Downhole gas separator

A tool (400) is disclosed for use in recovering gas from a gas well without the production of water as well. The tool (400) uses a member, such as plurality of vertically stacked balls (430) which are lighter than water to close a channel 422 when the water level (432) exceeds a certain level. As gas accumulates about the balls, the water level 432 will be moved downwardly, eventually causing the balls to move out of engagement with the seal surface (424), opening the channel (422) for passage of the gas upwardly for recovery. As the water level rises, the balls will again seal against the seal surface (424).

REFERENCE TO DISCLOSURE DOCUMENT 
A disclosure document, Document No. 278342 was filed in the U.S. Patent and 
Trademark Office on Apr. 9, 1991 with the title "Down-Hole Gas/Liquid 
Separator." A separate letter identifying this disclosure document is 
filed with this application. The U.S. Patent and Trademark Office is 
requested to retain this disclosure document with the patent application 
in accordance with the provisions of MPEP .sctn. 1706. 
TECHNICAL FIELD 
This invention relates to oil production, and in particular to a separator 
pump utilizing well gas pressure to separate gas and water. 
BACKGROUND OF THE INVENTION 
In the oil and gas production industry, natural gas wells frequently also 
produce salt water with the gas. This salt water frequently comes from the 
same geologic formation as the gas, and when lifted to the surface with 
the produced gas, must be disposed of in a safe and ecological manner. 
This fact places an economic burden upon a gas well since the salt water 
may only be disposed of in state regulated and approved wells, which 
frequently require the water to be trucked great distances due to their 
locations. Frequently, a pump jack must be used to lift the water to the 
surface. These are expensive to operate and have high maintenance costs 
and down time. In addition to the costs of pumping the water up, storage 
facilities must be provided on location to safely store the water. 
Trucking the water is costly, and a fee must be paid to use the state 
approved water disposal well. Thus, the concurrent production of salt 
water with natural gas places a heavy economic burden upon the gas well. 
Many otherwise profitable wells are rendered unprofitable by the economic 
burden of produced salt water. 
In gas wells that produce salt water, there has to date been no choice but 
to produce the water with the gas. If the water is not removed from the 
well bore, a column of water will rise vertically up the well bore until 
the hydraulic head of this column has become equal to the pressure of the 
formation from which it originated. When this point of equilibrium is 
reached, no further gas production will occur and the well will remain in 
this state until the hydrostatic head is decreased. 
The use of plunger pumps to produce oil from a well having usable gas 
pressure is well known. In basic principle, a plunger pump is dropped from 
the surface through the well casing or tubing and into the oil/gas mixture 
downhole. A mechanism, typically one operated by hydrostatic pressure, 
closes a passage in the plunger pump to allow gas pressure to build up 
beneath the pump. The gas pressure builds to a point where it lifts the 
pump, and a quantity of oil above the pump, to the surface where the oil 
is recovered. The gas pressure beneath the pump is relieved to allow the 
pump to fall downhole again to re-initiate the sequence. 
One example of a plunger pump is disclosed in U.S. Pat. No. 4,070,134, 
issued Jan. 24, 1978 to Gramling. However, this device has not proven 
reliable in actual use, and a need exists for an improved plunger pump 
which provides for efficient production of oil, condensate, and 
de-watering of gas wells, either through casing or tubing. For simplicity, 
the following discussion will be limited to the plunger pump application 
in casing, with the understanding that the same principles of operation 
can be applied to its use in tubing. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the present invention, a tool is provided 
for separating gas and water in a natural gas well. The well has a casing 
and production tubing within the casing. The tool is part of the 
production tubing and includes a body defining an upper chamber, a lower 
chamber and a passage interconnecting the upper and lower chambers. The 
tool also includes a member having a density less than the water in the 
gas well. A seal surface is defined on the body about the passage, the 
member floating against the seal surface to seal the passage from the 
lower chamber when the level of water exceeds a predetermined height and 
floating away from the seal surface to release the seal, permitting gas to 
flow from the lower chamber to the upper chamber through the passage when 
the level of water is below the predetermined height. 
In accordance with one aspect of the present invention, a tool is provided 
for pumping oil from a gaseous well through a casing of predetermined 
internal diameter extending from the surface to below the oil level. The 
tool includes a body formed of plastic, with the body defining an upper 
chamber and a lower chamber therein. At least one seal is employed to seal 
between the exterior of the body at a first position along the body and 
the inner surface of the casing to prevent oil or gas flow past the 
exterior of the body. In the preferred embodiment, two seals are utilized. 
The body has an upper vent to vent the upper chamber to the exterior of 
the body above the seals. The body also has a lower vent to vent the lower 
chamber to the exterior of the body below the seals. A separator is 
provided for separating oil from a gaseous oil mixture and permitting the 
separated oil to flow into the upper chamber. Structure is provided for 
stopping the flow of the separated oil into the upper chamber, permitting 
the gas pressure to build up in the casing below the tool and lift the 
tool, and the oil in the upper chamber and casing above the seal to the 
surface for recovery. 
In accordance with another aspect of the present invention, the plastic is 
ABS plastic. Further, structure can be provided for free communication 
between the upper and lower chambers prior to the tool being submerged 
below the oil level to provide for rapid movement of the tool from the 
surface to the oil level. Further, structure can be provided to control 
the fall of the tool from the surface to the oil level.

DETAILED DESCRIPTION 
With reference now to the drawings, wherein like reference numerals 
designate like or corresponding parts throughout the several views, and in 
particular to FIGS. 1 and 1A, a pump tool 10 is illustrated which forms a 
first embodiment of the present invention. 
The pump tool 10 is employed within a well 12 having a significant gas 
pressure to pump oil from its natural level 14 to the surface 16 by the 
use of the gas pressure within the well alone. The pump tool 10 operates 
within a casing 18 of relatively uniform interior diameter 20 which 
extends from the surface to well below the oil level 14. A stand 21 is 
secured in the casing 18 above the perforations into the producing 
formation. 
The pump tool 10 includes a body 22 which is preferably formed of ABS 
plastic. The body 22 has a hollow interior which is broadly separated into 
an upper chamber 24 and a lower chamber 26. 
At one position along the length of the exterior 28 of the body is formed 
an annular seat 30 for a cup seal 32. The cup seal 32 seals between the 
exterior of the pump tool and the inner wall of the casing 18 to prevent 
oil or gas from flowing around the exterior of the pump tool past the 
seal. Thus, the only path for gas and oil flow in the casing between the 
section above the seal and the section below the seal is through the 
interior of the tool 10 itself. 
A labyrinth passage 36 in the body connects the bottom of the lower chamber 
26 with the interior of the casing below the seal. The purpose of the 
labyrinth passage 36, as will be described in greater detail hereinafter, 
is to provide sufficient aerodynamic resistance to the tool as it drops 
freely from the surface to the oil level 14 to prevent the tool from 
exceeding a velocity that would be likely to cause excessive wear to the 
seal 32 or damage to the tool as it drops into the oil downhole. A series 
of gas vents 38 and 40 are formed through the body near the top of the 
lower chamber 26 at two positions along the length of the tool. 
The body 22 provides an annular opening 42 which connects the upper and 
lower chambers. However, a valve 44 is operable to seal against the body 
to close off the opening 42 and isolate the upper and lower chambers. The 
valve 44 is connected to a stem 46 extending into a sealed cylinder 48 
formed in the body. The end of stem 46 is attached to a piston 50 which 
moves in sealed sliding contact with the interior surface of the sealed 
cylinder 48. A spring 52 acts between the interior end of the cylinder 48 
and the upper surface of piston 50 to urge the piston 50 to the open 
position, allowing free flow between the upper and lower chambers. A gas 
is sealed within the cylinder in the chamber defined by the upper surface 
of the piston and the enclosing interior walls of the cylinder. The force 
of the spring 52 and the gas are sufficient to hold the valve open as the 
tool is dropped from the surface into the oil to facilitate rapid movement 
of the tool. However, once the tool drops below the oil level, the 
hydrostatic pressure of the oil will act on the lower face of the valve 
44, causing the valve 44 to close and isolate the upper and lower 
chambers. 
Forming the outer perimeter of the annular opening 42 is an annular plate 
54. A pair of tubes 56 extend from the plate 54 downward into the lower 
chamber 26. The tubes have a passage 58 therethrough which provide for 
communication between the upper chamber and lower chamber. Guided on tubes 
56 is an annular float 60. The float defines an annular chamber 62 which 
communicates with the lower chamber through ports 64 near the upper end of 
the chamber 62. The lower ends of tubes 56 extend through the float and 
into the chamber 62 as illustrated. A tube seal 66 is mounted at the 
bottom of chamber 62 beneath each of the tubes 56 to seal the passages 58 
from the chamber 62 if the chamber 62 floats upward to the position 
denoted in the dotted line in FIG. 1. Within each tube 56 is also provided 
a fall valve 68 which permits only one-way flow from the chamber 62 into 
the passages. 
The tubes 56, float 60 and seal ball 68 combine to form an oil separator 
for separating oil from a oil gas mixture in the lower chamber. The 
fundamental principles of the separator are disclosed in U.S. Pat. No. 
3,410,217, issued Nov. 12, 1968 to Kelly, et al, which patent is hereby 
incorporated by reference in its entirety. 
In operation, the float will move upward into the dotted line position, 
isolating the chamber 62 from passages 58, when there is an oil/gas 
mixture in the chamber 62. However, as oil rises in the casing to the 
level of the ports 64, the oil will fill the chamber 62, making the float 
heavier relative to the oil and gas mixture in the lower chamber and 
permitting the float to descend within the chamber to the position shown 
in FIG. 1. This opens the float connection between chamber 62 and the 
passages 58 to allow the pump tool 10 to descend further into the casing 
with the oil in chamber 62 moving through the passages into the upper 
chamber to fill the upper chamber, and out ports 34 to the interior of the 
casing above the cup seal 32. 
The pump tool 10 continues to drop within the casing, with a hydrostatic 
head of oil above the tool until valves 70 move downward in the tool in 
response to the increased hydrostatic head to seal off the tubes 56 from 
the upper chamber 24. The valves 70 are mounted on a rod 72 which extends 
into a second sealed cylinder 74. The end of rod 72 extending into the 
cylinder is connected to a piston 76 which moves in slidable sealed motion 
with the interior surface of the cylinder 74. The chamber 78 formed below 
the lower surface of piston 76 and the interior of the cylinder contains a 
gas at predetermined pressure and a spring 80 which both act to elevate 
the seals above the tubes to connect the upper chamber and passages 58. 
However, as the hydrostatic head of the oil above the tool increases, the 
seals and rod 72 are moved downward relative to the seal chamber against 
the force of the gas in chamber 78 and spring 80 until the seals seal 
against the upper ends of the tubes to isolate the passages from the upper 
chamber. When this happens, gas pressure begins to build up in the lower 
chamber and in the casing below the cup seal 32. The pressure build-up 
will eventually be sufficient to lift the tool 10, and the oil above it, 
to the surface where the oil can be recovered. Once the tool has reached 
the surface, and the oil has been recovered, a mechanism must be provided 
to release the gas pressure beneath the tool to allow the tool to fall 
again down the casing to begin the lifting cycle anew. 
With reference to both FIGS. 1 and 2 the body 10 can be seen to define a 
passage 82 which receives a release piston 84. In the absence of external 
forces, the piston 84 is centered over ports 86 which connect the lower 
chamber with the upper chamber by springs 88 and 90. A rod 92 is connected 
to the piston and extends upwardly through a hole 93 in the body and for a 
predetermined distance above the tool. Ports 94 are formed through the 
body and open into the portion of the passage containing springs 88 and 90 
to equalize the pressure on either side of the release piston 84. 
The release piston 84, which acts as a pressure differential release 
system, is very important to allow release of a stuck tool. An important 
aspect of this system is that the pressure can be released by pulling up 
on the tool, as opposed to the conventional manner of striking a valve 
with a suspended weight. For example, in Gramling's tool disclosed in U.S. 
Pat. No. 4,070,134, at least a 100 lb weight is required to strike the 
release valve. In the present invention, a conventional wire line fishing 
tool can easily release the back pressure and retrieve the tool all in one 
trip down the hole, without the problem of launching the tool when it 
becomes unstuck with a high pressure beneath it so that it becomes a 
projectile launched from the casing. 
As seen in FIG. 2, the upper portion of the casing is provided with a 
release piston activator 104 which is positioned in the path of the rod as 
the tool nears the surface to release the gas pressure and permit the tool 
to fall again into the casing. 
With reference to FIG. 3, a pump tool 110 forming a first modification of 
tool 10 is illustrated. The tool 110 is identical in many aspects with 
tool 10, and those elements of tool 110 identical to elements in tool 10 
are identified with the same reference numerals. However, as will be 
observed, the tool 110 is a simpler design which does not incorporate an 
oil separator as provided in pump tool 10. 
With reference now to FIGS. 4 and 5, a second modification of the present 
invention is illustrated as pump tool 200. Many elements of pump tool 200 
are identical in design and function to those in pump tool 10 and pump 
tool 110, and are therefore identified by the same reference numerals. 
However, the body 202 of pump tool 200 can be seen to provide two annular 
seats 204 and 206 to receive cup seals 208 and 210 to seal between the 
body and the interior surface of casing 18. Body 202 also mounts an oil 
intake tube or tail 212 which extends downwardly into the oil within the 
casing. The tail 212 consists of a flexible tube, preferably assembled of 
10 foot long sections which are attachable in series to any total tail 
length desired. Each section or length is weighted to keep the tail 
vertical and to allow it to sink into the oil. 
In operation, the pump tool will cause gas to stay below the tool body 202, 
in effect causing a gas bubble to grow in the casing as more oil is 
processed. As compared to pump tool 10 and 110, the gas bubble generated 
cannot shut down the separator when the bubble grows down past the oil 
intake for the separator, thereby depriving the unit of the oil supply. 
The tail 212 allows the separator to continue functioning since it will 
ensure an oil supply to the separator at all times. Oil will be forced up 
the interior passage through the tail by the pressure differential between 
the area above the tool 200 and the sealed off area below the tool. A tail 
length of 40' to 60' could be used, for example, to ensure adequate 
separation. 
As seen in FIG. 5, the upper end of the tail 212 opens into the separator 
214 which includes a cavity 216 which is vented at its upper portion to 
the casing through gas venting ports 218. The oil can flow into annular 
cavities 220 to the bottom of the cavities and then up the interior of 
tubes 222. The lower end of each tube 222 mounts a one-way ball valve 224, 
while the upper end of each tube opens through the annular plate 54. 
Referring again to FIG. 2, a movable arm 96 is provided at the surface 
which can be used to catch the tool 10, 110 or 200 for servicing. The arm 
can be moved from a stored position against the wall of the casing 18 to a 
central position, as seen in FIG. 2. The tool is then caught on its next 
upward trip by the arm. A spring loaded horseshoe 112 is mounted on the 
end of the movable arm which will lay horizontally, as seen in FIG. 2, 
until the head of the pump tool pushes it vertically as it passes by. When 
the head clears the horseshoe 112, spring loading will snap the horseshoe 
112 back to a horizontal position, in which it will be surrounding the 
long neck portion of head 114 of the tool 10, 110 or 200. When the tool 
completes its upward trip, and starts to fall back down, the portion 114 
will become wedged into the horseshoe, thereby leaving the tool hanging. 
The master valve 116 can then be closed and the tool safely removed for 
servicing. 
The rubber bumper 100 acts as a safety device designed to catch the tool if 
it comes up the casing too fast. Under normal operating conditions, the 
body will not even touch the bumper, since the springs in the top of the 
tool should adequately cushion a normal trip termination. However, should 
the tool come up too hard, the springs in the body would not be sufficient 
to prevent damage. The rubber bumper 100 is put in such a position as to 
catch the head of the tool before damage can occur to the tool. The 
concave area 118 of the bumper is cut to fit the head of the tool. If the 
tool hits it very hard, it will become wedged in and thus suspended in the 
bumper 100. The master valve 116 can then be closed and the tool removed 
for servicing. 
The use of a master valve 116 allows the well to be closed off before 
removing the tool, eliminating the risk of a blowout. A one-way pressure 
valve on top of the unit will allow for safe operation of a wire-line unit 
used for cleaning casings as well as placing the stand, or fishing for a 
stuck pump tool. Older systems required these operations to be done with 
the well open to the atmosphere, and blowouts and fire hazards were a very 
dangerous by-product due to methane escaping from the open well. 
The use of plastic in the tool has significant advantages. Plastic saves 
weight, which translates into more oil production per trip. Blowouts 
caused by sparks are a major danger for prior metal based tools. The use 
of plastic eliminates the risk of such sparks in removing or inserting the 
tool. Plastic can also function in salt water and hydrogen sulfide 
(H.sub.2 S) which corrode normal metal tools. Salt water is extremely 
common in wells, while hydrogen sulfide is less common, but does occur. 
The springs used in the tool will be of spring metal, but will be coated in 
a synthetic covering to prevent corrosion. The head 114 and plunger rod 92 
will be formed of brass or bronze, both of which are resistant to salt 
water and hydrogen sulfide corrosion. Further, neither brass nor bronze 
will spark against other metals, again lessening the chance of a fire. The 
stand 21 will utilize a mixture of plastic and coated metals, all of which 
will be corrosion resistant. 
The stand 21 is used to prevent the tool from falling all of the way to the 
bottom of the well should a valve malfunction. The stand 21 should be set 
at the nearest casing Joint above the perforations into the producing 
formation. As best seen in FIG. 6, the stand 21 can be seen to have spring 
loaded arms 240 which engage the sides of casing 18, preferably at a 
casing joint to provide a stable attachment of the stand to the casing. 
The manufacture of the body 22 in either pump tool 10 or pump tool 110 
provides a significant advantage. For example, the overall weight of the 
tool can be reduced to a weight between about 10 and 20 lbs. as opposed to 
a weight of about 80 lbs. for casing pumps having bodies of metal. The 
weight saving translates directly to increased production of oil. 
With reference now to FIG. 7, a horizontal wind turbine 300 can be seen 
which is mounted for rotation on a shaft 302. Shaft 302, in turn, is 
secured to pump tool 10, 110 or 200 so that the wind turbine is placed in 
the air flow through the tools as the tools descend within the casing. An 
air inlet screen 304 can be used to prevent debris from injuring the 
blades of the turbine 300. The turbine has blades which are set to spin as 
the air flows past the blades as the tools descend in the casing. This 
provides resistance to the downward motion of the pump tool to slow the 
descent speed of the tools. In addition, the turbine can be mounted on the 
shaft so that the shaft rotates as well, which gives rise to the 
possibility of powering an electrical device on the tool by connecting the 
shaft to a generator. 
FIG. 8 shows a modification of the wind turbine concept with a vertically 
mounted wind turbine 306. The turbine would be mounted on a horizontally 
extending shaft 308. An air inlet screen 310 and an air guide 312 can be 
used to direct the air flow directly to the blades of the vertical wind 
turbine as illustrated. 
FIG. 9 illustrates a magnetic valve seating apparatus 314 which can be used 
on pump tools 10, 110 and 200. The apparatus 314 includes an annular 
magnet 316 mounted on the tools as shown so that as valve 44 nears the 
closed position, the pressure that builds up around the valve face that 
could prevent full closure of the valve and a resulting stagnation of the 
rabbit, is overcome by the magnetic attraction of the valve 44 to the 
magnet 316 to assure complete closure. 
With reference now to FIGS. 10-15, a tool 400 forming a second embodiment 
of the present invention will be described. 
The purpose of tool 400 is to alleviate the need to produce salt water from 
gas wells completely, or, in the alternative, to substantially reduce the 
amount of salt water produced from gas wells. This will make many wells 
profitable that today that are unprofitable to operate, and enhance the 
profits on wells which produce a profit already. This invention will 
additionally provide a cheap, safe and ecologically sound alternative to 
present disposal methods in use. Utilization of this invention will 
substantially conserve the drive mechanism of water drive gas reservoirs 
by leaving the water in place in the formation. This invention will also 
have a beneficial ecological impact, because many operators currently use 
unapproved disposal wells to dump salt water, thereby polluting fresh 
water aquifers. Some operators also dump the water on the ground, 
sterilizing the soil for decades. This invention will remove the economic 
incentive to break the law. 
While the tool will function inside any annulus, in FIGS. 10-15 the tool is 
depicted as part of a standard section of production tubing 402 set inside 
a string of standard casing 404. A packer 406 is set between the casing 
and production tubing to form a seal therebetween. A pressure sensitive 
valve 408 forms part of tool 400 and has a valve body 409, a plunger 410 
and a stainless steel ball 412. The valve body 409 is secured to the tool 
400 and has a chamber isolated from the surrounding environment so that a 
pressure change will cause the plunger 410 to move one way or the other 
depending on a pressure change. When low pressure is encountered within 
the tool 400, the plunger 410 will be fully extended to engage ball 412 
with the valve seat 414 about orifice 416. When the ball engages the seal 
surface 414, movement of fluid or gas is prevented through the orifice 
416. Preferably, the orifice 416 is surrounded by a magnetic ring 418 
which has an attracting effect to the ball 412 when it is proximate the 
seal surface 414. 
Below the valve 408 is a block 420 with a channel 422 formed therethrough. 
The block 420 defines a downwardly facing seal surface 424. The block 420 
divides the tool into an upper chamber 426 and a lower chamber 428 within 
the tool. Below the block 420 are a number of free floating balls 430 
which have a density less than that of the water in the well, and 
preferably about one-half the density of the water in the well. 
If the ball 412 is sealed against the seal surface 414, the orifice 416 is 
completely sealed off. In this state, the production tubing 402 is totally 
sealed off below orifice 416. As gas bubbles out of the formation below 
the tool and rises in the water, it seeks the highest point obtainable. 
With the water level 432 relatively high in the tool, the uppermost ball 
430a is held against the seal surface 424 by the buoyancy of the other 
balls 430 acting on ball 430a. With the channel 422 closed, gas will 
accumulate at the underside of the block 420 and within the tool to form a 
gas head of a particular height. As more and more gas collects, it will 
form a gas head that starts to force the water level 432 downward within 
the tubing 402. When the water level 432 has been forced down the tubing 
to a point equal to approximately the center of the column of balls 430, 
the uppermost ball 430a will move away from the seal surface 424 because 
the buoyancy force acting on the balls will no longer be sufficient to 
hold the ball 430a against the seal surface 424. As ball 430a moves away 
from the channel 422, the channel 422 will open and gas will flow through 
the channel to the upper chamber 426 to equalize the pressure in the upper 
and lower chambers. The valve 408 will maintain the orifice 416 closed 
because the accumulated gas pressure is not yet sufficient to precipitate 
a change in the position of the plunger 410 by acting upon the valve 408. 
As the gas head continues to grow in size and pressure, it forces the water 
level even further downward. Eventually, the gas pressure will build to a 
point where it begins to act on the valve 408, causing the ball 412 to 
begin to open. However, the stainless steel ball 412 is held against the 
orifice 416 by the magnetic ring 418. When the gas head pressure reaches a 
point at which the retractive force of valve 408 overcomes the attractive 
force of the magnetic ring 418 on stainless steel ball 12, the valve will 
move out of engagement with the seal surface 414 and the orifice 416 will 
be open suddenly as the ball 412 breaks free of the magnetic ring. 
When valve 408 opens, the pressurized gas will rush through orifice 416 
into the tubing above the orifice 416. The movement of this gas has the 
effect of reducing the gas pressure below the orifice 416 and below the 
channel 422 so that the water level 432 begins to rise within the tool. 
Eventually, the water level will be sufficiently high to engage ball 430a 
with the seal surface 424 to seal off the channel 422 and stop the rise of 
the water level 432. As the pressure in the upper chamber 426 decreases by 
flow through the orifice 416, the valve 408 will react to urge the ball 
412 into sealing engagement with the seal surfaces 414 about the orifice 
416 to seal off the orifice. The cycle is then ready to repeat and will 
continue to repeat until the gas supply is no longer available. 
As can be understood, the present invention has the significant advantage 
of pressurizing the well below the tool 400 to control the water level and 
eliminate the discharge of water along with a gas which would require the 
costly disposal techniques discussed previously. 
It is also possible to use the tool 400 without the valve 408 and orifice 
416. The tool 400 will operate in substantially the same manner, with the 
balls 430 alternatively rising with the water level to close the channel 
422 and falling as the gas pressure builds up to open the channel 422 and 
let the gas pass through the channel. Balls are not required, any floating 
object placed in the tool that is capable of forming a seal at the top of 
the tool will perform the function adequately. For example, an elongate 
float with a seal end can be used. An important requirement is that the 
floating object be long enough in buoyancy effect to allow a generous 
amount of gas to accumulate at the top of the tool before the falling 
water level opens the tool to the annulus above. 
While the tool 400 will work with any suitable packer 406, one design for a 
packer 434 is illustrated in FIGS. 11-15. The present invention is best 
suited for use with a flexible seal which can be moved up or down within 
the bore hole easily. The packer 434 is attached to the tubing 402 by a 
collar 436. The packer 434, prior to being inserted into the casing 404, 
has a shape of an upside down parasol, as depicted in FIG. 11. When the 
packer 434 is inserted into the casing 404, the packer is folded back and 
upwards by the walls of the casing 404 as shown in FIG. 12. 
When the packer 434 is pushed down to the appropriate depth in the well, it 
must be pushed one casing joint 438 below its desired final position. This 
is so that the trailing edge 440 of the packer 434, which is in contact 
with the casing 404, will catch in the casing joint 438 as seen in FIG. 
13. As the packer 434 is pulled upwardly, the edge 440 becomes locked in 
the casing joint 438 and remains stationary as the packer 434 and tubing 
402 continue to move upwardly. The packer 434 will then start to turn 
inside out, as seen in FIG. 14. As the collar 436 and tubing 402 rises 
above the casing joint 438, the packer 434 is turned completely inside out 
as shown in FIG. 15. The packer 434 can then be raised to its final 
position, providing a complete seal between the casing 404 and the tubing 
402. As the pressure below the packer 434 increases, it will force the 
packer to expand against the inner surface of the casing 404. Thus, the 
greater the pressure, the tighter the seal against the casing. By 
repeating these procedures, it is possible to reposition the packer in the 
well bore as needed from time to time by simply moving the tubing 402 up 
or down within the casing. 
The invention 400 will function in any annulus where gas and liquid are 
present and a pressure differential zone can be created by use of the 
valve 400. A wide range of materials can be utilized in fabricating this 
invention, thus making it functional in many environments normally hostile 
to metals. 
This invention may be used in conjunction with gas powered plungers, such 
as those disclosed herein and the systems depicted in U.S. Pat. No. 
4,070,134 issued to Gramling and U.S. Pat. No. 4,696,624 issued to Bass. 
The use of the tool 400 in conjunction with the aforementioned plunger 
lift tools may be accomplished by placing the tool 400 below the lowest 
point of travel of the plunger lift tools, thereby supplying gas free of 
water to be used as a power source. The present invention may also be 
utilized in multiples in a single well. 
In certain wells, it may be necessary to keep channel 422 and orifice 416 
open to facilitate installation of the invention and allow complete 
swabbing of the well to initiate the production cycle. This can be 
accomplished with respect to channel 422 by placing a temporary uppermost 
ball 430 into the invention upon insertion into the well. This temporary 
ball 430 is constructed of a mesh-like material and is completely hollow. 
The temporary ball is also made of a water soluble material which 
dissolves at a known rate. The material can be altered to provide for more 
or less time to swab dry according to the characteristics of any 
particular well. When this temporary ball is in place, water will flow 
freely through it, thus keeping channel 422 open. Orifice 416 will remain 
open when there is any significant amount of water above it due to the 
pressure acting upon the valve 408. 
With reference to FIG. 16, a third embodiment of the present invention, 
tool 500, will be described. Many elements of tool 500 are identical in 
form and function to those in tool 400, and those elements have been 
identified by the same reference numeral. In some circumstances, it may be 
possible that the uppermost ball, ball 430a, in tool 400 could be held in 
place against the seal surface 424 by the differential in pressure, and 
thus never drop. To prevent this from happening, the uppermost ball 530a, 
as illustrated in FIG. 16, has an external surface 531 which is irregular 
enough to produce an imperfect seal against the seal surface 424 when it 
travels to the highest point in the lower chamber 428 against the surface 
424. This will allow the ball 530a to still create a significant drop in 
pressure on the valve 408, thus causing the valve 408 to close. However, 
the leaky seal between ball 530a and the seal surface 424 will eventually 
allow the pressure above and below the block 420 to equalize, thereby 
making it possible for the uppermost ball 530a to drop from the orifice 
when the water level has dropped far enough so that the ball is not held 
against the seal surface by buoyancy. The outer surface of the ball 530a 
can, for example, have a system of grooves or dimples on the sphere which 
produce a slow leak past the seal surface 424 even when the ball 530a is 
tightly urged against the seal surface 424 by the water pressure. The ball 
530a could have the external appearance of a golf ball, for example. The 
surface irregularities on the ball 530a should be sufficient to produce a 
slow leak that will equalize pressure across the block 420 within a period 
of several minutes or less. 
Tool 500 is also provided with a screen or mesh 502 which is attached at 
its upper end to the block 420 and extends downward through the lower 
chamber 428 to contain the ball 530a and the other balls 430 through their 
entire range of motion. The mesh 502 is intended to minimize the risk of 
any debris making its way up the lower chamber 428 to the seal surface 428 
or thereabove to the valve seat 414, thus preventing a complete closure 
from occurring. The mesh 502 extends only up to the seat for the uppermost 
ball 530, but would encase all the balls below that point. A ball guide 
520 can be used in conjunction with the mesh to facilitate the up an down 
motion of the balls. 
The tool 500 is also designed to be insertable and retrievable by wire 
line. A collar 504 is placed at the lower end of the last piece of tubing 
506. A mating collar 508 is mounted at the top of the tool 500 to be 
placed in the well. The tool 500 is then lowered into the well on a wire 
line through the tubing, and dropped through the collar 504 until the 
collar 504 and 508 meet and lock together. The tool 500 will have a 
standard fishing head 510 on the top of the tool for the wire line to 
engage in a manner well known in the industry. When the tool 500 must be 
removed for servicing, a wire line can be dropped through the tubing to 
engage the head 510 and the tool lifted in a manner to unlock collars 504 
and 508 and allow the tool 500 to be drawn to the surface through the 
tubing for servicing and repair. This avoids the requirement to pull the 
entire tubing string each time the tool needs to be serviced. 
With reference to FIGS. 17-20, a fourth embodiment of the present 
invention, tool 600, will be described. Tool 600 has an integral valve 
closure delay system as will be explained in detail hereinafter. Further, 
the tool has been formed into two units, upper unit 602 and lower unit 
604. This allows for fine tuning of the system by moving the upper unit 
602 to control valve timing. The upper unit may actually be placed at the 
surface in some wells. 
The lower unit 604 is designed to be installed in the tubing of the gas 
well just above the perforations, with a packer 606 placed adjacent, as 
seen in FIG. 17. Upper unit 602 is placed in the tubing above lower unit 
604 and at a predetermined height, even possibly at the surface. Both 
units are sealed against the inner wall of the tubing by O-ring seals 608. 
As noted previously, the reservoir pressure determines the water level 
within the reservoir. Thus, the reservoir pressure must be artificially 
controlled to eliminate waste water production. This is the function of 
the lower unit 604, and specifically the floating balls or members 430 and 
530a. As water encroaches up the tubing due to falling pressures, the 
water forces the floating balls or members 430 and 530a upward so that 
ball 530a moves into a sealed position against the seal surface 424. As 
noted previously, ball 530a is dimpled or etched to allow a slow pressure 
leakage. Even so, it will create an almost complete seal resulting in the 
buildup of pressure below the seal, which forces the water level to 
descend, replaced by the gas from the formation which will displace the 
water. 
However, because the seal against seal surface 424 is imperfect, the slow 
leak therethrough will eventually cause the pressure to equalize between 
upper unit 602 and lower unit 604. Thus, the only force holding the ball 
530a against the seal surface 424 is buoyancy. As the gas displaces the 
water beneath the ball 530a, the water will eventually lower in level to 
the point where the buoyancy forces no longer support the ball 530a 
against the seal surface 424, allowing the gas to pass up into the passage 
between lower unit 604 and upper unit 602. 
The upper unit 602 has a body 616 and a motile valve carrier 612 which can 
move vertically within body 616 as seen in FIG. 18. An area 610 is defined 
between the body 616 and part of carrier 612 which is air filled and 
sealed at a predetermined pressure. As the gas pressure builds in the 
volume between the upper unit and the lower unit, and passes into the 
upper unit 602 through apertures 614, the valve carrier is forced 
downwardly relative to the body 616 of the upper unit 602 against the 
force of the pressure in area 610. Use of a bellows 618, sealed at one end 
619 to the valve carrier and at the other end 621 to the body 616, allows 
the valve carrier to move while the pressure in area 610 remains constant. 
A spring 620 acts between the valve carrier 612 and the body 616 to assist 
the force of the pressure in area 610. 
During this time, the ball 412 of valve 408 will be urged into sealing 
engagement with the seal surface 414 by the pressure differential above 
and below the valve seat. Because the valve 408 is mounted on the carrier 
as the carrier 612 moves downward, the spring 622 will be compressed. 
A chamber 624 is formed within the body 616 and is filled with a suitable 
liquid 626. The valve carrier defines a piston 636 which divides the 
chamber into upper portion 632 and lower portion 628. As the valve carrier 
612 moves downwardly relative to the body, liquid is displaced from the 
lower portion 628 of the chamber through openings 630 in piston 636 and 
into the upper portion 632 of the chamber. A flap valve 634, best seen in 
FIG. 20, is mounted over all but one of the openings 630. However, as the 
carrier 612 moves downwardly, the flow of liquid through the opening 630 
deflects the flap valve 634 away from the openings and there is little 
resistance to downward motion caused by the motion of liquid 626. When the 
valve carrier 612 has moved a given distance downward, the ball 412 will 
be pulled from the seal surface 414 and cleanly snapped away from the 
orifice by the action of the spring 622. Gas can then flow from beneath 
the upper unit 602, through orifice 616 for recovery. 
As gas is produced, the reservoir pressure will begin to decline. As the 
pressure falls, the formation water will again rise and lift the floating 
members 430 and 530a in the lower unit 604. When the floating member 530a 
again engages the seal surface 424, the pressure above the lower unit 604 
will decline rapidly. The force of the pressure within area 610 will then 
drive the carrier 612 upwardly to close valve 408. However, this upward 
motion will be delayed at a predetermined rate by the interaction of the 
flap valve 634 and the liquid 626 attempting to move from the upper 
portion 632 of chamber 624 to the lower portion 628 of the chamber. The 
upward movement of the valve carrier 612 causes the flap valve to tightly 
seal against all but one of the openings 630. Thus, the fluid must pass 
through the sole unobstructed opening, which slows the movement of the 
valve carrier upward. This delay will prevent valve chatter, since by the 
time the carrier 612 returns upward for the ball 412 to seal against seal 
surface 414, the pressure above and below the valve seat will be 
equalized. With the floating members 530a firmly sealed against seal 
surface 424, there will be no significant pressure differential below and 
above the upper unit 602, thereby allowing a clean closure of the valve in 
the upper unit. 
While several embodiments of the present invention have been described in 
detail herein and shown in the accompanying drawings, it will be evident 
that further modifications, or substitutions of parts and elements are 
possible without departing from the scope and spirit of the invention.