05.07.2009

Drillships are exactly as they sound: ships designed to carry out drilling operations. These boats are specially designed to carry drilling platforms out to deep-sea locations. A typical drillship will have, in addition to all of the equipment normally found on a large ocean ship, a drilling platform and derrick located on the middle of its deck. In addition, drillships contain a hole (or ‘moonpool’) extending right through the ship down through the hull, which allow for the drill string to extend through the boat, down into the water. Drillships are often used to drill in very deep water, which can often be quite turbulent. Drillships use what is known as ‘dynamic positioning’ systems. Drillships are equipped with electric motors on the underside of the ships hull, capable of propelling the ship in any direction. These motors are integrated into the ship’s computer system, which uses satellite positioning technology, in conjunction with sensors located on the drilling template, to ensure that the ship is directly above the drill site at all times.

For instance when a country demands that international oil and gas companies active in the country direct a part of their output to the local market rather than to exports

A pipe through which fluids can be discharged, such as for the discharge of water after it has been used to cool a power station into the sea

In well cementing, the fluid, usually drilling mud or salt water, that is pumped into the well after the cement is pumped into it to force the cement out of the casing and into the annulus.

Clause which demands that the lessee commence drilling operations by a certain date or pay rental, failing which the lease would terminate. Drill, pay or forfeit. This clause sometimes enables a lessee to defer drilling

Intentional deviation of a wellbore from the vertical. Although wellbores are normally drilled vertically, it is sometimes necessary or advantageous to drill at an angle from the vertical. Controlled directional drilling makes it possible to reach subsurface areas laterally remote from the point where the bit enters the earth

Two lengths or joints of pipe joined together

These are features one can see on seismic that are caused by the seismic wave passing through a gas or oil filled section rather than a water filled section. Some DHI’s can also be caused by other geological features which have nothing to do with oil or gas, such as dykes or sills that will generate really good bright anomalies, as can water, wet gravels and anhydrites

A well, often a depleted oil or gas well, into which waste fluids can be injected for safe disposal.

Well used for disposal of saltwater into an underground formation