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Petroleum Geoscience

Open Hole Log Interpretation and Formation Evaluation

Bypassed pay is usually found years later in logs that were run, paid for and read too quickly. Careful open hole interpretation is the cheapest way to avoid leaving oil behind a casing string. Delegates begin with the borehole environment and mud filtrate invasion, then learn the physics and quick look use of gamma ray, spontaneous potential, resistivity, density, neutron, sonic and photoelectric tools. Porosity determination, water resistivity from SP and Pickett plots, and Archie water saturation come next, followed by lithology identification from crossplots. Formation pressure testers, fluid sampling and nuclear magnetic resonance are added to locate contacts and moveable fluids. The programme closes on net pay cut offs and a complete clean sand evaluation. Delegates leave able to run a full quick look and detailed interpretation and to defend their pay calls.

5 day course

Course objectives

  • Explain the borehole environment, invasion profile and its effect on readings
  • Interpret gamma ray, SP, resistivity, density, neutron and sonic logs
  • Calculate porosity from single and combined porosity tools
  • Determine formation water resistivity and Archie water saturation
  • Identify lithology using neutron density and other crossplots
  • Locate fluid contacts with pressure gradients and resistivity
  • Apply net pay cut offs and summarise a clean reservoir evaluation
  • Plan an open hole logging programme for an exploration well

Who should attend

  • Junior petrophysicists
  • Geologists and wellsite geologists
  • Reservoir and production engineers
  • Logging company field engineers
  • Petroleum agency staff reviewing well completion reports

Course outline

  1. 01Borehole environment and invasion
  2. 02Gamma ray and SP
  3. 03Resistivity tools
  4. 04Density, neutron and sonic porosity
  5. 05Lithology crossplots
  6. 06Water saturation and Archie's equation
  7. 07Pressure testing and fluid contacts
  8. 08Nuclear magnetic resonance
  9. 09Net pay and quick look evaluation

Scheduled sessions

Scheduled sessions for Open Hole Log Interpretation and Formation Evaluation
DatesVenueFormatPriceRegister
12 to 16 October 2026Lagos, NigeriaClassroomUSD 1,325 per delegate
9 to 13 November 2026Johannesburg, South AfricaClassroomR19,950 per delegate
30 November to 4 December 2026OnlineOnlineR8,500 per delegate
18 to 22 January 2027Maputo, MozambiqueClassroomUSD 1,325 per delegate

Open Hole Log Interpretation and Formation Evaluation

From R8,500

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