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The Chemistry and Technology of Petroleum
determined. Once the legal issues have been settled, the crew goes about preparing the land, which
is essential and involves the following steps:
1. The land is cleared and leveled, and access roads may be built.
2. Because water is used in drilling, there must be a source of water nearby. If there is no
natural source, a water-well is necessary.
3. A reserve pit, which is used to dispose of rock cuttings and drilling mud during the drilling process, and line it with plastic to protect the environment, is created. If the site is an
ecologically sensitive area, such as a marsh or wilderness, then the cuttings and mud must
be disposed offsite such as trucked away instead of placed in a pit.
Once the land has been prepared, several holes must be dug to make way for the rig and the
main hole. A rectangular pit (a cellar) is dug around the location of the actual drilling hole. The
cellar provides a workspace around the hole, for the workers and drilling accessories. The crew then
begins drilling the main hole, often with a small drill truck rather than the main rig. The first part
of the hole is larger and shallower than the main portion, and is lined with a large-diameter conductor pipe. Additional holes are dug off to the side to temporarily store equipment after which the rig
equipment can be brought in and set up.
6.3.2 drIllIng eQuIPment
Depending upon the remoteness of the drill site and its access, equipment may be transported to the
site by truck, helicopter, or barge. Some rigs are built on ships or barges for work on inland water
where there is no foundation to support a rig (as in marshes or lakes). Once the equipment is at the
site, the rig is set up (Figure 6.1). The anatomy of a drilling rig, although simple in a schematic representation, is in reality, quite complex and consists of the following systems:
1. Power system: (1) large diesel engines to provide the main source of power and (2) electrical generators powered by the diesel engines to provide electrical power.
2. Mechanical system that is driven by electric motors: (1) hoisting system that is used for lifting heavy loads and consists of a mechanical winch (draw works) with a large steel cable
spool, a block-and-tackle pulley, and a receiving storage reel for the cable and (2) turntable
that is part of the drilling apparatus.
3. Rotating equipment (used for rotary drilling): (1) swivel, that is, a large handle, which
holds the weight of the drill string, allows the string to rotate and makes a pressure-tight
seal on the hole; (2) kelly, that is, a four- or six-sided pipe that transfers rotary motion to the
turntable and drill string; (3) turntable or rotary table—drives the rotating motion using
power from electric motors; (4) drill string that consists of drill pipe (connected sections of
about 30 ft/10 m) and drill collars (larger diameter, heavier pipe that fits around the drill
pipe and places weight on the drill bit); and (5) drill bit(s) at the end of the drill that actually
cuts up the rock and comes in many shapes and materials (tungsten carbide steel, diamond)
that are specialized for various drilling tasks and rock formations.
4. Casing: large-diameter concrete pipe that lines the drill hole, prevents the hole from collapsing, and allows drilling mud to circulate (Figure 6.2).
5. Circulation system: pumps drilling mud (mixture of water, clay, weighting material and
chemicals, used to lift rock cuttings from the drill bit to the surface) under pressure through
the kelly, rotary table, drill pipes, and drill collars (Figure 6.3): (1) pump—sucks mud from
the mud pits and pumps it to the drilling apparatus, (2) pipes and hoses—connect pump to
drilling apparatus, (3) mud-return line—returns mud from hole, (4) shale shaker—shaker/
sieve that separates rock cuttings from the mud, (5) shale slide—conveys cuttings to the
reserve pit, (6) reserve pit—collects rock cuttings separated from the mud, (7) mud pits,
The Chemistry and Technology of Petroleum
determined. Once the legal issues have been settled, the crew goes about preparing the land, which
is essential and involves the following steps:
1. The land is cleared and leveled, and access roads may be built.
2. Because water is used in drilling, there must be a source of water nearby. If there is no
natural source, a water-well is necessary.
3. A reserve pit, which is used to dispose of rock cuttings and drilling mud during the drilling process, and line it with plastic to protect the environment, is created. If the site is an
ecologically sensitive area, such as a marsh or wilderness, then the cuttings and mud must
be disposed offsite such as trucked away instead of placed in a pit.
Once the land has been prepared, several holes must be dug to make way for the rig and the
main hole. A rectangular pit (a cellar) is dug around the location of the actual drilling hole. The
cellar provides a workspace around the hole, for the workers and drilling accessories. The crew then
begins drilling the main hole, often with a small drill truck rather than the main rig. The first part
of the hole is larger and shallower than the main portion, and is lined with a large-diameter conductor pipe. Additional holes are dug off to the side to temporarily store equipment after which the rig
equipment can be brought in and set up.
6.3.2 drIllIng eQuIPment
Depending upon the remoteness of the drill site and its access, equipment may be transported to the
site by truck, helicopter, or barge. Some rigs are built on ships or barges for work on inland water
where there is no foundation to support a rig (as in marshes or lakes). Once the equipment is at the
site, the rig is set up (Figure 6.1). The anatomy of a drilling rig, although simple in a schematic representation, is in reality, quite complex and consists of the following systems:
1. Power system: (1) large diesel engines to provide the main source of power and (2) electrical generators powered by the diesel engines to provide electrical power.
2. Mechanical system that is driven by electric motors: (1) hoisting system that is used for lifting heavy loads and consists of a mechanical winch (draw works) with a large steel cable
spool, a block-and-tackle pulley, and a receiving storage reel for the cable and (2) turntable
that is part of the drilling apparatus.
3. Rotating equipment (used for rotary drilling): (1) swivel, that is, a large handle, which
holds the weight of the drill string, allows the string to rotate and makes a pressure-tight
seal on the hole; (2) kelly, that is, a four- or six-sided pipe that transfers rotary motion to the
turntable and drill string; (3) turntable or rotary table—drives the rotating motion using
power from electric motors; (4) drill string that consists of drill pipe (connected sections of
about 30 ft/10 m) and drill collars (larger diameter, heavier pipe that fits around the drill
pipe and places weight on the drill bit); and (5) drill bit(s) at the end of the drill that actually
cuts up the rock and comes in many shapes and materials (tungsten carbide steel, diamond)
that are specialized for various drilling tasks and rock formations.
4. Casing: large-diameter concrete pipe that lines the drill hole, prevents the hole from collapsing, and allows drilling mud to circulate (Figure 6.2).
5. Circulation system: pumps drilling mud (mixture of water, clay, weighting material and
chemicals, used to lift rock cuttings from the drill bit to the surface) under pressure through
the kelly, rotary table, drill pipes, and drill collars (Figure 6.3): (1) pump—sucks mud from
the mud pits and pumps it to the drilling apparatus, (2) pipes and hoses—connect pump to
drilling apparatus, (3) mud-return line—returns mud from hole, (4) shale shaker—shaker/
sieve that separates rock cuttings from the mud, (5) shale slide—conveys cuttings to the
reserve pit, (6) reserve pit—collects rock cuttings separated from the mud, (7) mud pits,