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1 LEARNING OBJECTIVES RESISTIVITY LOGGING TOOLS AND INTERPRETATION CORE Open Hole Well Logging Refresher Discuss wireline logging concepts and describe surface and subsurface systems Explain how depths are determined during logging Discuss the difference between driller s depth and logger s depth Explain the differences between MD, TVD, and TVDSS and when each is needed Describe the early resistivity log the Lateral Log 1

2 WIRELINE LOGGING (REFRESHER) Logging Tool THE BIRTH OF RESISTIVITY LOGGING 2

3 THE BIRTH OF RESISTIVITY LOGGING THE FIRST RESISTIVITY LOGGING TOOL Long AO spacing Invaded zone resistivity has less influence on deep investigation spacing Distinguishing characteristic: AM = long MN = short Radius of investigation 18 8 (5.5 m) 3

4 THE EVOLUTION OF RESISTIVITY LOGGING TOOLS Lateral Log Late 1920s 1930s World War II Logging slowed Late 1930s Late 1940s West Soviet Union The Cold War Induction Log, Laterolog technology MODERN RESISTIVITY LOGGING UNITS Onshore Wireline Unit Courtesy of Schlumberger Russian Lateral Log, multiple electrode Well Log spacings Lateral Logs Offshore Wireline Unit Courtesy of Baker Hughes Evaluation

5 MODERN RESISTIVITY LOGGING UNITS Wireline Winch DEPTH: WHAT IS PROPER? Depth Computers Courtesy of Halliburton 5

6 DEPTH: WHAT IS PROPER? Driller s Depth (DD) Determined by adding drill pipe stands Used for LWD and open hole coring and analysis Generally less accurate than LD Logger s Depth (LD) Wireline measurement utilizing a calibrated cable and wheel All log analysis is carried out using the loggers depth Also Measured Depth (MD) Generally most accurate A correction is generally required from DD to LD because: DD is not stretch-corrected and LD is. LOGGER S DEPTH Most accurate Calibrated measurement wheel and magnetic marks on the cable Corrected for stretch Not perfect May not be lowered to the very bottom of the borehole Casing shoe TD: Depth logger Depth driller 6

7 THE LOGGING SYSTEM THE LOGGING SYSTEM WIRELINE CABLE Electrical Wireline Cable Head Wireline Fishing (a bad trip!) Electrical & mechanical connection Weak point 7

8 SAFE OPERATIONS SAFE OPERATIONS Equipment Hard hats Hearing protection Safety glasses Gloves Fire-retardant coveralls Steel-toed boots 8

9 SAFE OPERATIONS At the Wellsite Hazards radioactivity, explosives, pressure Job Hazard Analysis (JHA) Hot work permits Cold work permits Material Safety Data Sheet (MSDS) LOGGING DEPTH CONTROL First Survey in Well Usually GR/SP-Resistivity log Calibration using magnetic marks Subsequent Surveys (Same Section) Correlated to first survey Errors due to tool weight diff., traveling block movements Subsequent Surveys (New Section) First log must include GR Overlap of >50m (~165 ) with previous GR 1st Survey Casing shoe: Depth logger = Depth driller ±0.1% Subsequent Survey (same section) Subsequent Survey (new section) 9

10 LOGGING DEPTH CONTROL Stretch corrections to WL Vertical Well MD = TVD Deviated Well MD TVD TVD converts to TVDSS for geologist and reservoir engineer LOGGING DEPTH CONTROL Measured Depth Used for well operations Required to Run casing and tubing Perforate casing Set packers and plugs Other downhole activity True Vertical Depth Used for Geologic mapping Reservoir engineering Required to determine Pressure Temperature Fluid properties 10

11 NEWER GENERATION OF COMPACT LOGGING TOOLS Platform Express 38 feet (1.6 m) Standard Triple Combo 90 feet (27.4 m) NEWER GENERATION OF COMPACT LOGGING TOOLS Triple Combo 1. Resistivity 2. Density 3. Neutron porosity SP GR Micro-Resistivity Gamma Ray Neutron porosity Density Micro-resistivity Resistivity 11

12 NEWER GENERATION OF COMPACT LOGGING TOOLS Triple Combo Quad Combo NEWER GENERATION OF COMPACT LOGGING TOOLS Platform Express Specifications 38 ft (11.5 m) length 690 lbm (313 kg) 3⅜-in. (8.6 cm) minimum OD 4⅝-in. (11.75 cm) maximum OD 260 F (127 C) 10,000 psi (68,950 kpa) 6- to 16-in. (15-40 cm) hole sizes 3600 ft/hr (1100 m/hr) 12

13 LEARNING OBJECTIVES You are now able to: Discuss wireline logging concepts and describe surface and subsurface systems Explain how depths are determined during logging Discuss the difference between driller s depth and logger s depth Explain the differences between MD, TVD, and TVDSS and when each is needed Describe the early resistivity log the Lateral Log 13