The mechanics of this 2D oil drilling game are pretty simple. You bid for a patch of land, hire dowsers to find oil, build oil towers and drill until you hit an oil reservoir. Then, you transport the oil from the tower to tanks, or sell it at two factories. The oil price you can sell it for changes over time which results in boring busy work to make sure you don't miss a high price period. After one year, you return to the town, buy upgrades and bid for the next patch of land, or buy shares of the town.
New upgrades and game mechanics like rocks and gas reservoirs only slightly change the basic formula, so that in the end the game ends up being pretty repetitive. Still, if you are looking for a relaxing game that you can play without too much thought, you may want to give this a shot.
I wouldn't recommend it for the current full 10 EUR price tag, but this is very decent sale material.