Water Injection in Fractured Reservoirs

Transcription

1 Injection in Fractured Reservoirs Hassan Karimaie Department of Petroleum Engineering and Applied Geophysics NTNU 1 26-Oct-15

2 Outline: ackground Matrix / fracture system in fractured reservoirs injection in NFR Normal procedure in industry: Immersion test or Amott test rising in the fracture or Immersion? Cocurrent and Counter current imbibition Experiments Results and discussion Conclusion References 2 26-Oct-15

3 ackground Unique feature of NFR: Early breakthrough of injected fluid More uniform fluid composition Small pressure drop Absence of transition zone Matrix or Gas Invaded Zone Fracture 3 26-Oct-15

4 Analogue model 4 26-Oct-15

5 5 26-Oct-15

6 Problem Definition Idealization of fractured porous media Warren & Root model 6

7 Laboratory experiment: Is immesrion test or Amott test the right experiment for NFR? Oven Recovered Core rine 7 26-Oct-15

8 Visual Observation (Single lock) Low rate, No Counter-Current High rate, Co-Current And Counter-current Very High Rate Counter Current 8

9 Cocurrent and counter current imibibition 1-Counter-Current Imbibition: and oil flow through the same faces in opposite directions Nonlinear Diffusion Eq.: ( D( S x w S ) x w ) S t w (1) 2-Co-Current Imbibition: and oil flow through the opposite faces in the same direction. Nonlinear Convection- Diffusion Eq.: Sw Sw ( D( Sw) qt f ( Sw)) (2) x x t 9 26-Oct-15

10 Capillary-Gravity ratio (Schechter et al. 1994) 1 / N C k gh When N N 5 oth capillary and gravity forces 1 1 N 1 Capillary forces are dominant Counter-current flow Co- and counter-current flow Gravity forces are Dominant Co-current flow C = 0,4 for capillary tube model Oct-15

11 injection in fractured media wet sample (entheimer sandstone) Non-water-wet sample (Limestone outcrop-asmari,iran) Length (cm) (stack of blocks) Diameter (cm) Permeability (md) Porosity % Fluid system Kerosene-brine n-decane-brine Oct-15

12 Methodology: Experimental Set-up rising water level Co-current Co and counter current Electronic alance Pressure Transducer Counter current Pc- DATA ACQUISITION Spacer Pump Co-current and counter-curret imbibition test 12

13 Methodology: Experimental Set-up (immersion) rine Counter current Screw Spacer Counter-currentTest Oct-15

14 Recovery % Results: water-wet sample q=0.1 cc/min q=0.5 cc/min q=1 cc/min q=5 cc/min Immersion N g/cc 2.6 Time, min Oct-15

15 Recovery, fraction Results: water-wet sample 0.6 q q=0.5 = cc/min 0.5 cm 3 /min q q=1 = cc/min 1.0 cm 3 /min q q=5 = cc/min 5.0 cm 3 /min g/cc PV Injected N Oct-15

16 Recovery, fraction Recovery, fraction Recovery, fraction Results: water-wet sample Heavy oil N q=0.5 cc/min Light oil N Heavy N 1 oil 31 1 q=1 cc/min. 8 Light N oil PV Injected PV Injected Heavy oil N q=5 cc/min Light Noil Oct-15 PV Injected

17 Conclusion recovery due to water injection is highly influenced by gravity. Co current and counter current flow may occur in NFR depends on injecion rate, matrix block height, porosity, permeability, density difference and interfacial tension. Depending on injection rate, co-current flow may be more efficient than counter-current flow. ond number is an important dimensionless number for characterising co.current and counter-current flow Oct-15

18 References: H. Karimaie. Aspects of and Gas Injection in Fractured Reservoirs. Thesis for the degree of philosophiae doctor at NTNU. December ISN , ISSN: H.Karimaie, O. Torsæter, M.R.Esfahani, M. Dadashpour and S.M. Hashemi."Experimental Investigation of Recovery during Imbibition". Journal of Petroleum Science and Engineering (JPSE) 52 (2006) H.Karimaie and O.Torsæter. "Effect of Injection Rate, Initial Saturation and Gravity on Injection in Slightly -Wet Fractured Porous Media". Journal of Petroleum Science and Engineering (JPSE) 58 (2007) Pooladi-Darvish, M and Firoozabadi. A. Experiments and Modeling of Injection in -Wet Fractured Porous Media. JCPT volume 39, No (March). 26-Oct-15