API Drilling and Production 3 — Questions and Answers
Question 1: What is the main purpose of 'cementing' a casing string in a well?
- To increase the weight of the casing
- To provide zonal isolation and bond casing to the formation (Correct answer)
- To reduce the internal diameter for production tubing
- To prevent the casing from corroding
Correct answer: To provide zonal isolation and bond casing to the formation
Primary cementing provides zonal isolation between formations and permanently bonds the casing to the wellbore wall.
Question 2: In API well classification, what does a 'Class II' injection well typically receive?
- Hazardous industrial waste
- Fluids associated with oil and gas production (brine, produced water) (Correct answer)
- Municipal solid waste leachate
- Carbon dioxide for sequestration
Correct answer: Fluids associated with oil and gas production (brine, produced water)
Class II injection wells are regulated by EPA and are used to inject fluids associated with oil and gas production, such as produced water disposal or enhanced recovery.
Question 3: What is 'fishing' in the context of drilling operations?
- Sampling produced water for contaminants
- Retrieving lost or stuck equipment from the wellbore (Correct answer)
- Measuring formation porosity with acoustic tools
- Testing the wellbore for sand production
Correct answer: Retrieving lost or stuck equipment from the wellbore
Fishing refers to the operation of recovering equipment that has become stuck or lost in the wellbore during drilling.
Question 4: What does the 'kelly bushing' elevation (KB) datum refer to in well depth measurements?
- The depth of the surface casing shoe
- The reference point on the rotary table from which drilling depths are measured (Correct answer)
- The elevation of the wellhead above ground level
- The depth at which drilling fluid returns are measured
Correct answer: The reference point on the rotary table from which drilling depths are measured
Kelly bushing (KB) is the standard reference datum for depth measurements on a drilling rig, located at the rotary table on the rig floor.
Question 5: In well stimulation, what is the primary goal of hydraulic fracturing?
- To remove drilling mud damage from the near-wellbore region by dissolving mud solids
- To create or extend fractures in the formation to improve hydrocarbon flow to the wellbore (Correct answer)
- To inject steam to reduce oil viscosity in heavy oil reservoirs
- To perforate casing with shaped explosive charges
Correct answer: To create or extend fractures in the formation to improve hydrocarbon flow to the wellbore
Hydraulic fracturing pumps fluid at high pressure to create fractures in the rock, which are held open by proppant to improve permeability and production.
Question 6: What is the function of a 'packer' in a production well?
- To pack explosives for perforation guns
- To isolate zones in the annulus between the tubing and casing (Correct answer)
- To compact the proppant in a hydraulic fracture
- To seal the top of the drill string
Correct answer: To isolate zones in the annulus between the tubing and casing
A packer is a downhole mechanical device set to isolate the tubing-casing annulus and prevent fluid communication between different zones.
Question 7: What API standard governs the design and testing of drill bits?
- API Spec 5CT
- API Spec 7-1 (Correct answer)
- API RP 100
- API Spec 6A
Correct answer: API Spec 7-1
API Specification 7-1 covers the requirements for rotary drill stem elements including drill bits used in petroleum and natural gas drilling.
API Drilling and Production 3
What is the main purpose of 'cementing' a casing string in a well?