A block with lead or another relatively soft material on its bottom. it is made up of drill pipe or tubing at the surface, run into a well, and set down on the object that has been lost in the well. the block is retrieved and the impression is examined. the impression is a mirror [...]

An arrangement of pulleys, or sheaves, through which drilling line is reeved and which moves up and down in the derrick or mast. see block.

The surface area overlying an oil reservoir or reservoirs. the term usually includes not only the surface area, but also the reservoir, the wells, and the production equipment.

A lease or a number of leases of adjoining tracts of land that constitute a unit of acreage sufficient to justify the expense of drilling a wildcat.

An assembly of pulleys on a common framework; in mechanics, one or more pulleys, or sheaves, mounted to rotate on a common axis. the crown block is an assembly of sheaves mounted on beams at the top of the derrick. the drilling line is reeved over the sheaves of the crown block alternately which the [...]

A part of the brake mechanism consisting of a flexible steel band lined with a material that grips a drum when tightened. on a drilling rig, the brake band acts on the flanges of the drawworks drum to control the lowering of the traveling block and its load of drill pipe, casing, or tubing.

The set of pulleys or sheaves at the top of the mast on a rig.

A rotary tool that is hung from the rotary hook and traveling block to suspend the drill stem and to permit it to rotate freely. it also provides a connection fore the rotary hose and a passageway of the flow of drilling fluid into the drill stem.

A tapered connection with 8 threads per inch. one turn equals 0.125 inches of travel. very common oilfield connection.

A lead-filled cylindrical device used to ascertain the shape of a fish.

Oil-well, casing, tubing, or drill pipe.

To thread the drilling line through the sheaves of the crown block and traveling block. one end of the line is secured to the hoisting drum and the other to the derrick substructure.

A dual-speed traveling block, which permits one elevator to pick up stands as they are broken out while the traveling bock continues to move.

A standardized measure of casing-strength properties. since most oilfield casing is of approximately the same chemistry (typically steel), and differs only in the heat treatment applied, the grading system provides for standardized strengths of casing to be manufactured and used in wellbores. the first part of the nomenclature, a letter, refers to the tensile strength. [...]

1. a reduction in the permeability of a formation caused by the invasion of water into the pores.
2. a relative permeability problem usually occurring in a gas zone. highest potential formations for water blocks are low pressure gas sands (<0.25 psi/ft pore pressure), with small pore throats (<10 microns), lower permeability (<100 md), and when [...]