Abstract: A downhole connate water sample drawn from the formation surrounding a well is validated when mud filtrate concentration is acceptably low. A preferred method includes drilling the well with a water-based drilling fluid, or more generally a water-based mud (WBM), containing a water-soluble dye. The dye acts as a tracer to distinguish connate water from WBM filtrate in a downhole sample of formation fluid contaminated by mud filtrate from the water-based mud. Preferably, an optical analyzer in a sampling tool measures light transmitted through the downhole sample to produce optical density data indicative of dye concentration. Preferably, optical density is measured at a first wavelength to obtain a first optical density, and at a second wavelength, close in wavelength to the first wavelength, to obtain a second optical density. First and second optical density data are transmitted to the surface.

Abstract: A borehole wall cleaning apparatus and method for obtaining an improved seal between a fluid sampling device and a portion of the borehole wall. Clean drilling fluid is pumped into a drilling tool using a mud pump. A fluid diverter in the tool diverts all or part of the clean drilling fluid through a port to clear a portion of a borehole wall. A sealing pad is moved against the clean portion. A sampling port is exposed to the sealed portion for sampling and/or testing fluid from the formation.

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: The invention concerns a method of sampling the formation fluids in an earth formation surrounding a borehole, the region of the formation immediately surrounding the borehole being at least partially invaded by borehole fluids, and an apparatus for carrying out such a method. According to the invention, a borehole tool is adapted to be lowered into the borehole and is provided with a sampling probe device and means for urging the sampling probe device into contact with the borehole wall, the sampling probe device comprising an inner probe and an outer probe surrounding the inner probe for withdrawing respective fluid samples from the formation, wherein the ratio between the respective flow areas of the inner and outer probes is selected so as to tend to reduce the time taken to obtain via the inner probe a sample of the formation fluids having a given level of contamination by borehole fluids.

Abstract: A method for testing petroleum or water wells. A tool is secured to a tubing and run into the well and to the reservoir zone to be explored. An upper and a lower seal isolate the reservoir zone. A piston is run into the tubing and pumped down to the tool. When sampling is to take place, a valve is opened and the reservoir fluid, together with drilling fluid filling the well, is allowed to enter the tool while displacing the piston. At the same time, measuring is carried out to identify a tracer added to the drilling fluid. When the tracer no longer can be traced, the drilling fluid contaminated reservoir fluid is displaced out of the tool by the piston and clean reservoir fluid is allowed to enter the tool. The invention also relates to an apparatus for practising the method.

Abstract: A well fluid sampling tool (5) having a sample chamber (315) at least partly contained within an at least partially evacuated jacket (160, 165, 170), the outermost wall (160) of the jacket (160, 165, 170) being adjacent to or forming an outermost wall of the tool (5). In such a tool (5) the evacuated jacket (160, 165, 170) acts to maintain the sample as originally retrieved, e.g. in single phase form (at original temperature).

Abstract: An apparatus for discharging sample fluid from a bailer with a ball-joint and a method of using thereof. The apparatus has a body, an interior and an exterior, a top opening and a bottom opening, and a lip disposed around the top opening. The bottom of the apparatus has a bailer-support disposed across the diameter of the bottom opening. A pin is located at the center of the bailer-support. The apparatus functions as a bailer discharge device. The apparatus is designed to be placed into an opening of a bucket or drum and is adapted to discharge sample fluid from the base of a bailer into a bucket or drum when the bailer with a ball-joint is inserted through the top opening of the apparatus and rests on the pin attached to the bailer-support support. The pin acts to release the ball-joint thereby allowing the sample fluid to be discharged into the bucket or drum.

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. A sample chamber is also provided that includes a subtantially cylindrical body capable of safely withstanding heating at the surface, following collection of a formation fluid sample via the downhole tool and withdrawal of the sample chamber from the wellbore, to temperatures necessary to promote recombination of the sample components wihtin the chambers. Additionally, the body is equipped so as to be certified for transportation.

Abstract: A method for sampling a subsurface formation includes positioning a formation testing tool in a borehole having borehole fluid with a pressure less than formation pressure such that a pressure differential exists between the borehole and the formation. The method also includes establishing fluid communication between the tool and the formation, and inducing flow from the formation into the tool by exposing the tool to the pressure differential. The method further includes capturing a formation fluid sample in a sample tank by directing formation fluid to the sample tank and exposing the sample tank to the pressure differential. A system for sampling a subsurface formation includes a formation testing tool having a probe assembly, a sample tank, and a conduit system. The system also includes wellhead for controlling borehole pressure. The wellhead includes a sealing apparatus, a pressure increasing device, and a flow adjustment device.

Abstract: A method and apparatus for formation testing is disclosed. In a preferred embodiment, a formation testing tool includes a longitudinal body with a flowbore; a plurality of extendable centralizing pistons coupled to the body; an extendable sample device coupled to the body; and a centralizing hydraulic circuit configured to cause each of the plurality of centralizing pistons to extend at substantially the same rate. The centralizing hydraulic circuit includes a series of flow control and pressure-determining valves configured to extend the centralizing pistons at substantially the same rate, and to help maintain stability in the hydraulic circuit in response to external pressures. In some embodiments, the extendable sample device is preferably configured to be recessed beneath a surface of the body in a first position and to extend beyond the surface in a second position.

Abstract: A method of performing a formation rate analysis from pressure and formation flow rate data. Pressure and flow rate data are measured as fluid is withdrawn from a formation. Variable system volume is accounted for. The pressure and flow rate data are correlated using a multiple linear regression technique. Time derivative terms related to pressure and flow rate are smoothed using a summation technique, thereby providing better correlations than using the time derivatives directly. Formation parameters comprising formation permeability, formation pressure, and fluid compressibility may be determined from the correlation.

Abstract: An apparatus and method for extracting fluid from a subsurface formation is disclosed. A downhole sampling tool is provided with a probe having an internal wall capable of selectively diverting virgin fluids into one or more virgin flow channels for sampling, while diverting contaminated fluids into one or more contaminated flow channels to be discarded. The characteristics of the fluid passing through the channels of the probe may also be measured using techniques, such as optical density, to evaluate various fluid parameters, such as contamination levels. The data generated during sampling may be sent to a controller capable of generating data, communicating and/or sending command signals. The flow of fluid into the downhole tool may be selectively adjusted to optimize the flow of fluid into the channels by adjusting the internal wall within the probe and/or by adjusting the flow rates through the channels.

Abstract: Water-based mud filtrate concentration in a downhole fluid sample drawn from the borehole of an oil well is assessed. To measure water-based mud filtrate concentration, a water-based mud having a water-soluble fluorescent dye tracer is pumped into the borehole; sample fluid from a selected downhole location is pumped through a downhole flow line having a window; sample fluid flowing in an excitation region of the downhole flow line is illuminated through the window with fluorescence excitation light; and fluorescence emission from the excitation region is measured to produce a measured value. The measured value represents the fraction of water-based mud filtrate in the sample fluid. A calibration value is determined representing 100% water-based mud filtrate. A method for validating a sample of connate water as having an acceptably low WBM filtrate contamination tests for validation downhole, in real time.

Abstract: A downhole sampling tool and related method are provided. The tool is provided with a main flowline for communicating fluid from the formation through the tool. A main valve is positioned in the main flowline and defines a first portion and a second portion of the main flowline. At least one sample chamber with a slidable piston therein defining a sample cavity and a buffer cavity is also provided. The sample cavity is in selective fluid communication with the first portion of the main flowline via a first flowline and with the second portion of the main flowline via a second flowline. Fluid communication is selectively established between the sample cavity and the first and/or second portions of the main flowline for selectively flushing fluid through the sample cavity and/or collecting samples of the fluid therein. Fluid may also be discharged from the buffer cavity via a third flowline.

Abstract: A bailer collects a column of liquid fluid of predetermined height from a body of liquid fluid at a predetermined depth. The bailer is emptied without contaminating the collected liquid fluid with oxygen. The bailer has two check valves spaced apart from one another by a preselected distance so that it can collect liquid fluid at a predetermined depth below the surface of the body of liquid fluid. A vent opening is formed between the first check valve and the second check valve to enable the bailer to be emptied in the substantial absence of oxygen contamination.

Abstract: A formation fluid sampling and hydraulic testing tool for a drilling apparatus that includes a drilling string comprised of a drilling pipe and a drilling bit is provided. The tool has an outer tube disposed between the drilling pipe and the drilling bit. The outer tube is provided with a plurality of through holes for receiving formation fluid into the outer tube. An inner tube is disposed within, and spaced from, the outer tube to form an annular space between them. The inner tube is provided with a plurality of through holes that are adapted to communicate with the annular space. One end of the inner tube is connectable to a pumping mechanism for drawing formation fluid through the through holes of the outer tube and of the inner tube for the purpose of collecting a sample of the fluid and imposing a hydraulic stress on the formation. The through holes of the inner tube can be closed off or released.

Abstract: A method of performing a formation rate analysis from pressure and formation flow rate data. Pressure and flow rate data are measured as fluid is withdrawn from a formation. Variable system volume is accounted for. The pressure and flow rate data are correlated using a multiple linear regression technique. Time derivative terms related to pressure and flow rate are smoothed using a summation technique, thereby providing better correlations than using the time derivatives directly. Formation parameters comprising formation permeability, formation pressure, and fluid compressibility may be determined from the correlation.

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 apparatus for discharging sample fluid from a bailer with a ball-joint and a method of using thereof. The apparatus has a body, an interior and an exterior, a top opening and a bottom opening, and a lip disposed around the top opening. The bottom of the apparatus has a bailer-support disposed across the diameter of the bottom opening. A pin is located at the center of the bailer-support.

Abstract: The invention relates to a method for use in sampling, flow measuring, quantity gauging, or possibly other analysis performed in reservoir fluid found in a ground formation. An object of the invention is to perform the sampling, flow measuring and quantity gauging or the remaining analyses in situ on stabilized reservoir fluid that contains a negligible amount drill fluid. Analysis is possible by sealing off an area of the well at the hydrocarbon carrying layer and passing a volume of reservoir fluid into a drill string for analysis by accessories located in the drill string. After the analyses are performed, the reservoir fluid is returned to the hydrocarbon carrying layer.

Abstract: The invention concerns a method of sampling the formation fluids in an earth formation surrounding a borehole, the region of the formation immediately surrounding the borehole being at least partially invaded by borehole fluids, and an apparatus for carrying out such a method. According to the invention, a borehole tool is adapted to be lowered into the borehole and is provided with a sampling probe device and means for urging the sampling probe device into contact with the borehole wall, the sampling probe device comprising an inner probe and an outer probe surrounding the inner probe for withdrawing respective fluid samples from the formation, wherein the ratio between the respective flow areas of the inner and outer probes is selected so as to tend to reduce the time taken to obtain via the inner probe a sample of the formation fluids having a given level of contamination by borehole fluids.

Abstract: Retrieving a sample of formation fluid from a formation layer traversed by a cased borehole comprising making a plurality of perforation sets through the casing wall into the formation layer, wherein the orientation of the perforation sets is so selected that the angle between adjacent perforation sets equals 360° divided by the number of perforation sets; lowering a sampling tool into the borehole to the first perforation set; taking a sample from the formation and storing the sample in the first fluid sample container; positioning the sampling tool near the next perforation) set, taking a sample from the formation and storing the sample in the next fluid sample container; and repeating the latter step until samples from all perforation sets have been taken, and retrieving the sampling tool.

Abstract: Systems and methods particularly suitable for open hole formation testing are provided. In a described embodiment, a method of performing a test on a formation intersected by a wellbore includes the steps of flowing fluid into an apparatus from the formation, displacing a fluid barrier of the apparatus in one direction, flowing the formation fluid out of the apparatus and back into the formation by applying pressure to the apparatus, and displacing the fluid barrier in an opposite direction.

Abstract: The present invention is an apparatus and method for use in a well borehole drilled into a formation. The apparatus comprises a work string disposed in the borehole. The work string includes at least one modular body portion having at least one receptacle. A modular tool is disposed in the at least one receptacle for carrying out a drilling operation. The modular tool may be a tool for use in drilling a well borehole, it may be a tool for testing a formation surrounding a borehole, or the modular tool may be a combination. For example, one aspect of the present invention provides a modular steering rib. The modular steering rib may also include modular components for sampling and testing formation fluid.

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: A downhole connate water sample drawn from the formation surrounding a well is validated when mud filtrate concentration is acceptably low. A preferred method includes drilling the well with a water-based drilling fluid, or more generally a water-based mud (WBM), containing a water-soluble dye. The dye acts as a tracer to distinguish connate water from WBM filtrate in a downhole sample of formation fluid contaminated by mud filtrate from the water-based mud. Preferably, an optical analyzer in a sampling tool measures light transmitted through the downhole sample to produce optical density data indicative of dye concentration. Preferably, optical density is measured at a first wavelength to obtain a first optical density, and at a second wavelength, close in wavelength to the first wavelength, to obtain a second optical density. First and second optical density data are transmitted to the surface.

Abstract: A chamber for trapping soil gases as they evolve from the soil without disturbance to the soil and to the natural microclimate within the chamber has been invented. The chamber opens between measurements and therefore does not alter the metabolic processes that influence soil gas efflux rates. A multiple chamber system provides for repetitive multi-point sampling, undisturbed metabolic soil processes between sampling, and an essentially airtight sampling chamber operating at ambient pressure.

Abstract: A bi-directional seal assembly can be used in various types of cartridge valves including dirty fluid valves and a variety of other valves. The present seal assembly utilizes a seal spool, two O-rings and opposing seal cups. The O-rings are compressed during manufacture of the seal assembly and the valve more than typically recommended by O-ring manufacturers. Because of this compression, the O-rings serve a dual function. At lower pressures, the O-rings act as a spring causing the seal cups to contact the opposing seal plates and at higher pressures they act as seals between the seal assembly and the valve.

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 would cause substantial problems, a fluid flow path is arranged for fluid transfer between the first formation to be production tested and a second permeable formation. The fluid flow path is preferably 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 downhole tool for collecting data from a subsurface formation is disclosed. The tool is provided with a probe for testing and/or sampling an adjacent formation. The tool is also provided with a protector positioned about the probe for engaging and protecting the sidewall of the bore hole surrounding the probe. The protector prevents deterioration of the wellbore during the testing and/or sampling by the probe.

Abstract: A well logging instrument is disclosed which includes a housing operatively coupled to a well logging conveyance and movable within the wellbore. The housing has therein a formation testing system and an axial extension mechanism. The axial extension mechanism controllably extends and retracts to allow the formation testing system to perform tests and take samples in an axially fixed position in the wellbore while the housing moves through the wellbore.

Abstract: An apparatus and method is given for evaluating a well fluid sub-sample at the well surface 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. A pair of valves in series along the supply/discharge conduit respective to each tank accommodates extraction of a field sample to verify the sample integrity while still on location. 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 or transported to an analytical laboratory.

Abstract: An apparatus and method for collecting a sample from a low-yield well or perched aquifer includes a pump and a controller responsive to water level sensors for filling a sample reservoir. The controller activates the pump to fill the reservoir when the water level in the well reaches a high level as indicated by the sensor. The controller deactivates the pump when the water level reaches a lower level as indicated by the sensors. The pump continuously activates and deactivates the pump until the sample reservoir is filled with a desired volume, as indicated by a reservoir sensor. At the beginning of each activation cycle, the controller optionally can select to purge an initial quantity of water prior to filling the sample reservoir. The reservoir can be substantially devoid of air and the pump is a low volumetric flow rate pump. Both the pump and the reservoir can be located either inside or outside the well.

Abstract: A method and apparatus for maintaining the single phase integrity of a deep well formation sample that is removed to the surface comprises a vacuum jacket insulated single working cylinder divided by two free pistons into three variable volume chambers. The intermediate chamber is pre-charged with a fixed quantity of high pressure gas. Wellbore fluid freely admitted to one end chamber bears against one free piston to further compress the gas. The formation sample is pumped into the other end chamber to first, displace the wellbore fluid from the first end chamber and, sequentially, to further compress the gas to preserve the sample phase state upon removal to the surface.

Abstract: The present invention provides systems and methods for performing production testing in open holes and in cased holes that avoid transporting formation fluid to the surface. The invention essentially comprises a test string for testing a production zone intersecting a wellbore. The string further comprises a fluid communication member allowing flow of fluid therethrough, a sealing device for isolating a production zone intersecting the wellbore to allow fluid flow from the production zone into the fluid communication member, a second sealing device spaced apart from the first sealing device for isolating a second injection zone intersecting the wellbore, a pump for pumping fluid between zones, and flow control devices.

Abstract: A method for detecting inflow of fluid in a well while drilling, wherein the drilling is carried out using an installation including a hollow cylindrical drill string (3) wherein is injected fresh mud, a tubing (5) defining with the drill string (3) an annular space (7) through which the loaded mud rises; it involves continuously measuring a heat flow; then continuously calculating on the basis of the quantity the value of a characteristic representing a thermal equilibrium obtained in the absence of a fluid occurrence formation; and detecting variations in the characteristic, the variations representing a thermal imbalance, resulting from inflow of fluid in the well (1). The invention is particular by applicable in operating oil drilling installations particularly deep at sea.

Abstract: A downhole sampling tool and related method are provided. The tool is provided with a main flowline for communicating fluid from the formation through the tool. A main valve is positioned in the main flowline and defines a first portion and a second portion of the main flowline. At least one sample chamber with a slidable piston therein defining a sample cavity and a buffer cavity is also provided. The sample cavity is in selective fluid communication with the first portion of the main flowline via a first flowline and with the second portion of the main flowline via a second flowline. Fluid communication is selectively established between the sample cavity and the first and/or second portions of the main flowline for selectively flushing fluid through the sample cavity and/or collecting samples of the fluid therein. Fluid may also be discharged from the buffer cavity via a third flowline.

Abstract: A method for using a controller to control a fluid pump by controlling the rate at which the pump fills with fluid and subsequently discharges fluid. The pump includes a chamber for collecting fluid from within a well bore in which the pump is disposed. A user inputs a pump cycle time and a pump cycle volume to the controller. The pump cycle time input is used to determine a cycling period for the pump. The pump cycle volume is used to allot a portion of the cycling period to the refilling of the pump with fluid and the remaining portion of the cycling period to the discharging of fluid from the pump. The controller controls the pump such that the pump is vented to atmosphere during the refill portion, allowing the pump to fill with fluid, and such that pressurized fluid, such as compressed gas, is injected into the pump during the discharge cycle, causing fluid collected within the pump to be discharged. In another mode of operation, a sensor is coupled to the controller.

Abstract: A well tester adapted to select among members of an oil well family to provide a purged and clean vessel to receive samples of well production that include gas and oil, and by selective use of production pressure and lease water under pressure, allow for the separation and separate measure of the oil and gas, and optionally to provide for improved sampling of production fluids with high gas/oil ratios.

Abstract: A minimum volume apparatus and method is provided including a tool for obtaining at least one parameter of interest of a subterranean formation in-situ, the tool comprising a carrier member, a selectively extendable member mounted on the carrier for isolating a portion of annulus, a port exposable to formation fluid in the isolated annulus space, a piston integrally disposed within the extendable member for urging the fluid into the port, and a sensor operatively associated with the port for detecting at least one parameter of interest of the fluid.

Abstract: An apparatus and method for collecting a sample from a low-yield well or perched aquifer includes a pump and a controller responsive to water level sensors for filling a sample reservoir. The controller activates the pump to fill the reservoir when the water level in the well reaches a high level as indicated by the sensor. The controller deactivates the pump when the water level reaches a lower level as indicated by the sensors. The pump continuously activates and deactivates the pump until the sample reservoir is filled with a desired volume, as indicated by a reservoir sensor. At the beginning of each activation cycle, the controller optionally can select to purge an initial quantity of water prior to filling the sample reservoir. The reservoir can be substantially devoid of air and the pump is a low volumetric flow rate pump. Both the pump and the reservoir can be located either inside or outside the well.

Abstract: Methods, apparatus, and systems for low-flow sampling of a fluid source. One illustrative embodiment of the invention is directed to a method for manually sampling a fluid source in a well, including exerting a downward pressure on a sample tube, disposed within a well insert, to allow fluid to pass from the well through a portion of the well insert and into the sample tube to fill at least a portion of the sample tube with the fluid. Another illustrative embodiment of the invention is directed to a method for securing a well insert to an inner wall of a well, including arranging stabilizers on the well insert in a non-extended position, introducing the well insert into the well, arranging the stabilizers on the well insert in an extended position, and expanding a portion of a gasket on the well insert such that the portion of the gasket conforms to a circumference of the inner wall of the well.

Abstract: A device (10) for collecting fluid samples from a subsurface (100), injecting fluids into a subsurface and measuring the hydrostatic pressure of groundwater in a subsurface is described. The device includes an outer tube (12) with a center bore (12D) and openings (12E) at one end (12B) and a rigid inner rod (18) configured to be telescopingly inserted into the center bore of the outer tube. The inner rod provides support and prevents damage to the outer tube during insertion into the subsurface. The device is inserted into the subsurface until the openings in the outer tube are adjacent the testing area. The inner rod is then removed from the outer tube. To collect fluid samples, the samples are retrieved from the fluid which has moved from the subsurface through the openings to the center bore of the outer tube. To inject fluid into the subsurface, the fluid is injected into the center bore and flows through the openings to the subsurface.

Abstract: The present invention provides a system that monitors and controls the precipitation of asphaltenes in a formation fluid recovered from a subsurface formation or reservoir by using a sensor to make a direct real-time on-site measurement of the relative concentration asphaltenes from at least one location at a wellsite or in a pipeline. In a system including a fiber optic attenuated total reflectance probe for sensing asphaltenes and using a processor to compare sequential measurements, the system of the present invention can trigger the addition of additives in response to a change in asphaltene concentration in the formation fluid, preventing precipitation.

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 sample cavity to one of the first flowline and an outlet port. A first valve is disposed in the second flowline for controlling the flow of fluid from the first flowline to the sample cavity, and a second valve is disposed in the third flowline for controlling the flow of fluid out of the sample cavity, whereby any fluid preloaded in the sample cavity may be flushed therefrom using the formation fluid in the first flowline and the first and second valves.

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 apparatus and method is given for evaluating a well fluid sub-sample at the well surface 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. A pair of valves in series along the supply/discharge conduit respective to each tank accommodates extraction of a field sample to verify the sample integrity while still on location. 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 or transported to an analytical laboratory.

Abstract: An apparatus and method for obtaining core samples from a wellbore includes bringing a substance in contact with the core sample. The substance is adapted to retain at least a portion of fluids recovered with the core sample. A receptacle such as a core barrel contains the substance and is inserted into the wellbore and receiving the core sample in the receptacle. The substance may be sealed in the receptacle by a dissolvable plug mechanism. The substance is transformable between a highly viscous state and a substantially solid matrix.

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: 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.