CPA Drilling & Production Techniques 3 — Questions and Answers
Question 1: What is 'lost circulation' during drilling operations?
- Loss of rotation in the drill string
- Drilling fluid flowing into a formation rather than returning to surface (Correct answer)
- Decrease in bit rotation speed
- Failure of the mud pump system
Correct answer: Drilling fluid flowing into a formation rather than returning to surface
Lost circulation occurs when drilling mud flows into porous, fractured, or cavernous formations instead of returning up the annulus to surface.
Question 2: In hydraulic fracturing, what is a 'proppant'?
- A chemical used to initiate fracture propagation
- Granular material pumped into fractures to hold them open (Correct answer)
- A tool used to measure fracture width
- The fluid used to create the initial fracture
Correct answer: Granular material pumped into fractures to hold them open
Proppants such as sand or ceramic beads are pumped into hydraulic fractures to prop them open after pumping pressure is released, maintaining flow paths.
Question 3: What does API gravity measure in crude oil evaluation?
- The oil's sulfur content
- The relative density of oil compared to water (Correct answer)
- The oil's viscosity at reservoir temperature
- The gas-to-oil ratio of the crude
Correct answer: The relative density of oil compared to water
API gravity is a measure of how heavy or light crude oil is relative to water; higher API gravity means lighter, more valuable crude.
Question 4: What is the purpose of a 'christmas tree' in oil well production?
- A decorative safety marker on offshore platforms
- An assembly of valves and fittings that controls flow at the wellhead (Correct answer)
- A tree-shaped drill bit for hard formations
- A tool for measuring gas composition
Correct answer: An assembly of valves and fittings that controls flow at the wellhead
A Christmas tree is an assembly of valves, spools, and fittings installed on a producing wellhead to control and regulate the flow of oil and gas.
Question 5: Which artificial lift method uses a down-hole pump powered by a surface beam pumping unit?
- Electric submersible pump (ESP)
- Gas lift
- Sucker rod pump (beam pump) (Correct answer)
- Hydraulic jet pump
Correct answer: Sucker rod pump (beam pump)
A sucker rod pump uses a reciprocating beam unit at surface connected by a string of steel rods to a down-hole pump that lifts fluid to surface.
Question 6: What is 'primary recovery' in petroleum production?
- The first stage using only natural reservoir energy to produce fluids (Correct answer)
- Injection of water to maintain reservoir pressure
- Enhanced recovery using chemical flooding
- Thermal methods such as steam injection
Correct answer: The first stage using only natural reservoir energy to produce fluids
Primary recovery relies solely on natural reservoir energy — pressure, gas drive, or gravity — without any injection of supplemental energy.
Question 7: In well control, what is the 'driller's method' used for?
- Selecting the correct drill bit size
- A two-circulation kick-killing method that circulates the kick out before weighting up mud (Correct answer)
- Calculating the weight of the drill string
- Setting casing depth based on formation pressures
Correct answer: A two-circulation kick-killing method that circulates the kick out before weighting up mud
The driller's method kills a kick in two circulations: the first removes the influx with original mud, and the second circulates kill-weight mud.
CPA Drilling & Production Techniques 3
What is 'lost circulation' during drilling operations?