Changes

The ''[http://www.glossary.oilfield.slb.com/en/Terms/b/blowout_preventer.aspx blowout preventers] (BOPs)'' (38 in [[:file:Land rig example drawing.png|Figure 1]]) are the major component of the control system on a rig, and they are the last line of defence against a blowout. The BOPs are bolted to the wellhead and are not removed until the well is completed and production equipment is installed. BOPs usually have at least four sections:

The ''[http://www.glossary.oilfield.slb.com/en/Terms/b/blowout_preventer.aspx blowout preventers] (BOPs)'' (38 in [[:file:Land rig example drawing.png|Figure 1]]) are the major component of the control system on a rig, and they are the last line of defence against a blowout. The BOPs are bolted to the wellhead and are not removed until the well is completed and production equipment is installed. BOPs usually have at least four sections:

* ''[[Annular]]s'' are large, hard rubber slips that fit around any sized pipe. The size flexibility, however, is at the expense of the pressure rating.

* ''[http://www.glossary.oilfield.slb.com/en/Terms/a/annular_blowout_preventer.aspx Annular]s'' are large, hard rubber slips that fit around any sized pipe. The size flexibility, however, is at the expense of the pressure rating.

* ''[[Pipe ram]]s'' are metal donut-shaped sealing mechanisms that fit only a specific sized pipe but at a high pressure rating.

* ''[http://www.glossary.oilfield.slb.com/en/Terms/p/pipe_ram.aspx Pipe ram]s'' are metal donut-shaped sealing mechanisms that fit only a specific sized pipe but at a high pressure rating.

* ''[[Blind or shear ram]]s'' are edged high-carbon steel sealing mechanisms that can cut pipe and close the hole completely.

* ''[http://www.glossary.oilfield.slb.com/en/Terms/b/blind_shear_ram.aspx Blind or shear ram]s'' are edged high-carbon steel sealing mechanisms that can cut pipe and close the hole completely.

* ''[[Crossover spool]]s'' are metal junctions where the choke and kill lines attach.

* ''[[Crossover spool]]s'' are metal junctions where the choke and kill lines attach.

Additional control equipment includes the [[kill line]], [[choke line]], and [[flare line]]. The ''kill line'' is used to pump mud into the [[annulus]] at the crossover spool in the event that heavier mud is needed to control wellbore pressures. The ''choke line'' also helps control wellbore pressures by allowing drilling mud to circulate through a choke manifold (26) (which is a set of backpressure valves). The mud and gas can then be sent down the ''flare line'' for disposal or burning in the reserve pit (29).

Additional control equipment includes the [http://www.glossary.oilfield.slb.com/en/Terms/k/kill_line.aspx kill line], [http://www.glossary.oilfield.slb.com/en/Terms/c/choke_line.aspx choke line], and [[flare line]]. The ''kill line'' is used to pump mud into the [http://www.glossary.oilfield.slb.com/en/Terms/a/annulus.aspx annulus] at the crossover spool in the event that heavier mud is needed to control wellbore pressures. The ''choke line'' also helps control wellbore pressures by allowing drilling mud to circulate through a choke manifold (26) (which is a set of backpressure valves). The mud and gas can then be sent down the ''flare line'' for disposal or burning in the reserve pit (29).

Monitoring and measurement of the basic functions of the rig are usually made from the driller's console (17) located on the [[derrick floor]]. From this console, the driller can monitor equipment, distribute power, change gears, and oversee crew activities. Additional measurement equipment and records are located in the dog house (18) or service shed. The ''dog house'' is located to the side of the rig floor and contains the ''[[geolograph]]'', a device that makes a time-based chart record of several rig functions, including the following:

Monitoring and measurement of the basic functions of the rig are usually made from the driller's console (17) located on the [http://www.glossary.oilfield.slb.com/en/Terms/d/derrick_floor.aspx derrick floor]. From this console, the driller can monitor equipment, distribute power, change gears, and oversee crew activities. Additional measurement equipment and records are located in the dog house (18) or service shed. The ''dog house'' is located to the side of the rig floor and contains the ''[[geolograph]]'', a device that makes a time-based chart record of several rig functions, including the following:

* Kelly height or [[rate of penetration]] (ROP) (in ft/hr, m/hr, or min/ft)

* Kelly height or [[rate of penetration]] (ROP) (in ft/hr, m/hr, or min/ft)