the following description relates to one embodiment of the invention , and is made with reference to fig1 which is a stylized schematic drawing of an exemplary gas producing well , including the apparatus of the present invention . a well bore 5 containing the apparatus extends from surface 10 and passed into or through a gas - producing reservoir 12 . well bore 5 is lined with casing 16 . as is known , perforations 18 are formed through casing 16 adjacent reservoir 12 to permit reservoir fluids to enter the bore of the casing . the annulus about casing 16 is filled with cement or other sealants such that migration of fluids therethrough is avoided and instead fluids pass through perforations into the casing . a check valve 20 is installed in casing 16 above perforations 18 . valve 20 permits passage of fluids upwardly therethrough but seals against passage of fluids downwardly towards reservoir 12 . the valve can be a permanent installation or can be more temporary in nature . valve 20 can be any of various check valves such as , for example , a ball valve or a sprung flapper valve . a tubing string 26 extends within casing 16 from surface 10 and has a lower , open end 28 positioned above check valve 20 . with tubing string 26 , two conduits are provided for passage of fluids from reservoir to surface . the first conduit is the annulus 30 between casing 16 and tubing 26 and the second conduit it through the inner bore of tubing string 26 . valve 20 controls the passage of fluids from the reservoir to the two conduits . the tubing string can be a string previously run into the well for production or production - enhancement purposes or can be run in for the purpose of unloading the well bore of water . while tubing string 26 is preferably formed of standard production tubing , other tubing materials can be used . in any event , the tubing string must be able to withstand pressure differentials across its walls and must be able to support its own weight in the length required to extend from its hanger at or near surface to just above the check valve . it should be of inside diameter sufficient to efficiently move water in the required volumes within reasonable amounts of time with reasonable energy expenditures . in addition , the tubing string should have an outer diameter selected with consideration as to the casing &# 39 ; s inside diameter to permit efficient movement of gas past the tubing string over its length . in conventional production wells , tubing string diameters can be of various sizes and still be used in this invention . typical diameters are ½ ″, ¾ ″, 1 ″, 1¼ ″, 1½ ″, etc . the only requirement to operate this invention is that the tubing string &# 39 ; s bore ( if it is used as the exhaust conduit ) has to be of a size that the liquids being removed do not flow down past the gas flowing up the conduit ( for example , 3½ ″ outside diameter tubing is too large if installed in a 4 ″ inside diameter casing , as the compressed gas bubbles through the liquid , the liquid flows down past the gas , and in both instances the liquid is not produced to surface to unload the well ). lower open end 28 of the tubing string represents the lowest level to which water can be unloaded from the well . thus the tubing string must be extended down to a level selected with consideration as to the column of water that will be left in the well and the pressure of the gas in the formation . in particular , the tubing must be low enough such that the reservoir gas pressure exceeds the hydrostatic pressure of a water column extending to lower open end 28 . in one embodiment , end 28 is 0 . 01 - 3 . 0 meters above the check valve and the check valve is located just above , for example , 0 . 5 - 3 . 0 meters , the highest perforation in the casing . a casing valve 31 is provided at well head 32 which permits closure of either or both of tubing string 26 or annulus 30 . casing valve 31 permits various of the wellhead components 32 above it to be removed , while the well is shut down . at the well head , a seal 34 is positioned in annulus 30 to seal against the passage of fluids . this may be in the form of a coiled tubing hanger , for example . above seal 34 , tubing string 26 opens into a conduit 40 leading to a gas collection system ( not shown ) including gas / liquid separators , and communication to pipelines , etc . thus , any fluids , such as gas or produced water , flowing through tubing string 26 , as will be discussed hereinafter , can be passed to the collection system . below seal 34 , a conduit 42 opens through casing 16 into annulus 30 . conduit 42 opens into two further conduits 44 and 46 . conduit 44 , which can be closed by a valve 48 , permits flow of gas produced through the casing annulus 30 to a gas collection system ( not shown ) including gas / liquid separators , storage facilities , compressors , access to pipelines , etc . conduit 46 is in communication with a source 49 of pressurized gas , controlled by valve 51 , and permits flow of pressurized gas therethrough to annulus 30 . the source of pressurized gas can be air or produced gas from a compressor or gas from a high - pressure source such as a nearby high pressure well bore . where a gas produced by a high pressure gas well is used , no compressor will be needed . however , when using either a high pressure gas well or a compressor , various control systems must be used to ensure that gas is introduced to the well only at selected times and for selected duration &# 39 ; s or until desired results are achieved . seal 34 provided for separate handling of fluids from annulus 30 and fluids from tubing string 26 . as will be appreciated , other means can be used in place of the seal to maintain separate fluids from these two conduits . it will also be appreciated that other conduit arrangements can be used for effectively permitting introduction and removal of gases and liquids from the well bore . the apparatus as described may be used in the following method to dewater a gas well . when the reservoir 12 produces gas , it passed through perforations 18 and into casing 16 . after passing through the check valve 20 , the gas passes through annulus 30 and is collected through conduits 42 and 44 . alternately , produced gas can pass up both annulus 30 and tubing string 26 and be collected at surface therefrom . in another embodiment , tubing string can be removed during regular production and only run in for unloading of produced water , when necessary . in some wells , water 52 is produced and may collect at the well &# 39 ; s bottom . eventually the water level in the well bore will attain a height such that its hydrostatic pressure impairs the production of gas from reservoir 12 using the reservoir &# 39 ; s inherent pressure . this causes a decline or even cessation of gas flow from reservoir 12 to surface 10 for collection . in those circumstances , the apparatus described can be actuated to remove that accumulated water and other liquids . when the apparatus is used to remove water 52 , check valve 20 must be closed . the check valve can be closed by the hydrostatic pressure of water above the check valve exceeding the pressure from reservoir 12 below the check valve . alternately , check valve 20 is closed by introduction at wellhead 32 of pressurized gas from source 49 ( i . e . by closure of valve 48 and introduction of gas through conduits 46 , 42 ). a combination of those forces can also be used to close the check valve . once check valve 20 is closed , pressurized gas is introduced into the casing annulus 30 from source 49 , as indicated by the arrows g , which causes a pressure increase above accumulated liquid at the well &# 39 ; s bottom . seal 34 prevents any introduced gas from passing to conduit 40 , thus all gas passes down through annulus 30 . eventually , the pressure of the introduced gas exceeds the hydrostatic pressure of the accumulated liquid 52 and the pressure of the fluid in tubing string 26 above the liquid . this causes the tubing string to behave as a siphon and the accumulated liquid 52 to be thus forced to flow , as indicated by arrows w , to surface 10 and out through conduit 40 to a collection system . it will be appreciated by those skilled in the art that the source of pressurized gas will be required to provide sufficient gas to fill and pressurize the sealed casing . the volume of casing to be filled is easily calculated by reference to the casing &# 39 ; s inside diameter and its length . preferably , sufficient gas should be available to also fill the tubing string within the casing . the gas must be eventually at a pressure greater than the hydrostatic pressure of the accumulated water , which pressure can be easily calculated by the accumulated water . thus the pressures and volumes of gas required can be quite easily calculated using known information . for example , in a typical test well , equipped with 4½ ″ casing and 1½ ″ coiled tubing , and with reservoir pressure approximating 130 psi and well depth of 530 meters ( 1740 feet ), the hydrostatic pressure of a column of water within the casing of approximately 280 feet overcame the formation production pressures , at which stage the well ceased production ( 280 feet of salt - laden water equates to approximately 130 psi at bottom of the column ). gas was introduced to the well into the casing and reached a pressure of up to 750 psi at its maximum ( since that is the pressure induced by a 1½ ″ diameter column of salt - laden water 1740 feet high , being the exhaust tubing during the time when it is filled during the unloading exercise ). the above numbers are approximations for ease of description , and would vary with the salinity of the produced water and the depth of the well and its formation pressure . from this example , however , it is apparent that the pressure ranges for the introduced gas can be readily calculated from known or easily obtained information at the well - site . gas can continue to be introduced until all of the accumulated liquid down to the level of end 28 , as indicated by introduced gas exiting through conduit 40 , or for a selected period of time . when a selected amount of accumulated liquid is thus evacuated to surface and out of the well , the flow of pressurized gas is stopped . the valve 48 is opened , and the pressurized gas within tubing string 26 and annulus 30 is allowed to dissipate through conduits 40 and 42 to collection systems , which typically include separators , compressors and pipelines , etc . once the pressure of introduced gas is sufficiently dissipated and provided a sufficient amount of introduced gas is sufficiently dissipated and provided a sufficient amount of water has been removed , the check valve 20 opens and permits passage of produced gas from reservoir 12 . produced gas then continues to flow up through the casing to surface until produced water accumulates such that the check valve is again closed for water removal . while the described route of water removal is up through the tubing string , it is to be understood that the reverse operation could be used ( by altering the valve seal and pipe configuration at surface ) wherein compressed gas is introduced through the tubing string to force accumulated water up through the casing annulus . it will be apparent that the introduction of pressured gas can be initiated automatically or manually , and may be responsive to a timer , a pressure differential sensor system , a drop in production volumes which indicates an increase in accumulated liquids at bottom - hole , or other suitable indications . a person skilled in the art will understand that when the liquid is exhausted from the casing annulus 30 above lower open end 28 of the tubing string 26 , there will then be a large volume of introduced gas passing up through tubing string 26 to the collection system . in addition , there will be large volumes of introduced gas to be handled when the introduced gas is allowed to depressurize . thus , flow control means and perhaps chemical injection means would profitably be utilized to reduce such depressurization and the commensurate temperature drops and consequent hydrate formation and other mechanical problems associated with such events . it will be understood that various changes in the details , materials , arrangements of parts , and operating conditions which have been described and illustrated here in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention , and will not derogate from or limit the scope of the claims .