Abstract: An apparatus and method to provide monitoring of pressure outside the wellbore casing of a well in which a Wireless Sensor Unit is placed externally of a section of non-magnetic casing. An internal Sensor Energizer Unit is placed inside the wellbore casing. The Wireless Sensor Unit includes one or more sensors to measure the pressure and/or temperature of the surroundings. The Wireless Sensor Unit and the Sensor Energizer Unit communicate using electromagnetic modulation techniques, and the Wireless Sensor Unit may be powered by means of power harvesting from the Sensor Energizer Unit.

Abstract: A pressure balancing device for a transducer is provided. The pressure balancing device comprises: a pressure transmission device having a cross-sectional area and arranged, in use, to be exposed to a fluid; and a fluid chamber having a hollow shaft, the fluid chamber being arranged to be acted on by the pressure transmission device; wherein the cross-sectional area of the hollow shaft is less than the cross-sectional area of the pressure transmission device.

Abstract: An apparatus for performing a measurement in a borehole penetrating the earth, the apparatus including: a logging tool; an enclosed instrument cell disposed at the logging tool, the instrument cell being configured to perform the measurement; and a fill liquid disposed in the cell wherein the fill liquid remains in a liquid state and is nonflammable from 20° C. to 300° C.

Abstract: A method of inferring flow in a production string includes, monitoring pressure along a perforated production string, and inferring flow from the monitored pressure.

Abstract: Apparatus and method for determining pressure in a well is provided. A sensor for determining the rate of change of pressure in a well comprises: a first cavity body defining an enclosed volume, a portion of one wall of the cavity body being constituted by a pressure sensitive membrane capable of exposure to the well pressure so as to be responsive thereto; and a first capillary connected to the first cavity body at one end and being open to the well pressure at the other end so as to provide pressure communication between the well pressure and the interior of the first cavity body; wherein a length of the first capillary, an internal diameter of the first capillary, and the volume of the first cavity body are such that the sensor has a predetermined pressure response that comprises an input minus a low-pass filtered version of the input, and a predetermined time constant.

Abstract: Example methods and apparatus to perform pressure testing of geological formations are disclosed. A disclosed example method comprises positioning a testing tool in a wellbore formed in the geological formation, sealing a sample interval around the testing tool, sealing a first guard interval around the testing tool and adjacent to the sample interval, reducing a first pressure in the sample interval, reducing a second pressure in the first guard interval, maintaining a volume of a first chamber fluidly coupled to the sample interval during a time interval, and measuring a plurality of pressure data for a fluid captured in the first chamber during the time interval.

Abstract: Methods for making and systems employing pressure and temperature sensors are described. Embodiments include a capacitive element including a first conductor plate and a second conductor plate. Each plate includes a conductor layer formed on a substrate. In a pressure sensor embodiment, seal is positioned at or near the edges of the conductor plates, and a gas retained in a gap defined between the plates. In a temperature sensor embodiment, the gap defined between the plates is in fluid communication with the external environment.

Abstract: Methods are described for determining or estimating a wellbore schematic, one embodiment comprising running one or more measured distances of coiled tubing into a wellbore while pumping a fluid at varying flow rates through the coiled tubing, and calculating true vertical depth of the wellbore using pressure and flow rate data of the fluid. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It may not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: An apparatus and method for monitoring the water tables in boreholes, such as boreholes used as sampling wells for sampling contaminants in ground water. Fluctuations in one or more ground water levels can be monitored and recorded using transducers, and the changes in the water levels evaluated and considered, particularly in the context of sampling for contaminants where subsurface pollution remediation is contemplated or ongoing. The changes in ground water levels can be tracked in time and correlated, as desired, with the water sampling regime. The transducers used for monitoring pressure changes attributable to water table changes are located advantageously above the surface of the ground, where they are accessible for re-use, replacement, or repair. Apparatus and method for providing an air-coupling between the transducers and subsurface sampling points is disclosed.

Abstract: Exemplary systems and method are directed to a sensing device, and to a pressure sensing system and method. An exemplary method includes supplying electromagnetic energy to a transducer which is configured to reflect the electromagnetic energy at a ring frequency determined by an inductance of the transducer, wherein the inductance changes in response to compression of the inductive element. The ring frequency of electromagnetic energy reflected by the transducer is correlated to a pressure value.

Abstract: A method and apparatus for geobaric analysis. The method may include acquiring an in situ gas volume of a subterranean formation, acquiring a drilling fluid characteristic, determining a volume of gas excavated from the subterranean formation utilizing the drilling fluid characteristic, and estimating the formation pressure utilizing the in situ gas volume and the excavated gas volume.

Abstract: A rotating control drilling device includes an upper sealing element and a lower sealing element positioned around a drillstring and forming a chamber therebetween and a leak detection device. The leak detection device includes a piston in communication with the chamber, a magnet disc disposed on an end of the piston, and a plurality of magnetic sensors arranged in a magnetic sensing ring around the rotating control drilling device. Upon reaching a selected critical pressure in the chamber, a spring is configured to compress as the magnet disc is positioned proximate to the plurality of magnetic sensors. Furthermore, a method to detect leaks in a rotating control device includes positioning a leak detection device in communication with a chamber located between upper and lower sealing elements and signaling with the leak detection device when a pressure of the chamber exceeds a selected critical pressure.

Abstract: A refracture-candidate diagnostic test is an injection of compressible or slightly compressible fluid at pressures in excess of minimum in-situ stress and formation fracture pressure with pressure decline following injection test recorded to detect a fracture retaining residual width from previous stimulation treatments. The diagnostic consists of small volume injections with injection time being a small fraction of time required for compressible or slightly compressible reservoir fluid to exhibit pseudoradial flow. The fracture-injection portion of a test can be considered as occurring instantaneously. Data measurements are transformed into a constant rate equivalent pressure transformation to obtain adjusted pressures or adjusted pseudovariables which are analyzed to identify dual unit-slope before and after closure periods confirming a residual retaining width.

Abstract: A method and apparatus for verifying operation of process variable transmitters in process control or monitoring systems is provided. A process variable is measured with a process variable transmitter to verify operation of the process variable transmitter by comparing the process variable with a reference. A data entry is placed in a database which indicates operation of the process variable transmitter has been verified.

Abstract: A drilling operation wherein a borehole can be drilled through earth formations with a drill bit at the end of a drill string, using recirculating drilling mud that flows downward through the drill string, exits through the drill bit, and returns to the earth's surface in the annulus between the drill string and the borehole wall, at least a portion of which has a mudcake thereon, and a surface pumping system for pumping the mud to recirculate.

Abstract: A method of TI formation evaluation is disclosed. The method comprises receiving a plurality of borehole measurements; deriving a correlation between a first TI stiffness parameter and other TI stiffness parameters where the first and other TI stiffness parameters representing mechanical behavior of the TI formation; and computing the first and other TI stiffness parameters based on the borehole measurements and the derived correlation. The method further comprises evaluating TI formation elastic properties based on the computed first and other TI stiffness parameters. The method further comprises assuming that the shear modulus parallel to TI symmetric axis can be approximated from other moduli.

Abstract: An apparatus and a method for reducing phase noise in measurement signals from a sensor are provided. The apparatus and method, in one aspect, may use a multiphase counter to obtain a count for each sensor signals time cycle and a filter to reduce noise from the obtained counts. A suitable reference frequency, including the reference frequency of the sensor, may be utilized by the multiphase counter.

Abstract: A method for monitoring the pressure difference across an ESP comprises:—connecting the ESP (7) to a production tubing (6)—providing the production tubing (6) with a side pocket (9) which comprises an opening (13)—inserting a pressure sensor assembly (10) into the side packet (9) such that the opening (13) is located between a pair of annular seals (14, 15)—monitoring the pressure difference across the ESP (7) by inducing the sensor assembly to measure a pressure difference between an upper section of the side pocket which is in communication with the interior of the tubing and a middle section (16) of the interior of the side packet (9) which is located between the annular seals (14, 15).

Abstract: A well head barrier assembly (1, 2, 3) including a termination of an instrument tube (9) installed in a well and a primary pressure barrier (3) for the well pressure comprising a tool (10) arranged for being pushed into a passage (5) in which the instrument tube (9) is arranged. The closing of the passage (5) provides an additional secondary pressure barrier in the well head, thus enabling re-establishment of a double pressure barrier following a breakage of the instrument tube (9).

Abstract: It is shown that a pressure pulse originating in a well is correlated to a pulse observed at a distant well with a characteristic time. The correlation time is directly related to the diffusion time scale arising out of the pressure diffusion equation. The relationship is affected by the source-observer or observer-observer distance but the correction is small for large distances. In practice, further corrections have to be included for finite width pulses. For these pulses, a practical scheme for continuous permeability monitoring is presented.

Abstract: A cased hole pressure test tool is used to determine the integrity of cement between two points in a borehole in terms of permeability or transmissibility. The test tool drills at least one probe hole through the casing up to the cement. In one embodiment, two probes are set and the dissipation of a pressure pulse through the cement initiated by the first probe is observed by the second probe. In another embodiment, one probe hole is in hydraulic communication with the borehole fluid and a single offset probe is set in another probe hole. Fluid (water) is then added to the borehole to cause a pressure increase in the borehole fluid. Detection of the pressure increase through the cement by the offset probe is indicative of a loss of hydraulic isolation. Packers may be used to isolate the portion of the borehole under test. A mechanism for generating a pressure pulse of known magnitude is also described.

Abstract: A formation tester for determining the formation pressure of a subsurface formation traversed by a wellbore comprises of:—an elongate tester body;—a support plate (3) that is extendible outwardly from the surface of the formation tester body, said support plate carrying probe means (5) to establish a passageway between the inside of said formation tester body and said formation, and a sealing pad (6) connected to said probe means to isolate said passage way between the inside of said formation tester body and said formation;—anchoring means (7) to settle said tester body at a level within the wellbore. The elongate tester body comprises an eccentric portion (2) wherein said support plate is mounted such that a determined standoff is maintained between said elongate tester body and the wall of the wellbore when said tester body is settled at a level in the wellbore.

Abstract: Apparatus and method for determining pressure in a well is provided. A sensor for determining the rate of change of pressure in a well comprises: a first cavity body defining an enclosed volume, a portion of one wall of the cavity body being constituted by a pressure sensitive membrane capable of exposure to the well pressure so as to be responsive thereto; and a first capillary connected to the first cavity body at one end and being open to the well pressure at the other end so as to provide pressure communication between the well pressure and the interior of the first cavity body; wherein a length of the first capillary, an internal diameter of the first capillary, and the volume of the first cavity body are such that the sensor has a predetermined pressure response that comprises an input minus a low-pass filtered version of the input, and a predetermined time constant.

Abstract: Disclosed herein is a method of detecting a downhole washout. The method includes, positioning a plurality of sensors along a downhole drillstring, communicatively coupling the plurality of sensors to a processor, and analyzing data sensed by the plurality of sensors with the processor for relationships indicative of a washout.

Abstract: Example methods and apparatus to perform pressure testing of geological formations are disclosed. A disclosed example method comprises positioning a testing tool in a wellbore formed in the geological formation, sealing a sample interval around the testing tool, sealing a first guard interval around the testing tool and adjacent to the sample interval, reducing a first pressure in the sample interval, reducing a second pressure in the first guard interval, maintaining a volume of a first chamber fluidly coupled to the sample interval during a time interval, and measuring a plurality of pressure data for a fluid captured in the first chamber during the time interval.

Abstract: The present invention provides an apparatus and method for continuously monitoring the integrity of a pressurized well bore fluid sample collected downhole in an earth boring or well bore. The CDR continuous by measures the temperature and pressure for the down hole sample. Near infrared, mid infrared and visible light analysis is also performed on the small amount of sample to provide an on site analysis of sample properties and contamination level. The onsite analysis comprises determination of gas oil ratio, API gravity and various other parameters which can be estimated by a trained neural network or chemometric equation a flexural mechanical resonator is also provided to measure fluid density and viscosity from which additional parameters can be estimated by a trained neural network or chemometric equation. The sample tank is overpressured or supercharged to obviate adverse pressure drop or other effects of diverting a small sample to the CDR.

Abstract: A cased hole pressure test tool is used to determine the integrity of cement between two points in a borehole in terms of permeability or transmissibility. The test tool drills at least one probe hole through the casing up to the cement. In one embodiment, two probes are set and the dissipation of a pressure pulse through the cement initiated by the first probe is observed by the second probe. In another embodiment, one probe hole is in hydraulic communication with the borehole fluid and a single offset probe is set in another probe hole. Fluid (water) is then added to the borehole to cause a pressure increase in the borehole fluid. Detection of the pressure increase through the cement by the offset probe is indicative of a loss of hydraulic isolation. Packers may be used to isolate the portion of the borehole under test. A mechanism for generating a pressure pulse of known magnitude is also described.

Abstract: A pressure communication assembly external to casing with various forms of connectivity to a pressure source. A well system includes a casing string positioned in the well, with a bore extending longitudinally through the casing string; a chamber attached to the casing string and positioned external to the casing string bore; and a device which provides fluid communication between an interior of the chamber and a pressure source external to the casing. A method of monitoring pressure in a well includes the steps of: installing a casing string in the well with a chamber positioned external to a through bore of the casing string, and the chamber being isolated from the well external to the casing string; and then actuating a device to thereby provide fluid communication between the chamber and the well external to the casing string.

Abstract: Methods and related systems are described for making measurements at multiple locations in an annular region of a cased sequestration well. A first tool module is positionable within the well and adapted to directly or indirectly measure changing pressure at a first location in the annular region of the well. A pressure change is induced at the first location in the annular region. A second tool module is positionable within the well and adapted to directly or indirectly measure changing pressure at a second location in the annular region. The measured pressure changes at the second location are in response to the induced pressure change at the first location.

Abstract: Disclosed herein is a method of inferring flow in a production string. The method includes, monitoring pressure along a perforated production string, and inferring flow from the monitored pressure.

Abstract: A method of determining when to stop pumping proppant during hydraulic fracturing in a wellbore is described. By accurately detecting tip screen-out with a bottom hole pressure gauge mounted to a perforating gun, the optimal amount of proppant can be supplied to a fracture while avoiding the risks associated with wellbore screen-out.

Abstract: A method is provided for estimating the amount of supercharging in a formation penetrated by a wellbore. According to the method, pressure fluctuation measurements are obtained at a position in the formation accessible from the well bore and at an adjacent position in the wellbore, and a model is provided which relates variations in pressure with time at these positions to one or more adjustable parameters from which the amount of supercharging can be estimated. The or each parameter is then adjusted to optimize the fit between the pressure variations predicted by the model and the measured pressure fluctuations, and the amount of supercharging is estimated from the adjusted parameter(s).

Abstract: Examples of techniques for analyzing well data which may be encountered during formation testing are disclosed. Certain portions of the tests may exhibit an indication of anomalous behavior, defects, errors or events that may have occurred during testing. One or more confidence tokens may be identified during or after the execution of a test. One or more of these confidence tokens may be analyzed to determine whether such anomalous behavior, defects, errors or events have occurred during the test. These confidence tokens may then be used to determine a level of confidence in the results derived from the tests performed and/or their underlying data and interpretation.

Abstract: A drilling operation wherein a borehole can be drilled through earth formations with a drill bit at the end of a drill string, using recirculating drilling mud that flows downward through the drill string, exits through the drill bit, and returns to the earth's surface in the annulus between the drill string and the borehole wall, at least a portion of which has a mudcake thereon, and a surface pumping system for pumping the mud to recirculate.

Abstract: A method for determining true formation pressure in formations surrounding a fluid-containing borehole having a mudcake on the surface thereof, including the following steps: at a particular location in the borehole, monitoring the electrokinetic potential across the mudcake; modifying the borehole pressure at the particular location in the borehole; and determining the true formation pressure in the formations surrounding the particular location as being the borehole pressure at which the electrokinetic potential is substantially zero.

Abstract: A system for making pressure measurements in a formation surrounding a wellbore includes a sensor which, in use, is positioned into direct pressure communication with the formation from a predetermined location in the wellbore, and a means for isolating the sensor, when in use, from pressure effects arising from the wellbore.

Abstract: A method for determining the flow characteristics of a geological formation; in a particular embodiment the method comprising the steps of: providing a container such as a core barrel within the formation; adding a portion of the formation, such as a core sample, into the container; and whilst the container remains in the formation, injecting fluid into the container such that a portion of the fluid flows through said portion of the formation and measuring the flow of the injected fluid to give information on the nature, such as permeability, of the core sample. In preferred embodiments fluid is received from the portion of the formation in the container to give more information on the core sample. Certain embodiments include packers to direct the flow of the fluids within the container. Such in situ measurements provide more accurate data on the reservoir characteristics, such as reservoir permeability.

Abstract: Testing process for testing zero emission hydrocarbon wells in order to obtain general information on a reservoir, comprising the following steps: injecting into the reservoir a suitable liquid or gaseous fluid, compatible with the hydrocarbons of the reservoir and with the formation rock, at a constant flow-rate or with constant flow rate steps, and substantially measuring, in continuous, the flow-rate and injection pressure at the well bottom; closing the well and measuring the pressure, during the fall-off period (pressure fall-off) and possibly the temperature; interpreting the fall-off data measured in order to evaluate the average static pressure of the fluids (Pav) and the reservoir properties: actual permeability (k), transmissivity (kh), areal heterogeneity or permeability barriers and real Skin factor (S); calculating the well productivity.

Abstract: A method of analysing a reservoir pressure in an underground formation surrounding a well, comprising: determining the permeability of mud cake on the wall of the well in the region in which the pressure measurement is made; determining the thickness of mud cake on the well of the well in the region in which the pressure measurement is made; determining the hydrostatic pressure in the well in the region in which the pressure measurement is made; measuring the formation pressure at the wall of the well; calculating a pressure decay index from the mud cake permeability and thickness, the hydrostatic pressure and the measured pressure; and using the pressure decay index to analyse the measured pressure to derive the reservoir pressure.

Abstract: A system for measuring pressure in a well borehole using two pressure sensing gauges that are exposed to an area of common pressure. Pressure measurements are made with preferably two pressure gauge assemblies each containing a single pressure sensing gauge. The two pressure gauge assemblies are removably disposed within a receptacle or “pocket” in the outer surface of a wall of a formation tester tool section. When disposed or “side loaded” in the pocket, the gauges within the pair of assemblies are axially aligned and positioned in a plane that is normal to the radius of the formation tester tool section. Both pressure sensing gauges can be connected to respond to the same fluid pressure originating from a probe or port section of a formation tester tool. By disposing the pressure gauge assemblies in a receptacle or “pocket” in the outer surface or wall of a formation tester tool section, the pressure sensing gauges are exposed to wellbore fluids. Pressure sensing gauges are selected to have low mass.

Abstract: Exemplary systems and method are directed to a sensing device, and to a pressure sensing system and method. An exemplary method includes supplying electromagnetic energy to a transducer which is configured to reflect the electromagnetic energy at a ring frequency determined by an inductance of the transducer, wherein the inductance changes in response to compression of the inductive element. The ring frequency of electromagnetic energy reflected by the transducer is correlated to a pressure value.

Abstract: A cased hole pressure test tool is used to determine the integrity of cement between two points in a borehole in terms of permeability or transmissibility. The test tool drills at least one probe hole through the casing up to the cement. In one embodiment, two probes are set and the dissipation of a pressure pulse through the cement initiated by the first probe is observed by the second probe. In another embodiment, one probe hole is in hydraulic communication with the borehole fluid and a single offset probe is set in another probe hole. Fluid (water) is then added to the borehole to cause a pressure increase in the borehole fluid. Detection of the pressure increase through the cement by the offset probe is indicative of a loss of hydraulic isolation. Packers may be used to isolate the portion of the borehole under test. A mechanism for generating a pressure pulse of known magnitude is also described.

Abstract: A method and apparatus for geobaric analysis. The method may include acquiring an in situ gas volume of a subterranean formation, acquiring a drilling fluid characteristic, determining a volume of gas excavated from the subterranean formation utilizing the drilling fluid characteristic, and estimating the formation pressure utilizing the in situ gas volume and the excavated gas volume.

Abstract: A pressure meter includes a probe (1) and a piece of surface equipment (2), an inflatable sleeve (11), a non-deformable reservoir (4) containing a gas (G) and a liquid (L), a pressurized-gas source (21), various ducts (31, 32), gas-flow control elements (220-222), a pressure sensor (5), and a volume sensor. According to the invention, the reservoir (4) is supported by the probe, the gas flow is controlled by a nozzle (221) and a valve (222), and this pressure meter additionally includes pressure control members (7, 8) designed to open the valve (222), when establishing each new pressure level at a setpoint pressure (Kpi), for a time period (Tpi) corresponding to this setpoint.

Abstract: Methods and systems for investigating downhole conditions are described. One method comprises inserting a tubular into a wellbore, the tubular comprising a tubular section having upper and lower fluid injection ports, and having a thermally insulated fiber optic cable section positioned inside the tubular extending to the upper fluid injection port, and a non-insulated fiber optic cable section positioned outside of the tubular section and extending at least between the upper and lower fluid injection ports; positioning the tubular section having upper and lower fluid injection ports near a suspected thief or pay zone; injecting a fluid through the upper fluid injection port; determining a first differential temperature profile between the upper and lower fluid injection ports; injecting a fluid through the lower fluid injection port; and determining a second differential temperature profile at least between the upper and lower fluid injection ports.

Abstract: Fluid column weight correction using discrete point and fiber optic temperature measurement. A method for determining pressure at a distal end of a fluid column in a well includes the steps of: dividing the fluid column into multiple segments; determining a temperature of each segment; and determining a pressure and density for each segment. Another method includes the steps of: determining the temperature of each segment by measuring a temperature in the well near a proximal end of the fluid column, and using the measured temperature in conjunction with a thermal wellbore model to generate a temperature profile of the fluid column. Another method includes the steps of: causing a pressure change in the fluid column; recording multiple pressure measurements during the pressure change; and generating a temperature profile of the fluid column for each of the pressure measurements.

Abstract: A system and method is provided for sensing a variety of parameters in well-related environments. A skin sensor is deployed in downhole applications to obtain data used in analyzing well characteristics.

Abstract: A method and apparatus for measuring the pressure of a formation penetrated by a wellbore is provided. A downhole tool is positioned in the wellbore and a probe is extended therefrom into sealing engagement with the formation. A piston in the probe is retracted therein where by a cavity is defined for receiving a fluid from the formation. A pressure underbalance in the cavity draws fluid from the formation into the cavity. An oscillator may be used to fluctuate the flow of fluid into the cavity. A pressure gauge is used to measure the pressure of fluid in the cavity.

Abstract: A probe 10,170 is provided that measures the speed of sound and/or vortical disturbances propagating in a single phase fluid flow and/or multiphase mixture to determine parameters, such as mixture quality, particle size, vapor/mass ratio, liquid/vapor ratio, mass flow rate, enthalpy and volumetric flow rate of the flow in a pipe or unconfined space, for example, using acoustic and/or dynamic pressures. The probe includes a spatial array of unsteady pressure sensors 15-18 placed at predetermined axial locations x1-xN disposed axially along a tube 14. For measuring at least one parameter of a saturated vapor/liquid mixture 12, such as steam, flowing in the tube 14. The pressure sensors 15-18 provide acoustic pressure signals P1(t)-PN(t) to a signal processing unit 30 which determines the speed of sound amix propagating through of the saturated vapor/liquid mixture 12 in the tube 14 using acoustic spatial array signal processing techniques.

Abstract: Safety valve apparatus for a pressure telemetry system utilizing a small diameter tubing conveying pressure from a downhole pressure chamber to the surface, the system pressurized with a monitoring gas, is presented. A check valve assembly is placed along the fluid flow path having a check valve with an operating member. The operating member moves to a sealed position by floating on an activating fluid. The operating member must be of low effective specific gravity to float on wellbore hydrocarbon fluids, either liquid or gas. Consequently, in one preferred embodiment, the check valve operating member is a hollow dart which retains the monitoring gas inside the hollow portion, thereby effectively reducing its specific gravity such that it will float on the activating fluid.