FIELD OF THE INVENTION
The present invention relates to triple safety braking system assembly in wireline winch.
More particularly, invention relates to a mechanically, hydraulically and air-operated
5 braking system in wireline operations for oil and/or gas wells.
BACKGROUND OF THE INVENTION
Oil and gas well work over services utilize wireline procedures for performing a number
10 of downhole operations. Some of these downhole operations involve installing,
actuating, and removing various types of well equipments and removing tools. Well
wireline services utilize tools connected to a long length of steel wireline necessary to
reach the work area in the well.
15 A great deal of force, acceleration, speed, and control is needed to operate tools in the
well. Powerful mechanical rotational means such as diesel engine driven wireline reels
have been used to achieve the necessary pulling force. Both powerful torque and jarring
actions are required of a wireline reel system. The wireline service industry usually
achieves the requirement by various methods of gears, drive couplings, chains,
20 sprockets, levers, dog clutches, etc. connected to a large horsepower prime mover such
as a diesel engine. Inadequate braking system or assembly may lead to disasters during
the operation. Uncontrolled operations would obviously lead to increased downtime
and risk to life.
25 During the borewell operations a well tool is set, activated, deactivated, stuck, or being
removed. Uncontrolled winding would lead to accidents, losses due to down time and
risk on life. Braking systems are thus indispensable requirement for the winch assembly.
In general, single braking system is utilized for controlling winding speed. However,
there are known issues with existing braking system leading to frequent failures.
5 The state of the art winches have problems of frequent breakdown, increased downtime
and ineffective braking action which lead to frequent problems and
mismanagement of wireline operations. Inadequate braking system in a wireline
assembly is required to be addressed.
10 So far people have used single system to apply brake to the wire line winches used in
offshore or onshore operations. In case of failure of the system the oil companies run
into huge financial loss due to expensive devices and tools getting lost in the oil wells
which may necessitate fishing jobs which require expensive work-over operations. It
may result into losses worth several hundred crores of rupees.
15
In general, to hold the winch drum in a required position the unit is equipped with a
drum brake system. This brake can be applied by manual force or using a pneumatically
operated brake cylinder or by using a hydraulically brake cylinder. With pneumatic
power loss or hydraulic power loss the brake will automatically be applied holding the
20 drum in position. The brake band holding the drum in position applies directly on the
wireline drum. Using an angular setup, the brake band will automatically increase its
braking force when applied. In case of single braking system in wireline wince may lead
to frequent failures.
2 5 It is among the objects of the present invention to provide a winch apparatus which
obviates or mitigates these disadvantages. Therefore, it would be a useful advance if
systems and methods were devised for more safety braking system in wireline
operations.
OBJECT OF THE INVENTION
5
. Accordingly, the main object of the invention is to provide a wireline winch assembly
with improved braking system.
Another object of the invention is to provide a wireline winch assembly which is easy
10 and quick to control and operate.
Another object of the invention is to provide solution for the problem of controlling
winding during functioning of the winch.
15 . Still another object of the invention is to address the requirement of hassle free
functioning of wireline winch especially at the stage of winding in and out of the
wireline by providing adequate braking system.
Still another object of the invention is to provide an improved hydraulic, pneumatic and
20 mechanical control braking assembly for the winch.
Yet another object of the invention is to obviate the drawbacks of presently available
winch assemblies.
SUMMARY OF THE INVENTION
The present invention relates to triple safety braking system assembly in Wireline
Winch. More particularly, invention relates to a mechanically, hydraulically and air-
5 operated braking system in wireline operations for oil and/or gas wells.
The proposed invention is a system to be used in the wire line winches. The purpose of
this system is enabling the wireline winch to stop during the operation through air,
hydraulic, or mechanical means. If at any time, the air-brake fails, hydraulic-brake can
10 be applied and if both of these fail, the third one i.e. mechanical brake can be applied to
stop the system mechanically. The disclosed assembly is aimed at preventing accident(s)
in highly sensitive offshore areas where oil production is going on. The accidents in
offshore areas may cause not only loss of / damage to expensive tools and
instrumentation, but sometimes, there is also danger to the lives of the people
15 operating the systems.
The proposed invention is a triple safety braking system in wireline operations
comprising Air operated having pneumatic cylinders & control valves; Hydraulic
operated having hydraulic cylinders & control valves and mechanically operated having
20 leverage system.
The triple braking system in accordance with the present invention is equipped with
spring loaded, fail safe braking system operated hydraulically as well as pneumatically.
The braking system of the present invention mainly performs two functions 1) Acts as a
2 5 parking brake to prevent the brake from turning, due to downhole forces i.e. weight of
tool string and wireline or uphole forces i.e. well pressure, when in stationary position 2)
acts as an emergency brake, to halt the drum rapidly and smoothly in an emergency or
sudden failure of the wireline unit system.
Present system provides a triple safety braking system for the wire line winches and
gives 100% fool proof system against any loss or damage, by stopping the winch in case
of an accident, automatically without much human intervention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be more completely understood in consideration of the following
detailed description of various embodiments of the invention in connection with the
accompanying drawings.
FIG.1 is a schematic diagram of hydraulically driven wireline winch assembly in
accordance with the present invention.
FIG.2 is a schematic diagram of brake band assembly.
FIG.3 is a schematic diagram of brake lever assembly.
FIG.4a & FIG.4b are schematic diagrams of working principle of pneumatic/hydraulic
brake cylinders.
FIG.5 is a schematic diagram of manual braking system.
FIG.6 shows the force measuring process by a brake band according to the invention.
FIG.7 shows the force measuring process by a straight lever according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to exemplary embodiments of the present
invention, examples of which are illustrated in the accompanying drawings. It is to be
5 understood that other embodiments may be utilized and structural and functional
changes may be made without departing from the respective scope of the present
invention.
A winch assembly is illustrated in Fig.1. The winch assembly includes a reel drum
10 assembly 10, a braking system 11, a measuring head assembly 12, and a control panel
13 mounted in the winch assembly 1. The operator chair 14 is mounted in the winch
assembly to operate the control panel. The winch assembly comprises, but is not limited
to, at least one reel drum assembly, at least one braking system, a measuring head
assembly, control panel, and other devices as will be more fully described.
15
The braking system 11 as illustrated in Fig.1 is further comprises of a brake band
assembly 7, a brake lever assembly 8 and a pneumatic or hydraulic assembly 9. The
operator control panel 13 comprises controls for the operator to run the system of the
invention from an operating position advantageous to the wireline work being
20 performed. The operator control panel 13 is in communication with control and
monitoring systems of winch by means of hydraulic hoses and electrical cables.
Referring to FIG. 2, the brake band assembly 7 is illustrated in schematic view where
brake band assembly 7 further comprises of a spring steel strip 16 supporting on a non
25 asbestos brake band 17 and having a fixing bush 19 and a fixing block 18.
The brake band 17 is made up of auto woven roll linings metallic composition and
asbestos free materials. The asbestos free materials are bonded by high temperature
impregnate for enhanced mechanical strength and better anti-fade and wear properties
of the brake band. It has high coefficient of friction and is flexible enough to
accommodate with small changes in radius and to be used as band lining.
Referring to Fig.3, the brake lever assembly 8 is illustrated in schematic view where
brake lever assembly 8 is further comprises of a brake lever 20, a brake lever pin
assembly 21, a brake lever side plates 22 and a brake base plate 23.
Referring to Fig.4a & Fig.4b1 the pneumatic/hydraulic assembly 8 and its working
principle is illustrated in schematic view. The cylinder's design has a spring 25 fitted
inside of a hydraulic or pneumatic brake cylinder 24. This spring 25 is pre-compressed
during assembly and retained by the brake cylinder lid, when pressure is applied in the
brake whether pneumatic or hydraulic, the piston 26 extends, releasing the brakes. If
pressure is lost by pressing emergency button or a system failure, the spring 25 will pull
the brake piston back into the cylinder 24, resulting in applying the brake.
Referring to Fig.5, the manual braking system and its working principle is illustrated in
schematic view. The manual braking system further comprises of a non asbestos brake
band 17 supported with spring steel strip 16, manually operated by handle 26 and a
leverage system 27, 28, 29. The other end of band brake 17 is mechanically fixed by a
stud 30 with adjustable working length.
Referring to Fig.6, the force measuring process is illustrated according to the present
invention. The band brake consists of a flexible band of a steel liner with a friction
material, which embraces a part of the circumference of the drum. Here one end of the
brake is attached to a fixed pin while the other end is attached to a hydraulic or
pneumatic cylinder.
EXAMPLE-1
5 When a force P is applied by a hydraulic or pneumatic cylinder or manual
Let
TI = Tension in the tight side of the band.
Tz = Tension in the slack side of the band
8 = Angle of Lap(or embrace) of the band on the drum
10 r = radius of the drum
We know that limiting ratio of the tension is given by the relation:
Tl/T2= eve
2.3 Log [ Tl/T2] = p8
15 and braking force on the drum = TI-TZ
Braking Torque on the drum TB= (TI-T2)r
Now we know the value of permissible tensile stress (at) for the material of the band.
The maximum tension in the band:
Where W =Width of the band
t = Thickness of band
Now we have selected the brake band diameter as 490 mm. The coefficient of friction is
2 5 0.4. The brake band has a contact of 270'
r = 490/2 = 245 mm
N = 400 RPM
p = 0.4
8 = 270' = 270 x 4180 = 4.713 rad.
2.3 Log [ TIIT21 = p8
2.3 Log [ TIIT21 = 0.40 x 4.713
Log [ TIIT21 = 2.1212.3
= 0.9221
[ TlIT21 - 8.357 .......................... (i) (Taking antilog of 0.9221)
Let TB = Braking torque is 25 KW (25 x lo3 Watt)
We know that power absorbed,
= 597.22 N-m.
= 597.22 x lo3 N-mm.
We also know:
TB = (TI - T2) r
From equations (i) and (ii) we find that:
T2 = Tl / 8.356
Putting the valve of T2 in equation (ii)
Pneumatic Brake Cylinder:
Bore - 4" (101.6 mm)
r = 50.8 mm = 5.08 cm
Area = rcr2
= 3.14 x 5.08 x 5.08
.......................... (ii)
Force = Pressure x Area
Now we keep operating pressure 60 PSI (4.08 kg/cm2)
Force = P x A
= 4.08 x 81.03
= 334.6 Kg.
Hydraulic Cylinder:
Bore - 50 mm
Area = rcr2
= 3.14 x 2.5 x 2.5
= 19.625 cm2
15 Force = Pressure x Area
Now we keep operating pressure 17.0 kg/cm2
Force = P x A
= 17 x 19.625
= 333.6 Kg.
20
Referring to Fig.7, the force measuring process on lever is illustrated according to the
present invention. A lever is a rigid rod or bar capable of turning about a fixed point
called fulcrum. It is used as a machine to apply a load by application of a small effort.
2 5 EXAMPLE-2
Considering a straight lever with parallel forces acting in the same plane as shown in
Fig.7
The points A and B through which load and effort is applied are known as Load and
effort points respectively, F is the fulcrum about which the lever is capable of turning.
The perpendicular distance between the load point and fulcrum (Ll) is known as load
arm and the perpendicular distance between the effort point and fulcrum (L2) is called
5 as effort arm. According to the principle of moments:
WxL1=PxL2
W/P = L2/L1
i.e., Mechanical Advantage,
M.A = W/P = L2/L1
10
The ratio of the effort arm to the load arm i.e., L2/L1 is known as leverage.
Now it is clear that if a large load is to be lifted by a small effort than effort arm should
be much greater than the load arm. But it is not possible to provide a lever with large
15 effort arm due to space limitation. Therefore in order to obtain a great leverage,
compound levers are used. These compound levers are made of straight pieces, which
are attached to one another with pin joints.
According to the present a force of 331 N is required for braking,
20 So, W =331 N
Ll = 75 mm
L2 = 225 mm
Force to be applied at Handle,
25 P = WL1/ L2
= 331X75/25
= 110.3 N
About 110 N is the force which a man can exert on the working handle of the braking
system easily.
5
It should be noted that the remaining structure of the winch assembly is similar to that
1 existing in prior arts and as such no further description shall be given.
It should be understood that the embodiments described above are merely exemplary
and that modifications may be made thereto without departing from the scope of the
present invention. For example, the winch assembly of the present invention is shown
incorporated within a tool deployment system which is located subsea. However, the
winch assembly may be located in any desired position, such as at a surface location, for
example, on a platform or the like. Additionally, one or more of the various braking
assembly described above may alternatively include a different structure, or any other
structure. Also, one or more of the braking assembly may be provided within the
housing of the winch assembly.
Additionally, while the embodiments described above are used in conjunction with
wireline, any other medium may be accommodated, such as cable, ropes, chains, coiled
tubing or the like. It is to be understood that the present invention is not to be limited to
just the preferred embodiment disclosed, but that the invention described herein is
capable of numerous rearrangements, modifications and substitutions without
departing from the scope of the claims hereafter.

We Claim:
1. A winch assembly having triple safety braking system comprising:
a) at least one reel drum assembly (10);
b) at least one braking system (11);
c) a measuring head assembly'(l2);
d) a control panel (13); and
e) an operator chair mounted in the winch housing (1);
wherein:
the said braking system is a selectively controlled pneumatic, hydraulic and mechanical
brake command in wireline operations.
2. The winch assembly as claimed in claim 1, wherein the said operator control panel (13) is
in communication with control and monitoring systems in the said reel drum assembly
(10) by means of electrical cables.
3. The winch assembly as claimed in claim 1, wherein the said braking system further
comprises of a brake band assembly (7), a brake lever assembly (8), and a pneumatic or
hydraulic brake assembly (9).
4. The winch assembly as claimed in claim 3, wherein the said brake band assembly (7)
further comprises of a spring steel strip (16) supporting on a non asbestos brake band (17)
and having a fixing bush (19) and a fixing block (18).
5. The winch assembly as claimed in claim 4, wherein the said the brake band (17) is made
up of auto woven roll linings metallic composition and asbestos free materials.
6. The winch assembly as claimed in claim 5, wherein the said brake band has high
coefficient of friction and is flexible enough to accommodate with small changes in radius.
7. A method of triple braking system comprising steps of:
a) fitting a pre-compressed spring within the housing of hydraulic and pneumatic
brake cylinders;
b) retaining of the said pre-compressed spring by the brake cylinder lid;
c) applying pressure whether pneumatic or hydraulic enabling the piston to extend
and release the brakes; and
d) on emergency or system failure, enabling the spring (25) to pull the brake piston
back into the cylinder (24), resulting in applying the brake.
wherein:
the said braking system is a selectively controlled pneumatic, hydraulic and
mechanical brake command in wireline operations.
8. A method of triple braking system as claimed in claim 7, wherein the said triple brake
system activates the brake in response to the downhole pressure of oil and/or gas.