Date post: | 16-Apr-2017 |
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Technology |
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PERFORMANCE PREDICTION IN GAS CONDENSATE RESERVOIR GOWTHAM R PE16M012
GAS CONDENSATE
• producing both gas and condensate liquid at surface
• Above 45°API
• 5000-100000 scf/stb
• Condensate formation at reservoir condition in near well-bore
• Liquid drop out
CONSTANT VOLUME DEPLETION
PRESSURE DEPLETION
CONDENSATION - NEAR WELL-BORE
• Drop in gas productivity due to presence of condensate
• Wellbore k impairment
• Uncertainty in actual location of target condensate
• A thick layer of finite extent
• Spread as uniformly distributed thin film
• Combination of both
• CGR from initial well testing & history matching
CONDENSATE BEHAVIOR
• Based on
• Kr
• Capillary forces
• Viscous forces
• Gravity effects
FLOW BEHAVIOR IN GAS CONDENSATE
• Region 1 - both gas and oil flow simultaneously
• Region 2 - condensate build-up & Gas only flowing
• Region 3 – Single phase flow
INFLUENCE OF FORCES IN 2-PHASE REGION
• Dimensionless number
• Capillary No
Nc = Vµ/σ
• Bond No
NB = k g Δρ/ σ
GRAVITY EFFECTS
• Gravitational force acting on floating condensate
• ρgas < ρcondensate
• Pulling downward to lower edge
• Slow movement
INFLUENCE OF GRAVITY
• Vertically Oriented Micro-model
• Outward growth of wetting layer from pore wall
• ρnon wetting < ρwetting phase
• Narrow Neck of non-wetting phase formed
• Neck rupture if sufficient wetting phase
• Pore-Pore Movement
• Leading Segregation
RELATIVE PERMEABILITY
kr reduced Sc higher
saturation
INTERFACIAL TENSION
CONDENSATE BUILD-UP
NON-DARCY EFFECT
• High V (near wellbore)
-(dp/dx) = µV/k + (ρβV2)
co-efficient of inertial resistance β = (φSg / Kr )1/2
• Concern low – permeability
• Less important below the DPP
TO REDUCE CONDENSATE BANKING
• Hydraulic Fracturing
• Inducing new pressure profile
• Solvent Injection
• To decrease IFT
• Wettability Alteration
• Not well established
REFERENCES
• Jane-rune Ursin,2003.Fluid flow in gas condensate reservoirs: the interplay of forces and their relative strengths. JPSE 41(2004) 253-267
• G Coskuner Performance prediction in gas condensate Reservoirs, Journal of Canadian Petroleum Technology
ANY QUESTIONS???
THANK YOU