Abstract:
An improvement in a chemical delivery system for a plunger lift for enhancing oil and gas recovery in a well having a well head and which employs a plunger includes a chamber communicably connected to a top of the well head and operably disposed thereon and including a ball check valve device which controls communication between a first section which receives chemicals therein for delivery into the well and a second section which communicates chemicals from the first section to a plunger in the well, and means for retaining the ball valve in one of an open position and a closed position as a function of the well being shut in.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to 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. 
   2. Related Art 
   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 inventor or the instant invention provided an improvement in the field by providing apparatus for increasing oil and gas recovery in a well by enhancing oil and gas flow therein. In that invention, the apparatus includes a delivery mechanism which has chamber and valve mechanism for automatically delivering a flow enhancing substance to a head of the well and further included a plunger which includes a storage compartment with a valve for automatically receiving the flow enhancing substance from the delivery mechanism at the well head and releasing the flow enhancing substance upon reaching a lower portion of the well. 
   The prior invention was an improvement over chemical activated oil and gas flow enhancing liquids and sticks, such as soaps, which are commonly known to reduce scale, paraffin and the viscosity of the fluids in the well and thus increase production of oil and gas recovery. The prior invention was thought to be more economical or practical due to a reduction in manual intervention, additional equipment and costs associated therewith. 
   While the inventor provided improvement over the art, there remains a need to improve upon the delivery system. The current invention provides an improvement over the same. 
   SUMMARY OF THE INVENTION 
   An object is to improve secondary oil and gas recovery using an improved chemical delivery system. 
   Another object is to increase oil and gas production in an automated manner. 
   Accordingly, the present invention is 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. 
   The improvement includes modifications to the delivery means which includes a chamber communicably connected to a top of a well head. Operably disposed within the chamber is a valve device which controls communication between two sections of the chamber. More particularly, the valve device can be 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 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 (referred to as a “chemical spring follower”) and a disk (referred to as a “chemical chamber spring follower”) 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. 
   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. Other objects and advantages will be readily apparent to those skilled in the art upon viewing the drawings and reading the detailed description hereafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       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  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. 
       FIG. 4  is a schematic showing another mode of operation of the present invention showing the delivery of chemical from the chamber to the plunger. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings, the valve device improvement to which the invention is particularly concerned is generally referred to by the numeral  100  and will be described in detail hereinafter. The valve device improvement  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  10 . On top of the lubricator piping  22  is the valve device improvement  100 . The valve device improvement  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 improvement  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  (e.g., four ⅜″ ports evenly spaced) are formed in the ball valve cage  112  adjacent a first end near the annular seat  108 . Another opening  116  (e.g., a ⅜″ opening) 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  (such as a Delrin™ cushion) 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 . 
   A plunger  48  is employed and is a similar type to that known in the art, such as an interlocking expandable, wobble washer, brush plunger, etc. In its simplest form, 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. 
   When the well  10  is shut in by the controller  23 , pressure builds in the well  10  which causes the plunger  48  to rise and contact the dip tube  122  and in turn impact the impact stop  132  which drives it, the spring  134 , and the stop  130  upward. This action closes gap between stop  132  and stop  130 . The force from closing in the well  10  thus forces the first end  124  (ball impactor) up, through annular seat  108  (valve seat) to force check ball valve  120  off the seat  108 . The first end  124  (ball impactor) continues in an upward direction forcing the check valve ball  120  up past the ball retainers  118 . The check valve ball  120  remains suspended above ball retainers  118  allowing chemical to flow from section  102  (chemical chamber) down and around valve ball cage  112  and through the plurality of openings  114  (four ⅜″ ports). 
   Once disk  140  (chemical chamber spring follower) in section  102  (chemical chamber) through force of the spring  142  pushes chemical through check valve  101  and reaches a top of valve ball cage  112 , the protruding member  144  travels through opening  116  (e.g. ⅜″ opening) and pushes check valve ball  120  down past ball retainers  118 . This allows check valve ball  120  to free fall and seal back on annular seat  108 . This completes cycle for chemical moving from section  102  (chemical chamber) through valve  100  and down, through dip tube  122  into plunger  48 . The plunger  48  falls to the bottom of the well  10  once the flow is open as discussed herein. 
   The oil and gas flow enhancing substance  24  can be for example microorganisms, inhibitors, corrosion preventatives, paraffin solvents, foaming agents and/or gas expansion agents. The form of the substance  24  should be such to enable practice of the invention, which can preferably be liquid, or other gels or solids. 
   The well  10  is equipped with the controller  23  to open and shut the well fluid flow. The plunger  48  drops to the bottom of the well  10  or to a point where the plunger  48  impacts a fluid level. At such point, the impact the release of the substance  24  at the lower portion of the well begins chemically reacting releasing the oil and/or gas flow enhancing agent at the most desired point, the oil and/or gas zone. Once flow in the well diminishes below a predetermined flow rate as determined by the controller  23 , the controller  23  shuts then the valve  27  and the cycle is repeated. 
   While the preferred embodiment of the present invention is illustrated and described, it is to be understood that this is capable of variations and modifications and therefore, the applicant does not wish to be limited to the precise details set forth, but desires to avail himself of such changes and alterations as fall within the purview of the following claims.