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04/05/20151 NORSAR Seismic Modelling NORSAR-2D NORSAR-3D VelRock.

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Presentation on theme: "04/05/20151 NORSAR Seismic Modelling NORSAR-2D NORSAR-3D VelRock."— Presentation transcript:

1 04/05/20151 NORSAR Seismic Modelling NORSAR-2D NORSAR-3D VelRock

2 04/05/20152 NORSAR offices in Norway

3 04/05/20153 NORSAR vs. UiB  Agreement on cooperation between NORSAR and the University of Bergen.  NORSAR was providing Institute of Solid Earth Physics with software for use in research projects, theses and education, –includes commercial tools such as NORSAR-2D, NORSAR-3D, VelRock, HybriSeis, and –prototype software for special studies.  NORSAR is willing to extend this to include the newly formed Department of Earth Science and the CIPR.

4 04/05/20154 NORSAR-2D: Ray Modelling Two-point tracing Interactive Robust User-friendly

5 04/05/20155 NORSAR-3D: Ray Modelling Wavefront Construction (*) Open models Fits for PSDM Network of computers (*) NORSAR is the developer of Wavefront Construction!

6 04/05/20156 NORSAR-3D: Illumination Various Maps Simulated Migration Amplitudes Projects On-going research

7 04/05/20157 Rock Physics Modelling lithology fluids porosity permeability  V P : P-velocity V S : S-velocity V P = 2.6 km/s V S = 1.4 km/s  = 2.2 g/cm 3 Analysing and predicting how different reservoir properties of porous rocks affect the seismic properties. Rock Physics

8 04/05/20158 VelRock and N2D/N3D VelRock rock models can be used in N2D/N3D

9 04/05/20159 HybriSeis Modelling of Local Target

10 04/05/ Seismic Wave Simulation Tools Ray methods (standard software)  2D/3D Normal incidence ray tracing (zero offset unmigrated)  2D/3D Image ray tracing (zero offset migrated)  2D/3D Common shot (offset HSP/ VSP/OBC)  2D/3D Green’s functions  2D Anisotropic Ray Mapping Special methods (internal software)  1D Reflectivity (offset)  2D/3D Eikonal Method  2D Finite Difference  2D/3D Migrated Amplitudes  2D/3D HybriSeis

11 04/05/ Applications of NORSAR Software Typical tasks  Model based analysis of well log data.  Model based analysis of velocities measured on cores.  Structural and velocity macromodel building.  Geophysical reservoir model building.  Modelling of seismic responses.  Model based processing and analysis of seismic data. Special tasks  Time-lapse feasibility studies.  AVO modelling.  Survey planning.  Identification of multiples and peg-legs.  Greens functions for PSDM.  Amplitude and illumination maps.  Reflector-oriented amplitude recovery (ROAR).

12 04/05/2015 NORSAR-3D: Structural and Velocity Model Building 3D Wavefront construction NORSAR-3D

13 04/05/ Possible Input Data  Interpreted horizons (time, depth).  Pre-calculated interval velocities (const., grid, cube).  Stacking velocities, migration velocities.  Checkshots.  Well log data (P-velocity, S-velocity, density).  Petromarkers.

14 04/05/ Example: Undershooting of Salt Dome Receivers  Shot  Salt diapir  Targets (gas pockets)  

15 04/05/ Ray Paths and Reflection Points Raypaths Number of arrivals/receiver Reflection Points

16 04/05/ Example: Illumination of Gas Caps

17 04/05/ Marine Survey

18 04/05/ Wavefront Construction Raypaths  Wavefronts 

19 04/05/ Bulk Modelling  Depth model built from depth grids and velocity grids.  Ray modelling done by wavefront construction.  4011 shots simulated in parallel on 10 workstations in a few hours.  A total of about 24 million events for PP reflections from the target horizon (Top Reservoir) was found.

20 04/05/ Illumination Density Map {Event counts}/{nominal fold(30)}

21 04/05/ Min. Incidence Angle in CRP

22 04/05/ Max. Incidence Angle in CRP

23 04/05/ Amplitude along Target Horizon

24 04/05/2015 Real Model Example The example to follow was presented by Børge Rosland (Seispro) and Geir Drivenes (Enterprise Oil) in the paper “Large Scale 3D Seismic Modelling in Exploration”, paper no. C-42, EAGE meeting, Glasgow, 2000.

25 04/05/ Geometry Model  The first 5 reflectors are relatively flat.  The BCU reflector and pre- BCU reflectors are complex.  The P-velocity is shown on the left.

26 04/05/ Model and Marine Survey Every 2nd shot lines Target Horizon Receivers

27 04/05/ Bulk Modelling  Modelled shot records, ~ 40 million traces.  P-P reflection data from two reflectors: –one smooth Cretaceous reflector. –one complex pre-BCU reflector. Single Shot Footprint Pre-BCU Reflector

28 04/05/ Illumination Density Map Illumination Density Map: Number of reflection points in bin cells (50x25m) on the target horizon About reflected rays Highly-curved parts of the reflector are strongly illuminated

29 04/05/ Real vs Modelled Amplitudes Migrated Seismic Data Reflection Amplitude Migrated Modelled Data Reflection Amplitude

30 04/05/ Modelled Amplitudes Normal Incidence Reflection Coefficient Migrated Modelled Data Reflection Amplitude

31 04/05/2015 Integrated Modelling Based Reservoir Analysis NORSAR tools for rock physics and advanced seismic wave simulation

32 04/05/ Gullfaks Time Lapse Data and 1996 OWC Top Res. Courtesy of Statoil

33 04/05/ Integrated Rock Physics and Seismic Modelling Integrated rock physics and seismic modelling Seismic response Well log data MineralogyGeological model Fluid simulations Seismic data Lab. data

34 04/05/ Problems of integrated modelling  Complexity of model representation, with parameters that may not have an easy physical interpretation.  No generally applicable theory for all problems.  Processes that may be difficult to quantify.  Microscopic properties may be important for large-scale properties.  Different sources and scales of data may cause inconsistencies and problems.

35 04/05/ Rock Physics Models lithology fluids porosity permeability  V P : P-velocity V S : S-velocity V P = 2.6 km/s V S = 1.4 km/s  = 2.2 g/cm 3 Analysing and predicting how different reservoir properties of porous rocks influence on the seismic properties. Rock Physics

36 04/05/ Factors Influencing on Seismic Velocities velocity pore fluid gas oil brine velocity porosity velocity lithology velocity pore pressure velocity confining pressure velocity effective pressure velocity age / depth velocity temperature velocity cementation shaley sand shalesand T 1 T 3 T 2

37 04/05/ Seismic Response of Reservoir Properties  Rock physics is the key for understanding how geological properties are manifested in seismic observations, through bright spots, AVO characteristics etc.  Rock physics modelling allows for predicting seismic rock properties at other physical conditions than observed in wells or by laboratory measurements.  Improved understanding about how rock properties influence on seismic properties and seismic response is vital to the feasibility of seismic monitoring of hydrocarbon reservoirs.  Integrated rock physics and seismic modelling provide physically consistent tools for identifying and quantifying the important reservoir properties and predict their sensitivity to changes.

38 04/05/ Multi-well Log Data Sorting and Quality Control  fl =1.0

39 04/05/ Rock Model Calibration Rock model variables: Porosity, Lithology, Pore fluid.

40 04/05/ Model Based Analysis of Well Log Data  Use calibrated rock physics models for processing well log data, and predicting log properties.  Possible to combine with AVO analysis of modelled effects. Types of analyses:  Prediction of S-wave velocity.  Prediction of impedances, elastic moduli etc.  Prediction of geophysical properties assuming other saturating fluids (fluid substitution).  Corrections for drilling mud invasion.  Lithology and fluid sensitivity analysis.  Property cross-plotting analyses (QC and diagnosis).  Pressure effect sensitivity analysis (using core measurements).  Integration of fluid simulation results.  Upscaling and homogenization.

41 04/05/ Prediction of S-wave Velocity Logs Castagna Rock model Log data

42 04/05/ Model Derived from Interpolation Between Wells

43 04/05/ Grid of reservoir properties

44 04/05/ Integration with Fluid Simulations T0T0 T1T1 SgSg vPvP ZPZP S gas

45 04/05/ Rock Physics Modelling of Fluid Effects 0.1 g/cm km/s

46 04/05/ AVO Modelling of Fluid Effects Brine SaturatedGas Saturated

47 04/05/ Reservoir properties and amplitude variations Lateral change in fluid composition and shale contents. Modelled seismic response from NIP tracer

48 04/05/ Effect of Offset, Lithology and Saturating Fluid Zero Offset Section 2km Offset Section Homogeneous reservoir propertiesVertical trend in lithology OWC GOC

49 04/05/ Gullfaks 2D Reservoir Models Scenario 1 : S Oil =0.9Scenario 2 : S Oil =0.2 HybriSeis PSDM All offsets

50 04/05/ Schematic View of a Time-lapse Modelling Loop Rock physics Geological model Seismic modelling Seismic data Fluid flow simulations Inversion

51 04/05/ Reservoir Target Model Building

52 04/05/ Modelling Based Ananlysis


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