Classification of BOP - Blowout Preventer

There are several types of BOPs, as they can be classified according to their scope, and their conformation.

Classification for use:

The first subdivision distinguishes the onshore (offshore) BOPs . The first ones are generally smaller and simpler, and are used exclusively in drilling rigs on the mainland. Submarines BOPs, on the other hand, are designed to operate in offshore fields, and therefore are used in oil platforms or drillships . They have a more advanced technology, especially for what concerns the control mode of the BOP itself having to be activated from remote locations, and are also more impressive, because of the presence of a frame (chassis) of support, and the different conformation of the wells submarines.

The split of a Blowout preventer stack: the upper one is an annular BOP, the lower one represents a BOP on a jaw.

Classification by constructive technology :

The classification as a function of their architecture, distinguishes between the so-called BOP - blowout preventer

The first ones consist of a rubber ring, perforated in the center and whose hole diameter is equal to that of the well. The ring is contained in a steel crankcase . Inside the crankcase , and under the rubber ring, a hydraulic piston is mounted , which when actuated compresses or decompresses the ring from bottom to top or from top to bottom. In this way the ring (also called anular ) is closed or opened.

The jaws BOPs are also made of a metal casing, in which there are two opposing jaws, and may differ in "Combi", that is, with jaws coupled to two to two in two arms, or "Quad", with four distinct arms.

In the case of BOP for Coiled Tubing of Quad type, we find the following rams: Top Blind Rams, which have the function of hermetically closing the shaft; Shear Rams or Cutter Rams, which have the task of cutting the coiled tubing that is well with blades, followed by the Rams Slip, which have the shape of wedges, which have the task of supporting the coiled tube section cut and left in well. Finally there are the Rams Pipe that must ensure hydraulic seal on the tube and prevent the shaft pressure from creating a Blowout.

Between the Cutters and the Slip there is a kill line, a point where fluid can be pumped to "kill" the well, that is to provide a hydrostatic to the latter, which avoids the blowout. The jaws are controlled by hydraulic pistons through which they can be closed or opened. The first jawbone BOP was invented in 1922.