Which statement about primary oil production is accurate?

• A. It uses injected steam and gases to recover more oil.
• B. It refines crude oil to produce fuels.
• C. It involves exporting oil to markets.
• D. It relies on natural reservoir pressure to bring oil to the surface without injecting fluids.

Answer: (D)

Primary oil production relies on the natural energy stored in the reservoir to push oil to the surface without adding fluids. When the reservoir pressure is high enough and oil is buoyant, it flows up the well due to that natural drive, so no injection is needed in this phase. As pressure declines, production from this phase falls, which is why later stages use secondary or enhanced methods like water or gas injection to sustain flow.

The statement that describes using natural reservoir pressure to bring oil to the surface without injecting fluids captures this idea. The other statements describe actions outside this automatic, early-drive process: injecting steam or gases is a later, artificial method; refining is processing oil into fuels; and exporting is a marketing/distribution activity.