Modular Well Plunger And System For Use Of Same In A Well Bore

Abstract

A variable volume modular well plunger with fishing neck segment having an upper fishing neck receiver and a lower threaded receiver and defining therebetween an annular chamber, at least one extension segment having a first end threadedly engaging the lower threaded receiver and a second end and defining therebetween an extension annular chamber communicating with the fishing neck annular chamber; and an end means for sealing chamber; a loading means for charging a treatment material; a means for deploying the plunger into a well bore; and a means for diffusing the treatment material at a desired position in the wellbore. Surface treatments adapted to provide at least one desired characteristic interaction between the plunger and tubing through which it passes selected from the group of wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable may be used alone or in any combination of multi-surface configurations.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application Ser. No. 61/741,135 filed Jul. 13, 2012.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus for increasing oil and gas recovery. More particularly, but not by way of limitation, the invention relates to improvements in chemical delivery system for a plunger lift used in wells.

In the recovery of oil from oil-bearing reservoirs, it is often possible to recover only a portion of the oil contained in the underground formation by the so-called primary recovery methods which utilize the natural forces present in the reservoir. Thus, a variety of enhanced recovery techniques, so called secondary or tertiary recovery have been employed in order to increase the recovery of oil from subterranean reservoirs.

The invention provides an improvement in the field by providing an apparatus for increasing oil and gas recovery in a well by enhancing oil and gas flow therein The invention includes a delivery mechanism, which has a chamber for delivering a flow enhancing substance to a producing zone of a well and further includes a plunger with a variable volume storage compartment for receiving the flow enhancing substance from a delivery mechanism at the well head and releasing the flow enhancing substance upon reaching the producing zone of the well.

RELATED ART

The inventor in this case also has two related issued U.S. patents. U.S. Pat. No. 7,004,258 teaches a method and apparatus for enhancing oil and gas flow in a well, and it claimed priority based on U.S. provisional application No. 60/462,837. The inventor later obtained U.S. Pat. No. 7,654,314 for a chemical delivery system for a plunger lift, and this second patent did not claim priority from either his earlier provisional patent or from the '258 patent. Collectively, the two prior patents for the inventor will be referred to as Prior Farris Patents.

The Prior Farris Patents both were directed to improving secondary oil and gas recovery using an improved chemical delivery system. Another object of both was to increase oil and gas production in an automated manner. The improvement in the Prior Farris Patents included modifications to the delivery means which includes a chamber communicably connected to a top of a well head. The '258 patent taught an apparatus for automated delivery of a flow enhancing substance upon measurement indicating that the production flow rate dropped below a pre-determined level. The '314 patent improved on the automated means for charging a plunger with a flow enhancing substance.

Specifically, the '314 patent taught that operably disposed within the chamber was a valve device which controls communication between two sections of the chamber. More particularly, the valve device was disposed in a first annular member which extends radially inward from the chamber wall. An annular valve seat is fixably disposed in an inner surface of the annular member. A ball valve cage is fixably connected to the annular seat and extends into the first section of the chamber. Openings are formed in the ball valve cage adjacent a first end thereof near the annular seat. Another opening is formed at a second end of the ball valve cage. A ball retainer extends inwardly from a ball valve cage wall and is disposed between the ends of the ball valve cage. A ball valve is movably disposed within the ball valve cage such that the ball can be moved between a first closed position wherein the ball valve is seated on the annular seat to prevent fluid flow to pass therethrough at the first end and a second open position wherein the ball valve is seated against opening at the second end wherein fluid flow is permitted to pass through openings at the first end and through the annular seat. A dip tube provided includes a radially enlarged first end, an elongated second end having a relatively smaller radius to the first end. The first end also includes a cushioning member for impact absorption when striking the ball valve. In this regard, the dip tube is generally movably disposed within the second section of the chamber with the first end capable of passing through the annular seat. A first annular impact stop for impacting adjacent the first annular member receives the elongated end of the dip tube therethrough while preventing the first end of the dip tube from passing therethrough. A second annular impact stop receives the elongated end therethrough and a spring is disposed between the stops and biases against them. A second annular member extends radially inward within the second section of the chamber to retain the stop. The first section of the chamber comprises an area which receives the chemical to be delivered into the well. Operably disposed within the first section adjacent a terminal end of the first section is a spring retainer and a disk and a spring disposed therebetween which biases against them. The disk has a protruding member which is configured to extend through the opening of the second end of the ball valve cage and displace the ball valve from the open position to the closed position. The disk has an annular seal to prevent fluid passing thereby along the chamber. Accordingly, the '314 patent was directed to chemical delivery system for a plunger lift for enhancing oil and gas recovery in a well. The system includes improvements in the means for automatically delivering a flow enhancing substance to a head of the well. There is provided lubricator piping connected to a tubing string and a controller having a sensor operably interconnected to the lubricator piping and a supply container containing a flow enhancing substance, which is further operably connected to a sales flow line, the controller is programmed to sense when well flow diminishes below a predetermined flow rate and is equipped to shut in the well through a flow control valve operably connected to the sales flow line. A plunger is operably disposed in a manner to move within the tubing string and the lubricating piping and has means for automatically receiving the flow enhancing substance from the delivering means at the well head and releasing the flow enhancing substance upon reaching a lower portion of the well. By so providing, the present invention enables oil and gas flow enhancing material delivery in an improved automated manner with minimal cost and modification to existing equipment. In doing so, improved oil and gas recovery is obtained.

The oil and gas flow enhancing substance can be for example microorganisms, inhibitors, corrosion preventatives, paraffin solvents, foaming agents and/or gas expansion agents. The form of the substance should be such to enable practice of the invention, which can preferably be liquid, or other gels or solids.

Given the wide variety of flow enhancing substances that can be used with the technology and the wide variety of well flow rates and other variables, different sizes of plungers will be needed from well to well. Further, even for the same well, as different flow enhancing substances are used or as the flow rate of the well or other characteristics change over time, a different volume of a specific flow enhancing substance may need to be delivered by the plunger.

SUMMARY OF THE INVENTION

As natural gas is extracted from drilled wells, salt water that also occupies space in the rock strata is swept to the well bore along with the natural gas being produced from the well bore. This salt water poses numerous problems as it accumulates in the well bore. A commonly utilized salt water extraction system known as “plunger lift” incorporates a solid steel “plunger” to push the salt water to the surface. Removal of the associated salt water improves the flow of natural gas. A patented process known as chemical delivery system for plunger lift disclosed in U.S. Pat. Nos. 7,004,258 and 7,654,314 incorporates a hollow plunger with a sealed bottom end. Thus, allowing any liquid chemical to be transported to the bottom of the natural gas well by the plunger. This action is intended to improve the extraction of the salt water and neutralize the negative effects the salt water has on the steel components in the well bore. Typical solid steel plungers are not capable of transporting any liquid chemical due to the design parameters.

The present invention includes a plunger design capable of transporting any liquid chemical. In addition, this plunger design incorporates extension segments which may also be referred to as profile segments. When multiple extension/profile segments are assembled, their combined inner volumes or chambers allow the total interior volume of the assembled plunger to be manipulated by increasing or decreasing the number of segments assembled. The segments according to the present invention can vary in design and function. Thus, allowing the well operator to customize the plunger based on the well conditions, i.e., chemical volume needed, plunger profile needed and the ability to mix and match various components to best function in any given well bore based on needs and/or conditions. However, it is expected that a preferred embodiment may include each segment having an overall length of six inches.

Each segment of the modular plunger may incorporate a male thread on one end and a female thread on the other end to allow multiple segments to be joined. The one exception to this general construction architecture is the fishing neck segment that always is preferably positioned on top of a modular plunger. This fishing neck segment is unique in that it has a lower threaded end and an upper fishing neck at the other end to allow for removal of the assembly from the well bore with a fishing tool. A bottom termination segment is required to close the lower end of the assembly. This segment has a female thread in the open end of a closed end cap that is attached to the bottom most segment thus creating an assembly capable of accepting a volume of liquid chemical equal to the volume of all segments in the assembly.

The present invention overcomes the shortcomings in the prior art, inter alia, by providing a variable volume plunger that can, in the field, be resized to accommodate a larger or smaller volume of flow enhancing substances as may be indicated by the well conditions and the type of flow enhancing substance being used.

The invention relates to a modular well plunger apparatus where the modular plunger has a fishing neck segment having an upper fishing neck receiver and a lower threaded receiver and defining therebetween a fishing neck annular chamber, at least one extension segment having a first end adapted to threadedly engage the lower threaded receiver and a second end and defining between the first and second ends an extension segment annular chamber in communication with the fishing neck annular chamber; and an end means for sealing the second end of a terminal extension segment. The foregoing components cooperate with a loading means for charging a treatment material into the chamber defined by the fishing neck annular chamber in communication with each extension segment, a deployment means for deploying the plunger into a well bore, and a release means for diffusing the treatment material at a desired position in the wellbore, whereby, a variable-volume plunger can be assembled having a desired aggregate internal volume, which the internal volume can be filled with a treatment material, then deployed into a desired position in a well bore.

The various segments may each have a different surface treatment, and those may be selected from wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable and other surface treatments well known in the oil and gas industry. Some of the surface treatments are proprietary, and some are long-established. Either way, these surface treatments are intended to be included within and are claimed herein.

A chemical delivery system is provided for delivering a variable volume of well treatment material into a well bore. The system may comprise a reservoir of well treatment material, a chamber communicably connected to a top of the well head adjacent a sales flow line and substantially disposed on top of a tubing string and operably disposed thereon and including a ball check valve device which controls communication between a first section of said chamber which receives said flow enhancing chemicals therein from said source for delivery into the well and a second section of said chamber which communicates said flow enhancing chemicals received from said first section to a plunger, which is movably disposed along said tubing string as a function of pressure within said tubing string in said well, and means for retaining said ball valve in one of an open position and a closed position as a function of the well being shut in, wherein said ball check valve device includes a ball valve cage in the first section, a first opening formed in said ball valve cage adjacent a first end, a second opening formed at a second end of said ball valve cage, a ball retainer extending inwardly from said ball valve cage and disposed between said ends of said ball valve cage, a ball valve movably disposed within said ball valve cage such that said ball valve can be disposed between the first closed position wherein said ball valve is seated on an annular seat to prevent fluid flow to pass therethrough at said first end and the second open position wherein said ball valve is seated against said second opening at said second end wherein fluid flow is permitted to pass through said first opening and through to said second section and which further includes a dip tube having a first end and a second end, wherein said dip tube is generally movably disposed within said second section and wherein said first end of said dip tube contacts said ball valve under force of the well and moves said ball valve to said open position. The plunger in the system has the features described above.

There have thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. Additional benefits and advantages of the present invention will become apparent in those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientist, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

DESCRIPTION OF THE DRAWINGS

Incorporated herein by reference are figures from U.S. Pat. No. 7,654,314. They illustrate relevant components in a typical oil and gas well that may be used in conjunction with the present invention. The figures incorporated include FIG. 1A is a longitudinal schematic of well having an automated delivery mechanism and plunger of the present invention therein in one mode. FIG. 1B is a longitudinal schematic of well having an automated delivery mechanism and plunger of the present invention therein in another mode. FIG. 2 from the '314 patent is a cross section of an embodiment of a plunger, which can be employed in FIG. 1. FIG. 3 is a schematic showing one mode of operation of the present invention showing a chamber on a modified well cap being filled with chemical. Finally, FIG. 4 from the '314 patent is a schematic showing another mode of operation of the present invention showing the delivery of chemical from the chamber to the plunger.

FIG. 1 is an exploded representation of an embodiment of the present invention having a fishing neck segment and a bottom segment as well as two extension segments.

FIG. 2 is a detail side view of an extension segment.

FIG. 3 is a detail end view of an extension segment.

FIG. 4 is a schematic representation of the use of two retainer rings to maintain a wear pad adjacent to an extension segment.

FIG. 5 is a detail side view of a retainer ring having two opposing annular retainer rings.

FIG. 6 illustrates an alternative surface treatment for an extension segment.

DETAILED DESCRIPTION OF THE INVENTION

The use of the modular variable volume plunger according to the present invention is generally described herein in connection with a system for automated dispensing of a flow enhancing substance. However, the modular plunger could also be used in a manual operation for injection of a flow enhancing substance. Whether the process is automatically or manually controlled, the use of the modular plunger allows a user to deliver the desired volume of a flow enhancing substance into the producing zone of a well to be treated.

Referring to the drawings from U.S. Pat. No. 7,654,314, a valve device is generally referred to by the numeral 100 and will be described in detail hereinafter. The valve device 100 is for use in a well 10 having a well bore surface 12 drilled into the earth 14. Typical well string casing 16 exists within the well bore surface 12 and extends into the earth 14 to a gas and/or oil zone 18. A tubing string 20 is operably installed within the string casing 16 through which the gas and oil flow. Lubricator piping 22 is connected to the top of the tubing string 20. A controller 23 is operably connected to the lubricator piping 22 and sales flow line 25. The controller 23 senses the pressure in the well 10 and can shut in the well 10 through an operable connection to a flow control valve 27.

An oil and gas flow enhancing substance 24 resides in a supply tank or other suitable container, which can preferably be located adjacent the well. On top of the lubricator piping 22 is the valve device 100. The valve device 100 has a chamber 28 formed thereon with an open surface 30 therethrough for communicating between the lubricator piping 22 and chamber 28. The valve device 100 includes modifications to the delivery means which includes a chamber 28 communicably connected to a top of a well head via a threaded connection, for example. Operably disposed within the chamber 28 is a check valve device 101 which controls communication between two sections 102 and 104 of the chamber 28. More particularly, the check valve device 101 is disposed in an annular member 106, which extends radially inward from the chamber 28. An annular valve seat 108 is fixably disposed to a threaded adapter 109, which connects to an inner surface 110 of the annular member 106. A ball valve cage 112 is fixably connected to a part of the threaded adapter 109 adjacent annular seat 108 and extends into the section 102. Openings 114 are formed in the ball valve cage 112 adjacent a first end near the annular seat 108. Another opening 116 is formed at a second end of the ball valve cage 112. Ball retainers 118 extend inwardly from the ball valve cage 112 and are disposed between the ends of the ball valve cage 112. A ball valve 120 is movably disposed within the ball valve cage 112 between a first closed position wherein the ball valve 120 is seated on the annular seat 108 to prevent fluid flow to pass therethrough at the first end and a second open position wherein the ball valve 120 is seated against opening 116 at the second end wherein fluid flow is permitted to pass through openings 114 and through annular seat 108.

A dip tube 122 includes a radially enlarged first end 124 an elongated second end 126 having a relatively smaller radius to the first end 124. The first end 124 also includes a cushioning member 128 for impact absorption when striking the ball valve 120. In this regard, the dip tube 122 is generally movably disposed wherein the elongated end 126 moves in the second section 104 with that the first end 124 capable of passing through the annular seat 108 to contact the ball valve 120. A first annular impact stop 130 for impacting a part of the threaded adapter 109 extends into the second section 104 adjacent annular member 106 receives the elongated end 126 therethrough while preventing the first end 124 from passing therethrough. A second annular impact stop 132 receives the elongated end 126 therethrough and a spring 134 is disposed between the stops 130 and 132 and biases against them. An annular member 136 extends radially inward within the section 104 to retain the stop 132.

Section 102 of the chamber 28 includes an area which receives the chemical 24 to be delivered into the well 10 through an opening 129 in the chamber 28. Operably disposed within the section 102 adjacent a terminal end of the section 102 is a spring retainer 138 chemical spring follower and a disk 140 chemical chamber spring follower and a spring 142 disposed therebetween which biases against them. The disk 140 has a protruding member 144 which is configured to extend through the opening 116 and displace the ball valve 120 from the open position to the closed position. The disk 140 has an annular seal 146 to prevent fluid passing thereby. A controlled valve 50 connects to the chamber 28 through opening 129 and the supply tank of flow enhancing substance 24 and is controlled by controller 23 to enable a controlled amount of the substance 24 to enter the chamber 28 when the check valve ball 120 is in the closed position, thus not enabling communication with the lubricator piping 22.

Earlier inventions employed a plunger 48 such as an interlocking expandable, wobble washer, brush plunger, wear pad, or the like. In their simplest forms the plunger 48 can include an inlet 52 through which an amount of the substance 24 is received into an inner open surface 54 and upon reaching the well floor the chemical 24 can be forced out through natural forces.

FIG. 1 shows a Modular Well Plunger 200 consistent with the teachings of the present invention. A fishing neck segment 202 is provided in each assembly. The fishing neck assembly 202 has a fishing neck 210 at a first end and a female threaded receiver 212A at a second end. Defined there between is a fishing neck volume 214.

Fishing necks are well known in the oil and gas industry and an example of a fishing tool neck is taught by U.S. Pat. No. 5,242,201 to Beeman. Beeman teaches a fishing neck that is resettable. Traditional fishing tools required the use of sheer pins that had to be destroyed to allow releasing the fish. There are additional fishing tool attachment mechanisms that are well known in the art, and those are incorporated herein by reference including, but not limited to Beeman and the references cited by Beeman. Additional patents intended to be and incorporated herein by reference as it relates to fishing connections to be used in conjunction with the present invention include but are not limited to U.S. Pat. No. 8,141,634, which teaches a releasing and recovering tool, U.S. Pat. No. 7,152,674 which teaches a disconnect device, U.S. Pat. No. 7,096,951 which teaches a method and apparatus for retrieving an object from a well bore, U.S. Pat. No. 6,095,583 which teaches well bore fishing tools, U.S. Pat. No. 5,791,712 which teaches a spear fishing tool. All of the foregoing are intended to be embodied within the patent to the extent it discusses the fishing neck and its connection and deployment.

FIG. 1 also shows two extension segments 204A and 204B. The first extension segment 204A is connected to the fishing neck segment 202 by male threads 222A received within the female threaded receiver 212A. Once connected, the fishing neck volume 214 is in fluid communication with the extension segment volume 216A. As shown in FIG. 1, a second extension segment 204B is affixed to the first extension segment 204A. The second extension segment 204B is threaded into the first extension segment 204A, which allows the first extension segment volume 216A to be in fluid communication with the second extension segment volume 216B. According to the invention, there can be any number of repeating extension segments 204. As shown, there are two, but there could be one or as many as needed to provide an appropriate volume of flow enhancing material to be delivered down hole.

At the bottom of each modular well plunger 200 will be a bottom segment 206. The bottom segment shown also has a threaded male section 222B at the top for attaching it to the female threads 212C of the adjacent second extension segment 204B. Defined within the bottom segment 206 is a bottom segment volume 218. The bottom segment 206 as shown terminates in bottom section female thread 242, which can be sealed by a threaded end cap 208. The bottom segment 206 could also have an integral bottom portion which is inherently sealed. The end cap 208 could be affixed by other means besides threading, and it could be externally threaded as well.

FIG. 2 shows an extension segment 204 in greater detail. The male threads 222 at the first end are shown, and with outline indicators the female threads 212 are shown at a second end. Between the two ends is an extension segment volume 216.

FIG. 3 is an end view of the segment 204 shown in FIG. 2. In FIG. 3, an outside diameter 224 of the extension segment 204 can be seen. Preferably, the fishing segment 202, the extension segment(s) 204, and the bottom segment 206 will all have the same outside diameter. However, one or more of them may have a different external profile (such as a wear pad or wobble washer). An internal passage 226 is defined through the male threaded end 222, which allows fluid communication with the extension segment volume 216. The hatched lines show the internal diameter 228 of the extension segment volume 216.

FIG. 4 shows an embodiment with a wear pad 236 disposed outside of the outer diameter 224 of the first extension segment 204A. A retainer ring 230 is deployed between the fishing neck segment 202, and the first extension segment 204A. It defines a ring opening 234 therein allowing passage of the male threads 222 therethrough. At least one annular retainer ring 232 is defined at a periphery of the retainer ring 230 for receiving therein a retaining edge 238 on the wear pad 236. A cooperating pair of retainer rings 230 are thus adapted to trap and retain a wear pad 236 along an outer surface of one or more segments. The retainer rings could also be used to trap and retain other types of surface treatments, such wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable, which are well known to those skilled in the art of oil and gas production.

A retainer ring 230 with both an annular retainer ring 232 and an opposing annular retainer ring 244 is illustrated in in FIG. 5. The annular retainer ring 232 illustrated in FIG. 5 may be used where it is desirable to retain a surface treatment on more than one adjacent segment.

Another embodiment of a surface treatment 240 is shown in FIG. 6. As noted above, there are a variety of surface treatments that can be used, and the invention is intended to not be limited to the types of surface treatments shown in this embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. While various methods of use and structures of the present invention are described herein, any methods or structures similar or equivalent to those described herein may be used in the practice or testing of the present invention. All references cited herein are incorporated by reference in their entirety and for all purposes. In addition, while the foregoing advantages of the present invention are manifested in the illustrated embodiments of the invention, a variety of changes can be made to the configuration, design and construction of the invention to achieve those advantages including combinations of components of the various embodiments. Hence, reference herein to specific details of the structure and function of the present invention is by way of example only and not by way of limitation.

While the invention has been shown, illustrated, described and disclosed in terms of specific embodiments or modifications, the scope of the invention is not limited by the precise embodiments or modifications therein shown, illustrated, described or disclosed. Such other embodiments or modifications are intended to be reserved especially as they fall within the scope of the claims herein appended.

Claims

1. A modular well plunger apparatus comprising:

a. a modular plunger having— i. a fishing neck segment having an upper fishing neck receiver at an upper end thereof and a lower threaded receiver and defining therebetween a fishing neck annular chamber, ii. at least one extension segment having a first end adapted to threadedly engage the lower threaded receiver and a second end and defining between the first and second ends an extension segment annular chamber in communication with the fishing neck annular chamber; and iii. an end means for sealing the second end of a terminal extension segment;

b. a loading means for charging a treatment material into an aggregated chamber volume defined by the fishing neck annular chamber in communication with an internal volume of each additional segment;

c. a deployment means for deploying the plunger into a well bore; and

d. a release means for diffusing the treatment material at a desired position in the wellbore,

whereby, a variable-volume plunger can be assembled having a desired aggregate internal volume, which the internal volume can be filled with a treatment material, then deployed into a desired position in a well bore.

2. The plunger apparatus of claim 1 further comprising a surface treatment adapted to provide at least one desired characteristic interaction between the plunger and an inner surface of the tubing through which it passes.

3. The plunger apparatus of claim 2, each surface treatment being interchangeably retained between a pair of retainer rings.

4. The plunger apparatus of claim 2, the surface treatment selected from the group of wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable.

5. The plunger apparatus of claim 4, each surface treatment being interchangeably retained between a pair of retainer rings.

6. The plunger apparatus of claim 1 further comprising more than one different surface treatment adapted to provide at least two desired characteristic interaction between the two different segments of the plunger and an inner surface of the tubing through which they pass.

7. The plunger apparatus of claim 6, each surface treatment being interchangeably retained between a pair of retainer rings.

8. The plunger apparatus of claim 6, the surface treatments selected from the group of wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable.

9. The plunger apparatus of claim 8, each surface treatment being interchangeably retained between a pair of retainer rings.

10. A chemical delivery system for delivering a variable volume of well treatment material into a well bore, the system comprising:

a. a reservoir of well treatment material;

b. a chamber communicably connected to a top of the well head adjacent a sales flow line and substantially disposed on top of a tubing string and operably disposed thereon and including a ball check valve device which controls communication between a first section of said chamber which receives said flow enhancing chemicals therein from said source for delivery into the well and a second section of said chamber which communicates said flow enhancing chemicals received from said first section to a plunger which is movably disposed along said tubing string as a function of pressure within said tubing string in said well, and means for retaining said ball valve in one of an open position and a closed position as a function of the well being shut in, wherein said ball check valve device includes a ball valve cage in the first section, a first opening formed in said ball valve cage adjacent a first end, a second opening formed at a second end of said ball valve cage, a ball retainer extending inwardly from said ball valve cage and disposed between said ends of said ball valve cage, a ball valve movably disposed within said ball valve cage such that said ball valve can be disposed between the first closed position wherein said ball valve is seated on an annular seat to prevent fluid flow to pass therethrough at said first end and the second open position wherein said ball valve is seated against said second opening at said second end wherein fluid flow is permitted to pass through said first opening and through to said second section and which further includes a dip tube having a first end and a second end, wherein said dip tube is generally movably disposed within said second section and wherein said first end of said dip tube contacts said ball valve under force of the well and moves said ball valve to said open position;

c. the plunger having— i. a fishing neck segment having an upper fishing neck receiver at an upper end thereof and a lower threaded receiver and defining therebetween a fishing neck annular chamber, ii. at least one extension segment having a first end adapted to threadedly engage the lower threaded receiver and a second end and defining between the first and second ends an extension segment annular chamber in communication with the fishing neck annular chamber; and iii. an end means for sealing the second end of a terminal extension segment,

whereby, whereby, a variable-volume plunger can be assembled having a desired aggregate internal volume, which the internal volume can be filled with a treatment material, then deployed into a desired position in a well bore.

11. The system of claim 10 further comprising a surface treatment adapted to provide at least one desired characteristic interaction between the plunger and an inner surface of the tubing through which it passes.

12. The system of claim 11, each surface treatment being interchangeably retained between a pair of retainer rings.

13. The system of claim 11, the surface treatment selected from the group of wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable.

14. The system of claim 13, each surface treatment being interchangeably retained between a pair of retainer rings.

15. A modular well plunger apparatus comprising:

a. a modular plunger having— i. a fishing neck segment having an upper fishing neck receiver at an upper end thereof and a lower threaded receiver and defining therebetween a fishing neck annular chamber, ii. at least one extension segment having a first end adapted to threadedly engage the lower threaded receiver and a second end and defining between the first and second ends an extension segment annular chamber in communication with the fishing neck annular chamber; and iii. an end means for sealing the second end of a terminal extension segment;

b. at least one surface treatment adapted to provide at least one desired characteristic interaction between the plunger and an inner surface of tubing through which it passes;

c. each surface treatment being interchangeably retained between a pair of retainer rings;

d. a loading means for charging a treatment material into an aggregated chamber volume defined by the fishing neck annular chamber in communication with an internal volume of each additional segment;

e. a deployment means for deploying the plunger into a well bore; and

f. a release means for diffusing the treatment material at a desired position in the wellbore,

whereby, a variable-volume plunger can be assembled having a desired aggregate internal volume, which the internal volume can be filled with a treatment material, then deployed into a desired position in a well bore.

16. The plunger apparatus of claim 15, the surface treatment selected from the group of wear pads, spiral brushes, non-sprial brushes, wobble washers, grooved surface, and interlocking expandable.