| saddle bearing |
a bearing between the walking beam and the
sampson post of a pumping unit. |
| safety clamp |
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. |
| safety
factor of wire rope |
a measurement of load safety for wire rope
obtained by using the following formula: Safety Factor - B/W where: B=nominal catalog breaking strength of the wire rope, and
W = calculated total static load. Also called design
factor. |
| safety joint |
an accessory to a fishing tool, placed above
it. if the tool cannot be disengaged from the fish, the safety joint permits easy
disengagement of the string of pipe above the safety joint. Thus, part of the safety
joint and the tool attached to the fish remain in the hole and become part of the fish. |
| safety margin |
see trip
margin |
| safety release |
an emergency mechanism component enabling the
retrieval of a packer (or tubing) if stuck. |
| safety valve |
1. an automatic valve that opens or closes
when an abnormal condition occurs (e.g., a pressure relief valve on a separator that opens
if the pressure exceeds the set point, or the shutdown valve at the wellhead that closes
if the line pressure becomes too high or too low). 2. a valve installed at the top of the drill stem to prevent flow out of the
drill pipe if a kick occurs during tripping operations. |
| salt |
a compound that is formed (along with water)
by the reaction of an add with a base. A common salt (table salt) is sodium chloride
derived by combining hydrochloric add with sodium hydroxide. The result is sodium chloride
and water. Another salt is calcium sulfate, obtained when sulfuric acid is combined with
calcium hydroxide. |
| salt dome |
a dome that is caused by an intrusion of rock
salt into overlying sediments. A piercement salt dome is one that has been pushed up so
that it penetrates the overlying sediments, leaving them truncated. The formations above
the salt plug are usually arched so that they dip in all directions away from the center
of the dome, thus frequently forming traps for petroleum accumulations. |
| salt mud |
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. |
| saltwater clay |
see attapulgite |
| saltwater mud |
see salt mud. |
| saltwater flow |
an influx of formation salt water into the
wellbore |
| sample mud |
drilling fluid formulated so that it will not
alter the properties of the cuttings the fluid carries up the well. |
| sampler |
a device attached to pipeline to permit
continuous sampling of the oil, gas, or product flowing in the line. |
| samples |
1. the well cuttings obtained at designated
footage intervals during drilling. From an examination of these cuttings, the
geologist determines the type of rock and formations being drilled and estimates oil and
gas content. 2. small quantities of well
fluids obtained for analysis. |
| sand |
1. an abrasive material composed of small
quartz grains formed from the disintegration of preexisting rocks. Sand consists of
particles less than 2 millimeters and greater than 1/16 millimeter in diameter. 2. sandstone. |
| sand
consolidation |
any one of several methods by which the loose,
unconsolidated grains of a producing formation are made to adhere to prevent a well from
producing sand but to permit it to produce oil and gas. |
| sand content |
the insoluble abrasive solids content of a
drilling fluid rejected by a 200-mesh screen. usually expressed as the percentage
bulk volume of sand in a drilling fluid. This test is an elementary type in that the
retained solids are not necessarily silica and may not be altogether abrasive. For
additional information concerning the kids of solids retained on the 200-mesh screen, more
specific tests would be required. See mesh. |
| sand control |
any method by which large amounts of sand in a
sandy formation are prevented from entering the wellbore. Sand in the wellbore can
cause plugging and premature wear of well equipment. See gravel pack, sand
consolidation, screen liner. |
| sand cutter |
a device to salvage casing on a P&A job. |
| sand line |
a wireline used on drilling rigs and well
servicing rigs to operate a swab or bailer, to retrieve cores or to run logging devices.
It is usually 9/16 of an inch (15 millimeters) in diameter and several thousand
feet or meters long |
| sand line drill |
a device run on cable-tool drilling line, a
service machine, or sand line of a rotary rig to drill up tools, remove downhole debris,
and so on. |
| sand screen |
a screen joint placed opposite perforations in
sand control |
| sandstone |
a sedimentary rock composed of individual
mineral grains of rock fragments between 1/16 and 2 millimeters in diameter and cemented
together by silica, calcite, iron oxide, and so forth. Sandstone is commonly porous
and permeable and therefore a likely type of rock in which to find a petroleum reservoir. |
| sand-thickness
map |
a map that shows the thickness of subsurface
sands. See isopach map. |
| sanded up |
clogged by sand entering the well bore with
the oil. |
| satellite well |
usually a single well drilled offshore by a
mobile offshore drilling unit to produce hydrocarbons from the outer fringes of a
reservoir that cannot be produced by primary development wells drilled from a permanent
drilling structure (as a platform rig). Sometimes, several satellite wells will be drilled
to exploit marginal reservoirs and avoid the enormous expense of erecting a platform. |
| saturated
solution |
a solution that contains at a given
temperature as much of a solute as it can retain. At 68 degrees F it takes 126.5
lb/bbl salt to saturate 1 bbl of fresh water. See supersaturation. |
| saturation point |
a given point at a certain temperature and
pressure at which no more solid material will dissolve in a liquid. |
| SBHT |
abbreviation: static bottomhole
temperature |
| Schlumberger
(pronounced "slumberjay") |
one of the pioneer companies in electric well
logging, named for the French scientist who first developed the method. Today, many
companies provide logging services of all kinds. |
| scraper |
a device used to clean deposits of paraffin
from tubing or flow lines (see pig
or rabbit). |
| scratcher |
a device that is fastened to the outside of
casing to remove mud cake from the wall of a hole to condition the hole for cementing.
By rotating or moving the casing string up and down as it is being run into the
hole, the scratcher, formed of stiff wire, removes the cake so that the cement can bond
solidly to the formation. |
| screen analysis |
determination of the relative percentages of
substances, e.g., the suspended solids in a drilling fluid that pass through or are
retained on a sequence of screens of decreasing mesh size. Also called sieve
analysis. |
| screen liner |
a pipe that is perforated and often arranged
with a wire wrapping to act as a sieve to prevent or minimize the entry of sand particles
into the wellbore. Also called a screen pipe. |
| SCSSV |
abbreviation: surface-controlled subsurface
safety valve. |
| seal-bore
extension |
a tube extending the effective packer seal
bore; used where excessive tubing expansion or contraction is anticipated. |
| sealing agent |
any of various materials, such as mica flakes
or walnut hulls, that cure lost circulation. See lost circulation, lost circulation
material. |
| seal nipple
assemblies |
sealing members at the production tubing for
landing inside the packer's seal bore. |
| seal units |
extensions of the producing string with seals
to travel within a packer bore and/or extensions. |
| seawater mud |
a special class of saltwater muds in which sea
water is used as the fluid phase. |
| secondary
cementing |
any cementing operation after the primary
cementing operation. Secondary cementing includes a plug-back job, in which a plug
of cement is positioned at a specific point in the well and allowed to set. Wells
are plugged to shut off bottom water or to reduce the depth of the well for other reasons. |
| seconds API |
a unit of viscosity as measured with a Marsh
funnel according to API procedure. See API RP 13B, Marsh funnel viscosity. |
| sedimentary rock |
a rock composed of materials that were
transported to their present position by wind or water. Sandstone, shale, and limestone
are sedimentary rocks. |
| seismic data |
detailed information obtained from earth
vibration produced naturally or artificially (as in geophysical prospecting). |
| seismic survey |
an exploration method in which strong
low-frequency sound waves are generated on the surface or in the water to find subsurface
rock structures that may contain hydrocarbons. The sound waves travel through the
layers of the earth's crust; however, at formation boundaries some of the waves are
reflected back to the surface where sensitive detectors pick them up. Reflections from
shallow formations arrive at the surface sooner than reflections from deep formations, and
since the reflections are recorded, a record of the depth and configuration of the various
formations can be generated. Interpretation of the record can reveal possible
hydrocarbon-bearing formations. |
| seismograph |
a device that detects vibrations in the earth.
It is used in studying the earth's interior and in prospecting for probably
oil-bearing structures. Vibrations are created by discharging explosive in shallow
boreholes, by striking the surface with a heavy blow, or by vibrating a heavy plate in
contact with the ground. The type and velocity of the vibrations are recorded by the
seismograph indicate the general characteristics of the section of earth through which the
vibrations pass. |
| selective-set
shear |
the ability to predetermine where a tool will
set or release. |
| selective shear |
the ability to determine selectively, by the
quantity of shear screws or pins, when a tool will set |
| self-elevating
drilling unit |
an offshore drilling rig, usually with a large
hull. It has a mat or legs that are lowered to the sea-floor and a main deck that is
raised above the surface of the water to a distance where it will not be affected by the
waves. Also called a jackup drilling
rig. |
| self-potential
(SP) |
see spontaneous
potential. |
| semi-expendable
gun |
a perforating gun that consists of a metallic
strip on which encapsulated shaped charges are mounted. After the gun is fire, the
strip is retrieved. See gun-perforate. |
| semisubmersible |
See semisubmersible
drilling rig. |
| semisubmersible
drilling rig |
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. |
| separation sleeve |
a sleeve designed to shut off
tubing-to-annulus flow should the sliding sleeve become inoperative. |
| separator |
a cylindrical or spherical vessel used to
isolate the components in mixed streams of fluids. See oil and gas separator. |
| sequestration |
the formation of stable calcium, magnesium,
iron complex by treating water or mud with certain complex phosphates. |
| service well |
a Well drilled or completed for the purpose of
supporting production in an existing field. |
| set back |
to place stands of drill pipe and drill
collars in a vertical position to one side of the rotary table in the derrick or mast of a
drilling or workover rig. Compare lay down
pipe. |
| set casing |
to run and cement casing at a certain depth in
the wellbore. Sometimes called set pipe. |
| set-down tool |
a compression-set packer |
| setting tool |
a tool used to set drillable or permanent
tools, such as packers, retainers, plugs; can be mechanical, electric, or hydraulic. |
| settled
production |
a loose term used to described oil fields that
produce at nearly the same rate form day to day. |
| settling pit |
see shaker
tank |
| separator |
a cylindrical or spherical vessel used to
isolate the components in streams of mixed fluids. See oil and gas separator. |
| shake out |
to spin a sample of oil at high speed to
determine its BS&W content. |
| shaker pit |
see shaker
tank |
| shaker tank |
the mud tank adjacent to the shake shaker,
usually the first tank in to which mud flows after returning from the hole. Also
called a shaker pit. |
| shale |
a fine-grained sedimentary rock composed
mostly of consolidated clay or mud. Shale is the most frequently occurring
sedimentary rock. |
| shale shaker |
a vibrating screen used to remove cuttings
from the circulating fluid in rotary drilling operations. The size of the openings
in the screen should be carefully selected to be the smallest size possible that will
allow 100 percent flow of the fluid. Also called a shaker. |
| shaped charge |
a relatively small container of high explosive
that is loaded into a perforating gun. On detonation, the charge releases a small,
high-velocity stream of particles (a jet) that penetrates the casing, cement, and
formation. See perforating gun. |
| sharpshooter |
a long narrow shovel used in ditch digging. |
| shear |
action or stress that results from applied
forces and that causes or tends to cause two adjoining portions of a substance or body to
slide relative to each other in a direction parallel to their plane of contact. |
| shearometer |
an instrument used to measure the shear
strength, or gel strength, of a drilling fluid. See gel
strength |
| shear ram |
the component in a blowout preventer that
cuts, or shears, through drill pipe and forms a seal against well pressure. Shear
rams are used in floating offshore drilling operations to provide a quick method of moving
the rig away from the hole when there is no time to trip the drill stem out of the hole. |
| shear ram
preventer |
a blowout preventer that uses shear rams as
closing elements. |
| shear strength |
see gel strength |
| sheave |
a grooved pulley. |
| shoe |
a device placed at the end of or beneath an
object for various purposes (e.g., casing shoe guide shoe). |
| shoot |
1. to explode nitroglycerine or other high
explosives in a hole to shatter the rock and increase the flow of oil, now largely
replaced by formation fracturing. 2. in
seismographic work, to discharge explosives to create vibrations in the earth's
cruse. See seismograph. |
| short way |
the displacing of wellbore fluids from the
annulus up the tubing |
| shot |
1. a charge of high explosive, usually
nitroglycerine, detonated in a well to shatter the formation and expedite the recovery of
oil. Shooting has been almost completely replaced by formation fracturing and acid
treatments. 2. a point at which a photograph is made
in a single-shot survey. See directional
survey. |
| show |
the appearance of oil or gas n cuttings,
samples, or cores from a drilling well |
| shut in |
to close values on a well so that it stops
producing; said of a well on which the valves are closed. |
| shut-in bottomhole pressure (SIBHP) |
the pressure at the bottom of a well when the
surface valves on the well are completely closed. It is caused by formation fluids at the
bottom of the well. |
| shut-in
bottomhole pressure test |
a bottomhole pressure test that measures
pressure after the well has been shut in for a specified period of time. See
bottomhole pressure test. |
| shut-in
casing pressure (SICP) |
pressure of the annular fluid on the casing at
the surface when a well is shut in |
| shut-in
drill pipe pressure (SIDPP) |
pressure of the annular fluid on the casing at
the surface when a well is shut in. |
| shut-in pressure |
pressure at the top of a well when it is shut
in. |
