1. 0
BLOW OUT
PREVENTER
This project covers the insight of Hydril GX model BOP present on Deep
Driller 4, its functioning, annular and ram preventers and inspection.
Shresth Bisht
Graduate
Engineering Trainee

2. PREFACE
This project covers the detailed theory, ratings, specifications and preventive
measures of the most important equipment on the rig, BLOW OUT PREVENTER.
Sincere thanks to Mr. K.S Suhag, Rig superintendent for suggesting the topic and
forming the basic caricature of the project, Mr. R.S Negi, Rig Superintendent and
Mr. Ved Prakash, Toolpusher for continuous guidance and suggestions in making
me complete the project.
Shresth Bisht
GET, Drilling
Deep Driller 4

3. INTRODUCTION
Blowout preventer is composed ofvarious preventers which are required to operate
under various well conditions. This whole equipment consists of Annular preventers,
ram preventers, choke and kill lines. Ram preventers differ in size and design. The
main motive for BOP installation is well control, i.e, establishing control over the
well in case primary controlis lost which is hydrostatic column of mud. The primary
function of this system is to confine well fluid to the well bore, provide means to add
fluid to the well bore, allow controlled volumes to be withdrawn, hang off the string
and shear the string if necessary. This equipment maintenance is prime importance
for the rig crew as failure at the required time can cause fatality.
The hydrostatic pressure imposed on the formation by the column of drilling fluid is
the primary factor in preventing a well from blowing out. These preventers provide
us with shutting the well in casethe well starts flowing i.e formation pressure
exceeding the hydrostatic pressureof the mud. Blow out preventer should be
designed to:
1. Close the top of the hole
2. Control the release of fluids
3. Can pump in the string
4. Allow movement of the pipe
5. Can shear the pipe and blind the hole (If necessary)
The following are the topics which will be covered in the project:
1. Pressure ratings
2. Flanges and fittings
3. Casing and casingheads
4. Annular preventer
5. Ram Type preventer
6. Hydril Multiple Position Lock
7. BOP test

4. PRESSURE RATINGS
Any assembly of blowout prevention equipment must be rated by lowest pressure
item in the hook up, whether it is the casing, casing head, any of the preventers or
the fittings exposed to the pressure. The pressure capacity of the casing and
formation are determining factors for working pressureof the assembly. Following
table shows the pressure ratings of a blowout preventer published in API RP 53.
API CLASS WORKING PRESSURE (psi)
2M 2000
3M 3000
5M 5000
10M 10000
15M 15000
FLANGES AND FITTINGS
Choke and kill connections suffer a lot of mechanical stress while handling a kick
and even while drilling. For this reason, these connections are required to and fro
from the wellhead/BOP. As the pressure keeps on increasing, the vibration is
subjected to increase. For this reason, the choke and kill lines which are accustomed
to High pressure ratings and have coflex hose (rating 15M) to absorb vibration while
going to the choke manifold. Ample capacity for bleeding pressure is provided by
these lines. However, all these valves and lines should be larger in order to prevent
excessive back pressure at the wellhead while circulating out a kick. Choke
manifold is also equipped with target flanges with tungsten coating for withstanding
high pressure specially downstream pressure. Two chokes(in choke manifold) must
be provided along with two HCR valves so that in caseone falters during
emergency, the other one can be operated in case of washout of any valve/choke.
The lines and fittings should be arranged in such manner that emergency repairs can
be done without cutting or welding.

5. CASING AND CASING HEADS
The bottomor starting point of any blowout assembly is the casing. Surface casing is
important for blowout protection because it is usually set deep enough to reach
competent formations and is the base for the BOP. An intermediate string is
significant to blowout protection because it contains stronger pipe than the surface
casing and because it reaches formation which will not breakdown with considerable
pressure at the wellhead. Cement has its own relevance where the its bond strength
is tested behind the casing string which can be tested against the wellhead pressure
in case of flow.
The working pressure of a BOP assembly should exceed the least of the following
criteria:
1. The burst rating of the casing to which its attached
2. The formation breakdown pressure at the shoe of the casing string
3. The maximum anticipated surface pressure to which the equipment can be
exposed.
The wellhead is a vital link between BOP and casing. This part of preventer
assembly serves some important purposes. It is used:
1. To supporta large part of the weight of the subsequentstrings.
2. To provide a pressure seal between outer and inner casing strings
3. To provide side outlet flanges/valves to bleed off pressure.
ANNULAR PREVENTER
The first preventer normally closed when shut in procedure is initiated is the annular
preventer. The GX 183/4-10000 Annular Blow out preventer provides a means of
sealing on any size of pipe, Kelly, any shape object, wireline and even complete shut
off of the well. The four basic segments of annular preventer are head, body, piston
and steel ribbed elastomeric packing element. The sealing action is performed by an
elastomeric element actuated by a hydraulic piston. The supply for the piston to
actuate is provided by the BOP controlunit (Koomey unit). Hydraulic pressure acts
on the piston through the closing chamber which moves the piston providing a
sealing engagement with the pipe in the bore or on itself. (When annular preventer is
closed on open on open hole, the rubber element is subjected to high stress and

6. overall life of the element is reduced, so close it on itself only when its an
emergency) Similarly, the piston is moved downwards with hydraulic pressure
through the opening chamber which opens up the packing element and the element
regains its normal shape. Under certain circumstances, hydraulic pressure is reduced
to allow large diameter pipes and vice versa.
These are some technical data for Annular BOP Hydril GX model:
 Bore size 183/4”
 Working pressure 10000 psi
 Hydrostatic Shell test pressure 15000 psi
 Hydrostatic chamber test pressure 10000 psi
 Top connection 183/4” 10000 API Type 6BX Studded
API BX 164 Alloy Inlay Ring groove
 Bottom connection 183/4” 15000 API Type 6BX Studded
API BX 164 Alloy Inlay Ring groove
 Piston stroke 11.5” (292mm)
 Lifting Eye safe working load 55 tons (11000 lbs) per shackle
 Packing unit closure range CSO to 183/4”
 Packing unit temperature range 20 to 266 degrees Fahrenheit
 Operating chamber fluid 50/50 Water/Glycol mixture or Hydraulic fluid
 Hydraulic connections Close and open port 11/2” codeSAE flange
 Maximum operating pressure 3000 psi

7.  Operating volumes Closing and opening both58 gallons
Visual inspection for Annular preventer
The control hoses shouldbe isolatedprior inspectionof annular preventer.
Packing Element Packing element consists of rounded elastomer, reinforced with
steel segments that controlrubber flow and extrusion. When pressure is transmitted
from unit to packer, the element is deformed radially inwards forming a seal
providing a effective barrier between annulus and surface.
Following are the checks and precautions involved for packing element:
1. Cracked rubber surfaces and wear and tear on rubber or part of it missing.
2. Steel segment inspection
3. The packing element is relaxing to its full opening diameter since due to age
factor hardness of rubber increases and hinders flow of rubber.
4. Check for swelling in element.
5. The spare element should be stored in cooland dry place.
Bore Keyseats and underguage problems do occurin bore of the annular
preventer. Keyseats occurs due to rotating or stripping operation where bore is
touched/scratched continuously by the pipe. Can be recognized from top of the
annularhead.
Ring grooves Responsiblefor providing metal to metal sesal when bolted together
with ring gasket between them. Primary sealing area is outer ring groove. It should
be cleaned and rust should be duly removed. Outer diameter having pitting,
scratches and cracks require ring groove to be machined and stress relieved. Ring
groove inspection should be done to both top and bottom flange.
Bolts and boltholes Should be free of rust or debris to allow complete screwing in
of the bolts

8. Wear plate Wear plateis present between packing element and annular head to
avoid damage to either one of them and can be replaced if worn out.

9. RAM PREVENTER
The Hydril 18 3/4"-15,000 compactram blowout preventer (BOP) is hydraulically
operated ram type preventer. The ram preventer is a dual configuration, consisting
of a standard dual body.
The top connection of these rams: 183/4”-15000 API type 6BX studded flange with
BX 164inconel ring groove. The bottom connection is 183/4”-15000 API type 6BX
studded flange with BX 164inconel ring groove. The compactram BOP has two
side outlets per ram cavity, one on each side, for connection of the choke and kill
valves. Each side outlet is a 4 1/16"-15,000 studded flange with aBX-155 Inconel
ring groove. Side outlets not in use are fitted with blind flanges. Two 1" outlets in
each manifold/hinge of the BOP are provided for connection of the hydraulic lines.
The BOP bodyis drilled to allow mounting of the manifold/hinges on either side,
making it possible to install the bonnets so that they can swing open in either
direction. In addition, the seal seat and wear plate in each ram compartment are
field replaceable without removal of the BOP from the BOP stack. The wear plates
can be removed with allen bolt connection which needed to be opened and are
torqued. After opening the bolts, it is picked up or taken down and is duly replaced
with the same procedure. The seals are also replaced after swinging open the
bonnet.
The bonnets of the 18 3/4"-15,000 compactdual ram BOP are equipped with 15
1/2 MPL operators. In caseof any wear/tear to bonnet, it can also be field replaced
and any on the bonnet can be installed. The Hydril 18 3/4"-15,000 compactdual
ram BOP comes equipped with a set of blind/shear rams installed in the upper ram
cavity and a set of 5 7/8" fixed-bore pipe rams installed in the lower ram cavity.
The other two rams are variable with lower variable ram of size range from 31/2”-
57/8” which is above the pipe ram and can be readily available of holding the string
(including 31/2” pipe) in case of shearing or any change to upper BOP cavity. The
upper variable ram has its size range from 41/2”-7” and can hold to the tooljoint of
57/8” pipes and can be closed in addition to other rams if maintenance is required
on the annular preventer.
Ram preventers are manufactured with self-feeding action for the rubber sealing .
As rubber wears, the small extrusion plates are forced into increased area, which
allows additional rubber to come and help in complete sealing. That is one of the
reason that pipe ram should not be closed on empty pipes.
PIPE RAMS
These rams are designed to seal the wellbore around a fixed size of pipe
recommended by the manufacturer. The front packer of pipe rams has a groove in
front having the specific diameter to seal around the pipe in the wellbore.

10. The front packer is enclosed between two steel plates to push extra rubber for
sealing in case front packer wears out and to prevent extruding of rubber from top
and bottomdue to wellbore and losing pressure.
VARIABLE BORE RAMS
These rams are designed to seal on a certain range of pipe sizes depending on range
of the ram. The front packer of this ram have steel segments embedded in the
rubber and will take the shape of the pipe around it when closed.
SHEAR AND BLIND RAMS
These rams are designed to shear the pipe in the well as well as blind the hole
simultaneously. It has steel blades to shear the pipe and seals the annulus after
shearing. The pressure requirement for shearing varies with size of the pipe and
also its weight. When shear and blind rams are closed, both upper and lower blade

11. assembly moves closer and shear the pipe in the well bore. After shearing the pipe,
upper blade comes on top of the lower blade closing on the well and top seal on top
of it enhances the sealing mechanism sealing the annulus.
Shearing operation should be done on no load condition which can be achieved by
hanging the pipe/string by any ram below the shear ram.
Visual inspection of ram preventer
Bore : Should be inspected for key seating and gauging. Can be recognized from
top of the bore, where varying wall thickness of the remaining steel can be
observed by using S.S ring groove as a reference. If wear increases the bore
diameter by more than 3/16” of an inch, repair should be immediately done.
Ring grooves: All ring grooves should be inspected including side outlet ones.
Blemishes and rust should be removed .
Flange bolt and nuts: BOP stack vibrations can actually stretch flange bolts. Should
be checked with thread profile and the ones with damaged should be replaced.
Bonnet Doors: Ram blocks should be removed after opening bonnet doors. The
bonnet assembly should be washed properly. The gasket between doorand BOP
bodyshould be checked.

12. Body face: This area can be dented/damaged due to ram block contact during ram
change or misalignment of doorgasket. Pitting and debris should be removed
with emery paper or files.
Ram cavities: Should be checked if ram not holding pressure from down during
BOP test and damage is there on the top seal. Raised surfaces can damage the ram
block top seal and should be removed using file or emery paper.
Ram blocks: Ram blocks mainly have two seals, one is front packer and other is
top seal. Both the seals should be inspected for cracking, blistering, cutting or
missing rubber. Damaged seal should be immediately replaced. Shear ram blocks,
blades, top seals and blades should be replaced if damaged.
Bonnet bolts: The condition of bonnet bolts greatly affect the seal between bonnet
doorand body. Damaged threads can hinder the proper torque
Ram operating piston rod: The operating piston should be inspected for
scratches or pitting which could result in hydraulic fluid leak. Operating piston rod
leaks are associated with PRIMARY SEAL from the well bore side (also called
mud seal) and O ring between bonnet and piston rod seal from operating fluid side.
Weephole is located on the bottom half of the bonnet doorand is located in
between both seals mentioned above. That means if mud is dripping out of weep
hole then there is problem with mud seal and if hydraulic fluid is dripping out then
the O-ring is leaking.
Control hose connection: Inspect the condition of the threads for the hydraulic hose
connections. Ensure that no galled threads are there which can result in line
disconnection or leak when under pressure.

13. Tail rod

14. HYDRIL MULTIPLE POSITION LOCK
Locking devices are designed to hold the rams in the closed position when the
string is hanged on the ram, and if accumulator operating pressure is lost or
removed. Hydril GX model has a unidirectional clutch mechanism along with a
lock nut. When the BOP ram is closed, the unidirectional clutch which has a lock
nut on the threaded tail rod, permits piston to move freely in ram’s closing
direction. Once the ram is closed, the piston gets locked and lock nut prevents ram
to move in opposite direction and the upper and lower clutch gets engaged with
each other. When the opening force is applied, it acts on the cylinder liner which
moves the transfer ring to disengage the rear clutch plate from front clutch plate
and holds them separated till the operating pressure is maintained.
BOP TEST
BOP test can be done in two ways: Cup tester and test plug. Cup tester is sits on the
casing with side outlet valve closed which tests the wellhead also. In case of test
plug, it sits on wellhead with side outlet valve opened to check for any leak in the
test plug. The BHA used for BOP testing:
1. 2 HWDPs (For weight)
2. Crossover
3. Test plug
4. Port sub
5. X-over

15. 6. 15 feet pup joint
7. 2 joints drill pipe
8. 10 feet pup joint
9. Side entry sub
10. FOSVs
11. 1 joint drill pipe
The BOP is tested through hard chiksan lines connected to side entry sub and can be
tested through mud pumps/cementer.
All rams except shear ram can be tested with shear ram tested after unscrewing the
string from test plug/cup tester and keeping it above the shear ram and pumping
through kill/ choke line.
First, for every ram/preventer the testing is done at minimum pressure to check for
leak then test at maximum pressure which should be less than the BOP and wellhead
stack pressure. Whenever any leak is found, should be repaired immediately.
BOP test is due every 21 days or before starting of a new section.