Gas containing an appreciable quantity of hydrogen sulfide and/or mercaptans.

1.

A drilling mud in which the water has an appreciable amount of salt (usually sodium or calcium chloride) dissolved in it.

Also called saltwater mud or saline drilling fluid.

2.

A mud with a resistivity less than or equal to the formation water resistivity.

A spring-actuated metal band or ring(ferrule) used to expand a liner patch when making casing repairs.

See liner patch.

A conducting ring that gives current to or receives current from the brushes in a generator or motor.

A smaller well.

Thought to be cheaper to drill, but much more expensive to repair or workover and often limited on fluid flow rate potential.

A short, threaded piece of pipe used to adapt parts of the drilling string that cannot otherwise be screwed together because of differences in thread size or design.

A sub (i.e., a substitute) may also perform a special function.

Lifting subs are used with drill collars to provide a shoulder to fit the drill pipe elevators; a kelly saver sub is placed between the drill pipe and the kelly to prevent excessive thread wear of the kelly and drill pipe threads, a bent sub is used when drilling a directional hole.

A mud with the oil component replaced by a lower toxicity oil such as mineral oil.

A floating offshore drilling unit that has pontoons and columns that when flooded cause the unit to submerge in the water to a predetermined depth.

Living quarters, storage space, and so forth a reassembled on the deck.

Semisubmersible rigs are either self-propelled or towed to a drilling site and either anchored or dynamically positioned over the site, or both.

In shallow water, some semisubmersibles can be ballasted to rest on the seabed.

Semisubmersibles are more stable than drill ships and ship-shaped barges and are used extensively to drill wildcat wells in rough waters such as the north sea.

Two types of semisubmersible rigs are the bottle-type semisubmersible and the column-stabilized semisubmersible.

See floating offshore drilling rig.

A vertical pipe rising along the side of the derrick or mast, which joins the discharge line leading from the mud pump to the rotary hose and through which mud is pumped going into the hole.

The amount of heat required to cause a unit increase in temperature in a unit mass of a substance, expressed as numerically equal to the number of calories needed to raise the temperature of 1 gram of a substance by 1 degree c.

The pumping of a substance such as oil into an interval in the well.

1.

The process of raising the drill stem out of the wellbore when the well is shut in on a kick.

2.

The process of removing tubing from the well under pressure.

The old term for a mud pit.

See mud pit.

A device used to suspend a rod string after the pump has been spaced or when the weight of the rod string must be taken off the pumping equipment.

A sliding-sleeve ported casing section used in stage cementing.