Abstract: A system for stimulating the production of hydrocarbon containing substances, such as from oil and gas wells, by the use of a generally cylindrical, high energy producing transducer mechanism. The transducer comprises a series of aligned transducer elements, preferably formed of doped ceramic piezoelectric materials, encased in a housing maintained under controlled pressure by a pressure compensator to equalize the pressure within the housing to that of the surrounding strata containing the hydrocarbon substance. When energized, the respective transducer elements transmit a very narrow, horizontal beam of ultrasonic energy radiating omni directionally, preferably in a narrow band of about 2 to 3°, to thereby focus the energy horizontally for maximum penetration into the surrounding strata.

Abstract: The present invention is directed to a method of utilizing the piezoelectric effect to transport a target substance within an earth formation. An earth formation is identified which bears a target substance. The piezoelectric properties of the earth formation are examined in order to determine the extent of the piezoelectric effect and to determine any optimum frequency of excitation. A voltage is applied to a particular portion of an earth formation in order to develop mechanical stress in the earth formation utilizing the piezoelectric property. The mechanical stress effects the local temperature and permeability of the target substance within the earth formation. A combination of excitation due to the electric field, mechanical stress, the temperature increase, serves to alter the permeability in a desired manner in order to liberate greater amounts of target substance from the earth formation, and to facilitate removal of the target substance utilizing conventional technologies such as pumps.

Abstract: A fluid powered downhole vibration tool used in a well bore having fluids under pressure. The tool includes a resonant chamber with a through passage in communication with the fluids under pressure wherein the chamber vibrates as the fluids pass through the passage. The resonant chamber is coupled to the well bore, causing vibration of the bore as the chamber vibrates.

Abstract: A method is disclosed for installing a tubular member, having an upper end and a closed lower end, axially into and through an over-pressured region of the earth by using a mandrel to drive the tubular member from near the bottom, which results in a significant section of the tubular member being pulled through the over-pressured region. In another embodiment, a filler material is inserted into at least a portion of the tubular member, and the tubular member is driven from the upper end, with the filler material assisting the progression of the tubular member through the over-pressured region.

Abstract: A fluid powered downhole vibration tool used in a well bore wherein fluids are pumped from the surface into a formation through the well bore. The tool includes a fluid powered motor located within the well bore. The fluid powered motor is in communication with the fluids pumped from the surface. In one embodiment, an actuator coupling is rotated by the fluid powered motor. A seismic mass is rotated in the well bore by the actuator coupler, the seismic mass engaging the well bore and causing vibration of the well bore.

Abstract: For extracting a liquid (such as oil) from a porous medium, the liquid is subjected to pulses that propagate through the liquid flowing through the pores of the medium. The pulses cause momentary surges in the velocity of the liquid, which keeps the pores open. The pulses can be generated in the production well, or in a separate excitation well. If the pulses travel with the liquid, the velocity of travel of the liquid through the pores can be increased. The solid matrix is kept stationary, and the pulses move through the liquid. The pulses in the liquid can be generated directly in the liquid, or indirectly in the liquid via a localized area of the solid matrix.

Abstract: This invention provides an apparatus and process for producing heavy crude oil from a subterranean formation penetrated by a well bore. In accordance with the process, an aqueous alkaline chemical solution is introduced into or formed in the well bore penetrating the formation. The aqueous alkaline chemical solution mixes and reacts with produced heavy crude oil in the well bore and ultrasonic waves are emitted into the mixture whereby an emulsion is formed. The viscosity of the formed emulsion is less than that of the crude oil or the crude oil and water mixture flowing into the well bore which allows the oil to be more efficiently pumped to the surface and transported for further processing.

Abstract: A fluid powered downhole vibration tool used in a well bore having fluids under pressure. The tool includes a fluid powered motor located within the well bore, the fluid powered motor is in communication with the fluids under pressure. An actuator coupling is rotated by the fluid powered motor. A seismic mass is rotated in the well bore by the actuator coupler, the seismic mass engaging the well bore and causing vibration of the well bore.

Abstract: A self-firing and self-propelling gas impulse device which includes a housing having a longitudinal axis, a gas inlet port, and one or more gas discharge ports; an inlet chamber, arranged for gas communication with a source of compressed gas via the inlet port and operative to receive compressed gas therefrom; a pressurization chamber arranged for gas communication with the inlet chamber thereby to facilitate a build-up of pressurized gas therein, and arranged for selectable gas communication with the one or more discharge ports; and a piston unit arranged along the longitudinal axis of the housing between the inlet chamber and the pressurization chamber.

Abstract: There is described a process for the stimulation of an oil reservoir or an oil well for enhanced oil recovery and/or seismic mapping of the reservoir, wherein a sound source is used. This sound source is operated by pressurized oil from the oil well by a hydraulic power unit at the surface, and the oil is conducted to an accumulator located in the sound source via a supply line.

Abstract: A fluid powered downhole vibration tool used in a well bore having fluids under pressure. The tool includes a resonant chamber with a through passage in communication with the fluids under pressure wherein the chamber vibrates as the fluids pass through the passage. The resonant chamber is coupled to the well bore, causing vibration of the bore as the chamber vibrates.

Abstract: For extracting a liquid (such as oil) from a porous medium, the liquid is subjected to pulses that propagate through the liquid flowing through the pores of the medium. The pulses cause momentary surges in the velocity of the liquid, which keeps the pores open. The pulses can be generated in the production well, or in a separate excitation well. If the pulses travel with the liquid, the velocity of travel of the liquid through the pores can be increased. The solid matrix is kept stationary, and the pulses move through the liquid. The pulses in the liquid can be generated directly in the liquid, or indirectly in the liquid via a localised area of the solid matrix.

Abstract: An apparatus for use down a bore hole to reduce the viscosity of a hydrocarbon-containing fluid in the bore hole. The apparatus includes a housing having a size for disposition in the bore hole. At least one ultrasonic transducer is carried by the housing. The ultrasonic transducer preferably has an active element changeable from a first shape to a second shape in the presence of an electromagnetic field. An electromagnetic field is provided through at least a portion of the active element to change the shape of the active element. An acoustic element is coupled to the active element for providing ultrasonic energy to the hydrocarbon-containing fluid in the bore hole. A method for reducing the viscosity of a hydrocarbon-containing fluid in a bore hole is additionally provided.

Abstract: The present invention provides methods and apparatus for enhancing the production of liquid hydrocarbons from a subterranean formation penetrated by a well bore. The methods basically comprise placing one or more electric powered sonic energy transducers actuated by magnetostrictive actuators which preferably have drive rods formed of terfenol alloy in the well bore, and causing sonic energy to be emitted from the transducers in the form of pressure waves through the liquid hydrocarbons in the well bore and/or in the formation thereby causing the liquid hydrocarbons to flow into the well bore and to the surface more freely.

Abstract: A fluid powered downhole vibration tool used in a well bore having fluids under pressure. The tool includes a fluid powered motor located within the well bore, the fluid powered motor is in communication with the fluids under pressure. An actuator coupling is rotated by the fluid powered motor. A seismic mass is rotated in the well bore by the actuator coupler, the seismic mass engaging the well bore and causing vibration of the well bore.

Abstract: An apparatus for producing a shock wave in a borehole, such as a well, includes a pumping unit arranged at the wellhead, a tubing string extending downwardly into the production casing of the well, a hollow cylinder assembly connected with the bottom of the tubing string, and a pair of plungers arranged within the cylinder assembly and connected with the pumping unit with sucker rods and a polish rod for compressing liquid contained within the cylinder assembly and discharging the compressed liquid into the production casing, thereby generating a shock wave. The cylinder assembly includes a hollow upper cylinder, a hollow lower cylinder arranged below the upper cylinder, a crossover cylinder arranged between the upper and lower cylinders, and a compression cylinder containing a compression chamber arranged between the crossover cylinder and the upper cylinder.

Abstract: A pressure wave generator for use down a bore hole having fluid therein adjacent a hydrocarbon-containing formation. The generator includes an elastomeric member sized for disposition in the bore hole. A periodic compressive force is exerted on the elastomeric member in a first direction so as to cause the elastomeric member to expand in a second direction and thus produce pressure waves in the fluid to increase the effective permeability of the hydrocarbon-containing formation. A method for using the generator is provided.

Abstract: In preferred embodiments, an apparatus and method for enhancing the in situ removal of at least one contaminant from a contaminated body, the body being provided with at least one interstice, by generating and focusing vibrations toward the interstice, thereby exciting the contaminant within the body, whereby transport of the contaminant out of the body is facilitated. Preferably, the vibrations are sonic or ultrasonic. Vacuum extraction or transformation of the contaminant may also be effected.

Abstract: An apparatus and method for increasing subterranean fluid production are disclosed. A downhole stimulation apparatus produces elastic wave energy which propagates into the subterranean strata of nearby fluid fields. The wave energy creates gravity separation of the fluids, altering the phase permeability of subterranean formations and causing the fluid to migrate to wells in the field being stimulated. The stimulation apparatus employs an underground casing which provides a sealed vessel in which is supported a tubing string. The casing and tubing string are filled with a working fluid. A pumping unit reciprocates a plunger within the tubing string to cyclically pressurize and depressurize the working fluid, the depressurization of working fluid creating the elastic wave energy.

Abstract: An electrohydraulic drilling system for drilling holes in material such as rock utilizing a drill stem connected to a flexible cable. The electrical spark or plasma that creates the electrohydraulic pressure wave is powered by an electrical pulse propagated down the cable from a pulse generator to the drill stem. An advance mechanism on a jackleg support is utilized to move the drill into the rock during the drilling process. The drill stem and cable combination enable holes to be drilled in the roof of tunnels where the floor to roof height is less than the depth of the hole to be drilled. The electrohydraulic process provides higher drilling efficiencies than conventional systems.

Abstract: A method and apparatus are provided for improving the production of unswept and immovable oil from conventional oil wells. The oil recovery system utilizes an impulse wave device to produce impulse waves which travel down-hole and strike a bridge plug. When the impulse waves strike the bridge plug, weak elastic waves are created. After creation, the weak elastic waves propagate in all directions. The weak elastic waves are maintained in a general area near an oil formation by a conventional packer and a diffuser/deflector.

Abstract: A method of enhancing the remediation of contaminated soils and ground water, production of oil and gas, and production of any solid, gas, and/or liquid from subsurface geologic and man-made formations including the steps of estimating the geometric boundaries of the region containing the material to be recovered, drilling a recovery well(s) into subsurface in a strategic location to recover the material of interest, establishing multiple sources of acoustical power in an array about and spaced-apart from the surface or at various depths below the surface in a borehole(s) and/or well(s), directing a volume of acoustical excitation from the sources into the region containing the material to be recovered, the excitation in the form of either controllable sinusoidal, square, pulsed, or various combinations of these three waveforms, and controlling the phasing, frequency, power, duration, and direction of these waveforms from the sources to increase and control the intensity of acoustical excitation in the region

Abstract: Heavy crude oil containing at least 1% by weight water is hydrotreated and upgraded while being produced downhole in a production well. During production the heavy crude oil containing water is subjected to sonic energy at a low frequency of 400 Hz to 10 kHz downhole in the presence of a metal hydrogenation catalyst that causes the water in the crude oil to react and form hydrogen which then hydrotreats and upgrades the heavy crude oil during production. In another embodiment, if the heavy crude oil does not contain water, the hydrogen may be formed in-situ by contacting the heavy crude oil downhole with a chemical compound comprising ammonia, hydrazine and formic acid that in the presence of a metal hydrogenation catalyst and sonic energy causes the chemical compound to react and form hydrogen which then hydrotreats the heavy crude oil during production. Suitable catalysts include nickel on zinc dust, platinum on carbon and palladium on carbon, preferably nickel on zinc dust.

Abstract: An apparatus for cleaning wells using ultrasonic waves includes a plurality of magnetostrictive ultrasonic transducers and a water pump. The ultrasonic transducers are arranged in one or more planes and carried by an adjustment mechanism to allow the cleaning unit to be adjusted to different well diameters, while ensuring that each transducer remains properly oriented to direct the ultrasonic waves perpendicularly at the well casing from an optimum spacing distance. Any desired number of ultrasonic transducer modules can be connected together in the axial direction to ultrasonically clean a portion of the well having a desired axial length in each operating step. The ultrasonic transducers are operated with a power density of 8 to 12 W/cm.sup.2 of ultrasonic emitting surface area, at a frequency in the range of 18 to 25 kHz and preferably 20 kHz. In a first operating step, the ultrasonic transducers ultrasonically treat a first section of the well.

Abstract: A method of producing hydrocarbons from subterranean formations comprises an influence on a hydrocarbon containing bed (1) and extraction of hydrocarbons therefrom through a well (2). The influence on the hydrocarbon containing bed (1) is exerted by means of acting on an aquiferous bed (3) underlying the carbon containing bed (1) by elastic vibrations.

Abstract: A method is described for producing gas from fluid-containing formations, including the steps of generating elastic vibrations by a generator and stimulating a fluid-containing formation by the elastic vibrations, extracting gas from a gas trap through a well, the generating step involving the step of increasing frequency of elastic vibrations within a frequency range from 0.1 Hz to 350.0 Hz, followed by the step of reducing the frequency within the same frequency range.

Abstract: A method and apparatus for the in-situ bio-remediation of contaminated soil and groundwater. Perforated piping embedded within the contaminated region delivers a treatment fluid. The treatment fluid is either a mixture of water, contaminant-eating bacteria and nutrients or a chemical mixture of hydrogen peroxide, a catalyst and water. Ultrasonic or vibratory energy is supplied to the contaminated soil to momentarily increase the permeability thereof. The treatment fluid is then able to flow through the contaminated soil to mix with the contaminants. In one embodiment, an ultrasonic horn located within the perforated piping delivering the treatment solution is used to produce the ultrasonic energy. The ultrasonic horn emits ultrasonic sound waves having a frequency in the range of between 2,000 to 20,000 Hz. In other embodiments, the vibratory energy is emitted by a vibrating plate disposed on a surface of the soil or by a single or plurality of probes embedded within the soil.

Abstract: Disclosed is a method and apparatus for increasing the effectiveness of shock wave stimulation of oil-bearing formations by increasing the intensity of elastic oscillations in the oil accumulation. The device includes a pumping unit and a tubing string run in the production casing of the well, hung in a wellhead. A cylinder is installed on the end of the tubing string. A plunger works in the cylinder, traveling coaxially and coming out of the cylinder at the top of the pumping unit upstroke. The plunger is connected to the pumping unit by sucker rods and a polish rod. On the plunger upstroke the fluid in the tubing string is compressed. At the top of the pumping unit upstroke the fluid in the production tubing is discharged into the production casing generating a shock wave.

Abstract: Methods are provided for making use of an apparatus for generating vibrational energy in a borehole, the apparatus utilizes a mass and a rotary source for suspending the mass in a borehole or in casing in a borehole or in an instrument housing that may be positioned in an opened or cased borehole arranged to cause frictional contact with the surface of the rotating mass, the mass being rotatable about is rotational axis in one direction to cause it to backward whirl in the opposite direction, the centrifugal force of the whirling mass serving to generate vibrational energy that is used to obtain geophysical information as to the structure of the earth surrounding and adjacent to the borehole and for enhancing cementing and production enhancing techniques in oil or gas wells.

Abstract: Methods are provided for making use of an apparatus for generating vibrational energy in a borehole, the apparatus utilizes a mass and a rotary source for suspending the mass in a borehole or in casing in a borehole or in an instrument housing that may be positioned in an opened or cased borehole arranged to cause frictional contact with the surface of the rotating mass, the mass being rotatable about is rotational axis in one direction to cause it to backward whirl in the opposite direction, the centrifugal force of the whirling mass serving to generate vibrational energy that is used to obtain geophysical information as to the structure of the earth surrounding and adjacent to the borehole and for enhancing cementing and production enhancing techniques in oil or gas wells.

Abstract: A method and system for producing coal-bed methane gas from a wellbore is disclosed. The method consists of drilling a wellbore so that a coal seam is intersected, and thereafter casing and completing the wellbore. A transducer is lowered into the wellbore, with the transducer capable of converting electrical energy to a sound energy. The transducer is activated, and methane gas is then produced from the coal seam. The energy to the transducer may be varied so that a maximum rate of methane gas production is obtained.

Abstract: A method and an apparatus for recovering oil from a oil bearing formation having a mixture of oil and water. A first borehole and a second borehole are formed in oil bearing .formation and extend in a horizontal direction. The first borehole is disposed below the second borehole. Seismic waves are generated in the oil bearing formation to reorganize the mixture into oil and water to promote flow of the oil to the second borehole, the seismic waves emanating from the first borehole. The oil is then recovered from the second borehole.

Abstract: The present invention relates to the use of low frequency sonic energy within the range of 1.25 to 6.5 KHz, preferably less than 2.0 KHz and most preferably 1.25 KHz, for enhancing the dissolution of alkaline earth metal scales from well bores using a scale-removing solvent comprising an aqueous alkaline solution having a pH of about 8 to about 14 and containing EDTA or DTPA and a catalyst or synergist, preferably an oxalate anion. When the scale deposit is contacted with the scale removing solvent while simultaneously transmitting low frequency sonic energy through the solvent, substantially more scale is dissolved at a faster rate than previously possible.

Abstract: A method for supplying gas to gas consumers, which method resides in forming a storage reservoir above a gas-saturated water-bearing horizon under development, filling the storage reservoir thus-formed with gas by periodically subjecting the horizon under development to extraneous effects, followed by delivering the gas to gas consumers. Extraneous effects can be exerted by generating elastic vibrations, providing a pressure difference, raising the temperature, applying electromagnetic field oscillations, or combining these factors. If the method of the invention is used in seismically active areas or in regions exposed to effects of elastic vibrations, its efficiency is considerably increased.

Abstract: A method for selectively affecting the permeability of reservoirs to enhance fluid flow therein includes placing a plurality of acoustical wave generator means in a patterned array with respect to the reservoir and energizing them to create acoustic nodes at targeted areas of the reservoir. The acoustic wave generator means can be located solely on the surface, only below surface or in combination above and below surface. The acoustic wave generator means can be selectively simultaneously or sequentially energized to create nodes at targeted areas of the reservoir.

Abstract: Cement bonding and bond logs in wells are significantly improved by imparting random or periodic, pulsating, oscillating or vibrating pressure to the fluids present during all stages of a cementing operation. The effect is to eliminate gelation of the fluids to improve cement placement and to enable consolidation of the cement slurry. The pressure pulses can also be detected to monitor the condition of the setting slurry.

Abstract: The current invention is an improved method for preventing annular fluid flow following primary cementing of a casing string in a wellbore. The method involves injecting high pressure pulses of a working fluid into a liquid-filled casing string to produce tube waves that will propagate through the casing liquid until they encounter a casing restriction or barrier. This encounter vibrates the casing string. Vibration of the casing string helps to maintain the pressure of the cement slurry at or above the pressure of fluids in the surrounding formations, thereby preventing or reducing annular fluid flow.

Abstract: An improved sonic wave generating device and method transmits variable wave energy to a fluid medium that is transmitted to objects such as subsurface petroliforous formations to be treated. Reverberative pressures and wave energy are reduced by improvements to and from a positive pressure supplied feed pump which pumps the medium to the primary wave generating pump(s) includes means to maintain an increased hydrostatic or positive head to the suction inlet of the feed pump which prevents or neutralizes feed back energy waves from the wave generating device to the feed pump, along with a check valve located at the inlet to the primary pump(s) and a buffer system of conduits located between and in the outlet from the feed pump and the check valve to prevent and dampen recoiling energy waves produced by the pumps and augmenting cavitation valve system.

Abstract: A process and apparatus are provided to enhance the recovery of petroleum from onshore and offshore reservoirs. The process includes the simultaneous stimulation of the formation by elastic sound waves, created by a sonic source installed at the oil well so that the elastic sonic waves which are superimposed reduce the adherence forces in the layer between oil/water and the rock formation, and by the oscillating electrical stimulation of the same layer, as from the same wells subject to sonic treatment. The electricity heats the formation by using resistive heating, and thus increases the pressure, thus eliminating the surface tensions between the faces of the fluid as a consequence of the oscillatory action of the ions in the surfaces of the fluid and in addition, reducing the viscosity of the fluids.

Abstract: This invention relates to flow pulsing methods and apparatus for various applications including downhole drilling equipment and in particular to an improved flow pulsing method and apparatus of this type to be connected in a drill string above a drill bit with a view to securing improvements in the drilling process.

Abstract: A method and apparatus for stimulating fluid production in a producing well wherein a well stimulating tool comprising a sealed tool housing with an acoustic transducer in the housing. The tool is run into a producing well on an electric wireline and placed at a depth opposite perforations in a producing zone. The sealed housing of the tool contains a liquid to couple and enable pulses of acoustic energy from the acoustic transducer to be transmitted through the housing into well formation fluids surrounding the housing to reduce the viscosity of the formation fluids by agitation and thereby enhance fluid flow from the formation into the producing well.

Abstract: Without interrupting an enhanced oil recovery polymer flood of a subterranean formation, ultrasonic energy is used to maintain the injectivity of a polymer solution during the polymer flood by modifying the properties of the injected polymer solution.

Abstract: Various configurations of cylindrically shaped transducers are used as borehole seismic wave sources. The basic class of transducers of this invention has an outer shell that is generally cylindrical, and may be comprised of cylindrical sections. The shell or the sections may be pre-stressed or preformed to encourage certain bending motions. Depending on the configuration of the transducer, it approximates a monopole, dipole, or quadrupole radiator. Various actuating means, including magnetostrictive forces and piezoelectric forces, are used to drive the motions of the transducer. These transducers are especially useful for generating compressional, shear, or other elastic waves in solids. For example, in geophysical applications, the transducers are placed in boreholes for either hole-to-hole or single hole measurements.

Abstract: An ultrasonic energy producing device for reducing the viscosity of oil in an oil well. The device includes: an electroacoustic transducer for converting an alternating electrical power signal at a selected voltage into acoustic energy, the transducer being arranged to be disposed in acoustic communication with oil present in the well; a source of alternating electrical power at a voltage substantially higher than the selected voltage, the source being arranged to be disposed at ground level adjacent the well; and an electrical conductor of a length sufficient to extend from ground level to at least the level of oil in the well for conducting alternating electrical power from the source to the transducer.

Abstract: A portion of a formation is heated by introducing heated water into a borehole within the formation and imposing an oscillatory motion onto the heated water. The heated water can be introduced into the borehole by injecting water into the borehole and heating in situ the injected water, or by injecting heated water into the borehole, or by heating in situ water already present within the borehole. In one embodiment, the heated water is maintained as a liquid phase at a temperature of at least 180.degree. F. within the borehole by using electrically driven paddles to impose upon the heated water oscillatory motion having a frequency of from 1 to 100 hertz.

Abstract: The production of petroleum from a petroleum bearing formation through an electrically conductive production tubing suspended in a wellbore extending into said formation and lined by an electrically conductive tubular casing is accomplished by a plurality of method steps. A power source of low frequency alternating current is provided. Then, an electrical circuit path is completed, including the production tubing and casing as current paths. The low frequency alternating current is modified by creating transients in it. The modified low frequency alternating current is electrically coupled to the electrical circuit. Mechanical vibration is electrically induced in the casing and production tubing to substantially, continuously, mechanically vibrate the petroleum bearing formation and enhance petroleum production.

Abstract: This invention relates to flow pulsing methods and apparatus for various applications including downhole drilling equipment and in particular to an improved flow pulsing method and apparatus of this type to be connected in a drill string above a drill bit with a view to securing improvements in the drilling process.

Abstract: The method consists in generating periodically shock waves by initiating the electric discharge in a fluid filling in the well between the electrodes. To initiate the electric discharge, a current-conducting fluid comprising a dielectric fluid and a current-conducting powder material is fed additionally between the electrodes. The device for carrying the method into effect comprises a discharge chamber (5) with positive and negative a system of feeding an initials between the electrodes (3, 4), a system of feeding an initiator between the electrodes (3, 4), electrodes (3, 4), and a surge current generator (2). The device has at least one metering valve (12) with a drive (13) and an additional chamber (9) filled in with a dielectric fluid. A duct (10) having a pressure spool valve (11) is provided in the wall of the additional chamber (9). Inlet and outlet holes (7, 6) are provided in the wall of the discharge chamber (5).

Abstract: Apparatus for electrically generating hydraulic shock waves in a fluid bearing formation (14) of a bore hole (10) including a tool (16) having an upper electrode (42) and a lower electrode (46) forming a spark gap therebetween. The tool (16) has an upper end portion (40) comprised of a plurality of sections (40A-40E) threaded to each other in end to end relation and an armored electrical cable (18) having an outer metal sheath (34) is anchored to the uppermost section (40A). The tool (16) is particularly adapted for fitting within a casing having a four inch diameter and the electrodes (42,46) have diverging planar end surface portions (84) coated with tungsten carbide to provide wear resistant surfaces.

Abstract: A sonic wave generating device transmits variable wave energy to a fluid medium that is transmitted to objects such as subsurface petroliforous formations to be treated. A feed pump which pumps the medium to the devices includes means to maintain an increased hydrostatic or positive head to the suction inlet to the feed pump which prevents or neutralizes feed back energy waves from the wave generating device to the feed pump.