SPE - Society of Petroleum Engineers Production and Operations Questions and Answers 1 — Questions and Answers
Question 1: A production engineer is evaluating artificial lift methods for a deep, high-gas-oil-ratio (GOR) well that is expected to produce sand. Which of the following artificial lift systems is generally most suitable for these conditions?
- Sucker Rod Pump
- Gas Lift (Correct answer)
- Electrical Submersible Pump (ESP)
- Plunger Lift
Correct answer: Gas Lift
Gas lift is well-suited for deep, high-GOR wells and is very effective at handling abrasive materials like sand. Sucker rod pumps can be inefficient in deep wells and high GOR can cause gas interference. ESPs are susceptible to damage from sand and can have issues with gas locking. Plunger lift is most effective in gas wells with liquid loading issues, not typically high-volume oil producers.
Question 2: In surface production facilities, what is the primary purpose of a three-phase separator?
- To remove dissolved salts from the produced water.
- To increase the pressure of the gas for transport.
- To measure the individual flow rates of oil, water, and gas.
- To separate the well stream into its primary components: oil, water, and gas. (Correct answer)
Correct answer: To separate the well stream into its primary components: oil, water, and gas.
A three-phase separator is a vessel designed to separate the produced well stream into three distinct fluid phases: oil, water, and gas. This is a fundamental step in processing produced fluids at the surface. Desalting, gas compression, and metering are typically downstream processes.
Question 3: A well's production has significantly declined due to suspected near-wellbore permeability reduction. Which of the following intervention techniques is specifically designed to remove this type of damage and restore permeability by dissolving rock matrix or damaging materials?
- Hydraulic Fracturing
- Workover
- Acidizing (Correct answer)
- Production Logging
Correct answer: Acidizing
Acidizing is a well stimulation technique that involves pumping acid into the well to dissolve minerals, composites, and other damaging materials that are plugging the near-wellbore region, thereby restoring or enhancing permeability. Hydraulic fracturing creates new flow paths by fracturing the rock, rather than dissolving it. A workover is a broader term for well intervention, and production logging is a diagnostic tool, not a treatment.
Question 4: Which of the following is considered a primary mechanism of 'formation damage' that can occur during drilling, completion, or production operations?
- Gas lift valve optimization
- Reservoir pressure depletion
- Fines migration and plugging of pore throats (Correct answer)
- Casing collar locator signal interference
Correct answer: Fines migration and plugging of pore throats
Formation damage refers to the reduction of a reservoir's natural permeability, often in the near-wellbore region. Fines migration, where small particles of clay or silt are dislodged and plug pore throats, is a common mechanical cause of formation damage. The other options are related to production optimization, natural reservoir behavior, or logging tool operation, not causes of formation damage.
Question 5: A production logging tool (PLT) is run in a producing well. The spinner flowmeter shows a significant decrease in rotational speed across a set of perforations. What is the most likely interpretation of this measurement?
- The perforations are completely plugged and not producing.
- The fluid is exiting the wellbore and flowing into the formation at this interval.
- The fluid is entering the wellbore from the formation at this interval. (Correct answer)
- The tool is malfunctioning and providing an inaccurate reading.
Correct answer: The fluid is entering the wellbore from the formation at this interval.
A spinner flowmeter measures fluid velocity. As fluid enters the wellbore from producing perforations, the cumulative flow rate and velocity in the wellbore increase. Therefore, an increase, not a decrease, in spinner speed would be expected *above* the producing zone. A significant increase in rotational speed *after* passing a set of perforations indicates fluid entry from that zone. The question asks about the change *across* the perforations, implying a comparison from below to above. The scenario describes fluid entry, which causes the spinner speed to increase as it moves up past the inflow point.
Question 6: During a workover operation on a well with significant reservoir pressure, what is the first critical step that must be performed before removing the production tubing?
- Run a suite of production logs.
- Install the Christmas tree.
- Kill the well. (Correct answer)
- Stimulate the formation with acid.
Correct answer: Kill the well.
Before any major invasive intervention like pulling tubing, the well must be 'killed'. This involves pumping a fluid (kill fluid) into the wellbore to create sufficient hydrostatic pressure to overcome the formation pressure and stop the flow of reservoir fluids to the surface, ensuring the operation can be conducted safely.
SPE - Society of Petroleum Engineers Production and Operations Questions and Answers 1
A production engineer is evaluating artificial lift methods for a deep, high-gas-oil-ratio (GOR) well that is expected to produce sand.
Which of the following artificial lift systems is generally most suitable for these conditions?