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 
       [0001]    This application claims benefit of U.S. Provisional Application Ser. No. 61/741,135 filed Jul. 13, 2012. 
     
    
     FIELD OF THE INVENTION 
       [0002]    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. 
         [0003]    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. 
         [0004]    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 
       [0005]    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 &#39;258 patent. Collectively, the two prior patents for the inventor will be referred to as Prior Farris Patents. 
         [0006]    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 &#39;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 &#39;314 patent improved on the automated means for charging a plunger with a flow enhancing substance. 
         [0007]    Specifically, the &#39;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 &#39;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. 
         [0008]    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. 
         [0009]    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 
       [0010]    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. 
         [0011]    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. 
         [0012]    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. 
         [0013]    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. 
         [0014]    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. 
         [0015]    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. 
         [0016]    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. 
         [0017]    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. 
         [0018]    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. 
         [0019]    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 
         [0020]    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 &#39;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 &#39;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. 
           [0021]      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. 
           [0022]      FIG. 2  is a detail side view of an extension segment. 
           [0023]      FIG. 3  is a detail end view of an extension segment. 
           [0024]      FIG. 4  is a schematic representation of the use of two retainer rings to maintain a wear pad adjacent to an extension segment. 
           [0025]      FIG. 5  is a detail side view of a retainer ring having two opposing annular retainer rings. 
           [0026]      FIG. 6  illustrates an alternative surface treatment for an extension segment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    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. 
         [0028]    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 . 
         [0029]    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 . 
         [0030]    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 . 
         [0031]    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 . 
         [0032]    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. 
         [0033]      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  212 A at a second end. Defined there between is a fishing neck volume  214 . 
         [0034]    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. 
         [0035]      FIG. 1  also shows two extension segments  204 A and  204 B. The first extension segment  204 A is connected to the fishing neck segment  202  by male threads  222 A received within the female threaded receiver  212 A. Once connected, the fishing neck volume  214  is in fluid communication with the extension segment volume  216 A. As shown in  FIG. 1 , a second extension segment  204 B is affixed to the first extension segment  204 A. The second extension segment  204 B is threaded into the first extension segment  204 A, which allows the first extension segment volume  216 A to be in fluid communication with the second extension segment volume  216 B. 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. 
         [0036]    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  222 B at the top for attaching it to the female threads  212 C of the adjacent second extension segment  204 B. 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. 
         [0037]      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 . 
         [0038]      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 . 
         [0039]      FIG. 4  shows an embodiment with a wear pad  236  disposed outside of the outer diameter  224  of the first extension segment  204 A. A retainer ring  230  is deployed between the fishing neck segment  202 , and the first extension segment  204 A. 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. 
         [0040]    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. 
         [0041]    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. 
         [0042]    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. 
         [0043]    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.