Abstract: An NMR instrument for determining formation fluid properties includes a housing adapted to move in a wellbore; a magnet disposed in the housing adapted to induce a static magnetic field; an antenna assembly disposed in the housing adapted to resonate at a first frequency and a second frequency, the first frequency corresponding to a resonance frequency of a first nucleus, the second frequency corresponding to a resonance frequency of a second nucleus, wherein the first nucleus is different from the second nucleus; means for inducing an RF magnetic field; and means for detecting NMR signals at the first frequency. A method of NMR measurement includes inducing a static magnetic field having a selected magnetic field strength in an earth formation sample; acquiring NMR measurements having J coupling information; and deriving the J coupling information from the NMR measurements.

Abstract: The invention relates to a method of measuring a force F exerted on a piece in a given direction in the presence of external pressure Pe and temperature T. According to the invention: the response Rcap of a deformation sensor to the total force exerted on the piece is measured; said external pressure Pe and said temperature T are determined; and the force F exerted on the piece in said given direction is determined by a relationship between the response of said deformation sensor (Rcap) and a polynomial function of degree n of the pressure Pe [fn(Pe)], said relationship being such that: F=K.Rcap−fn(Pe) where K is a constant determined by calibration of the sensor.

Abstract: The invention is directed toward a subsurface gravity measurement device and a method for calibrating the same that includes a tilt meter and a gravity sensor. The method includes associating tilt information produced by the gravity sensor as a function of a relationship between tilt information produced by the tilt meter and a correction parameter. The tilt meter produces tilt data, and the gravity meter produces gravity data, corresponding to the tilt data. The tilt data and gravity data is fitted to a polynomial equation that has a plurality of initial coefficients associated therewith. The initial coefficients includes information concerning the correction parameter. The correction parameter is derived as a function of the initial coefficients.

Abstract: One embodiment of the present invention is a method for nuclear magnetic resonance imaging of an investigation region of formation surrounding a wellbore. The method comprises the steps of applying a series of magnetic field gradients to phase encode nuclear spins within the investigation region, wherein the strength of the magnetic field gradient applied is different from at least one previously applied magnetic field gradient within the series. Nuclear magnetic resonance signals are detected from the investigation region resulting from the series of magnetic field gradients.

Abstract: A method for measuring a downhole formation pressure is disclosed which includes lowering a formation testing tool to a desired measuring position in a well borehole. Then a nozzle in the tool is extended so that the nozzle extends through the mud cake layer on a surface of a formation, forming a seal between the mud cake layer and a sealing surface of the nozzle. In an embodiment of the invention, the nozzle has a porous tip that extends into the invaded zone beyond the mudcake layer and is exposed to the formation pressure. In an alternate embodiment, the nozzle has a retractable tip that retracts into the nozzle. The nozzle and retractable tip are positioned in the mudcake and the retractable tip is retracted into the nozzle. The formation pressure is then communicated through the nozzle to a pressure sensor operatively connected to the nozzle.

Abstract: An apparatus and method are disclosed for actively cooling instrumentation, such as electronic circuits, in a downhole tool. This apparatus includes a compressor, condenser and expansion valve connected in circuit to an evaporator or heat exchanger. The evaporator/heat exchanger includes an inner container positioned about the instrumentation, and an outer chamber positioned about the inner container. A cooling fluid absorbs heat from the instrumentation as it passes through the inner container. The fluid then passes into the outer container where it may absorb heat from the wellbore. The heated fluid is then pressurized via the compressor, condensed into liquid via the condenser and selectively released back into the internal container upon cooling via the expansion valve. The fluid continuously circulates through the system whereby the instrumentation is insulated from heat and/or cooled.

Abstract: A method comprising determining a characteristic of a mud mixture surrounding a drilling tool within an inclined borehole in which a drilling tool is conveyed. The method includes defining a cross-section of the tool which is orthogonal to a longitudinal axis of the tool. A bottom contact point of the cross-section of the tool is determined, which contacts the inclined borehole as the tool rotates in the borehole. The cross-section is separated into at least two segments, where one of the segments is called a bottom segment of the borehole which includes the bottom contact point of the cross-section of the tool with the inclined borehole. The tool is turned in the borehole. Energy is applied into the borehole from an energy source disposed in the tool, as the tool is turning in the borehole.

Abstract: A method and apparatus for controlling fluidic torque in a downhole tool is provided. One or more rotatable components of the downhole tool comprise a deformable material, such as rubber or SMA, selectively deformable in response to the flow of fluid through the downhole tool. The rotatable components may include a rotor and/or a turbine of a generator in the downhole tool. Non-rotatable components, such as the stator of the generator, may also be deformable. The rotor, the stator, and/or turbine may comprise a deformable material capable of selectively deforming in response to the flow of drilling mud through the generator. The desired deformation and/or the desired torque may be controlled by adjusting the parameters of the components.

Abstract: A method and apparatus is provided to support a gyroscope within a downhole drilling tool. A packaging system is positioned within a drill collar of the drilling tool and includes a housing for the gyro and at least one centralizer supporting the housing within the drill collar. The system may also be provided with a down-hole end cap, an up-hole endcap and a loading device. A gyro compression mechanism that is capable of holding wires may also be included to provide power and communication while compressing the gyro to isolate it from shock or vibration.

Abstract: A graphical user interface of a well logging display program for editing data records included in well logging data includes multiple windows and controls for user interaction. The well logging data includes measurements of logging variables collected at successive depths to define the data records. The multiple windows include a first window for displaying depth versus time measurements, a second window for defining a logging variable, a third window for selecting and displaying a first set of instances of the logging variable, and a fourth window for selecting and displaying a second set of instances of the logging variable. The multiple controls include a bar line for selecting a splice point, and an interface button for instructing the program to edit the data records. The edited data records include measurements corresponding to the first and second set of instances being spliced in accordance with a predefined function.

Abstract: A flow meter for multiphase flows, includes a holdup measuring device having a Venturi located upstream thereof and separated therefrom by a distance that results in flow through the holdup measuring device being at least partially homogenized by the effect of the Venturi on the fluids flowing therethrough.

Abstract: The present invention provides a graphical method to design and modify the trajectory of a well bore. A well bore trajectory plan is comprised of hold and curve sections. Hold sections are generally described by specifying the attitude of the hold and the length of the hold. Curve sections can be described and represented in a variety of ways. The present invention introduces control points that are formed at the intersection of extensions/projections of the two hold sections contacting a curve section. The hold sections contact the curve section at tangent points. The tangent points for a curve section have the same distance to the control point. In operation, as a control point is moved, the direction and inclination of multiple sections of the well plan are simultaneously modified. These simultaneous modifications enable the user to quickly and intuitively modify a well plan.

Abstract: Techniques for monitoring a pulsed neutron source include measuring a burst count rate while the pulsed neutron source is turned on using a monitor detector disposed proximate the pulsed neutron source; measuring a decay count rate while the neutron source is turned off using the monitor detector; and deriving a source strength indicator from the burst count rate and the decay count rate. A pulsed neutron tool includes a tool body; a pulsed neutron source disposed in the tool body; a monitor detector disposed in the tool body proximate the pulsed neutron source; at least one measurement detector disposed in the tool body at a predetermined distance from the pulsed neutron source; and circuitry disposed in the tool body for controlling the pulsed neutron source, the monitor detector, and the at least one measurement detector.

Abstract: A rock classification system involves the use of a Ternary Diagram (TD) Model and a set of rules in a rule base. A computer, which stores a rock classification software which includes the rule base, will be responsive to certain data points from a Spectroscopy Sonde, will compare each data point with each of the rules in the rule base, and, when a match is found, will generate a specific rock classification for that data point. When a plurality of data points are input to the computer, a corresponding plurality of rock classifications are generated.

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 is disclosed for reducing noise in a measured telemetry signal. The method includes tracking a characteristic of at least one harmonic of a noise component in the measured telemetry signal band. The at least one harmonic has a frequency outside a telemetry signal band. The characteristic of the noise component is determined for at least one other harmonic thereof. The at least one other harmonic has a frequency inside the telemetry signal band. A noise reference is generated from the characteristic of the in band harmonic, and the noise reference is combined with the measured telemetry signal to generate a noise-canceled telemetry signal.

Abstract: A method is disclosed which utilizes multiple overlapping surveys to estimate a position in a wellbore and related position uncertainty. Multiple surveys are often taken over the same portion of a wellbore either concurrently or sequentially and/or using various instruments. Each survey generates an estimated survey position and related uncertainty for a given location in the wellbore. By combining the estimated survey positions and uncertainties for these overlapping surveys, a resultant position and related ellipsoid of uncertainty is estimated. This resultant position estimates a position in the wellbore by incorporating the estimated survey positions and uncertainties of multiple overlapping surveys.

Abstract: Systems and methods for monitoring a subsurface formation property and for placing a borehole in the vicinity of a well in the formation. A slotted tubular is utilized to provide through-tubular signal transmission and/or reception using an antenna adapted to generate a magnetic dipole moment with a transverse or controllable orientation. Hydraulic isolation between the interior and exterior of the tubular at the slot is provided by a pressure barrier. The tubular also forms part of a system for accurately placing a well within a desired distance and orientation relative to an existing well.

Abstract: A system and method for enhancing the reception of electromagnetic (EM) waves in a fixed downhole receiver of an EM telemetry system is provided. In one embodiment, slots are formed in a portion of an outer casing and an EM receiver is positioned within the outer casing so as to be aligned with the slots formed therein. In another embodiment, an inductive coupling arrangement is provided to transfer signals from an EM receiver mounted on the outside surface of an outer casing to a wireline that is attached to the outer surface of an inner casing, which is disposed within the outer casing. In yet another embodiment, an insulated gap is formed in the surface of the outer casing. An EM receiver, mounted on the outer surface of the inner casing, is positioned above the insulated gap of the outer casing. An electrical coupling mechanism is further provided to electrically couple the inner and outer conductors at a point above the EM receiver.

Abstract: A method is disclosed for producing a single logging-while-drilling (LWD) merged caliper from several indirect LWD borehole size measurements. The merging accounts for the varying validity of each input borehole size measurement as a function of the environment, the formation, and the borehole size itself. In one embodiment, the method includes obtaining a plurality of borehole size measurements from a plurality of LWD sensors and weighting each measurement with varying measurement confidence factors. One embodiment of the method includes determining a set of mathematical equations representative of the responses of the multiple sensors and solving the equation set to determine the borehole size. A computer encoded with instructions for weighting borehole size inputs and iteratively processing the weighted inputs to determine the merged caliper is also disclosed.