Abstract: Systems and methods for downhole formation testing based on the use of one or more elongated sealing pads capable off sealing off and collecting or injecting fluids from elongated portions along the surface of a borehole. The modified sealing pads increase the flow area by collecting fluids from an extended portion along the surface of a borehole, which is likely to straddle one or more layers in laminated or fractured formations. A tester device using the elongated sealing pads can be deployed and withdrawn using an extendible element pressing the pads to the borehole. Various designs and arrangements for use with a fluid tester, which may be part of a modular fluid tool, are disclosed in accordance with different embodiments.

Abstract: A downhole fluid pump including a pump chamber, and a piston disposed in the pump chamber so that the piston will move in one selected from a charge stroke and a discharge stroke when the piston is exposed to a differential pressure. The downhole fluid pump may form part of a formation evaluation while drilling tool.

Abstract: A seal pad comprising a base plate and an expandable material engaged with the base plate. The expandable material comprises an outer surface where a portion of the outer surface is used to form a seal against a borehole wall. A portion of the outer surface of the expandable material is expanded during the sealing against the borehole wall. The seal pad also comprises a retainer for controlling the expansion of the expandable material. The retainer controls the expansion of the expandable material by engaging at least a portion of the outer surface of the expandable material. Thus when the seal is formed by expanding the expandable material, at least a portion of the expandable material is contained by the retainer.

Abstract: A method and an apparatus raise samples of liquid such as water from a low level to a higher level, for example for obtaining a sample of groundwater from a borehole. The apparatus comprises a pair of tubes (14 and 16) extending alongside each other, which are introduced into the borehole, linked by a connector (20) at their lower end, a valve (22) communicating between the inside and outside of one of the tubes (16) near its lower end, and a pig (46) insertable into the tube (16). By adjusting the pressure in each tube at their upper end, the pig (46) can be moved from one end to the other of the apparatus (10) and used to transfer samples of water.

Abstract: An apparatus and method for determining at least one downhole formation property is disclosed. The apparatus includes a probe and a pretest piston positionable in fluid communication with the formation, and a series of flowlines pressure gauges, and valves configured to selectively draw into the apparatus for measurement of one of formation fluid and mud. The method includes performing a first pretest to determine an estimated formation parameter; using the first pretest to design a second pretest and generate refined formation parameters whereby formation properties may be estimated.

Abstract: A method and apparatus is provided for reducing the purge volume of a well during purging and sampling operations. In some system embodiments, the apparatus can be retrofitted to existing small diameter wells. A further embodiment provides a method and apparatus for using direct pneumatic pressure to purge and sample small diameter wells using a removable valve. This aspect of the invention allows a direct pneumatic pressure pump with a primary valve to be withdrawn through the top of the inside to the pump's pressure holding structure without removing a riser pipe or the system's fluid inlet structure. The invention allows fitting or retrofitting small diameter wells with valves for direct pneumatic pressure purging and sampling.

Abstract: A method and apparatus for reducing debris in a perforation in a wellbore extending from the wellbore into a subterranean formations is provided. A housing is positioned in the wellbore, and an arm is extended therefrom. One or more plugs are positionable in the perforation via the arm. The plug is adapted to block debris from formation fluid flowing into the housing via the perforation whereby the contamination in the formation fluid is reduced. The plug may be a filter positionable in the perforation, or a bit activated to dislodge debris.

Abstract: The invention relates to a system and method for sensing the characteristics of a fluid in a sub-surface formation. In one embodiment, the invention relates to a sensor apparatus for sensing a chemical in a vapor emitted by a sub-surface fluid sample. In various configurations, the apparatus senses the presence and/or percentage of water, the presence of a gas, an oil/gas ratio, an aliphatic/aromatic hydrocarbon ratio, and/or the presence of corrosive or poisonous chemicals.

Abstract: The apparatuses and methods herein relate to techniques for extracting fluid from a subsurface formation. A downhole sampling tool is provided with a probe having an internal wall capable of selectively diverting virgin fluids into virgin flow channels for sampling, while diverting contaminated fluids into contaminated flow channels to be discarded. The characteristics of the fluid passing through the channels of the probe may be measured. 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. The configuration of the internal wall and/or the flow rates may be automatically adjusted by the controller and/or manually manipulated to further optimize the fluid flow.

Abstract: A well testing system and well testing method is described which can be operated as a closed system with no production of hydrocarbons outside the well or gas can be separated and flared at surface giving minimal environmental impact with the liquid hydrocarbon being re-injected. This is achieved by providing a string with at least two well conduits which may be arranged in a concentric or non-concentric parallel configuration. One conduit is used to produce formation fluids to surface or to produce/store unrepresentative initial flow products and the other conduit is used to store formation fluid. The storage conduit can be filled from the top (surface) or the bottom of the well. In a preferred arrangement a valve is provided between the storage conduit and the well annulus for well pressure control, and a shut-in or test valve, which is controllable from surface, is disposed in the non-storage production conduit.

Abstract: A formation fluid sampling tool including at least one sample tank mounted in a tool collar. The tool collar includes a through bore and is disposed to be operatively coupled with a drill string such that each sample tank may receive a correspondingly preselected formation fluid sample without removing the drill string from a well bore. At least one of the sample tanks further includes an internal fluid separator movably disposed therein. The separator separates a sample chamber from a pressure balancing chamber in the sample tank. The pressure balancing chamber is disposed to be in fluid communication with drilling fluid exterior thereto. The sampling tool further includes a sample inlet port connected to the sample chamber by an inlet passageway.

Abstract: A method for logging a wellbore includes actuating a positioning device to adjust the position of a module relative to a reference point or object such as a wellbore axis or proximally positioned downhole device. With respect to a wellbore, an exemplary positioning device can set the measurement tool such as an acoustic device to successive radial positions (e.g., substantial concentricity or substantial eccentricity relative to an axis of the wellbore). In one embodiment, the module includes a measurement tool to measure different parameters of interest (e.g., acoustic logging data, check-shot data measurement, bonding of cement to casing). With respect to an adjacent downhole device, the positioning device can provide a selected relative orientation (e.g., azimuth, inclination, radial displacement) between the module and the adjacent downhole device. The positioning device can also be adapted to apply a jarring force to a wall of the wellbore to free a downhole device.

Abstract: A receptacle (10) for use in collecting samples down a well bore (14) is provided, the receptacle comprising a plurality of interconnecting modules (22, 24, 26, 30, 32, 34). A main chamber (22) is capable of holding a sample, and sensors (58, 60, 62, 64) within the chamber detect physical and chemical characteristics of the sample. Valves (50, 52) in a chamber wall seal the chamber (22) after a fluid sample has been collected. A communication means is placed in communication with the chamber (22) so as to provide an externally accessible port which communicates with the inside of the chamber (22) and allows detection and analysis of sample characteristics without removing the sample from the sealed chamber (22). The chamber (22) includes a piston (82) which is adjustable to keep pressure constant in the chamber and a heating element (58) to keep temperature constant. A method for sampling downhole fluids is also provided.

Abstract: A method for treating a relatively permeable formation containing heavy hydrocarbons in situ may include providing heat from one or more heat sources to a portion of the formation. The heat may be allowed to transfer from the heat sources to a selected section of the formation. The transferred heat may pyrolyze at least some hydrocarbons within the selected section. A mixture of hydrocarbons may be produced from the selected section. A production rate of the mixture may be controlled to adjust the time that at least some hydrocarbons are exposed to pyrolysis temperatures in the formation in order to produce hydrocarbons of a selected quality in the mixture.

Abstract: An oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a desired temperature. A heating rate for a selected volume of the formation may be controlled by altering an amount of heating energy per day that is provided to the selected volume.

Abstract: An apparatus and method for determining at least one downhole formation property is disclosed. The apparatus includes a probe and a pretest piston positionable in fluid communication with the formation, and a series of flowlines pressure gauges, and valves configured to selectively draw into the apparatus for measurement of one of formation fluid and mud. The method includes performing a first pretest to determine an estimated formation parameter; using the first pretest to design a second pretest and generate refined formation parameters whereby formation properties may be estimated.

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: The present invention relates to a method and apparatus for detection of hydrogen sulfide in downhole operations. A downhole tool is provided with a coupon adapted to react at varying degrees to exposure to concentrations of hydrogen sulfide. The downhole tool is positioned in the wellbore with the coupon(s) exposed to downhole fluids. A reaction to a change in the coupon, such as coloration, is used to determine the presence and concentration of hydrogen sulfide.

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 and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation, determining a first formation characteristic during a first test portion, initiating a second test portion, the second test portion having test parameters determined at least in part by the determinations made during the first test portion, determining a second formation characteristic during the second test portion, and determining the formation parameter from one of the first formation characteristic and the second formation characteristic. The apparatus includes a draw down unit and a control system for closed loop control of the draw down unit. A microprocessor in the control system processes signals from a sensor in the draw down unit to determine formation characteristics and to determine test parameters for subsequent test portions.

Abstract: A method and system for drillstem testing multiple zones in a well with a single testing trip into the well. A multiple zone tester is landed in the lower completion to form separate controllable flow paths from each of the zones. The multiple zone testing system facilitates testing each zone singularly and performing commingled tests without pulling out of the well.

Abstract: The current invention provides a method for enhancing the formation stability of water sensitive, reactive formations penetrated by a wellbore. The method of the current invention provides an accurate evaluation of the impact of cementing fluids on water sensitive, reactive formations and provides the ability to accurately formulate cementing fluids in order to enhance the stability of such formations. When necessary, the method of the current invention additionally provides for the application of an osmotic semi-permeable membrane to the face of the formation.

Abstract: The apparatuses and methods herein relate to techniques for extracting fluid from a subsurface formation. A downhole sampling tool is provided with a probe having an internal wall capable of selectively diverting virgin fluids into virgin flow channels for sampling, while diverting contaminated fluids into contaminated flow channels to be discarded. The characteristics of the fluid passing through the channels of the probe may be measured. 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. The configuraton of the internal wall and/or the flow rates may be automatically adjusted by the controller and/or manually manipulated to further optimize the fluid flow.

Abstract: The groundwater well sample device is an elongated, cylindrical sample tube, having a top end and a bottom end. The top end is open. A knothole is formed through the wall of the sample tube near the top end. The knothole is large enough for the knotted end of a string to be easily passed through the knothole. A zigzagging string-retaining slot is formed through the sample tube wall, extending from the knothole toward the top end of the sample tube. The string-retaining slot is slightly narrower than the diameter of a string. The string-retaining slot terminates in a stress-reducing aperture. In use, the knotted end of a string is passed through the knothole, and the string then pulled into the string-retaining slot where the string, slightly compressed within the slot, is held tightly in place. The top end is angled to allow easy access to the string-insertion aperture.

Abstract: The multiple interventionless actuated downhole valve includes a valve movable between an open and a closed position to control communication between an annular region surrounding the valve and an internal bore and more specifically controlling communication between above and below the valve, and at least two remotely operated interventionless actuators in operational connection with the valve, wherein each of the interventionless actuators may be operated independently by absolute tubing pressure, absolute annulus pressure, differential pressure from the tubing to the annulus, differential pressure between the annulus and the tubing, tubing or annulus multiple pressure cycles, pressure pulses, acoustic telemetry, electromagnetic telemetry or other types of wireless telemetry to change the position of the valve and allowing the valve to be continually operated by mechanical apparatus.

Abstract: A portable groundwater sampling system utilizing an air pump in combination with a sampling tank, valves, and a pressure gauge to sample a liquid from a below ground surface monitoring well. The system includes a portable power supply for energizing the air pump and is mounted on wheels for mobility. The system also may include a flat work surface and storage container.

Abstract: A tank contains both Zeolite and a hydrate in a gas chamber formed beneath a piston in the sample tank. Out of safety considerations, we avoid using source cylinders of nitrogen whose pressures exceed 4000 psi. Thus, the gas chamber of the sample tank is initially pressurized by the source cylinder to no more than 4000 psi of nitrogen at room temperature at the surface. Nitrogen gas is sorbed onto the zeolite at room temperature. As the tank is heated by being lowered downhole, nitrogen desorbs from the zeolite and the gas pressure increases. However, once this tank reaches a temperature high enough to release the hydrate's water of hydration, the released water is preferentially sorbed by zeolite, displacing sorbed nitrogen, and causing the pressure in the gas volume to increase even further. Because well temperatures are not high enough to desorb water from zeolite, any water sorbed onto a Zeolite sorption site will permanently block released nitrogen from resorbing at that site.

Abstract: A method for retrieving a formation fluid sample through a cased borehole utilizing a sampling tool. Sampling tool straddle packers are set about a first set of perforations and annular fluid is drained from the isolated zone, through a central conduit in the tool and discharged above or below the packers. Formation fluid is induced to flow into the central conduit and into sample chambers. The packers are unset, the tool moved to the next set of perforations that are azimuthally offset from the first set of perforations and the sampling process repeated, with subsequent samples being placed in separate sample chambers.

Abstract: A mechanical bladder pump is provided for collecting fluid samples from a well. The pump includes an outer tubular member having a longitudinal bore, and an inner tubular member arranged within the bore of the outer tubular member. The inner and outer tubular members are connected at their lower ends to a compressible bladder, and are arranged for oscillating movement relative to each other to expand and compress the bladder. The lower end of the bladder is open to an inlet passage, and the upper end of the bladder is open to an outlet passage. First and second check valves are provided to control the flow of fluid through the bladder during operation of the pump. A return spring is used to store energy during a tension stroke of the inner tubular member and to release energy during a compression stroke thereof. The pump provides highly representative samples of groundwater.

Abstract: An apparatus and methods are provided for monitoring a well and for obtaining fluid samples from below the ground. The apparatus includes a single-piece, extruded plastic well stock that extends from the surface of the ground to the lowest sampling depth. Plural sampling intervals are defined between the surface and the lowest sampling depth. Sampling intervals are defined by isolating sections of the borehole by using packers that seal the annular space between the well stock and the borehole. The well stock includes plural longitudinal chambers. Inlet holes are put into the well stock so that inlets for each interval admit fluid to only one longitudinal chamber. Inert sealant is injected below inlets to prevent fluid from spreading below a desired level. Instructions are placed into the longitudinal chambers to monitor fluids in the chambers or to retrieve samples, or alternatively, the well stock can be removed to obtain samples.

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 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. Back-up rings are provided to engage the O-rings to control deformation of the O-rings. 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: For use in drawing samples of e.g water from a well. The sampling pipe is formed as an extrusion in polyethylene. The profile includes three equi-spaced channels. The profile, being triangulated, is rigid and resistant to buckling, which allows the sampling pipe to be coiled for transport to the site. Sample-tubes, pumps, etc, can be inserted into the channels. The channels can be plugged for isolation of sampling ports at different depths.

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: The present invention provides a method and apparatus for determination of the quality of a formation fluid sample including monitoring permeability and mobililty versus time to determine a filtrate contamination level, single phase state without gas and solids in the formation fluid, as it existed in the formation and the determination of laminar flow from the formation. The present invention also enables determination of an optimal pumping rate to match the ability of a subsurface formation to produce a single phase formation fluid sample in minimum time. The method and apparatus also detect pumping problems such as sanding and loss of seal with borehole.

Abstract: A method and apparatus for of determining a formation parameter of interest. The method includes placing a tool into communication with the formation to test the formation and drawing down a test volume at an increasing draw rate during a first draw period and decreasing the draw rate during a second draw period to create a smooth draw down cycle. The draw down can be step-wise or continuous. The formation parameter is determined using formation rate analyis and characteristics determined during the draw down cycle.

Abstract: The present invention discloses a full reservoir sampling and testing apparatus having a ground surface testing and controlling tool (36) and a downhole tool (1), the downhole tool (1) comprises a wireline bridle (21), an adapter joint AH64 (2) connected to the wireline bridle (21), a GR pup joint, an electric unit (4), a single probe unit (5), a pumping unit (6), a dual packer unit (7), and a multi sampling unit (8); the ground surface testing and controlling tool (36) comprises a power supply controller, a computer system and a relevant control, analysis and interpretation software; an upper portion of the pumping unit (6) is connected to the single probe unit (5) and a lower portion thereof is connected to the multi sampling unit (8).

Abstract: A formation testing tool and method for providing pressure controlled sampling is provided. A flow line delivers formation fluid to a sample chamber in the testing tool. A first valve controls the flow of formation fluid from the flow line to the sample chamber. A piston is slidably disposed in the sample chamber to define a sample cavity and a actuation cavity having variable volumes determined by movement of the piston. An actuator is also provided to move the piston in a first direction to increase the volume of the sample cavity and a second direction to decrease the volume of the sample cavity whereby formation fluid may be drawn into the sample cavity and pressurized therein using the actuator and the first valve.

Abstract: Systems and methods for downhole formation testing. The invention is based on the use of one or more elongated sealing pads capable of sealing off and collecting or injecting fluids from elongated portions along the surface of a borehole. The, modified probe pads of a device-made in accordance with the invention increase the flow area by collecting fluids from an extended portion along the surface of a borehole, which is likely to straddle one or more layers in laminated or fractured formations. A tester device using the elongated sealing pads is capable of fast deployment and withdrawal to speed up the measurement cycles. Various designs and arrangements for use with a fluid tester, which may be part of a modular fluid tool, are disclosed in accordance with different embodiments.

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.

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: The use of extruded plastic continuous-multi-channel (CMC) tubing for conveying water samples from different depths up out of boreholes is enhanced by the compressed-grommet sealing system as described. The rubber grommet is placed inside one of the many conduits of the tubing, and squeezed lengthwise, whereby the grommet expands laterally and seals and plugs the conduit. When forming a port in the conduit, an aperture is cut in the wall of the conduit, and plug-assemblies having the grommets are placed above and below the port. Ledges on the plug-assemblies engage the ends of the aperture, and operate in conjunction with spacer bars in the aperture to prevent the plug-assemblies being moved along the conduit by pressure in the conduit. Some of the conduits in the CMC tubing are left unplugged, for admitting probes, sensors, etc.

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 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 formation test tool and methods are described that enable sampling and measurements of parameters of fluids contained in a borehole while reducing the time required for taking such samples and measurements and reducing the risk of formation damage due to sampling induced pressure spikes. The tool has a quick response control system for controlling a fluid transfer device in response to fluid pressure near a sampling port.

Abstract: Determining the in situ effective mobility of a formation layer comprises selecting a location in the formation layer; lowering in the borehole traversing the formation layer a tool that comprises a central conduit having an inlet and being provided with a pressure sensor, a fluid receptacle having an inlet opening into the central conduit. a fluid analyser, and means for discharging fluid; making an exclusive fluid communication between the formation and the inlet of the central conduit; allowing formation fluid to pass through the central conduit, analysing the fluid, allowing the formation fluid to enter into the fluid receptacle when the fluid is the substantially uncontaminated formation fluid, and measuring the pressure build-up: and determining the effective mobility from the pressure build-up.

Abstract: The current invention provides a method for enhancing the formation stability of water sensitive, reactive formations penetrated by a wellbore. The method of the current invention provides an accurate evaluation of the impact of cementing fluids on water sensitive, reactive formations and provides the ability to accurately formulate cementing fluids in order to enhance the stability of such formations. When necessary, the method of the current invention additionally provides for the application of an osmotic semi-permeable membrane to the face of the formation.

Abstract: A tank contains both Zeolite and a hydrate in a gas chamber formed beneath a piston in the sample tank. Out of safety considerations, we avoid using source cylinders of nitrogen whose pressures exceed 4000 psi. Thus, the gas chamber of the sample tank is initially pressurized by the source cylinder to no more than 4000 psi of nitrogen at room temperature at the surface. Nitrogen gas is sorbed onto the zeolite at room temperature. As the tank is heated by being lowered downhole, nitrogen desorbs from the zeolite and the gas pressure increases. However, once this tank reaches a temperature high enough to release the hydrate's water of hydration, the released water is preferentially sorbed by zeolite, displacing sorbed nitrogen, and causing the pressure in the gas volume to increase even further. Because well temperatures are not high enough to desorb water from zeolite, any water sorbed onto a Zeolite sorption site will permanently block released nitrogen from resorbing at that site.

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.