| face seal |
a type of seal in which
deformation of the seal is accomplished by a plate or flat surface (face). |
| fatigue |
failure of a metal under repeated
loading. |
| fault |
a break in subsurface strata.
Often strata on one side of the fault line have been displaced (upward, downward,
or laterally) relative to their original positions. |
| feed in |
in drilling, the entrance of
formation fluids into the wellbore because hydrostatic pressure is less than formation
pressure. |
| female
connection |
a pipe or rod coupling with the
threads on the inside. |
| fermentation |
decomposition process of certain
organic substance, e.g., starch, in which a chemical change is brought by enzymes,
bacteria, or other microorganisms. Often referred to as "souring." |
| fibrous
material |
any tough, stringy material of
threadlike structure used to prevent loss of circulation or to restore circulation in
porous or fractured formations. |
| field |
an area consisting of
a single reservoir or multiple reservoirs all grouped on or related to, the same
individual geological structural feature and/or stratigraphic condition. |
| field
facility |
an installation designed for one
or more specific and limited extraction units, scrubbers, absorbers, drip points,
conventional single or multiple stage separation units, LTX low temperature separators,
and other types of separation and recovery equipment. |
| fill the
hole |
to pump drilling fluid into the
wellbore while the pipe is being withdrawn to ensure that the wellbore remains full of
fluid even though the pipe is withdrawn. Filling the hole lessens the danger of a
kick or of caving of the well or the wellbore. |
| fill-up
line |
the smaller of the side fittings
on a bell nipple, used to fill the hole when drill pipe is being removed from the well. |
| filter cake |
1. compacted solid or semisolid
material remaining on a filter after pressure filtration of mud with a standard filter
press. Thickness of the cake is reported in thirty-seconds of an inch or in
millimeters. 2. the layer of concentrated
solids from the drilling mud or cement slurry that forms on the walls of the borehole
opposite permeable formations; also call wall cake or mud cake. |
| filter
cake thickness |
a measurement of the solids
deposited on filter paper in thirty-seconds of an inch during standard 30-min API filter
test. See cake thickness.
In certain areas the filter cake thickness is a measurement of the solids deposited on
filter paper for 7-1/2-min. |
| filter loss |
the amount of fluid that can be
delivered through a permeable filter medium after being subjected to a set differential
pressure for a set length of time. |
| filter
paper |
porous unsized paper for filtering
liquids. API filtration test specifies one thickness of 9-cm filter paper Whatman
No. 50, S & S No. 576, or equivalent. |
| filter
press |
a device used in the testing of
filtration properties of drilling mud. See mud. |
| filtrate |
1. a fluid that has been passed
through a filter. 2. the liquid portion of
drilling mud that is forced into porous and permeable formations next to the borehole. |
| filtration |
the process of filtering a fluid. |
| filtration
loss |
the escape of the liquid part of a
drilling mud into permeable formations. |
| filtration
qualities |
the filtration characteristics of
a drilling mud. In general, these qualities are inverse to the thickness of the
filter cake deposited on the face of a porous medium and the amount of filtrate allowed to
escape from the drilling fluid into or through the medium. |
| filtration
rate |
see fluid
loss. |
| final circulating pressure |
the pressure at which a well is
circulated during well-killing procedures after killweight mud has filled the drill stem.
This pressure is maintained until the well is completely filled with killweight
mud. |
| fingering |
a phenomenon that often occurs in
an injection project in which the fluid being injected does not contact the entire
reservoir but bypasses sections of the reservoir fluids in a finger-like manner.
Fingering is not desirable, because portions of the reservoir are not contacted by
the injection fluid. |
| fire wall |
a wall of earth built around an
oil tank to hold the oil if the tank breaks or burns. |
| fish |
1. to recover from a well any
equipment left there during drilling operations, such as a lost bit or drill collar or
part of the drill string. 2. to remove from an older
well certain pieces of equipment (such as packers, liners, or screen liner) to allow
reconditioning of the well. |
| fishing |
the procedure of recovering lost
or stuck equipment in the wellbore. See fish. |
| fishing
assembly |
see fishing
string. |
| fishing
head |
a specialized fixture on a
downhole tool that will allow the tool to be fished out after it's used downhole.
See fish. |
| fishing
magnet |
a powerful permanent magnet
designed to recover metallic objects lost in a well. |
| fishing
neck |
a device placed on a piece of
equipment that is lowered into a wellbore so that the equipment may be retrieved by wire
line. |
| fishing
string |
an assembly of tools made up on
drill pipe that is lowered into the hole to retrieve lost or stuck equipment. Also
call a fish assembly. |
| fishing tap |
a tool that goes inside pipe lost
in a well to provide a firm grip and permit recovery of the fish. Sometimes used in
place of a spear. |
| fishing
tool |
a tool designed to recover
equipment lost in a well. |
| fishing-tool
operator |
the person (usually a service
company employee) in charge of directing fishing operations. |
| fishtail
bit |
a drilling bit with cutting edges
of hard alloys. Developed about 1900, and first used with the rotary system of
drilling, it is still useful in drilling very soft formations. Also called a drag bit. |
| fittings |
the small pipes and valves that
are used to make up a system of piping. |
| flag |
n. 1. a piece of cloth, rope or
nylon strand used to mark the wireline when swabbing or bailing. 2. an indicator of wind direction used during drilling or workover
operations where hydrogen sulfide (sour) gas may be encountered. |
| flag |
v. 1. to signal or attract
attention. 2. in swabbing or bailing, to
attach a piece of cloth to the wireline to enable the operator to estimate the position of
the swab or bailer in the well. |
| flange |
a projecting rim or edge (as on
pipe fittings and openings in pumps and vessels), usually drilled with holes to allow
bolting to other flanged fittings. |
| flange up |
1. to finish a job. 2. to use flanges to make final connections on a piping system. |
| flapper
valve |
a hinged closure mechanism
operating in a pivot manner, used to shut off tubing flow. |
| flash set |
a premature thickening or setting
of cement slurry, which makes it unpumpable. |
| flat gel |
a condition wherein the 10-minute
gel strength is substantially equal to the initial gel strength. |
| flipped |
when the opposite occurs of what
is intended in a drilling fluid. In an invert water-in-oil emulsion, the emulsion is
said to be flipped when the continuous and dispersed phases reverse. |
| float |
a long flat-bed semi-trailer. |
| float
collar |
a special coupling device inserted
one or two joints above the bottom of the casing string that contains a check valve to
permit fluid to pass downward but not upward through the casing. The float collar
prevents drilling mud from entering the casing while it is being lowered, allowing the
casing to float during its descent and thus decreasing the load on the derrick or mat.
A float collar also prevents backflow of cement during a cementing operation. |
| float shoe |
a short, heavy, cylindrical steel
section with a rounded bottom and attached to the bottom of the casing string. It
contains a check valve and functions similarly to the float collar but also serves as a
guide shoe in the casing. |
| floater |
See floating offshore drilling rig. |
| floating offshore drilling rig |
a type of mobile offshore drilling
unit that floats and is not secured to the seafloor (except for anchors). Floating
units include inland barge rigs, drill ships and ship-shaped barges, and semisubmersibles.
See mobile offshore
drilling unit. |
| flocculating
agent |
material or chemical agent that
enhances flocculation. |
| flocculation |
the coagulation of solids in a
drilling fluid, produced by special additives or by contaminants. |
| flocs |
abbreviation:
flocculates. |
| flood |
1. to drive oil from a reservoir
into a well by injecting water under pressure into the reservoir formation. See waterflooding. 2. to drown out a well with water. |
| floorman |
also called a rotary help.
See rotary helper. |
| flow a
well hard |
to let a well flow at too high a
rate. |
| flow bean |
a plug in the flow line at the
well head which has a small hole drilled through it through which oil flows, and which
keeps a well from flowing at too high a rate. |
| flow by
heads |
a well flowing oil at irregular
intervals. |
| flow chart |
a chart made by a recording meter
which shows rate of production. |
| flow
coupling |
a tubing sub made of
abrasion-resistant material and used in a tubing string where turbulent flow may cause
internal erosion. |
| flow line |
the surface pipe through which oil
travels from a well to processing equipment or to storage. |
| flow lines |
the surface pipes through which
oil travels from the well to storage. |
| flow tank |
a lease storage tank to which
produced oil is run. |
| flow test |
preliminary test to confirm flow
rate through a tool prior to going downhole. |
| flow
treater |
a single unit which acts as an oil
and gas separator, an oil heater, and an oil and water treater. |
| flow tube |
an interval device commonly found
in subsurface safety valves used to protect the tool's closure mechanism from the wellbore
media. |
| flow-line
sensor |
a device to monitor rate of fluid
from the annulus. |
| flow-line
treating |
process of separating, or breaking
down, an emulsion into oil and water in a vessel or tank on a continuous basis (i.e., no
interruption of flow of emulsion into the tank or vessel). Compare batch treating. |
| flowing
well |
a well which produces oil or gas
without any means of artificial lift. |
| flowstream |
the flow of fluids within a pipe. |
| fluid
density |
the unit weight of fluid, e.g.,
pounds per gallon. |
| fluid flow |
the state in fluid dynamics of a
fluid in motion is determined by the type of fluid (e.g., Newtonian, plastic,
pseudoplastic, dilatant); the properties of the fluid such as viscosity and density; the
geometry of the system; and the velocity. Thus, under a given set of conditions and
fluid properties, the fluid flow can be described as plug flow, laminar (called also
Newtonian, streamline, parallel, or viscous) flow, or turbulent flow. |
| fluid
injection |
injection of gases or liquids into
a reservoir to force oil toward and into producing wells. |
| fluid level |
distance between well head and
point to which fluid rises in the well. |
| fluid loss |
the unwanted migration of the
liquid part of the drilling mud or cement slurry into a formation, often minimized or
prevented by the blending of additives with the mud or cement. |
| fluid
saturation |
the amount of the pore volume of a
reservoir rock that is filled by water, oil, or gas and measured in routine core analysis. |
| fluidity |
the reciprocal of viscosity.
The measure of rate with which a fluid is continuously deformed by a shearing
stress; ease of flowing. |
| fluorescence |
instantaneous re-emission of light
of a greater wave length than that light originally absorbed. |
| flush
production |
the high rate of flow made by a
good well right after it is drilled. |
| flush-joint
casing |
a casing in which the outside
diameter of the joint is the same as the outside diameter of the casing itself. |
| flush-joint
pipe |
pipe in which the outside diameter
of the joint is the same as the outside diameter of the tube. Pipe may also be
internally flush-joint. |
| foam |
a two-phase system, similar to an
emulsion, in which the dispersed phase is a gas or air. |
| foaming
agent |
a chemical used to lighten the
water column in gas wells, in oilwells producing gas, and in drilling wells in which air
or gas is used as the drilling fluid so that the water can be forced out with the air or
gas to prevent its impeding the production or drilling rate. |
| formation |
a bed or deposit composed
throughout of substantially the same kind of rock; often a lithologic unit. Each
formation is given a name, frequently as a result of the study of the formation outcrop at
the surface and sometimes based on fossils found in the formation. |
| formation
breakdown |
an event occurring when borehole
pressure is of such magnitude that the exposed formation cannot withstand applied
pressure. |
| formation
competency |
the ability of the formations to
withstand applied pressure. Also called formation
integrity. |
| formation competency test |
a test used to determine the
amount of pressure required to cause a formation to fracture. |
| formation
damage |
the reduction of permeability in a
reservoir rock caused by the invasion of drilling fluid and treating fluids to the section
adjacent to the wellbore. Often call skin damage. |
| formation
fluid |
fluid (such as gas, oil, or water)
that exists in a subsurface rock formation. |
| formation fracture pressure |
the point at which a formation
will crack from pressure in the wellbore. |
| formation
fracturing |
a method of stimulating production
by opening new flow channels in the rock surrounding a production well. Often call a
frac job. Under extremely high hydraulic pressure, a fluid (such as distillate,
diesel fuel, crude oil, dilute hydrochloric acid, water, or kerosene) is pumped downward
through production tubing or drill pipe and forced out below a packer or between two
packers. The pressure causes cracks to open in the formation, and the fluid penetrates the
formation through the cracks. Sand grains, aluminum pellets, walnut shells, or
similar materials (propping agents) are carried in suspension by the fluid into the
cracks. When the pressure is released at the surface, the fracturing fluid returns
to the well. The cracks partially close on the pellets, leaving channels for oil to
flow around them to the well. See explosive
fracturing, hydraulic
fracturing. |
| formation
integrity |
see formation competency. |
| formation
pressure |
pressure at the bottom of a well
that is shut in. |
| formation
sensitivity |
the tendency of certain producing
formations to react adversely with invading filtrates. |
| formation
testing |
the gathering of pressure data and
fluid samples from a formation to determine its production potential before choosing a
completion method. Testing tools include formation testers and drill stem test
tools. |
| formic acid |
an organic acid, H2CO2
or HCOOH, used for acidizing oilwells. It is stronger than acetic acid but much less
corrosive than hydrofluoric or hydrochloric acid and is usually used for high-temperature
wells. |
| foundation
pile |
the first casing or conductor
string (generally with a diameter of 30 to 36 inches) set when drilling a well from an
offshore drilling rig. It prevents sloughing of the ocean-floor formations and is a
structural support for the permanent guide base and the blowout preventers. |
| fourble |
a section of drill pipe, casing,
or tubing consisting of four joints screwed together. Compare double, single,
thribble. |
| fracture
acidizing |
a procedure by which acid is
forced into a formation under pressure high enough to cause the formation to crack.
The acid acts on certain kinds of rocks, usually carbonates, to increase the permeability
of the formation. Compare matrix
acidizing. |
| fracture
gradient |
the pressure gradient (psi/ft) at
which the formation accepts whole fluid from the wellbore. |
| fracture
pressure |
the pressure at which a formation
will break down, or fracture. |
| fracturing |
application of hydraulic pressure
to the reservoir formation to create fractures through which oil or gas may move to the
well bore. |
| free point |
an area or point above the point
at which a tubular, such as drill pipe, is stuck in the wellbore. |
| free-point
indicator |
a device run on wireline into the
wellbore and inside the fishing string and fish to locate the area where a fish is stuck.
When the drill string is pulled and turned, the electromagnetic fields of free pipe
and stuck pipe differ. The free-point indicator is able to distinguish these
differences, which are registered on a metering device at the surface. |
| free water |
1. water produced with oil.
It usually settles out within five minutes when the well fluids become stationary in a
settling space within a vessel. 2. the
measured volume of water that is present in a container and that is not in suspension in
the contained liquid at observed temperature. |
| free-water knockout (FWKO) |
a vertical or horizontal vessel
into which oil or emulsion is run to allow any water not emulsified with the oil (free
water) to drop out. |
| freeze
point |
the depth in the hole at which the
tubing, casing, or drill pipe is stuck. |
| friction |
resistance to movement created
when two surfaces are in contact. When friction is present, movement between the
surfaces produces heat. |
| friction
loss |
a reduction in the pressure of a
fluid caused by its motion against an enclosed surface (such as a pipe). As the
fluid moves through the pipe, friction between the fluid and the pipe wall and within the
fluid itself creates a pressure loss. The faster the fluid moves, the greater are
the losses. |
| frost up |
icing of equipment due to the
cooling effect of expanding gas. |
| frozen up |
said of equipment of which the
components do not operate freely. |
| funnel
viscosity |
viscosity as measured by the Marsh
funnel, based on the number of second it takes for 1,000 cubic centimeters of drilling
fluid to flow through the funnel. |
| fusible
plugs |
a thermal device employed on
surface flow lines as part of an emergency shutdown. |
