US20170152726A1

US20170152726A1 - Downhole well conditioning tool

Info

Publication number: US20170152726A1
Application number: US15/366,039
Authority: US
Inventors: William J. Ross
Original assignee: White Bear Well Conditioning Inc
Current assignee: White Bear Well Conditioning Inc
Priority date: 2015-12-01
Filing date: 2016-12-01
Publication date: 2017-06-01
Also published as: CA2949859A1; CA2913573A1

Abstract

A downhole well conditioning tool for self-stimulating a well is provided. The down hole tool is a multi-stage stacked self-exciting tool that can alter a relatively steady flow of incoming fluid into pulsating fluid streams of rapidly cycling high and low pressure without the use of moving internal parts. The downhole tool can include a first stage operative to receive a steady flow of pressurized fluid though an inlet and discharge a pulsating fluid flow and a second stage connected to the first stage and operative to receive the pulsating fluid flow from the first stage and increase the pulsations of the fluid flow before the pulsating fluid flow is discharged out of the second stage.

Description

The present invention relates to a downhole well conditioning tool for stimulating a well and more particularly to a multi-stage stacked self-exciting tool that can alter a relatively steady flow of incoming fluid into pulsating fluid streams of rapidly cycling high and low pressure without the use of moving internal parts.

BACKGROUND

In a typical oil and gas well, the well itself will typically have a casing inside the well bore. This casing serves to maintain the integrity of the well but it also separates the oil or gas reservoir from the inside of the well. In order to produce oil or gas from the well, the casing must be “perforated” or in other words have holes made in the casing so that oil or gas from the reservoir can flow through these perforations into the interior of the well. Typically, these perforations are made with a perforation gun which carries a number of explosive charges and is lowered down the well to the desired position before being fired off and creating these perforations.
However, before oil and gas can flow well through these perforations, the perforations often have to be cleaned out. These perforations can fill with cement or other material as a result of the perforation process and this cement or material must be cleared out of the perforations to increase the flow of oil or gas through the perforations. Additionally, as oil or gas is produced from the reservoir through these perforations, material and paraffin contained in the oil may start to fill up the perforations and will have to be cleared out of the perforations at various intervals to keep effectively producing oil or gas from the reservoir.
There are a number of different prior art methods for cleaning and stimulating wells, however, they often suffer from drawbacks or are not as effective as they could be.

SUMMARY OF THE INVENTION

In an aspect, a downhole tool is provided. The downhole tool can include a first stage operative to receive a steady flow of pressurized fluid though an inlet and discharge a pulsating fluid flow and a second stage connected to the first stage and operative to receive the pulsating fluid flow from the first stage and increase the pulsations of the fluid flow before the pulsating fluid flow is discharged out of the second stage.
In a further aspect, the first stage can include a sub having: a generally tubular body with a top end and a bottom end; a fluid inlet at the top end; a single fluid outlet at the bottom end; and a plurality of passages fluidly connecting the inlet at the top end and the single outlet at the bottom end, the plurality of passages configured to induce pressure pulses in a steady stream of fluid entering the sub through the inlet at the top end and discharge the fluid as a single pulsating stream through the single fluid outlet.
In a further aspect, the second stage can include a nose. The nose can comprise: a central bore connected to the inlet in the top end of the nose; and at least one outlet passage extending from the central bore to the at least one outlet port.
In another aspect, a downhole tool is provided. The downhole tool can comprise a first stage comprising a sub having: a generally tubular body with a top end and a bottom end; a fluid inlet at the top end; a single fluid outlet at the bottom end; and a plurality of passages fluidly connecting the inlet at the top end and the single outlet at the bottom end, the plurality of passages configured to induce pressure pulses in a steady stream of fluid entering the sub through the inlet at the top end and discharge the fluid as a single pulsating stream through the single fluid outlet; and a second stage connected to the first stage, the second stage comprising a nose having: a top end; a bottom end; an inlet provided in the top end of the nose to receive the pulsating fluid flow from the first stage; and at least one port is provided in the bottom end of the nose, wherein the top end of the nose has external threads and the top end of the nose mates with the bottom end of the sub to form a pulsation chamber, and wherein the inlet in the top end of the nose is in fluid communication with the pulsation chamber, and wherein the at least one port of the nose is in fluid communication with the pulsation chamber.
A well tool can be used to stimulate a well including chemical injection and near well bore perforation clean out. The well tool can include a number of stacked stages where each stage functions to create pulsations in a fluid stream causing the fluid stream to rapidly cycle between high and low pressure (impulses) before the fluid stream is discharged from the well tool as a number of pulsating fluid streams directed towards the walls of the well bore. These pulsating fluid streams directed at the walls of the well bore can induce high velocity stresses on the well bore casing near the well tool and induce high frequency low amplitude displacement forces peripherally in the distal areas of reservoir when the well tool is used in a semi-permanent continuous configuration to clean perforations and mobilize fluid through the reservoir channels. The resulting forces both in the near well bore and periphery result in a dynamic state of enhanced fluid—chemical dispersion and mobilization in order to improve productivity in the well (Enhanced Oil Recovery—EOR).
The well tool can be conveyed in the well either as a drop tool and tubing string arrangement or coil tubing conveyed. The well tool can work well in both low volume (0.5 BBL/min) and high volume applications (5.0 BBL/min) depending on the specific application and well conditions.
This tool is easy to handle and plugs off less during field operations than other tools due to the synergistic nature of the multi-stage stacked design. The tool does not require large vehicle transport from job to job and is easily and efficiently assembled. The tool may have the external diameter modified to fit the well application, either larger or smaller. The smaller tool has an outer diameter such that it can be operated in well casings having a fairly small size so as to work in a range of sizes that are found in most producing wells.

DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which:

FIG. 1 illustrates a side sectional view of a downhole well conditioning tool;

FIG. 2 illustrates the downhole well conditioning tool of FIG. 1 separated into a sub and a nose;

FIG. 3 illustrates a side view of the nose;

FIG. 4 illustrates front view of the nose of FIG. 3;

FIG. 5 illustrates a side view of an alternate nose;

FIG. 6 illustrates a side sectional view of the nose of FIG. 5; and

FIG. 7 illustrates a sectional view of the nose taken along line AA in FIG. 6.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIGS. 1 and 2 illustrates a well tool 10 that is used down hole and can self-create pulsating fluid streams for well cleaning and stimulation. The well tool 10 can be suspended downhole in a well (not shown), such as an oil well. Typically, the well tool 10 will be suspended downhole on a running string, as a drop tool, or coiled tubing configuration running to the ground surface. Pressurized fluid can be forced down the running string or coiled tubing into the well tool 10 where the pressurized fluid stream will be self-excited in the well tool 10 before exiting the well tool 10 through outlet ports 83, 85, 87 as pulsating pressurized fluid streams to contact the inside surfaces of the well and also displace fluid distally in both the near well bore and the peripheral reservoir.
In a typical application, the well tool 10 can be lowered downhole so that the well tool 10 is located at a point in the well where perforations have been made in the casing of the well. These perforations will usually be made by conventional means, such as by use of a perforation gun, and will extend through the casing of the well and the cement holding the casing in place and into the formation behind the well casing. These perforations through the well casing allow hydrocarbons in the formation to pass through the perforations in the well casing and enter the well casing so that the hydrocarbon can be removed from the well casing to the ground surface.
Commonly, these perforations may not be as open as they could be. The initial perforation could have debris left in it from the perforation, be plugged from drilling material from the drilling process or particulate material from drilling fluid, etc. Additionally, during the production of hydrocarbons from the well, a buildup of scale, paraffin wax and asphaltenes in the perforations can reduce the amount of hydrocarbon that can flow through the perforations or this build up could even plug the perforations completely.
The well tool 10 can be lowered down hole and positioned proximate the perforations in the well. Pressurized fluid, such as water, chemicals, a mixture of water and chemicals or even a gas or mixture of gases at any suitable temperatures (in one aspect, steam could be pumped down the string or coiled tubing), can be pumped down the string or coiled tubing to the well tool 10 ideally as a steady pressurized stream. Once in the well tool 10, the pressurized fluid stream will be self-exited in a two-stage stacked process into a pulsating pressurized fluid stream and ejected out of the well tool 10 through the outlet ports 83, 85, 87. This pulsating pressurized fluid stream will be directed by the outlet ports 83, 85, 87 towards the perforations in the well casing to try and remove material from the perforations and unplug them. These pulsating fluid streams can disturb the walls of the perforations to remove debris from the perforations and displace any impermeable skin on the walls of the perforation tunnels. The pressure alterations and resonance waves created by the fluid streams can displace skin debris and fluid both in the near well bore and distally through the reservoir. Additionally, these pulsating pressurized fluid streams can reduce the impact of the well tool 10 plugging during operation.
These pulsating streams can take the form of streams of fluid exiting the outlet ports 83, 85, 87 where the pressure in the stream rapidly cycles between higher and lower pressure. Typically, the cycling of the pressure of the streams will occur substantially simultaneously in each of the streams exiting from the different outlet ports 83, 85, 87. In one aspect, although to the naked eye the streams will appear like relatively steady streams, closer examination (such as through slow motion capture) will show the streams can be formed of numerous fluid droplets forming the streams. The well tool 10 can produce a high volume and high pressure ejection pattern (800-900 psi) and high frequency pulsations as they exit the discharge nozzle (100-400) cycles per second.
The construction and arrangement of the well tool 10 is such that the annular volume between the well tool 10 and the well casing can be relatively small (depending on the size of the well tool 10 and the diameter of the well casing) which can concentrate the pressure fluctuations of the fluid streams in a manner that can significantly damage the skins (debris, paraffin, ashphaltenes, etc.) that may be obstructing the well bore perforations resulting in the removal of the obstruction, opening channels in the reservoir and further enhancing the displacement of chemistries intended to enhance oil recovery and improve long term well productivity results.
In one aspect, the well tool 10 may have a small enough outer diameter so that it can be run into the well on a tubing string, through the production tubing as a drop tool or on a coil tubing configuration.
The well tool 10 can have a sub 20 and a nose 60 and these components together can define a first pulse creating section 90 and a second pulse creating section 92.
The sub 20 can have a generally tubular shaped body with an open ended and externally threaded top end 22 and a internally threaded bottom end 24. The sub 20 can have a number of internal passages to cause an ideally steady pressurized stream of fluid entering the sub 20 through a fluid inlet 30 to become self-excited before entering a pulsation chamber 52 from a central passage 50 as a pulsating pressurized fluid flow. These passages between the fluid inlet 30 and the central passage 50 can define the first pulse creating section 90 of the well tool 10.
The fluid inlet 30 leads to a nozzle 32 that directs the flow of pressurized fluid into a first chamber 34. From the first chamber 34, two diffuser passages 36, 38 angle outwards towards the outside edges of the sub 20 at an angle from a central axis of the sub 20. A wedge-shaped splitter 40 can be formed between the two diffuser passages 36, 38 with a flat front surface 42 to split the steady pressurized stream of fluid into the two diffuser passages 36, 38. A transverse passage 44 can be provided connecting the two diffuser passages 36, 38 downstream from where the splitter 40 has split the flow of fluid into the two diffuser passages 36, 38. Opposite ends of the transverse passage 44 open into the two diffuser passages 36, 38, respectively.
Downstream from the transverse passage 44, the diffuser passages 36, 38 stop angling outwards from the central axis of the sub 20 and change direction to angle inwards towards the central axis of the sub 20 until the two diffuser passages 36, 38 meet in a central passage 50 before exiting into the pulsation chamber 52.
The orientation of the passages will cause the steady fluid stream entering the well tool 10 through the fluid inlet 30 to oscillate between the first diffuser passage 36 and the second diffuser passage 38. The steady pressurized fluid stream entering the fluid inlet 30 will be accelerated through the nozzle and into the first chamber 34. Instead of the splitter 40 splitting this accelerated fluid flow into two steady fluid streams with each steady fluid stream being directed down one of the two diffuser passages 36, 38, the relative positioning of the splitter 40, the diffuser passages 36, 38 and the transverse passage 40 causes the steady pressurized fluid stream to oscillates (or alternate) between first flowing through the first diffuser passage 36 and then the second diffuser passage 38 before once again flowing through the first diffuser passage 36. Instead of the steady flow being split by the splitter 40 between the two diffuser passages 36, 38, most of the fluid flow will tend to enter only one of the diffuser passages 36, 38 while little fluid will enter the other diffuser passage 38, 36. As the fluid stream flows down the first diffuser passage 36 (for example), the leading edge 42 of the splitter 40 will direct some of the fluid flow into a vortex that forms at the opening of the second diffuser passage 38. This vortex will discourage the flow of the fluid into the second diffuser passage 38 causing most of the fluid flow to be directed into the first diffuser passage 36.
The flow of the fluid stream through the first diffuser passage 36 will tend to continue until the flow is disturbed, causing the fluid stream to start flowing through the second diffuser passage 38 instead. This needed disturbance is created by the transverse passage 44 connecting the two diffuser passages 36, 38 downstream from the splitter 40. The fluid stream passing the by the transverse passage 44 as it flows down the first diffuser passage 36 will cause a vacuum (negative pressure condition) in the transverse passage 44. This negative pressure condition is communicated through the transverse passage 44 to the second diffuser passage 38 where it can disrupt the vortex blocking the entry of the second diffuser passage 38 and then this negative pressure in the second diffuser passage 38 can pull the fluid stream into the second diffuser passage 38. As the fluid stream begins to flow through the second diffuser passage 38 a vortex will be created in front of the inlet to the first diffuser passage 36 which will block the fluid stream from flowing through the first diffuser passage 36. As the fluid stream continues to flow through the second diffuser passage 38 a reduced pressure condition will occur in the transverse passage 44 and thereby reduce the pressure in the first diffuser passage 36 which in turn will eventually disrupt the vortex at the inlet of the first diffuser passage 36 and cause the flow to once again begin flowing through the first diffuser passage 36 rather than the second diffuser passage 38. A vortex will once again be created before the inlet to the second diffuser passage 38 which will direct the flow into the first diffuser passage 36.
In this manner, the steady pressure flow stream will alternate between flowing through the first diffuser passage 36 and the second diffuser passage 38 causing a high frequency oscillation of the fluid stream between these two diffuser passages 36, 38, with the stream of fluid alternating between mostly flowing through the first diffuser passage 36 and then mostly flowing through the second diffuser passage 38.
Rather than keeping these oscillating fluid streams separate in the well tool 10, the first diffuser passage 36 and the second diffuser passage 38 change direction and begin to angle inward downstream from the transverse passage 44 until the diffuser passages 36, 38 once again join in the central passage 50. The effect to the two oscillating fluid streams being joined in the central passage 50 results in a single fluid stream in the central passage 50 that is cyclically fluctuating in pressure (pulsating) rather than oscillating, with the velocity and pressure of the fluid stream increased and decreasing as it passes through the central passage 50.
From the central passage 50 the self-excited pulsating fluid stream passes into the second pulse creating section 92 of the well tool 10 and the pulsating fluid stream from the first pulse creating section 90 can be enhanced in this second pulse creating section 92. The second pulse creating section 92 is formed by both a portion of the sub 20 and the nose 60 and includes a pulsation chamber 52 formed by the connection of the nose 60 to the sub 20 and a central bore 70 leading out of the pulsation chamber 52.
FIGS. 3 and 4 show the nose 60. The nose 60 can have a generally tubular shape oriented around a central axis with a semi-spherical shaped bottom end 64. When the nose 60 is connected to the sub 20, the central axis of the nose 60 can be aligned with the central axis of the sub 20. The nose 60 can have a top end 62 that has external threads mating with the internal threads on the bottom end 24 of the sub 20. The top end 62 of the nose 60 can have a circular flat central portion 72 surrounding the inlet of the central bore 70. A tapered shoulder 74 can extend downwards and outwards from the circular flat central portion 72 to a flat shoulder 76 surrounding the circular flat central portion 72 and the tapered shoulder 74. The flat shoulder 76 can extend from the base of the tapered shoulder 74 to the outer diameter of the top end 62 of the nose 60.
The central bore 70 can extend along the central axis of the nose 60. A number of outlet passages 82, 84, 86 can extend outwards from the central bore 70 to outlet ports 83, 85, 87. These outlet passage 82, 84, 86 can extend downwards and outwards from the central bore 70 at an angle to the central axis of the nose 60, until they end in the outlet ports 83, 85, 87.
Referring to FIGS. 5, 6 and 7 an alternative nose 160 is shown. Like nose 60 shown in FIGS. 3 and 5, the nose 160 can have a generally tubular shape oriented around a central axis with a semi-spherical shaped bottom end 164. When the nose 160 is connected to the sub 20, the central axis of the nose 160 can be aligned with the central axis of the sub 20. The nose 160 can have a top end 162 that has external threads mating with the internal threads on the bottom end 24 of the sub 20.
Unlike the nose 60, nose 160 can have a tapered shoulder 174 surrounding an inlet of a central bore 170. The tapered shoulder 174 can extend downwards and outwards to a flat shoulder 176 surrounding the tapered shoulder 174. The flat shoulder 176 can extend from the base of the tapered shoulder 174 to the outer diameter of the top end 162 of the nose 160.
The central bore 170 can extend along the central axis of the nose 160 and a number of outlet passages 182 can extend radially outwards from the central bore 170 to outlet ports 183.
These outlet passage 182 can extend downwards and outwards from the central bore 170 at an angle to the central axis of the nose 160, until they end in the outlet ports 183.
Unlike nose 60 which where the outlet passages 82, 84, 86 will direct the pulsating fluid stream exiting the nose 60 downwards and outwards against the wall of a well, the outlet passages 182 extending radially in the nose 160 will direct the pulsating fluid stream discharged from the nose 60 substantially perpendicular to central axis of nose 160 and against the walls of the well.
Referring again to FIGS. 1-4, the second pulse creating section 92 of the well tool 10 will take the pulsating stream from the central passage 50 and further enhance the pulsation of this pressurized fluid stream. When the top end 62 of the nose 60 (or the nose 160) is threaded into the bottom end 24 of the sub 20 the pulsation chamber 52 is formed. On a top end of this pulsation chamber 52 the central passage 50 will enter into the pulsation chamber 52 and therefore the pulsating pressurized fluid stream will enter into the pulsation chamber 52. The pulsations of this pressurized fluid stream will be amplified by the pulsation chamber 52 before passing into the central bore 70 and eventually out the outlet passages 82, 84, 86 and the outlet ports 83, 85, 86. The outlet ports 83, 85, 86 can have different outlet configurations to optimize their effectiveness in different well bore configurations and depending on the fluid (water, chemicals, gas, steam, etc.) used.
The pulsation chamber 52 can be symmetrical around the central axis of the nose 60 and the sub 20, but the pulsation chamber 52 can have a larger diameter than the central passage 50 feeding into it resulting in the velocity of the fluid in the pulsation chamber 52 being much lower than the velocity of the pulsating fluid stream entering the pulsation chamber 52 from the central passage 50. The faster moving pulsating pressurized fluid stream exiting the central passage 50 meeting the slower moving fluid in the pulsation chamber 52 causes vortices to form in the pulsation chamber 52 as a result of the shear forces created when the fast moving fluid stream meets the slower moving fluid in the pulsation chamber 52. Because the central passage 50 is round, the vortices take the form of a circle in the pulsation chamber 52 and form a vortex ring encircling the inlet to the central bore 70. The circular flat central portion 72 and the tapered shoulder 74 can help to form this vortex ring. The vortex ring formed around the inlet of the central bore 70 will cause periodic pressure pulses in the fluid in the pulsation chamber 52. These pressure pulses will propagate upstream to where the incoming pulsating fluid stream shears with the fluid in the pulsation chamber 52 and induce vorticity fluctuations. This causes strong fluctuations in pressure of the fluid contained in the central bore 70 which in turn causes rapidly cycling of the fluid pressure in the fluid streams (a pulsed or pulsating jet of fluid) exiting the central bore 70 through the outlet passages 82, 84, 86. The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.

Claims

1. A downhole tool comprising:

a first stage operative to receive a steady flow of pressurized fluid though an inlet and discharge a pulsating fluid flow; and

a second stage connected to the first stage and operative to receive the pulsating fluid flow from the first stage and increase the pulsations of the fluid flow before the pulsating fluid flow is discharged out of the second stage.

2. The downhole tool of claim 1 wherein pulsating fluid flow discharged from the second stage is discharged at an angle to a centerline of the first second stage.

3. The downhole tool of claim 1 wherein the first stage comprises a sub having:

a generally tubular body with a top end and a bottom end;

a fluid inlet at the top end;

a single fluid outlet at the bottom end; and

a plurality of passages fluidly connecting the inlet at the top end and the single outlet at the bottom end, the plurality of passages configured to induce pressure pulses in a steady stream of fluid entering the sub through the inlet at the top end and discharge the fluid as a single pulsating stream through the single fluid outlet.

4. The downhole tool of claim 3 wherein the top end has external threads and the bottom end has internal threads.

5. The downhole tool of claim 3, wherein the sub further comprises:

a first chamber immediately downstream from the fluid inlet;

two diffuser passages having openings in the first chamber, each diffuser angling outwards from a central axis of the sub as the two diffuser passages extend from the first chamber;

a transvers passage running between the two diffuser passages and opening into each of the two diffuser passages; and

a single central passage, both of the diffuser passages exiting into the single central passage, the single central passage connected to the single fluid outlet at the bottom end of the sub,

wherein the two diffuser passages change direction and angle in towards the central axis of the sub downstream from the transverse passage.

6. The downhole tool of claim 5 wherein the sub further comprises a wedge shaped splitter formed between the two diffuser passages.

7. The downhole tool of claim 6 wherein the wedge shaped splitter having has a flat front surface.

8. The downhole tool of claim 1 wherein the second stage comprises a nose having a top end and a bottom end.

9. The downhole tool of claim 8 wherein an inlet is provided in the top end of the nose to receive the pulsating fluid flow from the first stage and at least one port is provided in the bottom end of the nose.

10. The downhole tool of claim 8 wherein the bottom end of the nose has a semi-spherical shape.

11. The downhole too of claim 4 wherein a top end of the nose has external threads and the top end of the nose mates with the bottom end of the sub to form a pulsation chamber.

12. The downhole tool of claim 11 wherein the inlet in the top end of the nose is in fluid communication with the pulsation chamber.

13. The downhole tool of claim 11 wherein the nose further comprises:

a central bore connected to the inlet in the top end of the nose; and

at least one outlet passage extending from the central bore to the at least one outlet port.

14. The downhole tool of claim 13 wherein the central bore of the nose extends along a central axis of the nose.

15. The downhole tool of claim 13 wherein the central bore of the nose is aligned with the central axis of the nose.

16. The downhole tool of claim 13 wherein the top end of the nose has a circular flat central portion surrounding the inlet.

17. The downhole tool of claim 16 wherein a tapered shoulder is provided extending downwards and outwards from the circular flat central portion on the top end of the nose to a flat shoulder surrounding the circular flat central portion and the tapered shoulder.

18. The downhole tool of claim 17 wherein the flat shoulder extends from a base of the tapered shoulder to an outer diameter of the nose.

19. The downhole tool of claim 13 wherein the at least one outlet passage extends downwards from where the at least one outlet passage connects with the central bore and at an angle to the central axis of the nose.

20. The downhole tool of claim 13 wherein the at least one outlet passage extends substantially radially outwards from where the at least one outlet passage connects with the central bore.

21. The downhole tool of claim 12 wherein the pulsation chamber is symmetrical around a central axis of the nose.

22. The downhole tool of claim 13 wherein the pulsation chamber has a larger diameter than the central bore.

23. The downhole tool of claim 11 wherein the central axis of the sub is aligned with the central axis of the nose.

24. The downhole tool of claim 18 wherein the external threads are provided on the outer diameter of the nose.

25. A downhole tool comprising:

a first stage comprising a sub having: a generally tubular body with a top end and a bottom end; a fluid inlet at the top end; a single fluid outlet at the bottom end; and a plurality of passages fluidly connecting the inlet at the top end and the single outlet at the bottom end, the plurality of passages configured to induce pressure pulses in a steady stream of fluid entering the sub through the inlet at the top end and discharge the fluid as a single pulsating stream through the single fluid outlet; and

a second stage connected to the first stage, the second stage comprising a nose having: a top end; a bottom end; an inlet provided in the top end of the nose to receive the pulsating fluid flow from the first stage; and at least one port is provided in the bottom end of the nose,

wherein the top end of the nose has external threads and the top end of the nose mates with the bottom end of the sub to form a pulsation chamber, and wherein the inlet in the top end of the nose is in fluid communication with the pulsation chamber, and wherein the at least one port of the nose is in fluid communication with the pulsation chamber.