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What is the difference between tubing and casing?

Tubing and casing are essential tools in petroleum exploitation.

Tubing is a pipe that runs into the casing of an oil well during normal production. In a blowout well, oil flows into the surface through tubing and enters the gathering and transportation process. In mechanical production Wells, a combination of tubing, sucker rod and deep well pump (i.e., "three pumping" equipment) pumps the oil to the surface and enters the gathering and transportation process.

Casing is in the end of drilling, down to the underground pipe, casing and well wall sealed with cement, and then with the perforating gun at the target layer of perforating, so that oil flow through the rock, cement ring, casing into the bottom of the well, and then into the tubing to the ground.

The main functions are:

1. Reinforce the shaft wall to prevent the stratum from collapsing

2. Isolate different oil and water layers to realize layered mining

3, easy to implement fracturing, acidification and other measures of operation and maintenance operations

4, the formation of oil flow channel, with tubing to achieve the purpose of oil recovery.

The sequence is: after the well is well drilled, the casing is put in, the cement between the casing and the well wall is sealed, and the tubing is put in the casing. There are oil packers, pumps and other downhole tools on the tubing. The sucker rod is lowered into the tubing, and the sucker rod pulls the piston of the pump to reciprocate up and down. Thus, the oil is pumped to the surface.