Abstract: A solvent for sulfur consisting of a dialkyl disulfide which is free of any basic substance. It is obtained from a commercial dialkyl disulfide by treatment with a reagent capable of eliminating or blocking the basic substances, particularly amines, which are customarily present in such a product. This reagent may be an acid.The use of the product, after treatment in this manner, for dissolving sulfur which has deposited in the casings of natural gas wells permits the reuse several times of the dialkyl disulfide employed.

Abstract: A method for treating a subterranean formation, or a well penetrating the formation, comprises injecting into the well an aqueous composition containing an aminopolycarboxylic acid and water-soluble organosilicon compound. By use of the method, scale is removed from well equipment and/or openings in the formation, and fine particles within the formation are stabilized to prevent their subsequent movement, resulting in increased, more stable fluid flow through the formation and well.

Abstract: A process for removing particulate matter from a non-dissoluble sand control pack containing grangulated ceramic material which pack is used to produce hydrocarbonaceous fluid from a subterranean formation. Said pack is contacted with a mineral acid of a strengh and composition sufficient to react with said particulate matter thereby removing said matter and increasing the permeability of said pack without damaging said pack.

Abstract: A method and apparatus for removing solid particles which have settled out in a region of a wellbore which employs at least one pair of conduit means, one of said conduit means having nozzle means thereon, said conduit means being disposed in the region of settled particle and passing fluid through one conduit means and the nozzle means into region of settled particles to mix with same and recovering the mixture of fluid and particles from said region by way of the other conduit means.

Abstract: Aqueous chemical washes suitable for use in conjunction with well cementing operations are disclosed which comprise water, an anionic or a non-ionic surfactant (or a combination thereof) and a fluid loss control agent of the type described in U.S. Pat. No. 3,891,566.

Abstract: A method of treating wells with the use of a foam as a circulating fluid provides for the steps of generating a stable foam, circulating the foam up the well to remove loose solids and fluids from the well, injecting solvents to dissolve liquid and solid hydrocarbons, circulating a mixture of foam and mineral acid to remove ferrous salts and calcium carbonate from the well, circulating a calcium sulfate converter to remove calcium sulfate, cleaning up any residue by circulating the foam up the well. The method also provides for the use of iron chelator and corrosion inhibitor. The method has applications in stimulation of the well production, when such production becomes adversely affected by a build-up of solids, during stimulation of water injection, stimulation of a source well, treatment of a disposal well, as well as treatment of a gas producing well.

Abstract: A process wherein energy generated from a high impulse device is used to jar, loosen, or dislodge scale from a wellbore, downhole production equipment, or near well formation flow channels. Such jarred, loosened, or dislodged scale allows for increased amounts of scale-forming ions to be removed. Alterwards, an emulsified liquid membrane system containing surfactants therein sufficient to remove scale-forming ions is placed in said wellbore. Said emulsified membrane system is removed when the scale-forming ions have been absorbed therein.

Abstract: A well cleanout system for removing accumulations of solid particles in a gravel pack screen or liner and in the vicinity of a casing or liner hanger includes a tubular extension member which may be lowered into the production fluid tubing string and secured to a nipple at the lower end of the tubing string. Coiled tubing with a nozzle arrangement on the distal end thereof is extended through the tubular extension member and into the wellbore for jetting a cleanout fluid into the wellbore to entrain solids in a fluid stream which is pumped to the surface through the production tubing. The coiled tubing, nozzle and extesnion member may be retrieved by unlocking the extension member and pulling the coiled tubing out of the wellbore.

Abstract: A method is provided for the controlled introduction of a reagent into a liquid, preferably a reagent peremeable substantially hydrocarbon liquid, which method comprises the steps of:(a) placing as in a geological crude oil reservoir solid polymeric bodies, each body comprising a reagent permeable polymeric matrix containing a substantially water insoluble reagent such as at least one of a wax crystal modifier, demulsifier, scale inhibitor, corrosion inhibitor, biocide, ashless dispersant, antioxidant and mixtures thereof in said liquid (includes both crude and refined hydrocarbon liquids); and,(b) leaching out said reagent from said bodies at a controlled and predetermined rate into said liquid.

Abstract: The present invention is a method and apparatus for injecting compressible fluids into multiple zones of a hydrocarbon bearing formation, in particular injecting compressible fluid at a predetermined, constant rate into multiple zones through a single tubing string. Producing zones are packed off and limited entry outlets are installed on the injection tubing string at each producing zone. Injection pressure is maintained and limited entry outlets are designed and sized such that the compressible fluid reaches sonic flow through the outlets so that the flow rate no longer responds to changes in downstream pressures.

Abstract: A method relates to the oil recovery and comprises feeding a bactericidal agent to the bottom-hole zone of a formation being worked, the bactericidal agent comprising gamma-radiation with a dose of at least 150 krad.

Abstract: An apparatus for pressurized cleaning of flow conductors. The apparatus utilizes a control slot formed in a zig-zag pattern and a pin which travels in the slot. The slot and pin assist in indexingly rotating the nozzle section of the apparatus when the apparatus is reciprocated in alternate directions in the flow conductor. Pressurized cleaning fluid is supplied to the apparatus and is directed radially outward through nozzles against the flow conductor in such a manner as to progressively clean the flow conductor as the nozzle section rotatively indexes. Another set of nozzles may be included, if desired, in the lower end of the apparatus to allow cleaning along the longitudinal axis.

Abstract: A mounting structure for a chemical injection tube for geothermal wells utilized for power generation from geothermal energy. A chemical injection tube is extended into a geothermal well, having an upper end fastened by a sealing flange and a lower end extending down below the flashing point in the well, wherein scale inhibiting chemicals can be supplied from the ground and injected through the tube directly to the geothermal fluid in the well. Thus, the chemical injection tube facilitates the prevention of carbonate scale deposition in the well and results in a stable power plant operation.

Abstract: A method for removing scale-forming ions from oil and gas production equipment. An external aqueous phase of a liquid membrane system contacts said scale and solubilizes said scale-forming compounds. Scale forming ionic compounds are then transferred into an immiscible liquid hydrocarbonaceous membrane phase having a complexing agent for scale forming ions. Said hydrocarbonaceous membrane phase envelops droplets of an internal aqueous phase which has a stronger complexing agent for scale forming ions than is contained in said hydrocarbonaceous membrane phase. Scale forming ions are transferred from said hydrocarbonaceous membrane phase and are accumulated and concentrated in said internal aqueous phase. Films of scale are thus progressively removed from surfaces where they have deposited.

Abstract: Apparatus for use in conducting well workover operations includes a coiled non-electrically conductive matrix shaped into a string and containing at least one conduit capable of conducting fluids and electrical conductor means capable of transmitting electrical energy through said matrix. Tool means for performing well operations is connected to the matrix string. Preferably, the matrix string contains three conduits. A variety of workover methods may be carried out using various tool means.

Abstract: A self-breaking, foamed, oil-in-water emulsion contains a water-immiscible organic solvent for paraffins and asphaltenes, an aqueous nonformation-damaging component, an inert gas, and surface active agents selected to promote a stable foamed emulsion despite contact of the treating fluid with the hydrocarbon and aqueous environment in the reservoir. Under conditions of agitation, the treating fluid is a stable foamed emulsion which undergoes spontaneous breakdown into two liquid phases under quiescent conditions. The treating fluid is injected and/or circulated as a stable foamed emulsion to dissolve paraffin and asphaltene-containing deposits from various substrata, such as a subterranean reservoir penetrated by a well, the well itself, or an industrial vessel or conduit. When injection or circulation is stopped, the foamed emulsion spontaneously breaks down so that the treating fluid can be readily pumped from the well.

Abstract: A well cleaning apparatus and method of treating a well includes a generally tubular implement which has a first section with adjustable, radially extending cables, and a second section with cable loops extending outward, a bottom cone-shaped plug and a top plug. The first section cables can be anchored by rotating or sliding a crimping tube therein, or by molten material poured therein. The second section cable length can be adjusted by a sliding base bracket. The first section chops up scale, sludge and tar while the second section cables sweep them away. The method includes these steps, as well as steaming the casing at high pressure and low water volume to aid cleaning, and stimulate formation flow without creating sand bailing problems. The apparatus can be attached to the bottom of a well pump, with several first sections spaced along the length of the work string of the pump to enable cleaning of the entire well casing by a limited upward and downward movement of the entire assembly.

Abstract: A fluid operated cylinder is suspended from a crane by a cable and has a piston rod connected by a cable to a cleaning unit for supporting the cleaning unit within the screened inlet portion of a water well casing extending into the ground. Air is supplied to the cylinder through a solenoid valve which is controlled in response to movement of the piston to produce reciprocation of the piston and corresponding movement of the cleaning unit within the well casing.

Abstract: The invention pertains to the removal of paraffin deposits from oil producing wells wherein hot fluids are used to melt the deposits. A conduit system consisting of tubing concentric to the well tube carries hot oil to the well tube at a location below the paraffin forming depth. Ports within the well tube permit the hot oil to enter the well tube during pumping, and the heated oil and melted paraffin is removed at the well head without interrupting pumping. A check valve within the hot oil conduit prevents pumped oil from entering the conduit and the apparatus permits paraffin to be removed from an oil well in less time and with less cost than previous paraffin removal systems, without interrupting pumping, and without contamination of the oil bearing formation.

Abstract: A composition for and method of removing polymeric material from a porous media such as a subterranean formation. The method comprises contacting the polymeric material with an aqueous composition having a pH of from about 2 to about 10 and comprising an oxidizing agent, a water soluble carboxylic acid, and optionally, a source which is effective in promoting the decomposition of the oxidizing agent.

Abstract: Pipe dope restricting fluid communication between a well bore and a subterranean formation is contacted with a liquid perhaloalkane having no more than three carbon atoms per molecule, such as 1,1,2-trichloro-1,2,2-trifluoroethane, to improve fluid communication. The halocarbon can also be contacted with pipe dope on tubulars to remove the pipe dope from the tubulars.

Abstract: Drilling fluid solids (mud, solids and oil) can be removed from completion/packer brines in a well system by employing a small effective amount of an aliphatic alcohol and a surface active chemical aid mixed with the contaminated brines. Under some conditions, the brine can become recontaminated in a well with a small amount of solids which settle to the production zone in the well bore. These settled solids obscure acoustic logging and plug perforations into the production zone. These settled solids are removed by spotting a chemical aid in selected volume and concentration. These solids now become buoyant and rise upwardly in the well bore leaving in the well the production zone with clean solids-free brine. As a result, the entire volume of brine does not require treatment.

Abstract: The present invention is a process to oxidize a contaminant in a permeable subterranean formation by introducing an aqueous treating solution into the formation which solution contains hydrogen peroxide and a compound to control the mobility of the aqueous solution by increasing the viscosity, the density, or modifying the interfacial properties of the aqueous solution within the formation. The aqueous treating solution may also contain stabilizers for the hydrogen peroxide, free radical initiators, or free radical traps. Optionally, the formation may be pretreated to modify the permeability of the formation, to deactivate or remove hydrogen peroxide decomposition catalyst or to uniformly distribute free radical initiators therein.

Abstract: Eliminating drilling mud and other solids from surface equipment of a well system (e.g. offshore platform) which is to receive solids-free completion and packer fluids having an affinity to entrain residual solids. These solids are mechanically removed (where possibly by scrapers, squeeging, etc.), and then the surface equipment is washed with water to carry the solids to a convenient disposal. Clean water is placed into the surface equipment and added to it are a surfactant and alcohol to produce a treated water. The treated water is circulated at turbulent (high shear) flowing conditions through the surface equipment. The treated water with entrained solids is removed to a suitable disposal by displacement with clean water whereby the surface equipment is sufficiently free of solids to avoid contamination of completion or packer fluids introduced thereinto.

Abstract: Improved bonding in a well system between cement, well tubular members and the formation about the well/bore at a pay zone. Drilling fluid materials (mud, solids, filter cake, etc.) are displaced at turbulent flow conditions by a slug of concentrate consisting essentially of a water-free mixture of surfactant and alcohol. The aqueous fluid cement immediately follows the slug. Residual filter cake and tubular member are water-wetted. The cement on hardening has an improved bonding to both tubular members and formation at the pay zone.

Abstract: The present invention is a process to stimulate the biooxidation of a contaminant in a subterranean formation by introducing an aqueous solution into the formation. The concentration of the hydrogen peroxide is increased thereby acclimating the biota to higher concentrations of hydrogen peroxide. Periodically the concentration of the hydrogen peroxide is increased for a short time sufficiently to be toxic to the biota at or relatively adjacent to the site of introduction, thereby increasing the permeability of the formation at or adjacent to the site of introduction.

Abstract: A method and apparatus for distributing fluids within a subterranean borehole wherein a submersible pump is introduced into the borehole at a first location. An intake port of the pump is connected to the first end of an intake duct having an unconnected second end located at a second location within the wellbore from which location fluid is to be withdrawn. An output port of the pump is connected to a first end of a second duct having an unconnected second end at a third location within the wellbore into which location fluid is to be introduced. By activating the pump, fluids, such as scale and corrosion inhibitors, are distributed from above the intake of a production pump to as low in the borehole as is required to protect wellbore contents.

Abstract: Process for increasing the water discharge of water delivering drilled wells, which can be characterized in that into the filter section of the well weak acids with a dissociation constant being less than K.sub.d =10.sup.-3 are introduced. After a dwelling period of longer duration, expediently 10 to 48 hours, as well as compressing, flushing is performed by means of a scavenging pump. Thereafter the solution of sodium bicarbonate and/or sodium hypochlorite is introduced into the filter section. After a longer dwelling period, expediently one to thirty-six hours, flushing is performed by means of the scavenging pump. As weak acids with a dissociation constant being less than K.sub.d =10.sup.-3 acetic acid, tartaric acid, citric acid, metaboric and/or tetraboric acid is used.

Abstract: Flow-restricting materials containing epoxy resins present in a well treated with an epoxy resin, for the purpose of coating and consolidating unconsolidated sand adjacent the well and/or gravel packing in the well, or of coating metallic equipment in the well, to prevent corrosion or the deposition of organic or inorganic solids on the equipment, by contacting the flow-restricting material with a solvent composition, comprising, N-methyl-2-pyrrolidone and a diluent in an amount of 0 to 80% by wt., for a time sufficient to form a flowable fluid and removing the flowable fluid from the well. Combination well treatments include consolidating sand and/or gravel in a well or coating metallic equipment in the well with an epoxy resin and, thereafter, subjecting the treated well to the above solvent treatment to remove flow-restricting materials from the well.

Abstract: Crude oil and gas production wells, which no longer produce oil or gas utilizing conventional primary and secondary means of recovery, can be returned to production by treatment comprising addition of a non-aqueous solution of certain phosphate ester surfactants followed by successive treatment with water or a hydrocarbon. Increased production also can be obtained in low-producing oil and gas wells by similar treatment with certain phosphate ester surfactants. Subsequent to treatment of a producer well, the phosphate ester surfactant is forced into the formation utilizing water or a hydrocarbon and said surfactant is allowed to remain in the producing well, for an effective period of at least 12 hours. Thereafter, pumping and/or conventional fluid drive means are then utilized to recover oil or gas from the subterranean oil or gas formation.

Abstract: The invention is directed to the stimulation of water flow into a substantially dry well shaft from adjacent rock and soil strata bearing water supplies by developing passages from such water supplies through the well walls. Liquid or gaseous nitrogen and liquid or gaseous carbon dioxide are introduced into the well either individually or in combination and alternately pressurized and depressurized to cause the rock structure between said well wall and said water supplies to be exposed to high pressures and fractured to thereby open a passage from said water supplies to said well. A well cap is provided to seal the well and retain the pressure developed therein while providing for the introduction of the required materials. Means are also provided to release the pressure in the well quickly to return same to its unpressurized condition.

Abstract: A tool for use downhole in a borehole for carrying out a backsurging method whereby existing open perforations are cleaned. The tool comprises an annular body having spaced cylindrical walls, each of which reciprocatingly receives spaced pistons which move individually relative to one another. A port is formed through each of the walls of each of the cylinders with the first port being normally closed by a first piston and the second port being normally open. The second piston is moved to close the second port. The tool is placed on the end of a tubing string or within a tool string and run downhole into the borehole. A packer device enables the pressure between the lower annulus, the upper annulus, and the tubing to be adjusted relative to one another. A bar is then dropped down the tubing string, contacts the second piston and moves the second piston to cover the second port. The tubing pressure is reduced to provide a pressure differential between the lower annulus and the interior of the tubing.

Abstract: A continuous flow well bore perforation washing tool is shown of the type having a tubular mandrel with sidewalls defining a flow passage, an upper end for connection in a pipe string and a lower end with means for blocking the flow of fluid from the pipe string through the mandrel. Upper and lower pressure responsive packer assemblies are carried on opposite ends of the mandrel. An outer setting sleeve surrounds the mandrel between the packer assemblies to define an annular chamber between the mandrel and setting sleeve. A continuous flow passage communicates the mandrel interior, the annular chamber, and the well bore. Selectively sized orifices in the setting sleeve form a restriction in a portion of the continuous flow passage. By selectively sizing the orifices, a back pressure buildup can be created in the annular chamber which is used to set the packer assemblies as fluid is continuously flowed through the continuous flow passage.

Abstract: A method and system for cleaning well liners employing a non-rotating tubing string attached to a hydraulic jet carrier assembly is disclosed. The assembly has a plurality of jet nozzles spaced along its length, each of said nozzles expelling a stream of fluid under pressure against the liner with a force which has an equal and opposite reactive force. At least some of the nozzles are oriented along the carrier such that the reactive force for each jet is directionally offset with respect to the central axis of the carrier, thereby creating a twisting moment tending to rotate the carrier about its central axis. During the cleaning operation, the bottom hole differential pressure of the fluid supplied to the jet carrier is varied to rotationally displace the carrier as it is moved vertically within the well bore. Moreover, in a preferred embodiment, the angle of rotational displacement can be calculated which will produce at least double coverage of the jet streams against the liner.

Abstract: There are provided wellbore treating fluids containing densifying salt dissolved in a solvent for this salt. This solvent contains at least about 50 percent by weight of a liquid non-aqueous solvent such as, e.g., N-methyl-2-pyrrolidone, such that the overall solvent has desirable properties with respect to the ability to dissolve salt, miscibility with water, melting point, boiling point, flash point and viscosity. Examples of such wellbore treating fluids include drilling, completion, packer and workover fluids.

Abstract: A method of chemical injection and of swabbing and/or flow testing a subterranean well by interconnecting a resettable packer and a circulating wash tool so that the packer may be positioned and set in the casing at a plurality of positions above the casing perforations. The introduction of pressurized chemical solution through the tubular work string produces an injection of the chemical solution into the perforations isolated by the vertically spaced annular sealing elements conventionally provided on the wash tool. Following the chemical treatment, the wash tool can be moved to a position above the perforations and a swab test run to measure the productive capabilities of the treated formation, all with a single trip of the wash tool and associated packer into the well.

Abstract: A method for removing scale and inhibiting the formation of scale in a well penetrating a subterranean formation for the production of fluids from the formation, the method comprising;(a) injecting an aqueous solution of EDTA into the well in an amount and for a time effective to remove scale from the well; and,(b) injecting a scale inhibitor through the well and into the subterranean formation surrounding the well.

Abstract: Step declines in the production rate from a well following an acid treatment, and a scale inhibitor treatment are reversed by use of an EDTA treatment.

Abstract: A tool (20) for washing the perforated zone of a well casing in an oil or gas well includes a tubular mandrel (24) having a flow passage (26) with means for connecting one end of the mandrel to a drill string (160) and the second end to a flow blocking valve (162). The mandrel (24) has a plurality of apertures (42) through its sidewall. A first and second radially expandable packer (64, 132) completely encircles and is carried on the mandrel at spaced positions. An outer sleeve (100) surrounds the mandrel between the packers and defines an annular chamber (116) between the sleeve and mandrel. The sleeve has apertures (104) therethrough having a combined area less than the combined area of the apertures (42) through the mandrel. First and second annular pistons (74, 100) are carried within the annular chamber (116) having one face communicating with the annular chamber and an opposite face engaging, respectively, the first and second packers.

Abstract: A method for treating a hot water-containing fluid stream passing through a conduit, under conditions of temperature and pressure whereupon at least a portion of the water flashes to steam, to inhibit the formation of scale deposited on the conduit and/or dissolve any such scale already formed, and to inhibit corrosion of the conduit wherein there is added to the fluid stream an effective amount of a solution of a water-soluble compound which provides a nitrogen-containing cation capable of flashing to become a gas at high temperatures selected from the group consisting of ammonium halides, ammonium salts of inorganic acids, ammonium salts of organic acids, ammonium salts of alpha hydroxy organic acids, quaternary ammonium halides, quaternary ammonium salts of inorganic acids, quaternary ammonium salts of organic acids, amine salts of inorganic acids, amine salts of organic acids and amides. Optionally the solution or dispersion also contains a water-soluble or dispersible polymer and/or a buffering agent.

Abstract: A process for eliminating drilling fluid (mud, solids and oil) from a well system prior to introduction of solids-free completion and packer brine. Drilling fluid is displaced by circulating through well pipe and annulus of a treated water (surfactant and alcohol) to complete removal of drilling fluid. A plug of a gelled aqueous spacer may be used before or after the treated water. The plug spacer is displaced from the well system by the following treated water or circulating therein of the solids-free brine. The spacer isolates efficiently the treated water from the displaced drilling fluid or the displacing brine. If the drilling fluid is inverted, the spacer can be an inverted gel of bentone, water and diesel oil.

Abstract: A method is disclosed for restoring permeability of injection wells which have become plugged with polymer residue, protein debris, biological matter and the like. The method includes treating the well for a period of time with an aqueous solution containing hydrogen peroxide and optionally a surfactant.

Abstract: An improved method of locating and measuring voids behind casings of wells in unconsolidated formations is disclosed featuring first and second logging operations carried out before and after perforation washing respectively to locate voids. The voids may thereafter be filled using conventional gravel packing techniques. In a preferred embodiment pulsed neutron logging is the logging tool chosen, and a washing fluid having a high neutron absorption cross-section is used.

Abstract: A cylindrical housing is adapted to receive and discharge fluid in a subterranean well. In a preferred form, a plate is positioned in the cylinder separating it into first and second chambers. Filter adapter receiving means are disposed across the plate, with a filter adapter securable therein, the adapter having a passageway extending to the chambers. The adapter has a cylindrical housing having an enlarged cartridge positioning portion. A grooveway is defined on the adapter extending exteriorly therearound for securing one end of a secondary cartridge filter. A secondary cartridge filter has an inner filter completely surrounded by a replaceable and reuseable primary sleeve filter and is positionable on the adapter, the filter providing a seal having an interiorly facing circumferentially extending lip for contact with the exterior of the cylindrical housing when the filter is located on the adapter, for sealingly securing the filter to the adapter.

Abstract: Means are provided for increasing the productivity of a hydrocarbon formation by modifying the formation in the vicinity of the borehole by a succession of treatments utilizing a first fluid which releases energy within the borehole and a second fluid modifying the fluid within the borehole. The means provides successive treatment of steam, carbon dioxide, oxygen, and inert gases in any order desired.

Abstract: A method of treating a subterranean formation penetrated by a well bore comprising injecting a gelled foamed fluid into said formation. The gelled foamed fluid is prepared by foaming an admixture of a fluid and a surface active foaming agent and admixing the foamed fluid with a gelled fluid whereby the foamed fluid is diluted by the gel to form the gelled foamed fluid.

Abstract: An improved displacement process for eliminating drilling mud (solids and oil) from a well system prior to introduction of solids-free completion and packer brine. Clean water is circulated in the well system to remove and carry the major portion of the drilling mud. A treated water is prepared from a surfactant and alcohol admixed in clean water. Without interrupting circulation, the treated water displaces the clean water carrying drilling mud from the well system. Circulation of the treated water continues in the well system in which the brine is to be received until substantially all of the drilling mud is carried in the circulating treated water. Again without interrupting circulation, the treated water is displaced from the well system to a suitable disposal region with solids-free clean water. Lastly, the solids-free clean water is displaced from the well system with the solids-free brine.RELATED PATENT APPLICATIONChemically Cleaning Drilling/Completion/Packer Brines; Ser. No. 310,653, filed Oct.

Abstract: This invention relates to a system for cleaning debris and precipitated materials from above a packer in a well bore. The tool includes a special overshot which attaches to a cut off tubing on a packer. The overshot has a closed off bore and a side opening which is coupled to a tubing string. A cleaning tool is pumped down the tubing and has a flexible tubing which passes through the side opening. Fluid can be circulated from the tubing to the annulus and remove precipitates. The cleaning tool has a collar location for position alignment.

Abstract: A well washing tool which may comprise: a tubular mandrel; first and second packer assemblies carried on the mandrel at opposite ends thereof; an outer tubular body surrounding the mandrel between the packer assemblies; an annular chamber between the mandrel and the surrounding tubular body; and a valve assembly carried within the annular chamber. The tubular mandrel is adapted for connecting the tool in a pipe string extending to the surface of the well and the lower end may be adapted for blocking flow of fluids from the pipe string through the mandrel flow passage. Ports are provided in the walls of the mandrel and the tubular body permitting fluid communication between the mandrel flow passage and the exterior of the tool. The valve assembly prevents such fluid communication by blocking one or more of the ports.

Abstract: A gravity system, the only moving parts of which are the valves, uses only the system pressures, and opening and closing of valves to feed treatment liquids to an oil well. The chemical treatment liquid is stored in a drum above a volume chamber. The volume chamber has five lines connected to it, each with a valve. A feed line with a feed valve connects the volume chamber to the treatment drum. A vent line with a vent valve vents the top part of the volume chamber to the atmosphere. A liquid pressure line with a pressure valve connects the flow line (connected to the oil well eduction tube) to the volume chamber. A flush line with a flush valve connects the bottom of the volume chamber to the well annulus. A gas line with a gas valve connects the volume chamber to the annulus. When the vent valve and feed valve are open and all other valves are closed, the volume chamber will fill with liquid by gravity from the chemicals within the treatment drum.