INTERTEK PERFORMANCE WELL CONTROL GLOSSARY

TERM DEFINITION
Accumulator The accumulator is a hydraulic system used to store energy to actuate
hydraulically-operated equipment, including the annular preventer, ram
preventers, and remotely-controlled valves.
Annular preventer Annular preventers have a doughnut shaped elastic element that is designed
to seal around any shape or size of pipe, and to close on an open hole. An
important function of annular preventers is to contain pressure within the
preventer while stripping the drill string in or out of a closed-in well.
Artesian flow Artesian flow in a well can result in abnormal formation pressure due to
fluids moving from one elevation to discharge at a lower elevation.
Background gas Background gas is gas that is liberated or released into the wellbore as the
drill bit penetrates through new formation. The background gas should be
monitored to possibly identify increasing formation pressure.
Barrier (combination) A combination barrier is a combination of fluid and mechanical barriers.
Barrier (controllable) A controllable barrier is a barrier that can be opened and closed.
Barrier (fluid) A fluid barrier is a barrier that uses hydrostatic pressure.
Barrier (mechanical) A mechanical barrier is a barrier that can be actuated.
Barrier (primary element) A well barrier primary element is the first component that prevents flow
from a source.
Barrier (primary) During drilling operations, the primary barrier is hydrostatic pressure that is
greater than or equal to the pressure of the formation.
Barrier (secondary A well barrier is the second component that prevents flow from a source.
element)
Barrier (secondary) During drilling operations, the secondary barrier is the blowout preventer
(BOP).
Barrier element A barrier element is a component part of a well, designed to prevent fluids
or gases from flowing unintentionally into the wellbore, from one formation
into another formation or from escaping at the surface.
Barrier envelope The well barrier envelope is a combination of a minimum of one primary
and one secondary well barrier elements that together constitute a method
of containment of fluids within a well.
Barrier envelope The well barrier envelope philosophy is to ensure that the well has at least
philosophy two independent, tested barriers working in combination to prevent the
unintended flow of formation fluids.
Blowout preventer (BOP) The blowout preventer (BOP) is a large valve at the top of a well that can be
closed in situations when there is a loss of control of the formation fluids.
BOPs come in a variety of styles, sizes and pressure ratings. The BOP
provides secondary well control during drilling operations.
Blowout preventer (BOP) The BOP control system provides the means to individually close and open
control system each BOP and valve in emergencies. The BOP control system can be used
when the primary rig power may not be available.

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BOP control pod The control pod is an assembly of hydraulically or electrically operated
valves and regulators used to direct hydraulic fluid to operate the BOP
equipment. Each pod contains open sub-plate mounted (SPM) valves and
close SPM valves for each function on the subsea BOP. Once actuated, the
hydraulic fluid from the active pod is directed to a function using a shuttle
valve. SPM valves are vented when not activated.
Bottom hole pressure Bottom hole pressure is the pressure at the bottom of the hole. It is
calculated from the true vertical depth and fluid densities in the wellbore.
Components of bottom hole pressure include: true vertical depth,
hydrostatic pressure, mud density, circulating pressures and shut-in
pressures.
Bullheading Bullheading is a well control method that may be used in certain
circumstances during drilling operations to pump an influx out of the
wellbore and back into the formation. Bullheading is typically used when
normal circulation is not possible and using the volumetric method is not
feasible.
Cementing operations Cementing operations are used in the completion of oil and gas wells to
isolate the wellbore, prevent casing failure, and keep wellbore fluids from
contaminating freshwater aquifers. Failure of the cement operation can lead
to annular fluid movement between zones and abnormally high annular
pressures. This abnormally high pressure can burst the outer casing or
collapse the inner casing.
Choke manifold The primary purpose of the choke is to apply back pressure during a well
control event. The choke manifold is used to direct flow from the wellhead
to the mud/gas separator, flare lines or away from the rig.
The choke manifold provides safety and flexibility when circulating out a
kick.
Christmas tree The christmas tree is an assembly of valves, fittings, chokes, and gauges
used to monitor and control producing, injection, and inactive wells. The
Christmas tree is assembled at the top of the well. During the production
stage, the christmas tree and wellhead are considered as barriers to flow.
Circulating pressure Circulating pressure is the sum of all the friction pressure losses in the
circulating system flow path. Pressures losses during circulation are due to
resistance from the friction of the fluid against the pipe and other
equipment in the circulating system. Factors that affect circulation pressure
losses include the dimensions of the system, fluid flow rate and properties
of the fluid, like density.
Cognitive biases ‘Cognitive biases’ is a term used to describe our tendency to think in certain
ways, which over time develop into mental shortcuts we use to make quick
decisions, however sometimes these mental shortcuts can lead to errors in
judgment.
Connection gas Connection gas is the small amount of gas that enters a well while the mud
pumps are stopped to make a connection. The gas is then circulated to the
surface and identified by a significant increase or spike. Appropriate actions
if connection gas is observed may include increasing the mud density,
minimizing the time the pumps are off during connections or reducing the

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 TERM DEFINITION
rate of penetration to ensure only one slug of connection gas is in the hole
at a time.
Dead man system (DMS) The dead man system (DMS) is used to to secure the well in the event of a
parted riser caused by a drift-off or drive-off of a dynamical positioning (DP)
vessel. The dynamic positioning system will auto-sense a drive off or drift off
and automatically activate the DMS, hence the name “dead man”. Battery
power provides the electrical power and signal, and the subsea
accumulators provide the hydraulic fluid power.
Decision making Decision making is the process you use to choose a course of action among
several alternate possibilities to meet the needs of a situation. Components
of decision making include identifying and assessing the options related to a
problem, selecting an option from your alternatives and communicating it to
others, and implementing and reviewing the outcomes of the decision.
Diverter Diverters and diverting systems are used to direct gas away from the rig
when gas is encountered. Diverters are used during the first phase of
drilling, called 'top hole' or 'shallow gas‘ drilling, to control the direction of
flow for an influx. Diverters are only good for short-term usage, and are
subject to wear and erosion.
Driller’s method The Driller’s method is a common method of killing a well using the
circulating system to maintain constant bottom hole pressure throughout
the procedure. The Driller’s method requires two circulations to kill the well.
The first circulation removes the influx using the existing mud density at the
time of the kick. The second circulation kills the well with kill weight fluid.
Equivalent circulating Equivalent circulating density (ECD) is the effective density combining the
density (ECD) annular pressure drop and the current mud density. Bottom hole circulating
pressure (BHCP) can be expressed in pounds per gallon (ppg). When this
pressure is expressed in pounds per gallon, it can be referred to as the
equivalent circulating density.
Final circulating pressure The final circulating pressure (FCP) is a calculation used during well control
(FCP) operations. The final circulating pressure is the drill string pressure required
to circulate at the selected kill-rate adjusted for increase in kill drilling fluid
density over the original drilling fluid density. It is used from the time kill
drilling fluid reaches the bottom of the drill string until kill operations are
completed or a change in either kill drilling fluid density or kill-rate is
effected.
Flow back fingerprinting Fingerprinting is the comparison and analysis of successive flow back
profiles measured over several down cycles. Flow back describes the return
of some drilling fluids to the mud pits during connections and other
operations when the pumps are turned off. Fingerprinting helps crews
recognize the difference between normal well behavior and a potential kick
indicator.
Flow check A flow check is a test to determine if the well is flowing by monitoring the
well for flow for a specified period of time.
Force, area and pressure Pressure is equal to the force exerted by the weight of an object divided by
the area the force is acting upon.
Force = Pressure x Area
Pressure = Force ÷ Area

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Formation integrity test A formation integrity test (FIT) is used to test a formation to a pre-
(FIT) determined value; the formation is not broken down or fractured. The test
is performed to a specified equivalent mud weight.
Formation pressure Formation pressure gradient is the rate of change in formation fluid
gradient pressure with depth.

Fracture pressure Fracture pressure is the amount of pressure required to permanently

deform (break or crack) the rock structure in a formation. Too much
pressure applied to a formation can cause loss of wellbore integrity,
formation damage, groundwater contamination or equipment damage.
Gas behavior When the pressure of a gas changes, the volume will also change. If the
pressure increases, the volume will decrease and, conversely, if the pressure
decreases the volume will increase. This relationship is usually expressed as
P1 x V1 = P2 x V2. (P1 is the original gas pressure, V1 is the original gas
volume, and P2 and V2 are the new gas pressure and new gas volume.)
Gas cap A gas cap is a source of abnormal pressure where a volume of gas exists at
the top of a permeable layer. The permeable layer can contain not only the
gas, but possibly oil and/or water, with the two fluids separating according
to density. A gas cap is often the driving mechanism for the production of
underlying oil. The reason for the abnormal pressure is the difference in
natural hydrostatic pressures.
Gas cut mud Gas cut mud is a drilling fluid that has gas bubbles in it. When drilling a gas
bearing formation, the mud weight will be gas cut due to the gas breaking
out of the pore space of the cuttings near the surface. The severity of the
influx will depend on the penetration rate, porosity and permeability, and is
independent of mud weight. The importance attached to gas cutting is that
gas is entering the wellbore in small quantities, which calls for caution.
Degassing is necessary to ensure that good mud is being pumped back into
the hole to prevent the percentage of gas from increasing with each
circulation, which would allow greater and greater bottom hole hydrostatic
pressure reductions.
Gas cutting alone does not indicate the well is kicking, unless it is associated
with pit gain. Allowing the well to belch over the nipple could cause
reduction in hydrostatic pressure to the point that the formation would start
flowing, resulting in a kick.
Hard shut-in procedure A hard shut-in is to close in a well using a BOP with the choke or choke line
valve closed. The type of shut-in used depends on company policy,
procedures and the well being drilled.
High pressure, high High pressure, high temperature (HPHT) drilling is more common as drilling
temperature (HPHT) technology advances. Understanding mud behavior in HPHT conditions is
drilling very important because of its impact on the bottom hole pressure and
downhole conditions. The kick detection methods used in HPHT wells is also
more challenging due to the effects of compressibility and temperature,
which increase the flow back.
Hydrostatic pressure Hydrostatic pressure is the pressure exerted by a static column of fluid, and
is affected by the density of the fluid and the true vertical depth.

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 TERM DEFINITION
HP = Fluid weightppg x 0.052 x True vertical depthft
HP = Gradientpsi/ft x True vertical depthft
Inflow testing The inflow test, also known as a negative pressure test, is the opposite of a
positive pressure test. The test reduces the pressure inside the well to a
level below the pressure outside the wellbore; the well is then monitored to
determine whether any hydrocarbons from the formation flow into the well.
The purpose of the negative pressure test is to ensure that when hydrostatic
pressure of the fluid column in the well is removed the barrier envelope will
prevent formation fluids from entering the wellbore.
Influx An influx is the flow of formation fluid into the wellbore. The term influx is a
synonym of a kick.
Initial circulating pressure The initial circulating pressure (ICP) is a calculation used during well control
(ICP) operations. The initial circulating pressure is the drill pipe pressure required
to circulate initially at the selected kill-rate while holding casing pressure at
the closed-in value. The ICP is equal to kill-rate circulating pressure plus the
shut-in drill pipe pressure.
Inside BOPs, full opening Inside BOPs, full opening safety valves and float valves are used to contain
safety valves & float formation pressure or to avoid back flow up the drill string.
valves

Kick A kick is an unintended flow of formation fluids into the wellbore. Most
kicks are unintentional and avoidable by maintaining mud to balance
formation pressure, maintain awareness and understanding of operations,
evaluating cuttings, monitoring pit levels, setting alarms, using the trip tank
and trip sheets, and monitoring the weight indicator and pump pressure
gauges.
Kick indicators Kick indicators demonstrate that a positive pressure situation exists in the
well. Kick indicators include an increase in the flow return rate while drilling,
the well flows with the pumps off, the well begins to flow while tripping,
gain in the trip tank volume when tripping or gain in the pit volume when
drilling.
Kick warning signs Kick warning signs suggest that the well may be about to kick. Warning signs
signal that formation pressure is increasing or that drilling has entered an
abnormally pressured formation. Kick warning signs include drilling breaks,
changes in mud properties, torque and drag, changes in the shape and size
of cuttings, improper fill during trips, and increasing background gas.
Kill sheet A kill sheet is a calculation tool designed to help personnel determine the
required pressures on the drill pipe during convention operations when the
well has experienced an influx. A kill sheet has two purposes: 1) It provides a
current record of pre-kick data and calculations for the total active fluid
system volume, including the strokes for one complete circulation down the
drill string and up the annulus. 2) After an influx has occurred, the kill sheet
is used to determine the required circulating pressures to keep the bottom
hole pressure constant when circulating out a kick and pumping the kill
weight mud.
Killing a well Killing a well is a term used to describe the process of safely circulating an
influx out of the wellbore and restoring primary well control.

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 TERM DEFINITION
Leak-off test (LOT) A leak-off test (LOT) is used to determine the fracture pressure of a
formation. The test is performed to the leak-off value, which is used as the
formation fracture value. The test may also indicate the integrity of the
casing and the quality of the cement job.
Lower marine riser The lower marine riser package (LMRP) provides an interface with the
package (LMRP) subsea BOP stack. The LMRP is the topmost component of the complete
subsea BOP package. Its key components include the annular BOP, a
connector to the main BOP stack, a flexible joint, choke and kill lines,
accumulators, subsea control modules, and riser boost line and valves.
Lubricate and bleed Lubricate and bleed is a well control method used to remove an influx when
it reaches the surface, typically after the volumetric method has been used.
During the lube and bleed procedure, kill weight mud (KWM) is pumped into
the wellbore and falls through the gas, then the gas is bled off under
controlled, calculated conditions and the process is repeated until the influx
is removed.
Maximum allowable MAMW is the maximum allowable mud weight, which is the formation
mud weight (MAMW) breakdown pressure represented as a fluid density.

Maximum allowable MAASP is the maximum allowable annular surface pressure that, when
annular surface pressure exceeded, would result in formation breakdown at the weakest point in the
(MAASP) well. Generally, the weakest point in the well is the highest point in the
open hole section – the casing shoe.
Maximum anticipated The maximum anticipated surface pressure (MASP) is the highest pressure
surface pressure (MASP) expected to occur at the surface of the well.
Mud return indicator The mud return indicator is a device placed in the flow line that indicates
the flow rate. The mud return indicator signals a change in flow rate, which
is a primary kick indicator.
Mud/gas separator A mud/gas separator is a device used to separate dangerous gases from the
mud returning from the well. A gas separator removes the free gas from the
mud returning to the well but is only used for well control situations. The
mud/gas separator has the potential for ‘blowthrough’ if the pressure in the
mud gas separator exceeds the hydrostatic pressure provided by the mud
leg.
Non-technical skills Non-technical skills is a term used to describe the generic skills that support
and enhance your technical skills. Non-technical skills include your ability to
take in information, your alertness and attention to detail, how you make
decisions, and how you communicate and interact with other people.

Overburden Overburden is the strata or layers that lie above a given formation. The
overburden exerts pressure on a formation at a given depth due to the total
weight of the rock and fluids above that depth.
Permeability Permeability is the measure of the ability of a fluid to move through the rock
matrix. The higher the permeability, the faster that the fluid will flow.
Porosity Porosity is the measure of the space between the solid grains in a rock. The
higher the porosity, the more fluid that is available.
Pressure (abnormal) Abnormal pressure is pressure greater than the normal pressure.

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 TERM DEFINITION
Pressure (normal) Normal pressure is the hydrostatic pressure of a column of water extending
from the surface to the subsurface formation of interest.
Pressure (subnormal) Subnormal pressure is pressure less than the normal pressure.
Primary well control During drilling operations, primary well control is the use of hydrostatic
pressure greater than or equal to the pressure of the formation to prevent
the unintended flow of formation fluids into the wellbore.
Ram (blind) Blind rams are designed to seal against open hole.
Ram (blind/shear) Blind/shear rams are designed to shear some sizes of pipe or tubing, and
then provide a seal on the resulting open hole.
Ram (pipe type) Standard pipe rams are designed to close around a specific size of drill string
or tubing.
Ram (variable bore pipe Variable bore pipe rams are designed to close around various size ranges of
type) drill string or tubing.
Ram type preventer Ram type preventers are designed to extend to the center of the wellbore to
restrict flow. Different rams can seal against the drill string, tubing, casing
or open hole, or can cut through pipe or tubing to shut in the well.
Remote operated vessel A remote operated vessel (ROV) is designed to provides the arms and eyes
(ROV) below the water, using cameras and manipulators, in support of the subsea
drilling operations. The subsea BOP is equipped with control panels for live
intervention with the BOP functions using the ROV.
Risk management Risk management is courses of action used to control the causes and
consequences associated with potential hazardous events. Risk is managed
using policies and procedures, people, and equipment and systems. The
greater the likelihood and severity of a well control event, the greater the
risk (Risk = Likelihood x Severity).
Rock matrix Rock matrix is a material in which fine grain materials are embedded.
For example: crystals, fossils and mineral veins can surround larger grains in
a rock.
Salt formation Salt formations can serve as a sealing mechanism. When salt is deposited
and buried, it forms an impermeable barrier against natural fluid upward
migration. But when salt is exposed to extreme pressure and temperature it
becomes pseudo-plastic in nature and offers little support to the overlying
formations. Consequently, the salt formation transmits much of the
overburden to underlying permeable formations.
Secondary well control During drilling operations, secondary well control is the use of the blowout
preventer and a column of fluid to prevent the unintended flow of
formation fluids into the wellbore.
Sedimentation Sedimentation is the deposition of sediment that is transported by moving
water. The deposited sediments build up in layers. The weight of the
sediments on top apply pressure to the sediments on the bottom. This is
called compaction. The water is squeezed out from the rock, and crystals of
different salts form. The crystals form a glue that binds the sediments
together. This process is called cementation. These processes form
sedimentary rock over millions of years.

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 TERM DEFINITION
Shallow hole kick A shallow hole kick is a kick that occurs while drilling in deep water when no
protective casing is set, or if an influx leaves the wellbore due to formation
fracture. Shallow gas is a pocket of gas space that is abnormally pressured
and occurs at a shallow depth. A shallow hole kick can occur during top hole
drilling operations without a riser and can result in severe well control and
safety problems for both the drilling rig and for personnel. A shallow hole
kick can result in a gas blowout in open water, producing a cone of low
density water and a discharge of highly flammable gas. Gas plumes beneath
a floating rig can cause a loss of buoyancy. This loss decreases with
increasing water depth. Fire will be a major threat if the gas cloud were to
immediately surround the rig.
Shut-in casing pressure The shut-in casing pressure (SIP) is the is the surface force exerted in the
(SICP) casing at the top of the wellbore when the well is shut-in. The SICP reflects
the difference between the formation pressure and the hydrostatic pressure
in the annulus.
Shut-in drill pipe pressure The shut-in drill pipe pressure (SIDPP) is the surface force exerted in the drill
(SIDPP) pipe at the top of the wellbore when the well is shut-in. The SIDPP reflects
the difference between the formation pressure and the hydrostatic pressure
in the drill string.
Shut-in procedures Shut-in procedures are immediately implemented when any positive
indications of a kick are observed, or a flow check shows that the well is
flowing. It is the driller's responsibility to shut-in the well as quickly as
possible to minimize the kick. The purposes of the shut-in procedure are to
stop more influx from entering the wellbore and to take pressure readings
that will be used for kill calculations.
Side outlet valves Side outlet valves route returns from the well to the choke manifold. Side
outlet gate valves placed on the blowout preventer stack are part of the
choke or kill lines and should have internal diameters at least equal to the
bore of the choke and kill lines. These valves are either manually or
hydraulically operated and are an integral part of the BOP system, designed
to rapidly shut off hazardous flow in the event of choke manifold equipment
failure.
Situational awareness Situational awareness is a term used to describe how we assess what is
occurring around us. Situational awareness put simply is, “knowing what is
going on around you”. Components of situational awareness include
gathering information from the world around you, understanding possible
risk by interpreting the information you collected, and anticipating what
might happen by thinking ahead about how the situation is likely to
progress.
Slow circulating rate The slow circulating rate pressure (SCRP) is the circulating pressure through
pressure (SCRP) the entire active fluid system at a reduced rate. Slow circulating rates are
used during well control operations to circulate out a kick. Slow circulating
rate pressures should be measured and recorded each tour, after any mud
weight changes, after each 500-1,000 ft of new hole drilled (or according to
your company’s specifications), after each bottom hole assembly (BHA)
change, after each trip and after any significant change in mud properties.
Soft shut-in procedure A soft shut-in is to close in the well using a BOP with the choke and choke
line valve open, then closing the choke while monitoring the casing pressure

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 TERM DEFINITION
gauge for maximum allowable casing pressure. The type of shut-in used
depends on company policy, procedures and the well being drilled.
Stripping Stripping is a technique for moving the drill string through the BOP stack
when the well is shut in under pressure. In most cases, stripping is required
to return the drill string to the bottom after shutting in on a kick with the bit
off the bottom. Stripping requires a high level of coordination among crew
members.
Subsea BOP stack The subsea BOP stack is a series of ram and annular BOPs designed for use
on subsea wellheads and wellhead assemblies to ensure pressure control of
a well. A typical configuration of a BOP stack has annular preventers at the
top and ram preventers at the bottom. The BOP stack also typically includes
drilling spools, adapters and valve configurations to allow the circulation of
fluids under pressure during well control events through the choke and kill
lines.
Subsea riser The subsea riser is the primary flow path for the mud circulated from the
wellbore to the surface for subsea drilling. The riser delivers fluid flow,
connections to power and control systems, and guides the drill string and
tools to the wellhead. The riser is not capable of high pressure mud sealing
since it has to connect to the seafloor BOPs and compensate for rig motion.
Surface BOP stack The surface BOP stack is a series of ram and annular BOPs designed for use
on surface wellheads to ensure pressure control of a well. A typical
configuration of a BOP stack has annular preventers at the top and ram
preventers at the bottom. The BOP stack also typically includes drilling
spools, adapters and valve configurations to allow the circulation of fluids
under pressure during well control events through the choke and kill lines.
Surge Surge is the increase in bottom home pressure, generally due to moving the
drill string down too fast, which increases the bottom hole pressure and can
damage the formation.
Swab Swabbing occurs when formation fluids are drawn into the wellbore,
generally due to moving the drill string up too fast, which decreases the
bottom hole pressure.
Trip gas Trip gas is an accumulation of gas, which enters the wellbore while tripping
pipe. Prior to a trip, consider adding a trip margin by increasing the mud
density to prevent or minimize trip gas. After a trip, the well should be
circulated to remove gas from the wellbore before drilling new formation
Trip margin A trip margin is any mud density over the amount needed to balance the
formation pressure with a static mud column. The margin is added to the
mud weight as mud density is usually just enough to balance the formation
pressure. A trip margin is based on the increase in the bottom hole pressure
needed.
Tripping Tripping is the operation of removing the drill string from the wellbore or
running it back in the hole. This operation is most likely undertaken when
the bit becomes dull, no longer drills the rock efficiently, or a specified
depth is reached.
Under-compacted shales Under-compaction, or incomplete sediment compaction, is the most
common cause of abnormal formation pressure. When shales with a
significant amount of organic content are deposited, the decomposition and

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 TERM DEFINITION
compaction processes will produce gas. When low permeability shales are
buried quickly there is little time for the gas to escape. If the gas is not
allowed to escape, the formation pressure will increase and abnormal
pressure will develop.
Uplift and erosion In uplift and erosion, a formation has been raised, through tectonic activity,
to a lesser depth than originally deposited. Although the formation pressure
may not be great, for its depth it is abnormally pressured if formations fluids
do not escape. The uplift may be visible on the surface in the form of rolling
hills, or erosion may have worn the surface features of the local topography
and mask the past geological events.
U-tube The u-tube concept describes the behavior of two connected columns of
fluid. The fluids in a well can be described as a u-tube, with one leg of the u-
tube representing the drill string and the other leg representing the annulus.
Vacuum-type degasser A vacuum-type degasser is a device used to separate dangerous gases from
the mud returning from the well. In operation, the vacuum pressure pulls
drilling fluid into the vacuum tank where it flows along the tank roof and
spills onto the baffle plates to increase the surface area of the fluid. The
vacuum pressure extracts the gas and sends it into the gas line while the
degassed fluid falls to the bottom of the tank.
Vessel motion Six vessel motions affect the stability of the rig and can impact well control.
These vessel motions include surge, sway, yaw, heave, roll and pitch. These
motions can cause change in the pit level and flow rate.
Volumetric method The volumetric method is a well control method used to remove an influx
when circulation is not possible or when gas is migrating in a shut-in well
The volumetric method is used when circulation is not possible, or
circulation is not recommended. If a gas kick cannot be circulated from the
well, gas migration may occur resulting in high surface, casing shoe and
bottom hole pressures. To minimize this, the volumetric method uses a
series of steps of migration and bleeding to allow the influx to expand in a
controlled way up the wellbore. The volumetric method maintains BHP
slightly above formation pressure.
Wait & weight method The Wait & weight method is a common method of killing a well using the
circulating system to maintain constant bottom hole pressure throughout
the procedure. The Wait & weight method generally requires only one
circulation to remove the influx. The influx is circulated out while the kill
weight mud is pumped into the well. The wait & weight method gets its
name from the fact that there is a “waiting” time while the mud weight is
increased or “weighted” up prior to circulating the influx out of the hole.
Well completion Well completion is the process for establishing production after the
production casing string has been set, cemented and pressure tested.
Well control Well control is the practices and technologies used to prevent the
unintended flow of formation fluids into the wellbore.
Well workover Well workover is the process for intervening after a well has been
completed for the purpose of maintaining or restoring productivity.

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