Drilling Engineering Lecture Notes

Flashcards covering the fundamentals of drilling engineering, including rig systems, drilling fluids, well control definitions, and directional drilling techniques.

What is the primary aim of drilling as defined in the lecture?

To make a hole connecting the reservoir with surface production facilities.

What was the name of the first commercial oil well and where was it drilled?

Drake’s Well, drilled in 1859 in Pennsylvania.

List the six main component systems of a rotary drilling rig.

(1) The rotary system, (2) The hoisting system, (3) The power system, (4) Well control system, (5) Well monitoring system, and (6) The fluid circulating system.

What is the function of the rotary system?

To transmit rotation to the drilling string and consequently rotate the bit.

What components make up the rotary system?

Swivel, Rotary hose, Kelly, Rotary drive (master pushing, kelly bushing), Rotary table, Drilling string, and bit.

What is the primary function of the hoisting system?

To provide a means of lowering or rising drillstrings, casing strings, and other subsurface equipment into or out of the hole.

What two specific purposes do the derrick and substructure serve?

To provide vertical height for pipe movement and to allow enough vertical space to install the Blow Out Preventer (BOP).

What is the typical total power requirement for most modern drilling rigs?

From $1000$ to $3000\,hp$.

Which two rig systems consume the majority of the power?

The hoisting system and the fluid circulating system.

What is the function of the well control system?

To prevent blowout and kick from taking place.

What is a BlowOut Preventer (BOP)?

Specialized valves used to seal, control, and monitor oil and gas wells to prevent the uncontrolled release of crude oil or natural gas.

How is a 'kick' defined in drilling?

The flow of formation fluids (water, oil, or gas) into the well in the presence of drilling fluid; the gas kick is considered the most dangerous.

What is a 'blowout'?

The uncontrolled flow of formation fluids to the surface, which can cause loss of life, equipment, and environmental damage.

What does a decrease in the mud level in a pit (mud tank) indicate?

It indicates fluid loss into the formation.

What does an increase in the mud level in the pit indicate?

It indicates a kick.

List several parameters recorded by the well monitoring system.

Depth, Penetration rate, Hook load, Pump rate, Pump Pressure, Mud density, Mud salinity, Pit level, Flow rate, and Mud gas content.

What is the primary function of the circulating system?

To remove the rock cuttings from the hole as drilling progresses.

Under what specific condition is air used as a drilling fluid?

For very low permeability formations where there is no water influx and cuttings do not stick inside the hole.

What are the six key functions of drilling mud?

1. Overcome formation pressure. 2. Carry drill cuttings. 3. Cool and lubricate bit. 4. Support well wall (mud cake). 5. Keeps cuttings in suspension. 6. Maximize drilling rate.

What is the definition of directional drilling?

Intentionally deviating the wellbore from vertical along a pre-selected trajectory to reach the target horizon.

How is horizontal drilling defined?

The process of directing a drill bit to follow a horizontal path oriented approximately $90^\circ$ from vertical.

What is the objective of a horizontal hole in a reservoir?

To enhance the productivity of the well and reduce the number of wells required to develop the whole field.

What is the permeability threshold for identifying 'tight reservoirs' as an application for horizontal drilling?

Permeability $<< 1\,md$.