From Spud to Completion: The Ultimate Drilling Operations Guide

Geological Survey and Site Selection [00:31]

• Geologists use seismic surveys to map underground rock formations and identify potential hydrocarbon reservoirs.
• Computer models analyze seismic data to pinpoint locations with suitable reservoir rock, porosity, permeability, and trap structures.
• The target reservoir in the example is at a depth of 12,000 feet.

  "Geologists use seismic surveys to map underground rock formations."

Site Preparation [01:10]

• Once a location is selected and permits obtained, site preparation begins.
• The drill site, or pad, must be cleared and leveled, typically covering 3 to 5 acres.
• The ground is graded and covered with compacted gravel to support heavy equipment exerting over 50,000 lbs per square foot.

  "The drill site called a pad must be cleared and leveled."

Cellar Excavation and Utility Installation [01:42]

• A cellar, approximately 10 ft deep and 10x10 ft, is excavated.
• The cellar provides workspace for wellhead equipment and houses the blowout preventer stack.
• Nearby utility systems, including electrical power, water, and fuel storage, are installed.

  "Workers excavate a cellar which is a rectangular bit approximately 10 ft deep and 10x 10 ft in dimensions."

Drilling Rig Assembly [02:13]

• The drilling rig arrives disassembled on multiple trucks and assembly takes several days.
• A modern land rig for 12,000 ft drilling includes power, hoisting, rotating, circulating, and well control systems.
• The substructure elevates the rig floor 20-40 ft above ground to provide clearance for wellhead equipment.

  "The drilling rig itself arrives disassembled on multiple trucks."

Hoisting System [02:33]

• The hoisting system includes the derrick (130-150 ft tall), drawworks (winch system), crown block (at the derrick top), and traveling block.
• This block and tackle system uses steel cable (drilling line) to lift heavy loads.
• The drawworks precisely controls the raising and lowering of the drill string.

  "The hoisting system includes the Durk, a tall steel tower, usually 130 to 150 ft high."

Rotating and Circulating Systems [02:52]

• The rotating system consists of a rotary table or a top drive system to turn the drill string.
• The circulating system uses mud pumps to move drilling fluid at high pressures.
• This system also includes mud tanks, shale shakers, and solid control equipment.

  "The rotating system consists of the rotary table, a circular opening in the rig floor that can rotate to turn the drill string or alternatively a top drive system."

Blowout Preventer (BOP) Stack [04:08]

• The BOP stack is a critical safety device installed on the wellhead, weighing up to 300,000 lbs and standing over 30 ft tall.
• It includes pipe rams (close around specific pipe sizes) and blind rams (can close and cut pipe).
• An annular preventer uses a rubber donut to seal around any size pipe or an open hole.

  "The plowout pretor commonly called the BOP is perhaps the most critical safety device."

Drilling Mud Functions [05:05]

• Drilling mud cools and lubricates the bit, carries rock cuttings to the surface, and exerts hydrostatic pressure to prevent formation fluid influx.
• It also forms a filter cake to stabilize the hole and prevent fluid loss.
• Mud can be water-based or oil-based, with additives like barite (density) and bentonite (viscosity) to control properties.

  "It cools and lubricates the drill bit which can reach temperatures over 400° F from friction and bottom hole temperature."

Drilling Operations and Monitoring [07:30]

• Drilling begins with the driller operating from a console monitoring parameters like weight on bit, rotary speed, torque, pump pressure, and rate of penetration.
• Typical weight on bit is 10,000-50,000 lbs, rotary speed 60-200 RPM, pump pressure 2,000-5,000 PSI, and rate of penetration 30-200 ft/hr.
• A mud engineer continuously monitors and adjusts mud properties like density, viscosity, gel strength, fluid loss, and pH.

  "Key parameters monitored include weight on bit, which is how much downward force is applied to the drill bit."

Well Types and Trajectories [08:23]

• Wells are categorized as exploration, appraisal, or development (production/injection) wells.
• Trajectories include vertical, directional, and horizontal wells.
• Multilateral and extended reach wells use multiple branches or long horizontal sections from a single surface location.

  "Wells in the oil and gas industry come in several types based on their purpose."

Conductor Hole and Casing [09:30]

• The first section drilled is the conductor hole (36 inches diameter, 40-100 ft deep) using a tricone bit.
• Drill collars provide weight, and drill pipe connects to the drill string.
• Conductor casing (30-36 inch diameter) is run and cemented to hold the casing, seal the annulus, and protect against corrosion.

  "The first section drilled is the conductor hole, typically 36 in in diameter and 40 to 100 ft deep."

Surface Hole and Casing [15:01]

• A smaller bit drills the surface hole (17.5 inches diameter, 1,000-3,000 ft deep) through the conductor casing.
• Formation samples are collected and analyzed by a mud logger.
• Surface casing (13 3/8 inch diameter) is run and cemented to protect freshwater zones and provide structural support.

  "The next section begins. A smaller bet is run through the conductor casing to drill the surface hole, typically 17 1/2 in in diameter, to a depth of 1,000 to 3,000 ft."

Intermediate Hole and Casing [16:58]

• The intermediate hole (12.25 inch diameter, 6,000-9,000 ft deep) transitions to higher pressure zones.
• Mud weight is increased to maintain pressure control within the drilling window.
• Intermediate casing (9 5/8 inch diameter) is run and cemented, requiring precise torque for connections.

  "The next section is the intermediate hole drilled with a 12.25 into 5 in bed to a depth that depends on the geology but typically 6,000 to 9,000 ft."

Directional Drilling and MWD/LWD [18:14]

• Directional drilling uses specialized equipment like bent subs to steer the well.
• Measurement While Drilling (MWD) tools provide real-time data on inclination, azimuth, and tool face orientation.
• Logging While Drilling (LWD) tools evaluate formation properties like radioactivity, resistivity, density, and porosity.

  "Many wells today are not drilled vertically but are intentionally deviated to reach targets that are horizontally offset from the surface location."

Production Hole and Completion [22:41]

• The production hole (8.5 inch diameter) is drilled to the target reservoir, requiring careful mud management to avoid formation damage.
• Oil-based mud is often used for its lower damage potential.
• Production casing (7 inch diameter) is run and cemented, followed by perforating the casing to create flow paths.

  "The production hole, typically 8.5 in in diameter, is drilled from the intermediate casing shoe down to the target reservoir."

Perforation and Tubing Installation [51:00]

• Perforating guns with shaped explosive charges create holes through the casing and into the formation.
• Underbalanced perforating allows immediate flow to clean up the perforations.
• Production tubing (2 3/8 to 3 1/2 inch diameter) is run, and a packer is set to isolate the annulus.

  "Perforating is the process of creating flow paths from the reservoir into the wellbor by shooting holes through the casing cement and a short distance into the formation."

Wellhead and Initial Flow Testing [54:16]

• A Christmas tree, an assembly of valves, is installed on the wellhead to control flow.
• The well is opened gradually to establish production characteristics, initially flowing load fluid before hydrocarbons appear.
• Flow rates are measured, and fluids are sampled for analysis of properties like API gravity and composition.

  "At the surface, a Christmas tree is installed on the top of the wellhead."

Stimulation and Production Facilities [57:10]

• If productivity is low, stimulation treatments like acidizing or hydraulic fracturing are performed.
• Fracturing uses fluid and proppant (sand or beads) to hold open fractures, enhancing flow.
• Once producing satisfactorily, wells are connected to permanent production facilities like gathering stations and pipelines.

  "If the well has lower productivity than expected due to formation damage, stimulation treatments may be performed."

Well Life Cycle: Decline, Artificial Lift, and Abandonment [59:18]

• Production rates decline over time, necessitating artificial lift methods like sucker rods, electric submersible pumps, or gas lift.
• Wells are plugged and abandoned when production falls below operating costs, with cement plugs sealing the wellbore.
• The site is reclaimed, completing the full life cycle from drilling to abandonment.

  "Over the life of the well, production rates will decline as reservoir pressure depletes."