U.S. patent application number 15/392939 was filed with the patent office on 2018-06-28 for downhole pulsing shock-reach extender method.
The applicant listed for this patent is Christopher Gasser, Brady Guilbeaux, Richard Messa, Ashley Rochon. Invention is credited to Christopher Gasser, Brady Guilbeaux, Richard Messa, Ashley Rochon.
Application Number | 20180179844 15/392939 |
Document ID | / |
Family ID | 62625521 |
Filed Date | 2018-06-28 |
United States Patent
Application |
20180179844 |
Kind Code |
A1 |
Messa; Richard ; et
al. |
June 28, 2018 |
DOWNHOLE PULSING SHOCK-REACH EXTENDER METHOD
Abstract
A downhole pulsing-shock reach extender method for overcoming
static friction resistance in coiled-tubing drilling-fluid-pressure
driven downhole operations, generating pulsed hydraulic shocks at
the workstring by creating a fluid-hammer condition by repeated
sudden opening and closing of a set-pressure snap-acting valve,
using an essentially constant or slowly changing normal
drilling-fluid pressure that will not damage other components of
the workstring, thereby extending the depth limit of downhole
operations. A poppet and calibrated spring act as a set-pressure
snap-acting valve, and a tapering constriction and constricted
throat in the main flow of drilling fluid or mud builds up higher
pressure to open the valve, while bypass portways allow for limited
flow and equilibration around the valve. The rapid equilibration of
pressure upon the opening of the valve, combined with the force of
the calibrated spring, allows a rapid closing of the valve, which
sets up a fluid-hammer hydraulic shock, in a repeating cycle.
Inventors: |
Messa; Richard; (Broussard,
LA) ; Gasser; Christopher; (Houston, TX) ;
Guilbeaux; Brady; (Maurice, LA) ; Rochon; Ashley;
(New Iberia, LA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Messa; Richard
Gasser; Christopher
Guilbeaux; Brady
Rochon; Ashley |
Broussard
Houston
Maurice
New Iberia |
LA
TX
LA
LA |
US
US
US
US |
|
|
Family ID: |
62625521 |
Appl. No.: |
15/392939 |
Filed: |
December 28, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 28/00 20130101 |
International
Class: |
E21B 31/00 20060101
E21B031/00; E21B 17/20 20060101 E21B017/20; E21B 21/10 20060101
E21B021/10 |
Claims
1. A downhole pulsing-shock reach extender method for overcoming
static friction resistance in coiled-tubing drilling-fluid-pressure
driven downhole operations, the downhole pulsing-shock reach
extender method comprising: (i) providing a pulsing-shock apparatus
comprising: (a) a tube body adapted to being mounted in a
coiled-tubing work string, having, in use, a wellhead end and a
well-bottom end; (b) an inflow chamber at the wellhead end of said
tube body, having a diameter essentially matching the inner
diameter of the coiled tubing; (c) a tapering constriction at the
well-bottom end of said inflow chamber; (d) a constricted throat at
the well-bottom end of said tapering constriction; (e) a poppet
chamber at the well-bottom end of said constricted throat; (f) a
poppet movably mounted inside said poppet chamber, adapted to
prevent flow from said constricted throat in a closed position and
to allow flow in an open position; (g) a calibrated spring mounted
inside said poppet chamber, adapted to exert a closing force
against said poppet sufficient to prevent opening when pressure
difference between said constricted throat and said poppet chamber
is small, and to allow opening when pressure difference is large;
(h) at least one bypass portway adapted to allow constant but
constricted flow and pressure equilibration between said inflow
chamber and said poppet chamber; and (i) an outflow chamber at the
well-bottom end of said poppet chamber, adapted to convey
pressurized drilling fluid to the other components of the
workstring; where said poppet and said calibrated spring function
as a set-pressure snap-acting valve; (ii) inserting said
pulsing-shock apparatus into the workstring for a coiled-tubing
downhole operation; (iii) pumping drilling fluid through the coiled
tubing to the workstring; and (iv) building higher fluid pressure
in said tapering constriction and constricted throat, acting upon
said poppet until sufficient pressure to overcome said calibrated
spring is reached, opening and allowing fluid to flow from said
constricted throat, in turn allowing an increase of flow and
pressure into said poppet chamber, equilibrating the pressure
difference between said inflow chamber and poppet chamber, in turn
allowing said calibrated spring to move said poppet back into
position sealing said constricted throat, in a continuing cycle;
where, in use, the continuing cycle of opening and closing the
set-pressure snap-acting valve formed by said poppet and said
calibrated spring sets up a fluid-hammer series of pulsing shocks
which assist in overcoming the static friction forces acting to
resist further entry of the drill string into the hole.
2. The downhole pulsing-shock reach extender method of claim 1,
where said tube body is made of steel.
3. The downhole pulsing-shock reach extender method of claim 1,
where said tube body has an outer diameter of 2.875 inches.
4. The downhole pulsing-shock reach extender method of claim 1,
where said tapering constriction has a taper of from 10 to 15
degrees, inclusive.
5. The downhole pulsing-shock reach extender method of claim 1,
where said constricted throat has a diameter not greater than half
the diameter of said inflow chamber.
6. The downhole pulsing-shock reach extender method of claim 1,
where said constricted throat has a length greater than its
diameter.
7. The downhole pulsing-shock reach extender method of claim 1,
where said poppet has a diameter double the diameter of said
constricted throat.
8. The downhole pulsing-shock reach extender method of claim 1,
where said poppet and said calibrated spring are made of brass.
9. The downhole pulsing-shock reach extender method of claim 1,
where said bypass portways are arranged as openings around the
diameter of said inflow chamber at the start of said tapering
constriction.
10. The downhole pulsing-shock reach extender method of claim 1,
where said outflow chamber has a diameter smaller than the diameter
of said inflow chamber.
11. The downhole pulsing-shock reach extender method of claim 1,
where said outflow chamber has a diameter not greater than 75% of
the diameter of said inflow chamber.
12. The downhole pulsing-shock reach extender method of claim 1,
where said outflow chamber has a diameter substantially equal to
the diameter of said inflow chamber.
13. The downhole pulsing-shock reach extender method of claim 1,
where said bypass portways accommodate from 10% to 33%, inclusive,
of the flow in said inflow chamber.
14. The downhole pulsing-shock reach extender method of claim 1,
where said bypass portways accommodate not greater than half of the
flow in said inflow chamber.
15. The downhole pulsing-shock reach extender method of claim 1,
where said tapering constriction has a length substantially twice
the diameter of said inflow chamber.
Description
BACKGROUND
[0001] This invention is a downhole pulsing-shock reach extender
method for overcoming static friction resistance in coiled-tubing
drilling-fluid-pressure driven downhole operations.
[0002] Drilling, in its broad sense, includes the initial drilling
of a hole plus many subsequent trips down the hole for workover and
inspection. Where older methods of drilling use sections of rigid
pipe threaded together, coiled-tubing drilling uses a somewhat
flexible, continuous tube that can be spooled when not in use.
Where the power for rigid-pipe drilling is applied at the turntable
on the rig, the power for coiled-tubing drilling is instead applied
at or near the drill bit or workstring by converting pressure
applied to drilling fluid or drilling mud at the wellhead,
transmitted down the great length of coiled tubing, and converted
to rotational force by a fluid motor or mud motor. This technique
allows directional drilling, including horizontal drilling, and
including changes of direction during drilling. In coiled-tubing
operations, the depth of a hole might include substantial portions
of horizontal or near-horizontal runs.
[0003] In rigid-pipe drilling, the function of drilling fluid or
drilling mud is to provide lubrication, flushing of tailings, and
counter pressure down the hole. Coiled-tubing drilling instead uses
the drilling fluid or mud for an additional purpose of transmitting
power or force to the workstring, which is underground, thousands
of feet distant.
[0004] Coiled-tubing operations will always encounter increased
resistance at increasing depths. Although the coiled tubing is
straightened before insertion, there is a likelihood of some
residual shape memory to nudge the deployed tubing away from being
perfectly straight. Directional drilling usually involves changes
of direction, and each change of direction provides a point of
increased drag while diminishing any benefit from downward,
insertion force applied at the wellhead. Because there is likely to
be at least some drag all along the surface of the deployed tubing,
a longer, or deeper, run will encounter increasing total drag.
Therefore, very deep coiled-tubing operations encounter increased
drag, or static friction, which eventually cannot be overcome. This
limits the depths attainable by the operation.
[0005] It is known that a given amount of force, when applied
gradually or constantly, will not be sufficient to overcome static
friction, but the same total amount of force, when applied as
pulses, will overcome the static friction. For example, a nail that
cannot be pressed into a block of wood can be hammered into it. The
pulse of force is able to work as intended for a brief time before
being dispersed. But in coiled-tubing operations, any pulse of more
pressure applied at the wellhead will dissipate, and will not be
felt at the distant workstring. All changes of pressure at the
workstring will necessarily be gradual, buffered changes. If too
great an amount of mud pressure is forced down the coiled tubing,
it will damage or destroy the mud motor.
[0006] The present art does not provide an effective way of
generating pulses of hydraulic shock within the workstring itself,
while avoiding the application of too much pressure within the long
run of coiled tubing and at the workstring, and while avoiding
damage to mud motors and other components of the workstring.
[0007] U.S. Publ. No. 2016/0312559 was published on Oct. 27, 2016
by inventors Ilia Gotlib et al. and assignee Sclumberger Technology
Corp., and covers a "Pressure Pulse Reach Extension Technique." The
pressure pulse tool and technique allows for a reciprocating piston
at a frequency independent of a flow rate of the fluid that powers
the reciprocating. The architecture of the tool and techniques
employed may take advantage of a Coanda or other implement to
alternatingly divert fluid flow between pathways in communication
with the piston in order to attain the reciprocation. Frequency of
reciprocation may be between about 1 Hz and about 200 Hz, or other
suitably tunable ranges. Once more, the frequency may be enhanced
through periodic exposure to annular pressure. Extended reach
through use of such a pressure pulse tool and technique may exceed
about 2,000 feet.
[0008] U.S. Publ. No. 2016/0130938 was published on May 12, 2016 by
inventor Jack J. Koll and assignee Tempress Technologies, Inc., and
discloses "Seismic While Drilling System and Methods." A bottom
hole assembly is configured with a drill bit section connected to a
pulse generation section. The pulse generation section includes a
relatively long external housing, a particular housing length being
selected for the particular drilling location. The long external
housing is positioned closely adjacent to the borehole sidewalls to
thereby create a high-speed flow course between the external walls
of the housing and the borehole sidewalls. The long external
housing includes a valve cartridge assembly and optionally a shock
sub decoupler. While in operation, the valve cartridge assembly
continuously cycles and uses downhole pressure to thereby generate
seismic signal pulses that propagate to geophones or other similar
sensors on the surface. The amount of bypass allowed through the
valve assembly is selectable in combination with the long external
housing length and width to achieve the desired pulse
characteristics. The bottom hole assembly optionally includes an
acoustic baffle to attenuate wave propagation going up the drill
string.
[0009] U.S. Publ. No. 2014/0048283, published by Brian Mohon et al.
on Feb. 20, 2014, covers a "Pressure Pulse Well Tool." The
disclosure of the Mohen publication is directed to a pressure pulse
well tool, which may include an upper valve assembly configured to
move between a start position and a stop position in a housing. The
pressure pulse well tool may also include an activation valve
subassembly disposed within the upper valve assembly. The
activation valve subassembly may be configured to restrict a fluid
flow through the upper valve assembly and increase a fluid pressure
across the upper valve assembly. The pressure pulse well tool may
further include a lower valve assembly disposed inside the housing
and configured to receive the fluid flow from the upper valve
assembly. The lower valve assembly may be configured to separate
from the upper valve assembly after the upper valve assembly
reaches the stop position, causing the fluid flow to pass through
the lower valve assembly and to decrease the fluid pressure across
the upper valve assembly.
[0010] U.S. Pat. No. 8,082,941 issued Dec. 27, 2011 to Alessandro
O. Caccialupi et al. for a "Reverse Action Flow Activated Shut-Off
Valve." The Caccialupi flow-activated valve includes an outer body
and a piston disposed in an inner cavity of the outer body. The
flow-activated valve also includes one or more fluid passage exits
in the outer body and one or more piston fluid passages in the
piston. The one or more fluid passage exits and the one or more
piston fluid passages allow fluid flow out of the valve. The
flow-activated valve also includes a flow restriction member
disposed in a piston inner cavity. In addition, the flow-activated
valve includes a shear member disposed in the outer body, and a
bias member disposed in an inner cavity of the outer body. The
flow-activated valve further includes a position control member
disposed in the piston and a sealing member.
[0011] U.S. Pat. No. 7,343,982 issued to Phil Mock et al. on Mar.
18, 2008 for a "Tractor with Improved Valve System." The system
covers a hydraulically powered tractor adapted for advancement
through a borehole, and includes an elongated body, aft and forward
gripper assemblies, and a valve control assembly housed within the
elongated body. The aft and forward gripper assemblies are adapted
for selective engagement with the inner surface of the borehole.
The valve control assembly includes a gripper control valve for
directing pressurized fluid to the aft and forward gripper
assemblies. The valve control assembly also includes a propulsion
control valve for directing fluid to an aft or forward power
chamber for advancing the body relative to the actuated gripper
assembly. Aft and forward mechanically actuated valves may be
provided for controlling the position of the gripper control valve
by detective and signaling when the body has completed an
advancement stroke relative to an actuated gripper assembly. Aft
and forward sequence valves may be provided for controlling the
propulsion control valve by detecting when the gripper assemblies
become fully actuated. A pressure relief valve is preferably
provided along an input supply line for liming the pressure of the
fluid entering the valve control assembly.
[0012] U.S. Pat. No. 2,576,923, issued on Dec. 4, 1951 to Clarence
J. Coberly for a "Fluid Operated Pump with Shock Absorber," relates
in general to equipment for pumping fluid from wells and, more
particularly, to an apparatus which includes a reciprocating pump
of the fluid-operated type. A primary object of the invention is to
provide an apparatus having cushioning means associated therewith
for absorbing any fluid pressure variations which may impose
hydraulic shock loads on the system. The fluid operated pumping
unit includes a combination of (1) a source of a first fluid at a
substantially constant pressure level; (2) a receiver for a second
fluid to be pumped; (3) a pump adapted to be operating by the first
fluid to pump the second fluid; (4) a shock absorber connected to
the pump and having movable fluid separating means within it; (5)
means for a first passage communicating between the source and the
shock absorber for admitting the first fluid into the shock
absorber on one side of the fluid separating means; (6) and a
second passage means communicating between the receiver and the
shock absorber for admitting the second fluid into the shock
absorber on the opposite side of the fluid separating means.
[0013] U.S. Pat. No. 8,967,268, issued to Larry J. Urban et al. on
Mar. 3, 2015, covers "Setting Subterranean Tools with Flow
Generated Shock Wave." In the Urban patent, a circulation sub is
provided that has a ball seat and a circulation port that is closed
when a ball is landed on the seat. An axial passage directs the
pressure surge created with the landing of the ball on the seat to
the port with the actuation piston for the tool. The surge in
pressure operations the actuation piston to set the tool, which is
preferably a packer. Raising the circulation rate through a
constriction in a circulation sub breaks a shear device and allows
the restriction to shift to cover a circulation port. The pressure
surge that ensues continues through the restriction to the
actuating piston for the tool to set the tool. The Urban patent was
assigned to Baker Hughes Inc. on Nov. 30, 2011.
[0014] U.S. Pat. No. 8,939,217, issued Jan. 27, 2015 to inventor
Jack J. Koll and assignee Tempress Technologies, Inc., covers a
"Hydraulic Pulse Valve with Improved Pulse Control," pictured at
right. Hydraulic pulses are produced each time that a pulse valve
interrupts the flow of a pressurized fluid through a conduit. The
pulse valve includes an elongated housing having an inlet
configured to couple the conduit to receive the pressurized fluid,
and an outlet configured to couple to one or more tools. In the
housing, a valve assembly includes a poppet reciprocating between
open and closed positions, and a poppet seat, in which the poppet
closes to at least partially block the flow of pressurized fluid
through the valve. A pilot within the poppet moves between
disparate positions to modify fluid paths within the valve. When
the valve is open, a relatively lower pressure is produced by a
Venturi effect as the fluid flows through a throat in the poppet
seat, to provide a differential pressure used to move the pilot and
poppet. An optional bypass reduces the pulse amplitude.
SUMMARY OF THE INVENTION
[0015] This invention provides a downhole pulsing-shock reach
method for overcoming static friction resistance in coiled-tubing
drilling-fluid-pressure driven downhole operations, generating
pulsed hydraulic shocks at the workstring by creating a
fluid-hammer condition by repeated sudden opening and closing of a
set-pressure snap-acting valve, using an essentially constant or
slowly changing normal drilling-fluid pressure that will not damage
other components of the workstring, thereby extending the depth
limit of downhole operations. A poppet and calibrated spring act as
a set-pressure snap-acting valve, and a tapering constriction and
constricted throat in the main flow of drilling fluid or mud builds
up higher pressure to open the valve, while bypass portways allow
for limited flow and equilibration around the valve. The rapid
equilibration of pressure upon the opening of the valve, combined
with the force of the calibrated spring, allows a rapid closing of
the valve, which sets up a fluid-hammer hydraulic shock, in a
repeating cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Reference will now be made to the drawings, wherein like
parts are designated by like numerals, and wherein:
[0017] FIG. 1 is a schematic view illustrating the downhole
pulsing-shock reach extender of the invention in use;
[0018] FIG. 2 is a sectional view of the downhole pulsing-shock
reach extender of the invention with the poppet sealing the
constricted throat;
[0019] FIG. 3 is a sectional view of the downhole pulsing-shock
reach extender of the invention with the poppet not sealing the
constricted throat;
[0020] FIG. 4 is a sectional perspective detail view of a portion
of the downhole pulsing-shock reach extender of the invention;
[0021] FIG. 5 is a sectional schematic view illustrating the
relative pressures within the downhole pulsing-shock reach extender
of the invention with the poppet sealing the constricted throat;
and
[0022] FIG. 6 is a sectional schematic view illustrating the
relative pressures within the downhole pulsing-shock reach extender
of the invention with the poppet sealing the constricted
throat.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Referring to FIG. 1, the downhole pulsing-shock reach
extender 10 of the invention is shown schematically, in use in
coiled-tubing, directional drilling, downhole operations,
specifically in the removal of a previously-placed cement plug.
[0024] The downhole pulsing-shock reach extender 10 assists
significantly in overcoming the static friction encountered in deep
downhole coiled-tubing operations by generating pulsed hydraulic
shocks by creating a fluid-hammer condition by repeated sudden
opening and closing of a set-pressure snap-acting valve, using an
essentially constant or slowly changing normal drilling-fluid
pressure that will not damage other components of the workstring,
thereby extending the depth limit of downhole operations.
[0025] In order to overcome static friction in coiled-tubing
directional drilling downhole operations, it is necessary to
provide some pulsation of energy at the workstring, which will take
advantage of the small window of time that a force is able to work
as intended before being dispersed, in a continuing cycle. No
pulsation from the wellhead can effectively reach the workstring.
Further, the application of an extreme amount of pressure will only
damage or destroy the workstring's components. The downhole
pulsing-shock reach extender 10 generates the needed pulsing shocks
at the needed locus of the workstring, using the available, normal
mud pressure, and without exposing the other components of the
workstring to damage or destruction from excessive pressures.
[0026] The hammer or shock set up in the drilling mud inside the
downhole pulsing-shock reach extender 10 will impart a jerk, also
known as jolt, surge, or lurch, to the body of the extender and the
other elements of the workstring, causing a mechanical or physical
shock, which assists the workstring in overcoming static
friction.
[0027] Referring to FIG. 2, the downhole pulsing-shock reach
extender 10 comprises a tube body 1 with an outer diameter matching
that of the coiled tubing itself and the other components of the
workstring. In an embodiment appropriate for standard 2.375-inch
tubing in a 5.5-inch casing, an outer diameter of 2.875 inches is
appropriate. Inside the tube body 1 is an inflow chamber 2 that
essentially matches the inside diameter of the coiled tubing. The
inflow chamber therefore receives a flow of drilling fluid or mud
at essentially the same pressure found in the adjacent portion of
the coiled tubing. Although a major portion of the drilling mud
will be channeled into a pressure-increasing configuration, a
smaller portion of the mud is channeled through one or more bypass
portways 3. Because this substream or these substreams are taken
from the inflow chamber 2 with no concentration of the substreams,
their pressure will not significantly rise, and that portion of mud
will be delivered to its destination, disclosed in more detail
below, substantially at equilibrium with the inflow chamber 2.
[0028] The major portion of the drilling mud is channeled into a
tapering constriction 4 of the inner diameter of the tube body 1,
and from the tapering constriction 4 into a constricted throat 5
having a significantly smaller inner diameter than the inflow
chamber 2. In accord with Bernoulli's Principle, the resulting
decrease in the speed of the fluid occurs simultaneously with an
increase in pressure or potential energy.
[0029] At the beginning of the cycle at issue here, the downstream
opening of the constricted throat 5 is sealed closed by a poppet 7
held against the opening by a calibrated spring 8. The poppet 7 and
calibrated spring 8 are mounted in a poppet chamber 8, in such a
way that the poppet 7 and calibrated spring 8 can move as
necessary. Drilling mud can flow into and through the poppet
chamber 6 as well. The poppet chamber 6 is the downstream
continuation of the flow of mud through the downhole pulsing-shock
reach extender 10. Even when the flow of mud is prevented by the
face of the poppet 7 sealing the downstream opening of the
constricted throat 5, there is still a small but significant flow
of mud from the inflow chamber 2, through the bypass portways 3.
This bypass flow ensures that other components of the workstring
are never completely starved of mud, and also allows for
equilibration of pressure between the inflow chamber 2 and the
poppet chamber 8, which substantially negates the contribution of
the overall pressure of mud in the coiled tubing, and makes the
opening and closing of the set-pressure snap-acting valve formed by
the poppet 7 and calibrated spring 8 dependent more precisely upon
the relative pressure increase in the tapering constriction 4 and
constricted throat 5 in relation to the pressure in the inflow
chamber 2, and therefore the poppet chamber 6.
[0030] Still referring to FIG. 2, with the set-pressure snap-acting
valve closed, the constricted throat 5 would be considered the vena
contracta, or the point in the fluid stream where the diameter of
the stream is the least, and fluid velocity is at its maximum, if a
fluid stream existed at that time. But such a fluid stream is
blocked by the face of the poppet 7, and the energy at the opening
of the constricted throat exists as increased pressure or potential
energy.
[0031] Referring to FIG. 3, the calibrated spring 8 is calibrated
to yield at a desired pressure differential between the constricted
throat 5 and the poppet chamber 6. Because there is additional
surface area on the face of the poppet 7, in addition to the
smaller area sealing the constricted throat 5, the initial surge of
pressure will also act upon that additional surface and further
snap the valve open. With that valve open, the pressurized mud from
the constricted throat 5 is allowed to rush into the poppet chamber
6, equalizing the pressure. Additionally, the opening of the
constricted throat 5 to the poppet chamber 6 allows the Venturi
Effect to cause a reduction in fluid pressure just past the
downstream opening of the constricted throat 5.
[0032] Therefore, within an extremely brief time, the downstream
opening of the constricted throat 5 changes from being the locus of
highest relative pressure to being the locus of lowest relative
pressure. Consequently, the force of the calibrated spring 8 is
sufficient to quickly close the set-pressure snap-acting valve, and
the opening is abruptly shut. This abrupt shutting sets up an
iteration of fluid hammer or hydraulic shock, which provides a
beneficial effect to drilling or other operations underway. The
cycle then repeats.
[0033] An outflow chamber 9 is provided to accept the flow of mud
from the poppet chamber 6, to allow the velocity and pressure of
the mud to equilibrate, settle, or buffer, and to feed the flow of
mud into the rest of the workpiece and ultimately to the mud motor.
The diameter of the outflow chamber 9 can be smaller than the
inflow chamber 2, which will increase the velocity and pressure of
the mud flow to the mud motor, and compensate for energy lost to
heat and entropy in the hammering cycle. The diameter of the
outflow chamber 9 can be much smaller, which will amplify the
velocity and pressure of the mud flow to the mud motor above the
velocity and pressure in the coiled tubing. Or the diameter of the
outflow chamber 9 can be larger, which will decrease the velocity
and pressure of the mud flow to the mud motor.
[0034] Referring to FIG. 4, the forces generated in the constricted
throat 5 are initially focused upon just a smaller portion of the
face of the poppet 7, and then when the poppet 7 begins to separate
from the downstream opening of the constricted throat 5, the forces
additionally act upon the rest of the face of the poppet 7,
enhancing a desired snap-acting quality.
[0035] Referring to FIG. 5 & FIG. 6, in use, the flow of
drilling mud under normal pressure enters the inflow chamber 2. A
portion of the flow is channeled via the bypass portways 3 into the
poppet chamber 6. The bulk of the mud flows into the tapering
constriction 4 and the constricted throat 5. This constriction of
the flow increases the pressure or potential energy of that portion
of the mud flow. Initially, the face of the poppet 7 seals the
downstream opening of the constricted throat 5. The calibrated
spring 8 presses the poppet 7 into the sealing, closed position.
The pressure difference between the constricted throat 5 and the
poppet chamber 6 forces the poppet 7 open, allowing the flow of the
higher-pressure mud into the poppet chamber 6, which increases the
flow of mud and increases the pressure in the poppet chamber 6. Mud
continues to flow through the tapering constriction 4 and
constricted throat 5. With the constricted throat 5 open to the
larger poppet chamber 6, the Venturi Effect causes a reduction in
fluid pressure just past the opening of the constricted throat 5
into the poppet chamber 6. Pushed by the calibrated spring 8, the
poppet 7 moves into the area of reduced pressure, and re-seals the
downstream end of the constricted throat 5, setting up a fluid
hammer or hydraulic shock, and repeating the cycle. The drilling
mud then flows into the outflow chamber 9 where it is allowed to
equilibrate to a velocity and pressure slightly above that of the
inflow chamber 2, and out to the rest of the workstring.
[0036] An embodiment of the downhole pulsing-shock reach extender
10 is made of steel, as is known in the art. The types of drilling
fluid or mud used with coiled-tubing, mud-motor operations will
sufficiently cool and lubricate a unit made of steel, and will
suppress any potential sparking. Other embodiments could be made
from, or could have components made from, non-sparking brass or
from non-corroding composite materials, if such qualities are
needed.
[0037] Many other changes and modifications can be made in the
system and method of the present invention without departing from
the spirit thereof. I therefore pray that my rights to the present
invention be limited only by the scope of the appended claims.
* * * * *