Tight Gas Reservoir Characterization

Transcription

1 المعهد الجزاي ري للبترول INSTITUT ALGERIEN DU PETROLE JOURNEES D ETUDES TIGHT & SHALE RESERVOIRS Septembre 2013 Sheraton, Alger Tight Gas Reservoir Characterization PRÉSENTATEUR : M. Farid CHEGROUCHE ORGANISME : ENAGEO

2 Outline Objectives workflow o o o o analysis AVO/AVA analysis Conventional Pre-stack inversion analysis interpretation Conclusion

3 Objectives Available data 1. Seismic data: pre-stacked data 2. Well data Well 1 Cali GR Th, K, U PEF DT NA RHOB NPHI Resistivity Cali GR Th, K, U PEF DT SDT RHOB NPHI Resistivity 3. Engineering data 4. Geology data Problematic: - well 1 : gas traces - : DST test ( gas traces) -Core data : grain size (very fine, fine to medium ) Are wells well positioned? o o o At pay sandstone At hydrocarbon anomaly At good quality reservoir

4 Objectives Objectives 1. Reservoir mapping 2. Fluid nature & distribution identification 3. Reservoir quality study Solid Fraction Fluid Fraction Mineral Clay Shale water Water Hydrocarbon Sandstone volume Shale volume Effective Porosity

5 Workflow

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7 Interprétation Sismique Isochone Dip variance

8 Interprétation Sismique Model

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10 Workflow Wavelet Extraction Input CDP gather, well log Well Tie Target zone analysis well location at Build initial model 3D Volume inversion Output attributs Ip, Is, ρ,λρ,μρ Result

11 attributs

12 attributs

13 AVO/AVA Workflow Well Ties Modeling (Zoeppritz) QC AVO classes Partial stacks Intercept/Gradient Output: AVO Attributes Result interprétation Horizon Slice

14 AVO/AVA attributs Scaled Poisson Fluid Factor

15 Porosity (φ) Volume (patent) Matrix Volume Connectivity φ e volume τ tortuosité volume (patent) Water Saturation S w Permeability (K) volume Zone 3 Grain size volume

16 High rigidity Matrix volume Rigidity volume

17 Poor quality Low rigidity High rigidity Initial location Proposed location Matrix volume Rigidity volume High quality

18 Low porosity Matrix volume Porosity volume

19 Total porosity P impedance Low porosity with low density Shear impedance Bulk Density Porosity

20 Total porosity P impedance Shear impedance P Impedance S Impedance

21 low I s & low I p Initial location Proposed location P Impedance P Impedance S Impedance S Impedance high I s & low I p

22 Water saturation Water saturation Poisson Ratio Bulk density V p /V s

23 Water saturation Initial location 1 st Lame Modulus Proposed location Poisson Ratio V p /V s Ratio

24 Analyse AVO / AVA Paleozoique TMTN-O TMTNO TIL-1 Classe 1 Zone 2 TIL 1 Reservoir Top Scaled Poisson < 0 Fluid Factor < 0 Zone 1 Reservoir Base Scaled Poisson > 0 Fluid Factor > 0 Zone 3

25 Scaled Poisson Fluid Factor Top Scaled Poisson < 0 Fluid Factor < 0 Scaled Poisson Fluid Factor Base Scaled Poisson > 0 Fluid Factor > 0

26 Top Scaled Poisson < 0 Fluid Factor < 0 Base Scaled Poisson > 0 Fluid Factor > 0 Initial location Scalled Poisson Proposed location Initial location Fluid Factor Proposed location

27 Permeability Scaled Poisson connectivity Fluid Factor Fluid Factor Permeability connectivity

28 Permeability Scaled Poisson connectivity Fluid Factor Permeability Grain size

29 Obstacle effect (Tortuosity) Tortuosity Grain size

30 Obstacle effect (Tortuosity) Grain size connectivity Grain size connectivity

31 Conclusion In this work a detailed tight gas reservoir characterization study was presented. Two innovative approaches have been introduced: Porosity and Tortuosity. Unlike conventional methods, water saturation was calculated from Durbin model using tortuosity. As a result, an interpretation of gas indications observed at production well has been proposed