1984,
31CO2 injection rate; 136.1 metric tons/day (2.62 MMSCF/day
Critical velocity: 2.2 ft/d
CO2 front velocity designed at 1.6 ft/d or 70% of critical
0 300 600
N
CO2 Injection WellProducer
Fault
Unco
nfor
mity
8,000
7,800
7,600
7,400
GW
C 7,514
Structure Map 8,000 ft sand
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Business ConfidentialTiffany Unit N2 ECBM Pilot
Reeves and Oudinot, 2005
Farmington
Durango
Bloomfield
Aztec
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Business ConfidentialTiffany Unit N2 Production Response
Reeves and Oudinot, 2005
38
Business ConfidentialTiffany Unit N2 Production Response
Reeves and Oudinot, 2005
Table 2: Summary of Model Forecast Results
39
Business ConfidentialConclusions
Future reserve additions in large mature fields will primarily come from GDR.
Reserve additions will occur through:Pressure maintenanceMiscible displacementImmiscible displacementDriving agent for slug/bufferGravity drainage
GDR typically increases both sweep and displacement efficiency in oil and gas reservoirs.
Reserve growth targets can range from 10 to 45 % of OOIP/OGIP
