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1 RESISTIVITY LOGGING TOOLS AND INTERPRETATION CORE LEARNING OBJECTIVES The Quest for R t By the end of this lesson, you will be able to: Explain the borehole environment architecture that can cause R t determination to be difficult Describe the limitations of the conventional induction log and Laterolog and discuss why the modern array tools provide better data Explain what is different about the 3DX induction tool and how it can provide better in anisotropic formations Identify the process and advantages of the inversion and modeling approach to R t determination 1

2 THE ANISOTROPHIC ENVIRONMENT Isotropic Anisotropic FACTORS WITHIN THE ANISOTROPHIC ENVIRONMENT Bed 1 Bed 2 Bed 3 Mud salinity Mud filtrate invasion Tool Borehole diameter Formation layering (bed thicknesses) 2

3 LIMITATIONS OF STANDARD TOOLS Induction Log Response in a Highly Deviated Well OVERCOMING LIMITATIONS OF STANDARD TOOLS Problem Standard tools are not suitable for: Thinly layered reservoirs Deep invasion Highly deviated and horizontal wells Anisotropic laminated reservoirs Solutions Spherically focused log (SFL) Array induction and array Laterolog tools 3dx (or tilt) induction tools Inversion processing Standard deepinduction curve 3

4 RECONCILIATION OF RT IN LAMINATED SEQUENCES Log Response of Oil-Producing Thin Beds 6585 High-Resolution Laterolog Array (HRLA) HRLA GR Production test: 1750 bbl/d DLL 4

5 5

6 Mainly Isotropic Thick beds Good reservoir quality 6

7 Mainly Anisotropic Laminated sand/shales Good reservoir quality Mainly Isotropic Thick beds Good reservoir quality Mainly Anisotropic Laminated sand/shales Good reservoir quality Mainly Isotropic Thick beds Good reservoir quality HDIL 7

8 True 8

9 HDIL True Vertical Horizontal 9

10 Capillary pressure Horizontal saturation Hydrocarbon saturation 10

11 3-D EXPLORER Conventional Tilt / Shale (low R t ) Sand (high R t ) RECONCILIATION OF R T IN LAMINATED SEQUENCES Shale ~1 Ω-m Laterolog Response in Laminated Shaly Sands Laterolog response ~4 Ω-m Sand ~10 Ω-m 3DX 11

12 INVERSION AND MODELING INVERSION AND MODELING Field Log Model-Generated Log 12

13 INVERSION AND MODELING Modeling of the Laterolog Resistivity Tool Response Laterolog deep curve R t curve resulting from inversion and modeling INVERSION AND MODELING 1-D Model 2-D Model 3-D Model Formation layers Bed dip Borehole deviation Formation layers Bed dip Borehole deviation Invasion Formation layers Bed dip Borehole deviation Invasion 13

14 INVERSION AND MODELING Inversion of ILD Compared with Halliburton s High-Resolution Induction HDRS THE QUEST FOR R t Does it really matter? Conventional ILD Halliburton highresolution induction Inversion and modeling 14

15 THE QUEST FOR R t North Sea Reservoir (44 degree dip) Modeling and inversion resulted in 8% higher yields! LEARNING OBJECTIVES By You the now end can: of this lesson, you will be able to: Explain the borehole environment architecture that can cause R t determination to be difficult Describe the limitations of the conventional induction log and Laterolog and discuss why the modern array tools provide better data Explain what is different about the 3DX induction tool and how it can provide better in anisotropic formations Identify the process and advantages of the inversion and modeling approach to R t determination 15