Introduction to Well Logging and Unconventional Reservoirs by Dr. Mustafa

Speaker Introduction

• Dr. Mustafa: 5 years in petroleum industry, PhD from NC State, Masters from Egypt.
• Early career in academia in both Egypt and the USA.
• Extensive experience across the globe in various positions within petroleum industry.

Lecture Overview

• Objective: Link well logging knowledge to upcoming lectures on unconventional reservoirs.
• Importance: Understand well logging to comprehend unconventional reservoirs.

Key Points from Previous and Current Lecture

• Industry Segments: Identification, Drilling, Evaluation, Completion, Production, Field Management.
• Interconnected Processes: All segments are linked; none are isolated.

Well Logging Types

• Wireline Logging: Occurs after drilling, uses a wire to connect tools to the surface.
• Logging While Drilling (LWD): Conducted during drilling, tools are part of bottom hole assembly.
• Application: Choice between Wireline and LWD depends on well type (vertical vs. horizontal).

Essential Measurements in Well Logging

1. Borehole Size: Measured by caliper tool, crucial for well stability and cementing operations.
2. Porosity: Measured by neutron porosity tool, indicates void spaces for hydrocarbons.
3. Lithology: Measured by density tool, determines formation type (sandstone, limestone, etc.).
4. Fluid Saturation: Measured by resistivity tool, differentiates between water and hydrocarbons.
5. Rock Mechanical Properties: Measured by sonic tool, important for fracturing operations.

Understanding Borehole Size

• Borehole size varies due to mud interaction, drilling process, rock properties, etc.
• Tools: Caliper with 2, 4, or 6 arms measures borehole diameter at different depths.
• Importance: Essential for knowing wellbore shape and planning cementing operations.

Clay and Shale in Logging

• Clay Minerals: Harmful as they reduce porosity, clog pores, and limit hydrocarbon storage.
• Terminology: Every clay is a shale; not every shale is clay. Crucial for understanding unconventional reservoirs.

Tools for Measuring Key Properties

• Caliper Tool: Measures borehole diameter.
• Gamma Ray Tool: Detects clay based on radioactivity (potassium, thorium).
• Neutron Porosity Tool: Measures porosity by detecting hydrogen atoms in fluids (water, oil, gas).
• Resistivity Tool: Differentiates fluid saturation by measuring electrical resistivity.
• Induction Tool: Used when mud is non-conductive, measures resistivity using electromagnetic waves.
• Density Tool: Measures formation density by counting electrons, relates to mass and determining formation type.
• Sonic Tool: Measures compressional and shear properties of the formation, essential for fracturing.

Important Concepts in Well Logging

• Phase and Attenuation in Electromagnetic Waves: Used to determine resistivity in non-conductive muds.
• Understanding Logs and Scales: API standards for scales, importance of recognizing porosity values (negative porosity query).
• Combination of Tools: Choice of tools based on the information required and economic considerations.

Conclusion

• Many tools available for formation evaluation, choice depends on the required measurements and economic factors.
• Each tool relies on physical properties and detection methods to measure specific parameters crucial for well and reservoir management.

Contact Information

• Dr. Mustafa's email address for further questions.

Next Steps: Q&A session to follow and deeper exploration in next lecture on unconventional reservoirs.