Pathfinder Energy Services, Inc.

Halliburton Energy Services, Inc.

Halliburton Company

Schlumberger Technology Corporation

Smith International, Inc.

Robert Anthony Moore

Eugene J Linyaev

John Preston Rogers

Gordon Layne Moake

Roger Lynn Schultz

Neal Gregory Skinner

Paul David Ringgenberg

Harold Kent Beck

James Robert Birchak

Kevin R Manke

Graham A McElhinney

Gregory A Kliewer

Horacio Alberto Zea

Edward P Karisch

A method for magnetizing a portion of a pre-deployed casing string includes deploying an electromagnetic array in a cased wellbore and energizing the array. The array includes a plurality of axially spaced electromagnets and is configured to generate a magnetic field pattern having at least first and second pairs of magnetically opposing poles. Passive ranging measurements of the induced magnetic field may be advantageously utilized, for example, to survey and guide continued drilling of a twin well. The electromagnetic array may also be used in active ranging applications. An array of permanent magnets providing a similar magnetic field pattern may also be used in active ranging applications.

Methods for improved active ranging and target well magnetization

An apparatus for making azimuthally sensitive resistivity measurements of a subterranean formation is disclosed. The apparatus includes a magnetically permeably ring deployed about an electrically conductive tool body. An AC voltage supply is coupled to the tool body on opposing sides of the magnetically permeable ring, with at least one connecting conductor crossing outside the ring. Exemplary embodiments of this invention may further include one or more current sensing electrodes deployed in and electrically isolated from an outer surface of a blade deployed on the tool body and may be utilized to make azimuthally resolved formation resistivity measurements.

Logging while drilling tool for obtaining azimuthally sensitive formation resistivity measurements

A loop antenna useful, for example, in investigation of earth formations. Embodiments of the invention provide a loop antenna circuit comprising a loop antenna disposed to generate, in response to an electromagnetic wave, a pick-up signal on an output node. Loop antenna circuit further includes a tuning network coupled to the loop antenna. The tuning network is disposed to provide simultaneous tuning at a plurality of interrogation frequencies. Further embodiments include a preamplifier circuit coupled to the loop antenna. The preamplifier circuit is disposed to receive the pick-up signal on an input node and provide a high impedance load to the loop antenna for a first of the plurality of interrogation frequencies to reduce the secondary radiation from the loop antenna to below a predetermined value at the said first interrogation frequency.

Series-resonant tuning of an LWD receiver

An apparatus for making azimuthally sensitive resistivity measurements of a subterranean formation is disclosed. The apparatus includes a magnetically permeably ring deployed about an electrically conductive tool body. An AC voltage supply is coupled to the tool body on opposing sides of the magnetically permeable ring, with at least one connecting conductor crossing outside the ring. Exemplary embodiments of this invention may further include one or more current sensing electrodes deployed in and electrically isolated from an outer surface of the tool body and may be utilized to make azimuthally resolved formation resistivity measurements.

Well logging apparatus for obtaining azimuthally sensitive formation resistivity measurements

An apparatus for obtaining tool face angles on a rotating drill collar in substantially real time is disclosed. In one exemplary embodiment the apparatus includes a magnetoresistive magnetic field sensor deployed in a tool body. The apparatus further includes a programmed processor configured to calculate tool face angles in substantially real time from the magnetic field measurements. The programmed processor may optionally further be configured to correlate the calculated tool face angles with logging while drilling measurements for use in borehole imaging applications.

Measurement tool for obtaining tool face on a rotating drill collar

Series-resonant tuning of a downhole loop antenna

An azimuthally sensitive logging while drilling tool is disclosed. The tool may be suitable, for example, to measure azimuthal variations of electrical properties of a subterranean formation. The tool includes at least one transmitter disposed to transmit electromagnetic energy and a longitudinally spaced receiver array. The receiver array includes a plurality of discrete magnetic field sensors deployed about a circumference of the tool body. In one exemplary embodiment, the tool includes six or more magnetic field sensors selected from either giant magnetoresistive sensors or anisotropic magnetoresistive sensors.

Azimuthally sensitive receiver array for an electromagnetic measurement tool

Fluid property sensors and associated methods of calibrating sensors in a well provide enhanced well monitoring and control. In one described embodiment, an external venturi flowmeter is utilized to determine a flow rate of fluid from a zone into a tubing string, independent of flow into the tubing string of fluid produced from any upstream zone. In another described embodiment, a gamma ray fluid density sensor utilizes a unique combination of gamma ray sources and detectors to determine a density of fluid flowing through a tubing string. In yet another embodiment, external tubing string sensors are used to determine properties of fluid from a zone into a tubing string, independent of flow into the tubing string of fluid produced from any upstream zone. In still another embodiment, sensor systems for multiple independently produced zones are calibrated.

Fluid property sensors and associated methods of calibrating sensors in a subterranean well

A method and apparatus for measuring properties of fluid flowing through a bore, using a signal transmitted substantially perpendicularly to the direction of flow. A preferred embodiment uses a pair of acoustic transducers mounted in the annular body of the fluid conduit. The tool is constructed so as to be able to operate for a period of years in a downhole environment without maintenance or replacement. An transducer is also described that is adapted to fit within the dimensions of an annular body without suffering a reduction in the length of the transducer backing.

Acoustic transducer system for monitoring well production

A method and apparatus are disclosed for correcting erroneous downhole resistivity measurements. In particular, capacitive coupling downhole leads to erroneous resistivity readings. The invention compensates for such coupling by measuring a survey voltage between the resistivity tool voltage and a reference voltage on the wireline cable. A correction voltage is measured between a point on the armor around the wireline cable and the reference voltage. The characteristics of a transmission wireline used at a specific site are measured and are combined with the measured downhole correction voltage and survey voltage to determine more accurately formation resistivity.

Method of compensating laterlog measurements for perturbation of survey voltage by cable armor voltage

An electric coupling for two electric circuits in a well includes an electric contact and a contact receiver connected to respective ones of the circuits so that a contact/receiver pair is formed when the contact and receiver are moved together The receiver is sealed by a sealing member. The sealing member is disposed so that it is penetrated by the contact when the contact and receiver are moved together. A coupling including two such pairs is preferably used to connect two electric wires in the well to form a current conductive loop linking two electric coils. One of the coils is adapted to be moved in the well relative to the other coil which is adapted to be fixed in the well. In a preferred embodiment, one coil is on a wireline tool and the other coil is on a downhole tool. The current conductive path established across an intervening space between the tools is electrically insulated from the bodies of the tools and preferably has a resistance sufficiently low that the current conductive path is not effectively short-circuited by fluid in the intervening space which the path crosses.

Apparatus and method for communicating electrical signals in a well,

In an induction logging system supported on a sonde, an improved received signal processing system is disclosed. The sonde supports transmitting and receiving coils. The transmitter sends pulses at a frequency F.sub.1, normally 20 kilohertz. The receiver includes a frequency multiplier circuit driven with a frequency F.sub.2. The multiplier forms an output to a phase sensitive detector driven by a gating signal F.sub.3 where F.sub.3 =F.sub.1 -F.sub.2. This reduces error arising in the receiver.

Coherent detection system for use in induction well logging apparatus

In a dual guard type resistivity logging apparatus, the improvement having the preferred and illustrated form of a short guard electrode pair for making shallow resistivity measurements in a formation is disclosed; a long guard electrode pair is also incorporated for making deep resistivity measurements. The long and short guard pairs are driven by separate oscillators operating at the same frequency or at different frequencies. An electronic switch driven at a low frequency selectively connects the current emitting electrodes to a current return electrode for both long and short guard pair electrodes. The electronic switch empowers one measuring system to operate while the other is inoperative. The switching frequency at is typically of 20-40 Hertz. This enables both measuring systems to provide essentially continuous data in light of the dynamics of the use of such a log, and yet furnishes the two formation current signals wherein the operation of one resistivity measuring system does not interfere with the other resistivity system. A single electrode is used as the return current electrode, and a single voltage reference electrode on the tool is a reference electrode for voltage measurements by both measurement systems.

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Katy, TX, United States of America

Robert Anthony Moore