SPE Well Completions and Stimulation 2 — Questions and Answers
Question 1: What is the primary purpose of a packer in a well completion?
- To isolate zones and seal the annulus between tubing and casing (Correct answer)
- To increase wellbore diameter
- To measure downhole pressure continuously
- To prevent gas migration to surface
Correct answer: To isolate zones and seal the annulus between tubing and casing
Packers isolate production zones and seal the annulus to direct fluids through the tubing string.
Question 2: In a gravel pack completion, what is the primary function of the gravel?
- To increase permeability around the wellbore
- To filter formation sand while maintaining fluid flow (Correct answer)
- To chemically stabilize clay minerals
- To act as a proppant in hydraulic fractures
Correct answer: To filter formation sand while maintaining fluid flow
Gravel packs filter formation sand particles, preventing them from migrating into the wellbore while allowing hydrocarbons to flow.
Question 3: Which type of perforation gun system is conveyed on electric wireline?
- Tubing-conveyed perforating (TCP)
- Coiled tubing perforating
- Wireline-conveyed perforating (Correct answer)
- Drillpipe-conveyed perforating
Correct answer: Wireline-conveyed perforating
Wireline-conveyed perforating guns are run on electric wireline and fired electrically from surface.
Question 4: What does the term 'skin factor' represent in well completions?
- The thickness of the formation damage zone
- A dimensionless measure of near-wellbore flow restriction or enhancement (Correct answer)
- The permeability of the gravel pack
- The depth of perforation penetration
Correct answer: A dimensionless measure of near-wellbore flow restriction or enhancement
Skin factor is a dimensionless number quantifying additional pressure drop (positive skin = damage, negative skin = stimulation).
Question 5: What is the main advantage of an openhole completion over a cased-hole completion?
- Better zonal isolation
- Lower cost and no perforation damage (Correct answer)
- Easier workover operations
- Higher wellbore stability
Correct answer: Lower cost and no perforation damage
Openhole completions avoid the cost of cementing and perforating, and eliminate perforation-induced damage near the wellbore.
Question 6: Which fluid property is most critical when designing a hydraulic fracturing treatment to prevent premature screenout?
- Fluid viscosity and leak-off coefficient (Correct answer)
- Fluid pH and salinity
- Fluid density and temperature
- Fluid color and turbidity
Correct answer: Fluid viscosity and leak-off coefficient
Viscosity controls proppant transport and fracture width, while leak-off determines fluid efficiency; both are critical to prevent screenout.
Question 7: In a smart well completion, what do Inflow Control Devices (ICDs) primarily accomplish?
- Measure reservoir temperature at multiple points
- Balance flow contributions along the wellbore to delay water or gas breakthrough (Correct answer)
- Provide zonal isolation between pay zones
- Inject chemicals into the formation
Correct answer: Balance flow contributions along the wellbore to delay water or gas breakthrough
ICDs create a pressure drop that equalizes inflow along horizontal wellbores, delaying early water or gas breakthrough from high-permeability zones.
SPE Well Completions and Stimulation 2
What is the primary purpose of a packer in a well completion?