Abstract: An apparatus and method for maintaining the pressure of a well fluid sample as the sample is transported to the well surface from a downhole wellbore location. The invention collects a formation fluid sample under pressure. The fluid sample is further pressurized with a traveling piston powered by the hydrostatic wellbore pressure. The pressurized formation fluid sample is contained under high pressure within a fixed volume chamber for retrieval to the well surface. Multiple collection tanks can be lowered into the wellbore during the same run to sample different zones with minimal rig time. The tanks can be emptied at the well surface with an evacuation pressure so that the fluid sample pressure is maintained above a selected pressure at all times.

Abstract: A tool string for use in wellbore includes a sampler device having a port to receive pressure in an annulus region of the wellbore. An elevated pressure is communicated to a rupture disk assembly located in the port to rupture the rupture disk assembly. The elevated pressure is then communicated through a passageway to an activating mechanism of a sampler device. The activating mechanism is adapted to open a flow control device that controls flow through one or more ports of the sampler device. In another arrangement, the activating mechanism of the sampler device may include a pressure transducer for receiving pressure pulse signals. In response to pressure pulse signals of predetermined amplitude and pulse width, the pressure transducer may generate an activating signal to an actuator to operate the flow control device. Yet another arrangement includes a timer for activating the sampler device. The timer is actuatable by an elevated pressure.

Abstract: An apparatus and method capable of incrementally decreasing the borehole pressure at a variable rate by controlling a test volume within the borehole. The system includes an incrementally controllable pump, closed loop feedback and a controller for drawing down the pressure of a test volume to a level just below formation pressure. This incremental drawdown system will significantly reduce the overall measurement time, thereby increasing drilling efficiency and safety.

Abstract: A tool that is usable in a subterranean well to sample well fluid from a zone does not include a pump to remove well fluid from the zone for purposes of sampling. Instead, the tool includes a flow path that is in communication with the zone and a region of the well above the zone to use a pressure differential created or naturally occurring between the zone and the region of the well above the zone to flow well fluid from the zone. The tool may also include a flow path that is in communication with the region of the well above the zone and the region of the well below the zone to equalize pressure along the tool and thereby prevent unintended axial movement of the tool. A fluid sampler of the tool samples a composition of the well fluid from the zone.

Abstract: A universal well screen filter assembly for installation in a borehole formed in a fluid bearing formation to filter fluid passing therethrough. The screen filter includes an outer cylindrical perforated screen member and an inner cylindrical perforated screen member which is aligned concentrically with the outer screen member. The inner screen member has a smaller diameter than the outer screen member and positioned to define an annular filter space therebetween. This space is substantially filled with a filter medium which is designed to filter particulate materials from fluid passing through the medium. An upper end cap is secured to an upper end of each of the spaced apart screen members to seal the annular space therebetween and a lower end cap is secured to a lower end of each of the spaced apart screen members to also seal the annular space therebetween. A tubular member is aligned concentrically and extends through the screen filter.

Abstract: A sample module for use in a downhole tool includes a sample chamber for receiving and storing pressurized fluid. A piston is slidably disposed in the chamber to define a sample cavity and a buffer cavity, and the cavities have variable volumes determined by movement of the piston. A first flowline is provided for communicating fluid obtained from a subsurface formation through the sample module. A second flowline connects the first flowline to the sample cavity, and a third flowline connects the first flowline to the buffer cavity for communicating buffer fluid out of the buffer cavity. A first valve capable of moving between a closed position and an open position is disposed in the second flowline for communicating flow of fluid from the first flowline to the sample cavity. When the first valve is in the open position, the sample cavity and the buffer cavity are in fluid communication with the first flowline and therefore have equivalent pressures.

Abstract: An early formation evaluation tool is provided which includes formation fluid sampling capabilities. In one embodiment, fluid pressure in a drill string in which the tool is interconnected is utilized to operate packers of the tool and to operate fluid samplers of the tool. To successively control actuation of the samplers, a ratchet mechanism responsive to altering fluid pressures in the drill string aligns a piercing member with a series of frangible pressure barriers associated with the samplers.

Abstract: A well monitoring apparatus for burial in the ground to sample and monitor subsurface water having a cylindrical bailer unit with an internal reservoir chamber for collection of samples communicated thereto from outside the bailer. A pressurization system allows for selected pressurization of the chamber from a remote location to transmit fluid therform to a remote location for inspection. The bailer may be buried separately or attached to the lower end of a conventional well casing.

Abstract: One embodiment of my invention comprises a tool string for testing a wellbore formation that includes a production inlet, an injection outlet, and a sampler apparatus. Fluid is taken from a production zone, into the tool string through the production inlet, out of the tool string through the injection outlet, and into the injection zone. Within the interior of the tool string, the sampler apparatus takes samples of the fluid flowing therethrough. In another embodiment, a large volume of sample fluid is trapped within the interior of the tool string, such as between two valves, and is removed from the wellbore along with the tool string subsequent to the test. In another embodiment, the tool string includes at least one perforating gun to perforate one of the production and injection zones. The tool string may also include two perforating guns to perforate both the production and injection zones.

Abstract: A sample module is provided for use in a downhole tool to obtain fluid from a subsurface formation penetrated by a wellbore. The sample module includes a sample chamber carried by the module for collecting a sample of formation fluid obtained from the formation via the downhole tool, and a validation chamber carried by the module for collecting a substantially smaller sample of formation fluid than the sample chamber. The validation chamber is removable from the sample module at the surface without disturbing the sample chamber. In another aspect, the present invention provides an improved sample chamber for use in a downhole tool to obtain fluid from a subsurface formation penetrated by a wellbore.

Abstract: A substantially leak-free bailer includes an improved valve assembly at its lowermost end. A valve body is mounted to the lowermost end of a valve stem and the valve stem is slideably received within and guided by a central bore formed on a support member that spans the hollow interior of the bailer at its lowermost end. The valve body may be hemispherical, frusto-conical, or elongate and downwardly tapered. The valve seat is configured to match the contour of the valve body. An annular ridge circumscribes the valve seat and serves as a barrier to particulate matter so that the valve body sits in the valve seat without interference from such particulate matter.

Abstract: A downhole tool and method of operation is described for collecting fluid samples in a downhole environment. The tool is connectable on a work string and is activated by dropping a ball through the work string. On activation a sleeve arranged on the body of the tool is caused to shift from a first to a second position thereby creating a chamber between the sleeve and body. The sample fluid is drawn into the chamber as it is created and is prevented from exiting by a non-return valve. The tool locks the sleeve in the second position to fix the chamber. The sample can then be retrieved along with the tool.

Abstract: The extraction of intact, representative fluid samples in well-defined depths, such as from wells sunk into the ground, has until now been very difficult, and in many cases impossible to perform. A method is provided as well as a sample extractor for the extraction of intact fluid samples, in particular from a well (26) sunk into the ground, by submersion of a compressible hollow flexible body (22) fitted in a supporting device which, subsequent to submersion to the sample extraction depth, is acted upon to effect liquid entry through an inlet. In particular, hollow flexible body (22) is held in the support device in the form of a pressure vessel (2) and fully compressed by pressurized gas inside the pressure vessel, whereupon the pressure vessel is caused to change in such a way that a surrounding fluid seeps into the hollow flexible body (22), whereupon the vessel (2) with the body (22) containing the fluid sample is hoisted out of the well (26).

Abstract: A test system and method for testing a well having a first and second zone includes a chamber and an isolation device moveable in the chamber. The isolation device separates a first and a second portion of the chamber. The chamber is adapted to receive fluid in the second chamber portion from the first zone. The isolation device is adapted to be moved in the chamber in a first direction by the first zone fluid. The first chamber portion can be charged with fluid pressure to move the isolation device in a second direction to pump the first zone fluid inside the second chamber portion into the second zone.

Abstract: A drilling fluid analyzing apparatus has at least two sensors is used to analyze drilling fluid that contains cuttings. The sensors are mounted vertically spaced in a well riser and in communication with well return fluid. The sensors convert the pressure exerted by the return fluid to signals that are then conveyed to a processor. The processor determines the density of the return fluid, and the fluid density is indicative of borehole cleaning efficiency. Two additional sensors may be added to the drilling fluid input mud pipe to sense the pressure exerted by the drilling mud before it is contaminated with cuttings.

Abstract: One embodiment of my invention comprises a tool string for testing a wellbore formation that includes a production inlet, an injection outlet, and a sampler apparatus. Fluid is taken from a production zone, into the tool string through the production inlet, out of the tool string through the injection outlet, and into the injection zone. Within the interior of the tool string, the sampler apparatus takes samples of the fluid flowing therethrough. In another embodiment, a large volume of sample fluid is trapped within the interior of the tool string, such as between two valves, and is removed from the wellbore along with the tool string subsequent to the test. In another embodiment, the tool string includes at least one perforating gun to perforate one of the production and injection zones. The tool string may also include two perforating guns to perforate both the production and injection zones.

Abstract: An early formation evaluation tool is provided which includes formation fluid sampling capabilities. In one disclosed embodiment, fluid pressure in a drill string in which the tool is interconnected is utilized to operate packers of the tool and to operate fluid samplers of the tool. To successively control actuation of the samplers, a ratchet mechanism responsive to altering fluid pressures in the drill string aligns a piercing member with a series of frangible pressure barriers associated with the samplers.

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 test system and method for testing a well having a first and second zone includes a chamber and an isolation device moveable in the chamber. The isolation device separates a first and a second portion of the chamber. The chamber is adapted to receive fluid in the second chamber portion from the first zone. The isolation device is adapted to be moved in the chamber in a first direction by the first zone fluid. The first chamber portion can be charged with fluid pressure to move the isolation device in a second direction to pump the first zone fluid inside the second chamber portion into the second zone.

Abstract: A method of performing a downhole well completion cleanup is provided. In a described embodiment, completion fluids from a first zone are flowed into a tubular string, and then the fluids are discharged into a second zone. An apparatus usable in the method is provided, in which a downhole pump is utilized to pump the fluids from one zone to the other. The pump may be operated in a variety of manners. The apparatus may also include fluid identification sensors and telemetry devices for monitoring the progress of the cleanup operation.

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: When production testing a permeable first formation, fluid flowing out from the first formation is subjected to a pressure measurement and a flow rate control. In order to avoid bringing up the fluid flowing out during the production test to a surface position, where the fluid's inherent explosion and fire risk as well as poisonousness could cause substantial problems, a fluid flow path is arranged for fluid transfer only between the first and second formations. The fluid flow path which, in a suitable apparatus, is constituted by a channel-forming pipe. From this channel, the second permeable formation receives the fluid and keeps it for some time. In the position of use, the apparatus is assigned sealing devices such as annulus packers, which are placed such that fluid flow between the formations is limited to only follow the fluid flow path.

Abstract: A formation fluid sampling probe uses two hydraulic lines to recover formation fluids from two zones in a borehole. One of the zones is a guard zone and the other is a probe zone. The guard zone and the probe zone are isolated from each other by mechanical means, with the guard zone surrounding the probe zone and shielding it from the direct access to the borehole fluids. Operation of the tool involves withdrawal of fluid from both zones. Borehole fluids are preferentially drawn into the guard zone so that the probe zone recovers the formation fluid substantially free of borehole fluids. Separation of the guard zone from the probe zone may be accomplished by means of an elastomeric guard ring, by inflatable packers or by tubing. The device can be adapted for use either on a wireline or in an early evaluation system on a drillstring.

Abstract: An in situ underground sample analyzing apparatus for use in a multilevel borehole monitoring system is disclosed. A casing assembly comprising a plurality of elongate tubular casings (24) separated by measurement port couplers (26) is coaxially alignable in a borehole (20). The measurement port couplers (26) include an inlet measurement port (70b ) for collecting fluid from an underground measurement zone (32) and an outlet measurement port (70a) for releasing fluid into the measurement zone (32). An in situ sample analyzing probe (124) is orientable in the casing assembly. The in situ sample analyzing probe (124) includes inlet and outlet probe ports (148b and 148a) alignable and mateable with the inlet and outlet measurement ports (70b and 70a). The inlet and outlet measurement ports (70b and 70a) typically include valves.

Abstract: A method and apparatus for installing a groundwater sampling device into the ground includes a generally cylindrical housing open at top and bottom end portions and defining a recess therein. An expendable tip member is removably connected to the bottom and portion of the housing. A well tubing or casing is positioned generally centrally in the recess and includes top and bottom end portions. An elongated spiral-wound cylinder is slidably positioned in the recess of the housing and in a surrounding relationship to the tubing. The tubing is attached to the tip member at the bottom end portion thereof and includes a lower section having a plurality of perforations about the periphery thereof to allow fluid to enter the interior of the tubing.

Abstract: A flexible liner system provides for instrumentation and sampling within a cavity. An elongated flexible liner effectively contacts wall portions of the cavity when inflated within the cavity and has a top and a bottom and has perforations open to the cavity wall portions at selected locations along the liner. At least one sleeve is sealed to the flexible liner and extends from the top portion of the liner to a perforation at one of the selected locations along the liner to define a sealed interior open to a cavity wall portion. A well casing may be place within the sleeve for fluid sampling or for emplacing instrumentation adjacent the perforations in the flexible liner.

Abstract: A device for sensing and recording downhole data relating to an ambient environment in a production well and a method for obtaining such downhole data utilizing the device. Further, the device is used in combination with a downhole pump, and preferably, in combination with a strainer for the downhole pump. The device is connected with the downhole pump, and particularly the strainer, such that the device and the downhole pump may be conveyed or transported within, and retrieved from, the production well together or as an integral unit.

Abstract: A method of determining the real time bubble point pressure of a fluid originating from a subsurface earth formation using an adjustable choke positioned downhole adjacent to the formation. The adjustable choke is placed into communication with the wellbore fluid flowing from the formation to the surface. The adjustable choke has a remotely adjustable choke opening for selectively restricting the flowrate of the fluid flowing through the choke. The adjustable choke has a pressure sensor for measuring the fluid pressure downstream of the choke opening. The method includes obtaining downstream fluid pressure data as a function of choke size for generating a plot of downstream pressure versus choke size data which exhibits substantially linear behavior having two different slopes.

Abstract: A probe for monitoring groundwater flow seepage velocity and direction has an electrical heater and a plurality of temperature sensors located equidistant from the heater. The probe with the heater and temperature sensors is lowered into a monitoring well and positioned so as to be immersed in the groundwater. Energy is sent to the heater, and the temperature response at the temperature sensors is measured and recorded. From the measured response to temperature, the groundwater flow velocity and direction are computed and recorded. The temperature sensors may be resistance temperature detectors, thermocouples, or any other state-of-the-art temperature sensing device.

Abstract: A sampling device for use downhole is provided comprising a hollow body (24) having a fluid inlet port (26) for fluid entry to the interior thereof, characterised by a gas extraction system (64) associated with the hollow body (24) and capable of securing as a non-volatile component at least part of a volatile component dissolved in a fluid entering the hollow body (24), the gas extraction system being removable therefrom to allow quantitative analysis of the non-volatile component to be undertaken. The gas extraction system (64) is placed in a supplementary chamber (46) having an inlet (50) and an outlet (52) which is attached to the hollow body and through which fluid passes to enter the hollow body. The gas extraction system is iron oxide to fix sulphur from volatile hydrogen sulphide for later analysis.

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: An apparatus and process for obtaining representative samples of fluids produced from one or more oil wells by means of a closed vessel chamber with lease water supply port connected to a lease water supply line, where a pressure sensor within such internal chamber is used together with a flowmeter and liquid-sensing probe or oil/water interface sensor employed in the fluid flow path lines to determine a rate of well production along with absolute or relative amounts of oil, water and gas contents.

Abstract: A non-flashing fluid sampler for use in obtaining a well fluid sample. The sampler comprises a body defining a first chamber, a second chamber, a third chamber and a sampling port therein. The sampling port is in communication with the first chamber and with an outside zone outside the body. The second and third chambers are initially isolated from one another by a control valve. Upon activating the control valve, fluid may flow from the second chamber to the third chamber through a flow restriction. An extendable floating piston is disposed between the first and second chambers, and the floating piston defines a variable volume therein. An initial amount of well fluid flows into the variable volume, thus trapping dirty fluid, and subsequently, a well fluid sample is flowed into the first chamber. An isolation valve is provided for allowing hydrostatic pressure into the sampler after the fluid sample has been taken.

Abstract: A non-flashing fluid sampler for use in obtaining a well fluid sample. The sampler comprises a body defining a first chamber, a second chamber, a third chamber and a sampling port therein. The sampling port is in communication with the first chamber and with an outside zone outside the body. The second and third chambers are initially isolated from one another by a control valve. Upon activating the control valve, fluid may flow from the second chamber to the third chamber through a flow restriction. An extendable floating piston is disposed between the first and second chambers, and the floating piston defines a variable volume therein. An initial amount of well fluid flows into the variable volume, thus trapping dirty fluid, and subsequently, a well fluid sample is flowed into the first chamber. An isolation valve is provided for allowing hydrostatic pressure into the sampler after the fluid sample has been taken.

Abstract: This invention is directed toward apparatus and methods for gathering liquid samples from a reservoir of liquid using a submersible pump and subsequently retrieving the samples for analysis. The invention is more specifically directed toward the gathering and preparing of water samples for analysis for tritium content, where the samples are collected from underground formations penetrated by a borehole or collected at varying depths in surface canals and the like. The samples are subsequently transferred to the surface of the earth for analysis. The submersible pump is operated by means of a surface valving system and solenoid systems mounted on the submersible pump. The pump inlet valve is set to open or "crack" at a predetermine pressure, however the pump is not filled until a vacuum is applied to the pump. After filling, the pump is purged thereby transporting the sampled liquid to the surface by applying pressure.

Abstract: To take a sample of liquid and/or gaseous hydrocarbon at the surface or down an oil well, use is made of a flexible bag suspended by a tube from a top region of a wall of a closed receptacle. The bag and the tube are made of a flexible material that is leakproof and inert relative to the sample to be taken, such as a cross-linked polymer. The volume of sample admitted into the bag is controlled so as to avoid stretching the wall of the bag.

Abstract: A well assembly device comprises an outer tubular sleeve with a first end and second end. An inner tubular member has a first end and a second end, and the inner tubular member is disposed within the outer tubular sleeve. The inner tubular member includes a screened portion at its second end. A tip is frictionally secured to the second end of the outer tubular sleeve, so that the outer tubular sleeve and the tip may selectively disengage.

Abstract: In an in-ground vapor monitoring device for use with a conventional, hollow stemmed drill rig including a novel swivel assembly which attaches to a drill rod and which has a central passage formed therethrough. A fluid outlet port and an outlet channel joining the outlet port and central passage are formed in the swivel assembly. The device further includes an auger having an inlet port formed on its operational end which is connected by an inlet channel to a central passage. A vapor filter is disposed in the inlet channel. By applying an external vacuum source, vapor from a borehole is drawn off through the inlet port and filtered by the vapor filter. A gas chromatograph or other vapor analyzer is connected to the outlet port to analyze the drawn off vapors. The novel features of the auger portion of the device may be provided in the form of an auger plug engageable with a conventional auger.

Abstract: In this invention, drill pipe or tubing is attached to a sampling tool that is suspended in a borehole. A wireline cable also connects the tool to surface equipment and establishes electrical communication between the tool and the surface equipment. A valve located in the docking head assembly controls fluid flow between the borehole and the drill pipe through a port located within the drill pipe assembly which is opened and closed as required. During operations, the tool takes fluid samples from the formation and analyzes them for contamination levels. Unacceptable fluid is pumped or flowed through the tool via a flowline and into the drill pipe where it is stored until it is disposed of at the surface. Once the flowing fluid reaches acceptable levels of contamination, this fluid is pumped or flowed into a sample chamber(s) in the tool.

Abstract: A non-flashing fluid sampler for use in obtaining a well fluid sample. The sampler comprises a body defining a first chamber, a second chamber, a third chamber and a sampling port therein. The sampling port is in communication with the first chamber and with an outside zone outside the body. The second and third chambers are initially isolated from one another by a control valve. Upon activating the control valve, fluid may flow from the second chamber to the third chamber through a flow restriction. An extendable floating piston is disposed between the first and second chambers, and the floating piston defines a variable volume therein. An initial amount of well fluid flows into the variable volume, thus trapping dirty fluid, and subsequently, a well fluid sample is flowed into the first chamber. An isolation valve is provided for allowing hydrostatic pressure into the sampler after the fluid sample has been taken.

Abstract: An in situ underground sample analyzing apparatus for use in a multilevel borehole monitoring system is disclosed. A casing assembly comprising a plurality of elongate tubular casings (24) separated by measurement port couplers (26) is coaxially alignable in a borehole (20). The measurement port couplers (26) include an inlet measurement port (70b) for collecting fluid from an underground measurement zone (32) and an outlet measurement port (70a) for releasing fluid into the measurement zone (32). An in situ sample analyzing probe (124) is orientable in the casing assembly. The in situ sample analyzing probe (124) includes inlet and outlet probe ports (148b and 148a) alignable and mateable with the inlet and outlet measurement ports (70b and 70a). The inlet and outlet measurement ports (70b and 70a) typically include valves.

Abstract: A nipple is provided downhole as part of a tubing (drill string or production) string. The nipple has an interior passage with recesses therein and a seat. A data probe attached to a wireline traverses inside of the tubing from the surface to the nipple. The data probe forms a valve that seats in the nipple so as to shut in the well and allow formation fluid pressure to build. A first latch deploys into a recess in the nipple to retain the probe in place against the formation pressure. A bypass is provided so as to equalize pressure across the data probe, when the probe is to be released. The bypass is kept closed by a second latch that deploys into another nipple recess. When the probe is to be retrieved to the surface, the bypass is opened by unlatching the second latch, thereby allowing pressure to equalize. The probe is unseated by unlatching the first latch. The probe has instrumentation and a sampling chamber which can be brought to the surface during flow periods of a test.

Abstract: A well tool and method are provided for evaluating a subterranean formation through an exposed formation surface, such as the wall of a newly drilled well bore. The tool has a tubular main housing that is connectable into a well work string. A probe and a scraper are extendible from the main housing in response to a first signal of a signal set transmitted from the surface. The probe and the scraper are returnable to the main housing in response to a second signal set transmitted from the surface. The probe provides an isolated fluid conduit from the formation surface to a sensor for measuring a condition in the well. The scraper is for removing debris and for smoothing the formation surface, thereby helping to establish a sealed engagement of the probe to the formation surface. The tool can also be provided with a sampling vessel for taking samples of formation fluids obtained via the isolated fluid conduit in the probe.

Abstract: A method of monitoring the quality of water at a ground water sampling site without human intervention. Water at the sampling site is purged until at least one preselected purge criterion is satisfied. At least one water quality attribute is automatically measured at the sampling site, and the quality of water at the site is determined based on the measured water quality attribute. The method is performed by a system including a control unit which, in accordance with a computer program, controls the taking of water quality attribute measurements at the sampling site. The control unit may be equipped with a port for downloading data to a technician on site and with a transceiver for communicating data to a base station via a communications network.

Abstract: A downhole choke and associated methods provide enhanced efficiency and accuracy in well sampling and testing operations due to its capability for substantially minimizing the amount of time needed to establish steady state flow conditions in a well, and the ability to sample fluids downhole at varying downhole flow restrictions. In a described embodiment, a downhole choke is operable to restrict fluid flow therethrough by applying a predetermined fluid pressure to an annulus formed between the choke and the wellbore. The downhole choke has an axial flow passage formed therethrough, a portion of which has interchangeable flow areas. The flow areas are interchanged upon application of the predetermined fluid pressure, and again interchanged upon expiration of a time delay. One of the flow areas permits substantially unrestricted fluid flow therethrough, and another of the flow areas permits restricted flow therethrough.

Abstract: A sampling device having a fluid collecting portion adapted to recover a fluid sample from a subsurface. Fluid entering the fluid collecting portion passes through a valve which may be remotely actuated. After the sampling device has been driven into the subsurface and a fluid sample has been collected in the fluid collecting portion, the valve is closed to prevent cross-contamination of the fluid sample in the fluid collecting portion.

Abstract: A method of measuring a parameter in a well, under isobaric conditions, including such parameters as hydraulic gradient, pressure, water level, soil moisture content and/or aquifer properties the method as presented comprising providing a casing having first and second opposite ends, and a length between the ends, the casing supporting a transducer having a reference port; placing the casing lengthwise into the well, second end first, with the reference port vented above the water table in the well; and sealing the first end. A system is presented for measuring a parameter in a well, the system comprising a casing having first and second opposite ends, and a length between the ends and being configured to be placed lengthwise into a well second end first; a transducer, the transducer having a reference port, the reference port being vented in the well above the water table, the casing being screened across and above the water table; and a sealing member sealing the first end.

Abstract: A deep well system for obtaining artesian samples is set forth. There is a first sample recovery pump which is operated to recover a sample and deliver it to the surface and through a sample flow line. It is surrounded by a packer which is inflated to isolate the region below the sample pump. The sample pump inlet is on the bottom side.

Abstract: This invention provides a formation evaluation tool for collecting a formation fluid in a chamber at a predetermined pressure and for maintaining the pressure of the collected fluid at a desired level during the retrieval of the chamber to the surface. The formation fluid is pumped into the chamber while a piston exposed to the hydrostatic pressure maintains the chamber pressure at the hydrostatic pressure. During retrieval of the chamber, the pressure in the chamber is maintained at a predetermined level by pumping wellbore fluid to the piston. A control unit at the surface is utilized for controlling the operation of the formation tool.

Abstract: A sampling port is provided which has threaded ends for incorporating the port into a length of subsurface pipe. The port defines an internal receptacle which is in communication with subsurface fluids through a series of fine filtering slits. The receptacle is in further communication through a bore with a fitting carrying a length of tubing there which samples are transported to the surface. Each port further defines an additional bore through which tubing, cables, or similar components of adjacent ports may pass.