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