DEVEX 2016 Masterclass Pt:2 Continuous core data = Less Uncertainty? Craig Lindsay Core Specialist Services Limited

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1 DEVEX 2016 Masterclass Pt:2 Continuous core data = Less Uncertainty? Craig Lindsay Core Specialist Services Limited

2 Themes for discussion: Sampling frequency Impact of heterogeneity Value of continuous data? Examples of detailed characterisation Instrumentation / Technology

3 Core analysis standard practice Industry standard practice for routine analysis : Cut core plug every 25 cm or 1 ft. in reservoir rock May measure saturation of fluids in fresh state Measure porosity, permeability and matrix density in clean condition OK in homogeneous rock (large scale beds) Finely bedded formations poorly characterised Value in consistent practice but potential consequences Reservoir model scale is >> core plug

4 Core analysis standard practice Approaches to heterogeneous rock: Whole core analysis Continuous core data = higher resolution than 1 ft or 25 cm Attempt to capture or characterise heterogeneity Core gamma long established procedure (main application to establish core log depth shift Probe permeability High resolution core imaging Currently many more options

5 Plug scale effects (data averaging) All core plugs ranked (1-5): 1 Sandstone, no apparent bedding 2 - Sandstone, laminated (minimal clay) 3 - Sandstone / Shale (siltstone) laminations (sand dominated) 4 - Shale (siltstone) / Sandstone laminations (shale dominated) 5 - Shale / Siltstone with or without sand laminations

6 Impact of heterogeneity at core plug scale Arithmetic average (mean) permeability is considered to represent inflow from a series of parallel horizontal layers, i.e. equivalent to flow parallel to bedding. Geometric average permeability is considered to be perhaps of the greatest use in general application. The Geometric average is used to estimate effective - large scale - permeability from smaller scales (core plug). Harmonic average is heavily weighted by low permeability samples and is not a typical value in the overall distribution. However, the harmonic mean does have some application in flow calculations. 28 m interval

7 Scratch Testing Unconfined Compressive Strength

8 UCS vs. Gamma

9 UCS vs. Facies

10 Sampling for Geomechanics Study Continuous core data: Incredibly valuable aid for Representative Sampling Advanced testing = few samples Unrepresentative sampling may have very serious impact on data applications

11 Detailed characterisation Unconventional reservoir or cores for stratigraphic benchmarking and commodity exploration may be much more complex Multi-sensor core scanning can generate a wealth of high value data in complex formations Analysis of multiple data types apparently not directly correlated may reveal hidden correlations of great value for geological characterisation Genetic algorithms, FUZZY logic, neural nets etc. multi-dimensional analysis New petrophysical workflows? Continuous data scale = dimension of smallest lamina sub mm

12 Detailed characterisation - example 1. High resolution X-ray imaging (100 micron) on whole core to identify heterogeneity within the core 2. High resolution XRF logging on the 1/3 slabbed section of core 3. Using a set of known mineralogical profiles generate an estimated mineralogical profile 4. Intelligent and targeted sub-sampling for XRD and thin section analysis to better define the chemical stratigraphy 5. Update of XRF-mineral stratigraphy with XRD and thin section data to produce a continuous mineralogical profile

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14 Multi-Sensor Instrumentation Instrument Standard Multi- Sensor Core Logger (MSCL-S) Description Accepts nearly any form of core material Most flexible with respect to sensor arrangement Continuous core logging XZ Multi-Sensor Core Logger (MSCL-XZ) Bench-top core logging platform Surface core measurements Main use for split or slabbed core samples XYZ Multi-Sensor Core Logger (MSCL-XYZ) Multiple core workstation Accepts core boxes Surface core measurements Main use for split or slabbed core samples X-ray CT Machines (MSCL-(R)XCT) Accepts nearly any form of core material High resolution (c. 100 microns) Capable of measuring down to 30 microns) 01/06/2016 Core Analysis Instruments 14

15 Multi-Sensor Technology Sensor Acquisition Parameter Requirements Attenuated gamma P-wave transducers Non-contact resistivity Magnetic susceptibility loop or point Gamma density (g/cm 3 ) Fractional porosity P-wave velocity (m/s) Impedance Electrical resistivity (ohm.m) Magnetic susceptibility (SI or cgs) Non-fractured core Non-metallic liner Non-metallic liner Saturated sediments Non-metallic liner Natural Gamma Colour Spectrophotometer X-ray fluorescence Natural gamma radiation (cps) K,U,Th derivation Munsell colour code, L*,a*,b*, RGB Elemental composition (ppm or %) Non-fractured core Clean and open core surface Clean and open core surface ASD Visible and Near Infrared Mineral composition (wt%) Dry and open core surface Geotek linescan camera Visible and UV 14-bit Tiff image Open core surface 01/06/2016 Core Analysis Instruments 15

16 Multi-Sensor Core Logger Automated core logging platform Cores are pushed passed sensors Measurement geometry is constant Provision of continuous high resolution downcore multi-parameter stratigraphy Multiple sensors (up to 8) can be installed at once Depth co-registration of data Data are collected simultaneously Variable resolution 01/06/2016 Core Analysis Instruments 16

17 Case Study: ONDRAF/NIRAS Multi-Parameter Stratigraphy 01/06/2016 Core Analysis Instruments 17

18 Multi-sensor core data = Less Uncertainty?! Give me more now! Effective cost low Effective value very high