Page 96 - 4714

that neither company normally keeps on hand. So, service and supply
companies provide the required tools and services to expedite the
drilling of the well. Supply companies sell expendable and
nonexpendable equipment and material to the operator and the drilling
contractor. Expendable items include drill bits, fuel, lubricants, and
drilling mud – items that are used up or worn out as the well is drilled.
Nonexpendable items include drill pipe, fire extinguishers, and
equipment that may eventually wear out and have to be replaced but
normally last a long time. Likewise, supply companies market safety
equipment, rig components, tools, computers, paint, grease, rags, and
solvents. Think of any part or commodity that a rig needs to drill a
well, and you'll find a supply company on hand to provide it.
Service companies offer special support to the drilling
operation. For example, a mud logging company monitors and records,
or logs, the content of the drilling mud as it returns from the well. The
returning mud carries cuttings and any formation fluids, such as gas or
oil, to the surface. The operator can gain knowledge about the
formations being drilled by analyzing the returning drilling fluid.
In many instances, when a well reaches a formation of interest
(usually, a formation that may contain oil or gas), the operator hires a
well logging company. A logging crew runs sophisticated instruments
into the hole. These instruments sense and record formation
properties. Computers in the field generate special graphs, called
“well logs”, for the operator to examine. Well logs help the operating
company determine whether the well will produce oil or gas.
Another service company provides casing crews. A casing
crew runs special pipe, casing, into the well to line, or case, it after the
rig drills a portion of the hole. Casing protects formations from
contamination and stabilizes the well. After the casing crew runs the
casing, another service company – a cementing company – cements
the casing in the well. Cement bonds the casing to the hole.
Most offshore rigs, and land rigs in very remote fields, require
cooking and housekeeping services, since personnel live as well as

95