Lecture on Oil Drilling Processes

Introduction

• Nomadic existence for oil drilling operations
• Moving the drilling rig with every new location
• Setting up can take a few days to a couple of weeks

Site Selection for Drilling

• Chosen by geologists and geophysicists
• Based on knowledge of rock layers below
• Example: Dome-shaped fold in rock layers revealed by seismic survey
• It's a gamble; oil and gas might have migrated into the Dome

Drilling Process

• Initial drilling with a large bit through soft surface layers (up to 1000 feet)
• Target is over 10,000 feet down
• Drill driven by a rotary table on the platform

Drilling Fluid (Mud)

• Used to cool the bit and carry rock fragments to the surface
• Mud is recycled through screens, separators, and settling pits
• Circulates continuously
• Every 30 feet drilling stops to add another section of pipe

Roles and Responsibilities

• Tool pusher supervises the process, orders supplies, and ensures timely delivery
• Steel casing used to stabilize the well at shallow depths
• Cement pumped to set the casing in place
• Blowout preventers installed to seal off the hole if high-pressure gas, oil, or water is encountered

Offshore Drilling

• Similar procedures followed as on land
• Equipment fitted by remote control
• Marine riser connects the rig to the blowout preventers and drill hole

Monitoring and Maintenance

• Constant checks on the composition, viscosity, and density of mud
• Monitor drill bit performance; bits are changed when dull
• Deviation drilling used to bypass blockages or collapsed sections
• Prepared for hazards like mud contamination and high-pressure gas

Testing for Oil and Gas

• Inspection of rock cuttings for indications of oil
• Electrical, acoustical, and radioactive properties measured to determine content of rock layers
• Flow tests conducted to assess oil potential
• Drilling additional wells for a comprehensive picture of the reservoir

Development and Production

• Planning based on reservoir assessment
• Additional wells drilled for maximum extraction
• Water injected back to maintain pressure
• Offshore fields require centralized installations
• Deviation drilling techniques used for offshore development

Conclusion

• New oil reserves are harder to find and often in difficult locations
• Importance of human and environmental safeguards
• Objective is to recover as much oil as possible for as long as possible