Chemical Engineering @ChemengFiles.Com

Most oil wells are drilled with rotary method. In this method, a tower holds the drill string, consisting of a series of tubes attached.

The chain linking it to the bank spins rotating in the floor of the tower. The drill bit at the end of the chain usually consists of three bevel gears with hardened steel teeth. The drill is brought to the surface by a continuous circulating fluid system driven by a pump.

Oil trapped in a reservoir is under pressure if not trapped by impermeable rocks would have continued rising due to buoyancy to erupt in the earth's surface.

Thus, when drilling a well that goes to an accumulation of oil pressure, oil spreads into the area of low pressure created by the well in communication with the surface.

However, as the well is filled with liquid shows a counter pressure on the tank and quickly stop the flow of additional fluid into the well if there were no other circumstances.

Most of the oil contains a significant amount of natural gas in solution, which remains dissolved due to the high pressure tank. When oil goes to the low pressure zone of the well, the gas ceases to be dissolved and begins to expand. This expansion, together with the dilution of the oil column of gas, less dense, makes oil come to the surface.

As we continue removing fluid reservoir, the pressure decreases very slowly, and the amount of dissolved gas. This makes the liquid flow rate into the well becomes less and less gas is released. When the oil no longer reaches the surface it is necessary to install a pump in the well to continue extracting oil.

Finally, the oil flow rate is so small, and the cost rises to the surface increases so much that the cost of operating the well is higher than the revenue to be gained from the sale of crude oil (after deducting operating expenses, taxes, insurance and capital gains). This means that it has reached the economic limit of the well, so it leaves your farm.