Exploration & Production Processes Flashcards

What is the purpose of perforating a cased wellbore during completion operations?

Answer: To create channels through casing and cement into the formation

Perforating punches holes through the casing, cement, and into the formation to establish a flow path for hydrocarbons.

Which secondary recovery method involves injecting water into a reservoir to maintain pressure and displace oil toward producing wells?

Answer: Waterflooding

Waterflooding is the most widely used secondary recovery technique, using injected water to sweep oil toward producers.

What does the 'gas-oil ratio' (GOR) trend over time in a solution-gas-drive reservoir typically indicate?

Answer: GOR rises sharply as reservoir pressure falls below bubble point

Below the bubble point, free gas expands rapidly relative to oil, causing GOR to increase significantly.

Which wireline log is primarily used to identify lithology and clay content by measuring natural radioactivity?

Answer: Gamma ray log

The gamma ray log measures natural radioactivity from potassium, uranium, and thorium, with shales showing high values and clean sands showing low values.

In hydraulic fracturing, what is the role of the proppant material injected with fracturing fluid?

Answer: To keep induced fractures open after pressure is released

Proppant (typically sand or ceramic beads) props open hydraulic fractures after pump pressure is removed, maintaining a conductive flow path.

Which type of trap is formed by a fold where reservoir rock is arched into a dome-shaped structure?

Answer: Anticline trap

An anticline is an upward-arching fold where buoyant hydrocarbons migrate and accumulate beneath an impermeable cap rock.

What is 'ultimate recovery factor' (RF) in petroleum engineering?

Answer: Percentage of original oil in place produced over a field's life

Recovery factor is the fraction of original oil (or gas) in place that is ultimately recovered, typically expressed as a percentage.