Oil wells are resource buildings in Tropico 3 and Tropico 4. They're used to pump Crude Oil from veins in the earth. However, each vein has a limited amount of oil inside it; once it's all pumped out, it becomes necessary to find another or begin importing oil.
If possible, oil wells should be built only if an oil refinery can't be; refineries not only pump Crude Oil from nearby underwater sources but automatically refine it into more expensive Oil Products, which can be exported without upsetting Middle Eastern relations.
Oil wells are raw resource buildings in Tropico 5. They're used to pump Oil and Natural Gas from veins in the earth. However, each vein has a limited amount of fossil fuels inside it; once it's pumped dry, it becomes necessary to find another deposit or begin importing the materials.
- Coiled Tubing Rig: For $1,000, coiled tubing can be lowered into an oil well to pump chemicals into the deposit, increasing the Natural Gas and Oil reserves by 15,000 units each.
- Fracking Posts: For $3,500, an oil well can be set up to use fracking techniques, increasing its effectiveness by 20 but causing it to generate 30% more pollution.