Abstract: A formation tester places an isolation device, preferably a probe, in fluid communication with a formation to determine formation pressures. The tester's controller uses a pressure pre-test process to autonomously control operation. The controller measures drawdown pressure and interval as the tester draws down pressure in flowline coupled to the probe. If the drawdown pressure indicates a dry test has occurred, the process is aborted. Otherwise, the controller measures buildup pressure and interval by allowing buildup of pressure of the flowline. The controller permits this to continue until the interval is longer than the drawdown interval and/or until a rate of the buildup falls below a predetermined rate. If the buildup pressure is too tight relative to the drawdown pressure, the controller aborts the test. Eventually, the controller measures a final buildup pressure when the buildup terminates. A new drawdown rate and volume can be determined for subsequent formation tests.

Abstract: A driveshaft assembly includes a driveshaft with a pair of universal joints disposed at each end of the driveshaft. Each of the universal joints provides torque transfer from the driveshaft to an adapter disposed to driveshaft using a plurality of elliptical projections that mate with interior grooves of the adapter. Stress concentration on the projections may be reduced in some embodiments by providing a variable radius fillet around each of the projections at the intersection of the projection with the driveshaft.

Abstract: This invention relates to a measurement tool and method of use, and in particular to a measurement tool for use in determining a parameter of a stationary or moving fluid. The measurement tool has been designed primarily for use in borehole formation testing. The measurement tool can measure the dielectric constant of a fluid within a pipe or surrounding the tool. The pipe or wall between the tool and the fluid is electrically insulating. The tool has pair of capacitor plates mounted adjacent to the pipe or wall, a signal generator which can deliver an alternating electrical signal to at least one of the capacitor plates, and a detector for measuring a signal dependent upon the electrical capacitance between the capacitor plates. The measurement tool can additionally measure the electrical resistivity of the fluid.

Abstract: Detector assembly for downhole spectroscopy includes a near-infra-red quaternary photodiode that can operate at high temperatures without cooling it to the standard operation temperature range of the photodiode. High temperature operation of the photodiode right shifts the detector assembly's responsivity curve to include wavelengths of up to 2400-nm. The photodiode has manageable dark current at temperatures even at 200° C., and it can be packaged using high temperature construction. The photodiode is operated in photovoltaic mode at high temperatures but can be operated at photoconductive mode at lower temperatures. At least partial cooling can be provided above a predetermined temperature.

Abstract: A reservoir evaluation system enables end users to plan jobs for performing formation tests at remote wellsites. In the planning, the end user defines the toolstring to be constructed at the remote wellsite by service personnel and defines the details for the formation tests to performed with the toolstring. While the tests are performed, the system obtains data via a satellite or other communication link with the remote wellsite and stores the data for retrieval and processing. The data measured from the formation tests conducted with the toolstring can be obtained in real time from the wellsite. The system processes the obtained data to produce analysis for the end user, who can then remotely access the data and analysis with a secure network connection via the Internet or the like.

Abstract: Downhole drilling vibration analysis uses acceleration data measured in three orthogonal axes downhole while drilling to determine whether drilling assembly's efficiency has fallen to a point where the assembly needs to be pulled. In real or near real time, a downhole tool calculates impulse in at least one direction using the measured acceleration data over an acquisition period and determines whether the calculated impulse exceeds a predetermined acceleration threshold for the acquisition period. If the impulse exceeds the threshold, the tool pulses the impulse data to the surface where the calculated impulse is correlated to efficiency of the assembly as the drillstring is used to drill in real time. Based on the correlation, operators can determine whether to pull the assembly if excessive impulse occurs continuously over a predetermined penetration depth.

Abstract: This invention relates to a measurement tool, and in particular to a measurement tool for use in determining the density and/or viscosity of a stationary or moving fluid. The measurement tool has been designed for use in borehole applications during the location and exploitation of oil and gas reserves. The measurement tool has a resilient pipe with a substantially uniform cross-section along its length, and the fluid is located within the pipe. The pipe carries an exciter which is connected to a signal generator, the exciter and signal generator being adapted to impart transverse and/or rotational oscillations to the pipe. Measuring the frequency of the oscillations can be used to determine the density and/or the viscosity of the fluid within the pipe.

Abstract: An acoustic transmitter with preferably a plurality of piezoelectric plates configured to optimized acoustic pressure output within a desired frequency range while meeting physical restrictions of LWD and MWD logging systems. The transmitter is disposed in a recess in the perimeter of a logging tool housing to reduce acoustic pressure waves transmitted directly along the tool housing and to optimize acoustic energy transmission into the borehole environs. In order to increase acoustic pressure output at a desired logging frequency range, the plurality of piezoelectric plates are connected electrically in parallel and fired simultaneously. The polarity of the plates and the wiring arrangement are such that each plate expands or contracts in a common direction during simultaneous firing by an applied voltage. The desired output frequency is obtained by selectively polarizing and dimensioning the plates within the plate assembly.

Abstract: Downhole drilling vibration analysis uses acceleration data measured in three orthogonal axes downhole while drilling to determine whether drilling assembly's efficiency has fallen to a point where the assembly needs to be pulled. In real or near real time, a downhole tool calculates impulse in at least one direction using the measured acceleration data over an acquisition period and determines whether the calculated impulse exceeds a predetermined acceleration threshold for the acquisition period. If the impulse exceeds the threshold, the tool pulses the impulse data to the surface where the calculated impulse is correlated to efficiency of the assembly as the drillstring is used to drill in real time. Based on the correlation, operators can determine whether to pull the assembly if excessive impulse occurs continuously over a predetermined penetration depth.

Abstract: A method and system is provided for minimizing delays in a magnetic ranging method. Delays are minimized by establishing synchronicity between triggering of a three-axis magnetometer and energisation of a solenoid assembly deployed in the borehole being drilled and the first borehole, respectively. Synchronicity enables measuring various components of the alternating magnetic field created by energisation of the solenoid assembly by the magnetometer, the moment the solenoid assembly is energised. The recorded components are used for computation of steering data for drilling the second borehole relative to the first borehole. The steering data can be determined at the surface or downhole.

Abstract: A driveshaft assembly includes a driveshaft with a pair of constant velocity joints disposed at each end of the driveshaft. Each of the constant velocity joints provides torque transfer from the driveshaft to an adapter disposed to driveshaft using a plurality of elliptical projections that mate with interior grooves of the adapter. Stress concentration on the projections may be reduced in some embodiments by providing a variable radius fillet around each of the projections at the intersection of the projection with the driveshaft.

Abstract: A system for measuring an acoustic property of material penetrated by a well borehole. The system uses a borehole logging tool comprising preferably one acoustic transmitter and preferably a plurality of acoustic receivers. An independent measurement is used to determine azimuthal orientation of the tool within the borehole. Firings of the transmitter are based upon azimuthal orientation of the tool. Receiver responses resulting from preferably a plurality of transmitter firings per tool revolution are combined to form at least one composite transmitter response. The composite receiver response is compensated for adverse effects of the tool operating eccentered within the borehole.

Abstract: A multi-channel source assembly for downhole spectroscopy has individual sources that generate optical signals across a spectral range of wavelengths. A combining assembly optically combines the generated signals into a combined signal and a routing assembly that splits the combined signal into a reference channel and a measurement channel. Control circuitry electrically coupled to the sources modulates each of the sources at unique or independent frequencies during operation.

Abstract: A downhole fluid analysis tool has a housing and a flow passage for downhole fluid. A device disposed in the tool housing relative to the flow passage has a one or more sources, one or more sensing optics, one or more detectors, and control circuitry. The source generates an input signal. The sensing optic has a refractive index (RI) higher than crude oil and other expected constituents. A sensing surface of the optic optically coupled to the source interfaces with a downhole fluid. When the variable RI of the downhole fluid reaches a defined relationship to the optic's RI, the input signal interacting with the sensing surface experiences total internal reflection, and the reflected signal from the sensing surface remains in the sensing optic and reflects to a detector. The control circuitry monitors the detector's response and indicates gas break out if the response is above a threshold.

Abstract: A refractive index sensor having one or more sources, an adaptive optical element or scanner, imaging optics, a sensing optic, and one or more detectors. The scanner impinges a signal from the source into the sensing optic and onto a sensor-sample interface at sequential angles of incidence. The detector response increases dramatically to signals reflected from the interface at corresponding sequential angles of reflection equal to or greater than a critical angle. The refractive index sensor also uses an input lens between the scanner and the sensing optic and uses an output lens between the sensing optic and the detector. A processor controls the sensor and can determine index of refraction of the fluid sample based on the detector response and scan rate. The sensor can be used in several operational environments from a laboratory to a downhole tool, such as a formation tester to determine properties in a borehole environment.

Abstract: A downhole deburring tool is equipped with retractable cutters which permit it to fit through restrictions in a wellbore—e.g., a subsurface safety valve—and subsequently expand to deburr or scrape a section of tubing having an internal diameter greater than that of the restriction. In one preferred embodiment, tapered surfaces on the tool act to effect retraction of the cutters during withdrawal of the tool from a wellbore. Deburring operations with the tool may increase the effectiveness of bridge plugs and/or ball sealer systems to permit chemical treatment of selected zones. Scraping operations with the tool to remove scale, corrosion and other material from the inner surface of a well tubular can increase the effective diameter of the tubing thereby allowing greater production.

Abstract: A logging tool has three seismic sensors that generate seismic signals in response to microseismic events and can be a Triaxial Borehole Seismic system. The tool also has additional sensors, such as a wireline tension measuring circuit, a gamma ray sensor, an inclinometer, and a gyroscope. The tool deploys downhole with a multi-conductor (i.e., seven conductor) wireline. For the seismic signals, a telemetry unit on the tool derives frequency-modulated carrier signals from the seismic signals, and a transformer of the unit transmits these carrier signals to surface acquisition equipment using cross-wired pairs of conductors in the wireline connected to the transformer's terminals. For the signals from the other sensors, the telemetry unit derives analog carrier signals from their signals and transmits the analog carrier signals to the surface acquisition equipment using remaining conductors of the wireline.

Abstract: Apparatus and methods for removing the effects of directional drilling systems drilling fluid pulses to allow a MWD mud pulse telemetry system to operate without interference. The methodology is based upon Synchronous Time Averaging (STA). With STA, any pressure fluctuation that is cyclical (or synchronous) with a measurable event can be profiled and subsequently subtracted from a mud pulse telemetry signal. STA functions by placing a strobe in such a manner that the strobe is triggered for each cyclical event. The cyclical event in this disclosure is one (or more) revolution(s) of the drill string. If there is a pressure fluctuation that correlates to that cyclical event, it will be identified by a stable profile of that pressure fluctuation. This pressure profile is then used to remove the cyclical pressure fluctuation from the input mud pulse telemetry signal thereby allowing normal operation of the mud pulse telemetry system.

Abstract: A logging system for measuring anisotrophic properties of the materials penetrated by a borehole. A downhole or “logging tool” element of the system comprises a source section that comprises either a unipole or a dipole acoustic source. The receiver section comprises a plurality of receiver stations disposed at different axial spacings from the acoustic source. Each receiver station comprises one or more acoustic receivers. The system requires that the source and receiver sections rotate synchronously as the logging tool is conveyed along the borehole. Receiver responses are measured in a plurality of azimuthal angle segments and processed as a function of rotation angle of the tool. The logging system can be embodied as a logging-while-drilling system, a measurement-while-drilling system, and a wireline system that synchronously rotates source and receiver sections. All embodiments require that the acoustic source operate at a relatively high frequency.

Abstract: A borehole formation testing system that measures resistivity of near borehole formation in situ rather than the measuring resistivity of fluid drawn into a formation tester tool. A radially extendable probe assembly contacts and forms a hydraulic seal with the wall of a borehole using a pad. Electrode contacts are disposed on the contact surface of the pad and electrically contact the near borehole formation. Response of the electrode contacts are used to determine resistivity of the near borehole formation. This resistivity is with a deeper formation resistivity measurement to determine if virgin formation fluid is at or in the vicinity of the pad. Alternately, a plurality of resistivity measurements is made at the formation tester pad and virgin formation fluid at or near the pad is determined from the rate of change of the plurality of resistivity measurements.