well_control_equipment

7/30/2019 well_control_equipment

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Well Control Equipment

n Surface & Subsea BOP Equipment

– BOP annular and rams.

– Choke Manifold / Chokes.

– Accumulator unit and hydraulic lines.

n Mud Gas Separator.

n Drill string valves.

n Diverter.



Well Control Equipment

At the end of this section you should be able to:

n Identify surface and subsea blowout preventors and

equipment.n Identify additional well control equipment at the rig site, and

describe their functions.

n Identify drill string valves and describe their functions.

n Identify the diverter equipment.



Well Control EquipmentWell Control Equipment

If primary well control is lost*, the BOPs are closed and the well control equipment andtechniques are used to control the well.

The proper selection and utilization of the blowout preventers, chokes, choke manifolds,mud-gas separators, degassers, mud-monitoring equipment and all other well controlrelated equipment is an important aspect of well control. Among the main factorsaffecting the selection of well control equipment, there are:

n Pressure: working pressure rating must exceed the maximum anticipated surfacepressure.

n Temperature: rating of all elastomers (BOP rams, annular preventer bags, bonnets,valves, marine riser, kill/choke line connections, etc).

n Nature of well fluids: such as the presence of H2S.

n Fluid compatibility: the resistance of elastomers to OBM and completion fluid.

*Primary well control is achieved by controlling formation pressures with the hydrostatic pressure of the drillingfluid.



Surface BOP StackSurface BOP Stack

The BOP stack is located over the wellhead and under drill floor in surfaceBOP’s.

They might include:

n Pipe ram preventer.n Drilling spool.

n Blind/shear ram preventer.

n Casing head housing.

The BOP’s is assembled inmany arrangements depending

upon requirements.Choke line

HCR

TOP RAM S

BLIND RAM S

BOTTOMRAMS

ANNULAR

BOTTOM RAM S

Kill line

VR plug m aybe installed in

casing head

Choke lineHCR

TOP RAM S

BLIND RAM S

BOTTOMRAMS

ANNULAR

BOTTOM RAM S

Kill line

VR plug m aybe installed in

casing head



Subsea BOP StackSubsea BOP Stack



BOP StackBOP Stack

The BOP stack consists of severalvalves, called preventers, stackedon top of each other. There are twokinds of preventers: annular preventer and ram preventers.

n Annular Preventer. – Close/seal on any object in the

wellbore.

– Sizes from 7-1/16 to 29-1/2 in.

– Pressures from 2K to 20K psi – Often called “the Hydrill”



BOP StackBOP Stack

Ram Preventers:

n Pipe Rams:

– Fit a specific pipe size. – Need pipe to make a seal. – Reliable and field proven.

– Only hold pressure from bottom.

n Shear/Blind Rams: – Both shears drill pipe and seals

the hole.

– Capacity to cut through 5” drill

pipe. – Emergency equipment. – Top seal and side packers. – Can seal on open hole.

Top seal

Side Packers

Large frontal area

Top seal

Side Packers

Large frontal area



Choke ManifoldChoke Manifold

The choke manifold is made up of specialhigh-pressure piping and valves. Thechoke manifold and chokes are used tocirculate formation fluids out of the well ina controlled manner. Fluid returning fromthe well flows from the BOP stack to thechoke manifold through a choke line.

Functions:

n Restrict flow to maintain backpressure, to prevent further influx.

n Divert fluid from well.

The choke can be opened and closed fromthe rig floor using the choke control panel.



AccumulatorAccumulator

The accumulator unit pressurizes hydraulic fluid and stores it at highpressure to provide hydraulic energy to operate the BOPs.



Mud Gas SeparatorMud Gas Separator

The mud-gas separator is a low-pressure vessel that removes gas from returningdrilling fluid. Proper design and efficiency of the mud-gas separator is very importantto ensure that drilling fluid is not carrying flammable gas to confined areas or mudtanks where rig personnel are working.

From c hoke

I m p i n g e m e n t

p l a t e

Baffle plates

1. Diameter and length controls theamount of pressure in separator

2. Height and diameter and internaldesign control separation efficiency

Drain linew/valve

Vent line

No valves!!

M UD

G A S

3. Height of ‘U’-Tube (D) and distancefrom bottom of separato r to top of ‘U’-Tube (d) contr ols fluid level and stopsgas from going out of the bottom

S i p h o n b r e a k e r

D

d N o v a l v e s ! !

M ud

From c hoke

I m p i n g e m e n t

p l a t e

Baffle plates

1. Diameter and length controls theamount of pressure in separator

2. Height and diameter and internaldesign control separation efficiency

Drain linew/valve

Vent line

No valves!!

M UD

G A S

3. Height of ‘U’-Tube (D) and distancefrom bottom of separato r to top of ‘U’-Tube (d) contr ols fluid level and stopsgas from going out of the bottom

S i p h o n b r e a k e r

D

d N o v a l v e s ! !

M ud



Drill String ValvesDrill String Valves

Used to prevent the formation fluids going up the drill string. Different types of drillstring valves are:

n Full Opening Safety Valve: installed on top of the drill string when a kick is taken whilsttripping.

n Inside BOP: one-way valves that allow flow from drill string to annulus but not from annulusto drill string. An example is the float valve (flapper or ball valves), installed just above thebit.

Full openingsafety valve

Float valves



DiverterDiverterThe diverter system is not an element of the well control equipment, it is notintended to shut-in or halt well flow. The diverter system, provides a low-pressure flowcontrol system to direct controlled or uncontrolled wellbore fluids away from theimmediate drilling area for the safety of personnel and equipment, while drillingsurface hole (prior to setting the surface casing on which the BOP stack and chokemanifold will be installed).

Surface

Casing shoe

Conductor

Diverter

Inf lux

Fl ow l in e

Dr i l ling str ing

Dive r te r l i ne

Ful l opening va lve ( in ter locked)

Sur face ho le

RiserSurface

Casing shoe

Conductor

Diverter

Inf lux

Fl ow l in e

Dr i l ling str ing

Dive r te r l i ne

Ful l opening va lve ( in ter locked)

Sur face ho le

Riser

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