Abstract: A tubing conveyed casing collar locator system that detects the casing collars in a wellbore and acoustically transmits the information through the tubing to the surface where it is detected and processed in a surface processor. The system comprises a downhole tool which comprises downhole sensors, a signal processor with memory, a drive circuit, a battery pack, and a signal generator. The surface system comprises a surface processor, depth system, and acoustic signal transmitter/receiver. The downhole tool detects casing collars as the tool is moved through the collar and acoustically transmits the data or stores the data in downhole memory according to programmed instructions. In one embodiment, the tool compares sensor signals from production elements, such as valves, to stored sensor signatures to uniquely identify the downhole element. In one embodiment, the downhole tool changes operating modes in response to surface command.

Abstract: A method and apparatus for unblocking particulate plugs that develop in a well that produces fluid laden with suspended particles when a pump in the well is idled are described. In order to remove the plugs, a valve is inserted in the production tubing above the pump, the valve permitting the well fluid to flow up past the valve but inhibiting the well fluid from flowing down past the valve so that a majority of particles that settle from the well fluid when the pump is idle are trapped above the valve and do not plug the pump. A volume of well fluid trapped between the bottom of the valve and the top of the pump permits pressure waves induced by starting and stopping the pump to be generated. The pressure waves force fluids past the valve until the particles in the plug are resuspended to permit production to resume. The advantage is a simple, low cost solution to a long standing problem which required pulling of the production tubing from the well in order to remove the particulate plug.

Abstract: Methods and apparatus are provided which permit well testing operations to be performed downhole in a subterranean well. In various described methods, fluids flowed from a formation during a test may be disposed of downhole by injecting the fluids into the formation from which they were produced, or by injecting the fluids into another formation. In several of the embodiments of the invention, apparatus utilized in the methods permit convenient retrieval of samples of the formation fluids and provide enhanced data acquisition for monitoring of the test and for evaluation of the formation fluids.

Abstract: A method for optimizing production from a rod-pumping system includes the steps of providing a well having a rod-pumping system for pumping a fluid from a downhole location of the well to a surface location of the well; providing a mathematical model for determining a dynagraph relationship for the well from power consumption of the rod pumping system; measuring power consumption per cycle of the rod pumping system; determining a downhole dynagraph relationship from the power consumption per cycle and the model; measuring real time values of wellhead pressure and preferably wellhead temperature; and determining an optimum operating condition for the rod-pumping system from the downhole dynagraph relationship and the real time values.

Abstract: A wireless coiled tubing joint locator for locating joints or collars in a production tubing string. An electromagnetic coil assembly or giant magnetoresistive digital field sensor senses the increased mass of a pipe joint, and provides a signal to an electric circuit which generates a signal received by a pilot solenoid valve. The solenoid valve momentarily opens a pilot passageway which activates a piston to close a circulation port in the joint locator, resulting in an increase in a surface pressure reading observable by the operator. In one embodiment, a rupture disk is provided so that pressure cannot be applied to any downhole tool below the joint locator prematurely. A seat sleeve prevents premature communication of fluid to the rupture disk but can be opened by dropping a ball into the joint locator. A second embodiment may be used for either logging or washing operations or both. The electronic circuit can provide a selected one of a plurality of time delays.

Abstract: A combustor method and apparatus is provided. The method utilizes flameless combustion with one or more of three improvements to enhance ignition of the flameless combustor. A catalytic surface can be provided within a combustion chamber to provide flameless combustion at least in the vicinity of the catalytic surface at a temperature that is much lower than the autoignition temperature of fuel in air without the presence of the catalytic surface. Nitrous oxide or supplemental oxygen may also be used as an oxidant either instead of air or with air to reduce ignition temperatures. Further, electrical energy can be passed through the fuel conduit, raising the temperature of the conduit to a temperature above which the fuel will ignite when combined with the oxidant.

Abstract: A self-contained mobile repair unit for repairing wells includes the hydraulic and pneumatic tooling required to do a variety of jobs including the installation and removal of an inner pipe string, sucker rods and a pump. The repair unit, hydraulic tooling and pneumatic tooling share a common engine and a common process monitor. Access to data gathered by the monitor is restricted at the job site itself. Instead, the data is transmitted to a remote home base for the purpose of monitoring operations form a central location.

Abstract: A formation fluid sampling apparatus (40) for verification of monophasic samples is disclosed. The apparatus (40) comprises a housing (42) having a sampling chamber (48) and a sampling port (50) defined therein. The sampling port (50) is in communication with the sampling chamber (48) and the formation traversed by the wellbore such that formation fluids may be collected in the sampling chamber (48). A temperature monitoring device (52) monitors the temperature of the formation fluids collected in the sampling chamber (48). A temperature recorder (46) that is operatively connected to the temperature monitoring device (52) is used to record the temperature fluctuations of the formation fluids in the sampling chamber (48) to determine whether the formation fluids undergo phase change degradation during collection of the fluid sample and retrieval of the formation fluid sampling apparatus (40) from the wellbore.

Abstract: A system and method of fail safe communication of information between surface equipment and downhole equipment are disclosed. The system comprises two or more repeaters (34, 35, 36) disposed within a wellbore (38) such that two repeaters (34, 35) will receive each signal carrying information that is telemetered. The repeater (35) that is farther from the source (44) will include a memory device (292) that stores the information carried in the signal. A timer device (293) also in the repeater (35) that is farther from the source (44) will trigger the retransmission of the information after a predetermined time period unless the repeater (35) that is farther from the source (44) has detected a signal carrying the information generated by the repeater (34) that is closer to the source (44).

Abstract: A self-contained mobile repair unit for repairing wells includes the hydraulic and pneumatic tooling required to do a variety of jobs including the installation and removal of an inner pipe string, sucker rods and a pump. The repair unit, hydraulic tooling and pneumatic tooling share a common engine and a common process monitor. Access to data gathered by the monitor is restricted at the job site itself. Instead, the data is transmitted to a remote home base for the purpose of monitoring operations form a central location.

Abstract: A system allows the pumping of viscous fluids from a wellbore. The system includes a submergible pump and a pump intake through which a fluid may be drawn. A submergible electric motor powers the submergible pump, and a heater is connected in the pumping system to heat the wellbore fluid. Additionally, a combination of heaters may be employed to heat the desired production fluid both externally to the pumping system and internally to the pumping system.

Abstract: A method for optimizing production from a gas lift well includes the steps of: obtaining a statistical model of production behavior of a gas lift well, the production behavior including known patterns of at least one production characteristic and corresponding operating parameters; operating the gas lift well at initial operating parameters; obtaining a real time value of the production characteristic from the gas lift well at the initial operating parameters; comparing the real time value of the production characteristic to the model to determine whether a known pattern is detected; and if a known pattern is detected, adjusting the operating parameters to the corresponding operating parameters. An apparatus is also provided.

Abstract: A method for fracturing an underground formation surrounding an oil and/or gas well comprises positioning a fracturing tool in a selected orientation in the borehole and expanding the tool such that it exerts a circumferentially varying pressure against the borehole wall over a selected period of time thereby initiating in the surrounding formation one or more fractures which each intersect the borehole wall in a selected orientation and simultaneously injecting a proppant into the fracture(s).

Abstract: The invention is a method to operate a heat injection well, the method comprising the steps of: providing a heat injection well comprising a metal casing and a controllable source of heat within the casing; determining the maximum temperature of the casing which can be applied to the metal casing as a function of external pressure; providing a formation stress measurement device within the formation in the vicinity of the wellbore; providing a temperature measurement device effective for determining the temperature of the casing; determining the formation stress during operation of the heat injection well; and controlling heat released from the controllable source of heat to maintain the formation stress below a predetermined fraction of the collapse stress of the casing.

Abstract: A system and method for monitoring a formation surrounding a borehole in a production well. The method encompasses the use of a downhole sensor permanently mounted in the well to sense at least one downhole formation parameter which is not normally present within the wellbore. The system includes a formation evaluation sensor permanently located downhole in a production well having at least two boreholes, wherein at least one of the boreholes is a branch borehole, the sensor sensing a formation parameter which is not normally present within the borehole.

Abstract: A downhole electromagnetic signal repeater (76) for communicating information between surface equipment and downhole equipment and a method for use of the repeater (76) is disclosed. The repeater (76) comprises a receiver (120) and a transmitter (124). The receiver (120) receives an electromagnetic input signal and transforms the electromagnetic input signal to an electrical signal that is inputted into an electronics package (122) that amplifies the electrical signal and forwards the electrical signal to the transmitter (124) that transforms the electrical signal to an electromagnetic output signal that is radiated into the earth.

Abstract: A method and apparatus for selectively producing fluids from multiple lateral wellbores that extend from a central wellbore. The apparatus comprises a fluid flow assembly with a selectively openable and adjustable flow control valve in communication with a production tubing, located in the central wellbore between packers, and a lateral wellbore, and a selectively openable access door located adjacent the lateral wellbore allowing and preventing service tool entry into the lateral wellbore. The valve and door are individually controlled from the earth's surface.

Abstract: A well fluid sampling tool and method for retrieving reservoir fluid samples from deep wells. The sampling tool is lowered to the required depth, an internal sample chamber is opened to admit well fluid at a controlled rate, and the sample chamber is then automatically sealed. The temperature of the sampled well fluid is maintained at or near initial as-sampled temperature to avoid the volumetric shrinkage otherwise induced by temperature reduction, mitigate precipitation of compounds from the sample, and/or maintain the initial single-phase condition of the sample. The sample chamber is thermally insulated, provided with a storage heater, electrically heated, given a high hear capacity, and/or pre-heated to sample temperature.

Abstract: A combustor method and apparatus is provided. The method utilizes flameless combustion with one or more of three improvements to enhance ignition of the flameless combustor. A catalytic surface can be provided within a combustion chamber to provide flameless combustion at least in the vicinity of the catalytic surface at a temperature that is much lower than the autoignition temperature of fuel in air without the presence of the catalytic surface. Nitrous oxide or supplemental oxygen may also be used as an oxidant either instead of air or with air to reduce ignition temperatures. Further, electrical energy can be passed through the fuel conduit, raising the temperature of the conduit to a temperature above which the fuel will ignite when combined with the oxidant.

Abstract: A permanently installed, remotely monitored and controlled transient pressure test system is provided. This system utilizes shut-in/choke valves, pressure sensors and flow meters which are permanently associated with the completion string to perform transient pressure tests in single and multiple zone production and injection wells. The present invention permits full bore testing which thereby eliminates undesirable wellbore storage effects. The present invention further allows for pressure testing limited only to a selected zone (or zones) in a well without expensive well intervention and without halting production from, or injection into, other zones in the well. The permanently located pressure test system of this invention also allows for real-time, downhole nodal sensitivity and control. This pressure test system may be permanently deployed either in production wells or injection wells.

Abstract: A method is provided for automatically determining an optimum gas injection rate for a gas-lifted oil well. The optimum gas-lift slope for the oil well is initially provided and stored in the memory of a programmable logic controller. A lift gas is injected into the well at an initial gas injection rate to displace a liquid at an initial liquid production rate from the well. The initial liquid production rate and initial gas injection rate are stored in the memory. Thereafter, the lift gas is injected into the well at a first incremental gas injection rate differing from the initial gas injection rate by a first incremental value. Additional liquid is displaced from the well at a first incremental liquid production rate and the first incremental liquid production rate and first incremental gas injection rate are stored in the memory. The first incremental slope is determined from the stored data points and compared to the optimum gas-lift slope.

Abstract: A side pocket mandrel arranged to receive a measuring instrument such as a pressure gauge in the open-bottomed side pocket thereof includes an electrical contact mounted at the top of the side pocket and connected to a cable extending upward to the surface, and an instrument lowered on a wireline kickover tool and inserted upward into the pocket and latched in place with a mating electrical connector automatically engaging the contact. Placement of the electrical contact at the top of the pocket prevents debris from settling around it and preventing reengagement after removal of the gauge for any reason.

Abstract: A system for extending the life span of electronic components in a high temperature well. A thermal electric cooler is located in a position thermally communicating with the electronic component in the well. The thermal electric cooler lowers the temperature of the electronic component to a temperature that retards the deterioration of the electronic component, and is particularly useful in well completion tools requiring an extended life. A vacuum is maintained about the thermal electric cooler or the electronic components to reduce convection energy losses.

Abstract: A downhole control system for a production well is associated with permanent downhole formation evaluation sensors which remain downhole throughout production operations. These formation evaluation sensors may include, for example, neutron generator, gamma ray detector and resistivity sensors which can, in real time, sense and evaluate formation parameters including important information regarding formation invading water entering the producing zone. Significantly, this information can be obtained prior to the water actually entering the producing geological formation and therefore corrective action (i.e., closing of a valve or sliding sleeve) can be taken prior to water being produced. This real time acquisition of formation data in the production well constitutes an important advance over current wireline techniques in that the present invention is far less costly and can anticipate and react to potential problems before they occur.

Abstract: A downhole control system for a production well is associated with permanent downhole formation evaluation sensors which remain downhole throughout production operations. These formation evaluation sensors may include, for example, neutron generator, gamma ray detector and resistivity sensors which can, in real time, sense and evaluate formation parameters including important information regarding formation invading water entering the producing zone. Significantly, this information can be obtained prior to the water actually entering the producing geological formation and therefore corrective action (i.e., closing of a valve or sliding sleeve) can be taken prior to water being produced. This real time acquisition of formation data in the production well constitutes an important advance over current wireline techniques in that the present invention is far less costly and can anticipate and react to potential problems before they occur.

Abstract: A well pipe string joint locator for attachment to the end of a length of coiled tubing and moved within the pipe string as the coiled tubing is lowered or raised therein is provided as well as methods of using the joint locator. The joint locator is comprised of an elongated tubular housing having a longitudinal fluid flow passageway therethrough and having at least one lateral port extending through a side thereof. Electronic means are disposed within the housing for detecting the increased mass of a pipe joint as said locator is moved through the joint and generating a momentary electric output signal in response thereto. Valve means are disposed within the housing responsive to the electric signal for momentarily opening or closing the lateral port of the housing to thereby create a surface detectible pressure drop or rise.

Abstract: An apparatus for imaging the thermal properties of fluids in a wellbore. The apparatus includes a tool mandrel adapted to traverse the wellbore. The apparatus includes temperature sensors positioned at spaced apart locations along radially extendible arms attached to the mandrel. A temperature measuring circuit connected to each one of the sensors. The apparatus includes a circuit for applying a momentary current pulse to each of the temperature sensors, for momentarily raising their temperatures. Momentary increases in the sensor temperatures are provided so that the thermal transient response of the fluid in contact with each sensor can be determined. The invention includes a method of determining the flow regime of the fluid flowing in the wellbore. The method includes the steps of measuring the temperature of fluids in the wellbore at spaced apart locations within the cross-sectional area of the wellbore, using a tool having temperature sensors positioned at spaced apart locations.

Abstract: An apparatus and method for selectively restricting fluid flow in a well or well conduit. A dissolvable core material is positioned in the well and is isolated from the well fluids with an inpermeable sheath. The sheath is punctured with a control mechanism or other device so that the sheath is breached. The fluid dissolves the core material and permits fluid flow through the well or well conduit. The sheath can be punctured by pressurizing the well fluid, or by controlling the fluid pressure to activate a pressure sensitive control mechanism.

Abstract: A downhole control system for a production well is associated with permanent downhole formation evaluation sensors which remain downhole throughout production operations. These formation evaluation sensors may include, for example, neutron density, gamma ray porosity and resistivity sensors which can, in real time, sense and evaluate formation parameters including important information regarding water entering the production tubing. Significantly, this information can be obtained prior to the water actually entering the producing fluid and therefore corrective action (i.e., closing of a valve or sliding sleeve) can be taken prior to water being produced. This real time acquisition of formation data in the production well constitutes an important advance over current wireline techniques in that the present invention is far less costly and can anticipate and react to potential problems before they occur.

Abstract: A telemetry system for obtaining loggings by an independently guiding logging probe provided with a sensor includes the logging probe ejected in a drill string, so that the sensor projecting through a drill bit of the drill string has an access to the bottom and walls of the drill bore, a pick-up probe injectable into the drill string to form a wireless connection with the logging probe and connected to a portable computer which initializes the logging probe, loggings stored in the logging probe are readable from the portable computer upon recovering the logging probe from the bore string.

Abstract: A method and apparatus for controlling a production facility containing a well that produces subterranean fluids and gas is disclosed. The production facility is connected to a receiving facility by a pipeline having a pipeline pressure. The production facility has a remote control system that has operably associated therewith a controlling valve member, and a safety system containing a surface valve, and a subsurface valve. Generally, the method comprises the steps of setting the following pressures: a pipeline high pressure level, a pipeline low pressure level, a control system upper pressure level, and a control system lower pressure level. Next, the receiving facility is shut-in, and the pipeline pressure is monitored. According to the pressure level achieved in the pipeline, a signal in response thereto is generated, and thereafter a remote control system valve member may be activated thereby closing the valve.

Abstract: Apparatus and method for detecting varying flow velocity at differing points outside the casing in a wellbore are provided. The flow is detected by stationary temperature sensors inside the casing. Logging means, sensors left in the well with data storage, data telemetry to surface and downhole alarm systems are provided. Measurements are used for detecting lack of mechanical integrity of a wellbore, hydraulic fracture extent along a wellbore, vertical flow in a formation or other occurrences of non-uniform flow.

Abstract: A well rod pump having a filter system to remove particulate material from the fluids produced from the well and an automatic back flush system using pumped fluid to flush particulate material from the filter system in response to increased pressure differential across the filter system, including a rod moved by a piston to open the valves of the pump, and a time delay connected to continue to hold the valves open for a period sufficient to allow back flushed particles to settle in the well. Well treatment chemicals may be injected into the well with the back flushing fluid.

Abstract: A method and related system for operating a downhole tool connected to coiled tubing comprises introducing the tool and the coiled tubing into a wellbore providing to the earth's surface a signal indicative of compression, tension and/or impact forces applied to the tool, using the signal to determine at the earth's surface the location of the tool within the wellbore, and then operating the tool.

Abstract: This invention is directed to a system for determining the position and depth of downhole equipment in a wellbore which includes an elongate spoolable composite coiled tubing for running the downhole equipment into the wellbore. The composite coiled tubing string has multiple layers of fibers arranged in a generally cylindrical shape, wherein each layer has a plurality of fibers arranged in a predetermined orientation to form a composite coiled tubing string having sufficient strength to be pushed into and pulled and out of the borehole. A plurality of detectable indicia (such as metallic, magnetic or encoded sections) overlay at least one of the layers of fibers and are integral to the composite coiled tubing string and spaced apart along the length of the tubing string at predetermined distances.

Abstract: A detector structure is used to sense and log the joints in a downhole jointed tubular structure, such as a well bore casing or production tubing, in a subterranean well. The detector is moved through the jointed tubular structure on an elongated positioning member, representatively a slick line, through a series of joints to be logged. As the detector passes through each joint it electromagnetically senses the joint and responsively generates an electric output signal. The output signal is used to momentarily cause a drag structure portion of the detector, in cooperation with the interior side surface of the tubular structure, to momentarily create a detectable tension change in the elongated positioning member. Alternatively, a pyrotechnic or compressed gas device may be used to create the detectable changes in response to the generation of the electrical output signals.

Abstract: A method is provided for the stabilization and control of the two-phase flow of hot fluid containing water issuing from the top of an upwardly rising conduit or riser of a horizontal oil-production well. The fluid enters the bottom of the riser at a temperature higher than the saturation temperature of water at the conditions prevailing at the top of the riser. A first mass rate flow controller is coupled to a mass rate flow detector at the top of the well for controlling mass flow at a substantially constant rate over a short time interval. Signals indicative of the optimal flow rate for the process are input to a second controller. The second controller adjusts the mass flow rate setpoint of the first controller. The second controller has a time constant significantly longer than that of the first controller.

Abstract: A downhole shut-in tool includes in one aspect a pilot valve which when opened places a differential pressure across a piston which in turn operably engages a shut-in valve element to close the shut-in tool. An electronic timer assembly and electric drive motor are provided for controlling the action of the pilot valve. The drive motor is controlled by a load sensor which senses that the motor has stalled when an actuator engages a movement limiting abutment. In another aspect a pilot value is provided which can selectively communicate the pressure differential across the piston so as to repeatedly open and close the shut-in valve element. Efficient methods of drawdown and buildup testing using such an automated multiple operating shut-in tool are provided. Associated automated sampling tools are also disclosed.

Abstract: An electromechanical detector structure is used to sense and log the joints in a downhole jointed tubular structure, such as a well bore casing or production tubing, in a subterranean well. The detector is lowered into the tubular structure on an elongated positioning member, representatively a slick line, through a series of joints to be logged, and then pulled upwardly through the joints. As the detector passes upwardly through each joint it electromagnetically senses the joint and responsively generates an electric output signal. The output signal is used to momentarily drive a drag structure portion of the detector into forcible, motion inhibiting contact with the interior surface of the tubular structure. This, in turn, momentarily creates a detectable tension increase in the elongated positioning member.

Abstract: Apparatus and method for detecting flow outside Casing in a well are provided. The flow may be detected by logging tools or by fixed equipment inside casing. An alarm system is provided for lack of mechanical integrity of a wellbore. Stationary temperature sensors are placed in contact with the inside wall of the casing. Electronic circuits are used to provide output signals sensitive to differences in temperature of the sensors.

Abstract: A well treating tool string run on coiled tubing and having packers to isolate a zone to be treated in response to operation of a selector valve, pressure and temperature transducers in the tool string and a telemetry system which samples the measurements made by the transducers, an electrical conductor cable extending from the telemetry system up to the surface through the coiled tubing and to the inner end thereof on its storage reel, and a surface telemetry, data processing and display system that sends and receives encoded signals to and from the downhole telemetry system from which temperature and pressure values can be read out on the surface display in real time as the treating operation proceeds.

Abstract: A downhole shut-in tool includes in one aspect a pilot valve which when opened places a differential pressure across a piston which in turn operably engages a shut-in valve element to close the shut-in tool. An electronic timer assembly and electric drive motor are provided for controlling the action of the pilot valve. The drive motor is controlled by a load sensor which senses that the motor has stalled when an actuator engages a movement limiting abutment. In another aspect a pilot valve is provided which can selectively communicate the pressure differential across the piston so as to repeatedly open and close the shut-in valve element. Efficient methods of drawdown and buildup testing using such an automated multiple operating shut-in tool are provided. Associated automated sampling tools are also disclosed.

Abstract: A method to reduce water coning in viscous oil formations during primary oil production wherein a horizontal wellbore is heated by circulating steam therein thereby heating a radial area near the wellbore. Near wellbore heating alters a pressure profile in the radial area near the wellbore. Reduced inflow pressure gradients near the wellbore flatten out a pressure sink associated with the wellbore. This reduces substantially water coning which allows more oil to be produced before high water production begins.

Abstract: A downhole shut-in tool includes in one aspect a pilot valve which when opened places a differential pressure across a piston which in turn operably engages a shut-in valve element to close the shut-in tool. An electronic timer assembly and electric drive motor are provided for controlling the action of the pilot valve. The drive motor is controlled by a load sensor which senses that the motor has stalled when an actuator engages a movement limiting abutment. In another aspect a pilot valve is provided which can selectively communicate the pressure differential across the piston so as to repeatedly open and close the shut-in valve element. Efficient methods of drawdown and buildup testing using such an automated multiple operating shut-in tool are provided. Associated automated sampling tools are also disclosed.

Abstract: A downhole tool comprises an apparatus including an electrical member and a cooling system to maintain the electrical member within a rated temperature operating range. The cooling system includes a container holding a refrigerant. The cooling system also includes heat transfer elements for conducting refrigerant from the container in proximity to the electrical member so that a temperature adjacent the electrical member is less than ambient well bore temperature and preferably less than the maximum of the rated temperature operating range. The cooling system further includes a device for moving refrigerant from the container and through the heat transfer elements in response to pressure in the well bore. In a preferred embodiment, the refrigerant is recycled through the heat transfer circuit back to the container.

Abstract: There is provided a flow-through cell with a diverter valve for continuously monitoring specific parameters of a fluid which passes through the flow-through cell. The diverter valve diverts a portion of fluid flow from a fluid line to the flow-through cell. The flow-through cell has an analyzing probe capable of monitoring a plurality of conditions of the fluid that is flow through the cell. By continuously monitoring specific parameters of the fluid as it moves through the flow-through cell, it is possible to constantly monitor the condition of the fluid and react to changes or stabilization of the readings provided by the probe.

Abstract: This invention describes a method of stimulating production from an oil well by removing solid wax deposits from a production zone. An electrical resistance heater comprised of a packed bed of spherical heating elements is lowered through the tubing on a wireline and placed adjacent to the perforations. Solvent is pumped through the heater to raise its temperature by 200.degree. C. and then into the formation to contact wax deposits. The solid wax deposits are liquified and together with the oil and the solvent form a single liquid phase. The wax is then removed from the formation by placing the well back on production. Because the invention completely avoids the use of either water or gas, the saturation of the water and gas phases in the formation is minimized, thereby maximizing the mobility of the liquid phase containing the wax and facilitating the removal of the liquified wax from the treatment area before it reprecipitates.

Abstract: A chemical injector system for wells includes a solenoid operated valve delivering bursts of supply gas to a piston driven chemical injector pump. The solenoid valve allows very low cycle rates and also avoids plugging up of the gas supply line because the bursts of supply gas create high enough velocities to keep water and debris moving. A stand having a spike and a plate welded thereto supports the injector pump.

Abstract: A downhole shut-in tool includes in one aspect a pilot valve which when opened places a differential pressure across a piston which in turn operably engages a shut-in valve element to close the shut-in tool. An electronic timer assembly and electric drive motor are provided for controlling the action of the pilot valve. The drive motor is controlled by a load sensor which senses that the motor has stalled when an actuator engages a movement limiting abutment. In another aspect a pilot valve is provided which can selectively communicate the pressure differential across the piston so as to repeatedly open and close the shut-in valve element. Efficient methods of drawdown and buildup testing using such an automated multiple operating shut-in tool are provided. Associated automated sampling tools are also disclosed.

Abstract: A fluid sampling apparatus is disclosed for withdrawing samples of groundwater or other fluids from a well or other monitoring site. The apparatus preferably includes pump means, conduit means and a wellhead assembly that are substantially permanently installed at such well or monitoring site and are thereby dedicated thereto in order to avoid or minimize cross-contamination of samples from site to site. The apparatus preferably also includes a removable and portable controller means adapted for easy and convenient transportation and connection to such dedicated fluid sampling components at various wells or monitoring sites.The questions raised in reexamination request No. 90/001,494, filed Apr. 18, 1988, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CRF 1.570(e).