Page 507 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 483

[ ]
Glossary

electrically charged ions or parts of the molecules due to loss or gain
of one or more electrons. Loss of electrons results in positive charges
producing a cation. A gain of electrons results in the formation of an
anion with negative charges. The valence of an ion is equal to the
number of charges borne by it.

Ionic. A chemical bond between atoms whereby an incomplete
electron orbit in one atom gains an electron from the other bonded
atom. This creates two ‘ions’ where one is an atom with a positive
charge (lost electrons) and the other is an atom with a negative
charge (gained electrons). Groups of atoms can also lose or gain
electrons to form ionic compounds, such as Magnesium Carbonate -
Magnesium (Mg) donates two electrons, Carbonate (CO ) gains two
3
electrons to form an ionic compound, MgCO . Some Ionic com-
3
pounds are partially covalent as one of the atoms will retain some
control over its donated electron. Ionic compounds with a low
valency (e.g., sodium chloride, NaCl) are usually soluble in water,
whereas ionic compounds with a high valency (e.g., Calcium
Carbonate, CaCO ) are not.
3

Jet Perforating. An operation similar to gun perforating except that a
shaped charge of high explosives is used to burn a hole through the
casing instead of the gun which fires a projectile in gun perforating.

Jetting. The process of kicking off a well in soft formations by using
strongly directional mud flow at the bit, oriented in the direction of
kickoff. Also known as Badgering.

Jetting. The process of periodically removing a portion of or all of
the water, mud and/or solids, from the pits, usually by means of
pumping through a jet nozzle arrangement.

Kelly or Kelly Joint. A heavy square, triangular or hexagonal pipe
which transmits torque from the rotary table to the drillstring by
means of a drive bushing.

Kelly. A heavy square or hexagonal pipe or other configuration that
works through a hole in the rotary table and rotates the drill stem.

483