Schlumberger Technology Corporation

Miguel F Pabon

David B Ayers

Fernando Garcia Osuna

Brian Oliver Clark

Jaideva C Goswami

Jan Stefan Morley

Fernando Garcia-Osuna

Roger Griffiths

Mark A Fredette

Wade D DuPree

Mark Flaum

W Robert Sloan

Jean-Pierre Masson

Scott Ritter

Betty Rong

A method and apparatus are provided for making directional measurements toward a formation of different resistivity that is proximate to the borehole, but which is not penetrated by the borehole. The methods and apparatus include the use of at least one insulated gap and at least one magnetometer positioned within a non-magnetic housing that is disposed within a non-magnetic tubular. An electric current is applied across the insulated gap, which results in current leaking into the surrounding formations. When a formation of contrasting resistivity is proximate to the logging apparatus, the magnetometer detects a secondary magnetic field due to the contrasting formation. The direction of the secondary magnetic field can be used to determine the direction to the contrasting formation. The magnitude of the secondary magnetic field can be used to determine the distance position to the contrasting formation.

Method and apparatus for directional well logging

A method for drilling a well includes applying a current across a drill collar that surrounds an internal magnetometer. The current travels across the drill collar and along one or more other current paths to return to the drill collar. The method also includes using the magnetometer to measure magnetic fields due to the current being applied across the drill collar and the current across one or more other current paths while the drill collar is disposed at a first angle of rotation and rotating the drill collar to a second angle of rotation. The method further includes measuring the magnetic fields using the internal magnetometer while the drill collar is disposed at the second angle of rotation and determining a relationship between the current across the drill collar and a portion of the magnetic fields due to the current across the drill collar measurable by the internal magnetometer.

Method for calibrating current and magnetic fields across a drill collar

Acoustic communication apparatus for use with downhole tools are described. An example acoustic communication apparatus for use in a wellbore includes a first acoustic transducer to generate first acoustic signals. The first acoustic transducer is mounted in an interior of a first drill collar to transmit the first acoustic signals via at least a portion of a body of a drillstring or a mud channel within the drillstring to a second drill collar. Additionally, the example acoustic communication apparatus includes a first receiver mounted to the first drill collar to receive second acoustic signals transmitted from the second drill collar.

Acoustic communication apparatus for use with downhole tools

A downhole tool for subsurface disposal is provided. The tool comprises an elongated tool body, an enclosure attached to an exterior surface of the tool body. The enclosure comprises at least one transducer disposed at an angle with respect to a longitudinal axis of the enclosure, and an electronics board coupled to and disposed adjacent to the at least one transducer. The enclosure also defines an internal cavity, and the internal cavity contains a fluid for insulating the at least one transducer from a downhole environment. The fluid is in direct contact with the at least one transducer and the electronics board.

Enclosures for containing transducers and electronics on a downhole tool

An enclosure for housing a transducer and electronics for disposal on a downhole tool. A transducer is disposed at an angle with respect to a longitudinal axis of the enclosure, wherein the enclosure contains a fluid surrounding the transducer. Enclosures also include transducers linked to motor means for selective rotation of the transducers within the enclosure. Enclosures with transducer arrays for phased or targeted signal transmission/detection.

A measurement package for disposal on an apparatus such as a downhole tool or a tool like device. The measurement package including an enclosure, a first acoustic transducer housed within the enclosure, a second acoustic transducer housed within the enclosure and electronics housed within the enclosure that is in communication with the first and second transducers. Further, an acoustic transmitter and receivers can be disposed at an angle with respect to a longitudinal axis of the enclosure. The enclosure can contain attenuative material surrounding the transmitter and receivers, and electronics for controlling the transmitter and receivers and communicating with the downhole tool.

The disclosure relates to methods and apparatus for determining the velocity of an ultrasound pulse in drilling fluids in downhole environments. A method for determining a velocity of ultrasound propagation in a drilling fluid in a downhole environment includes emitting an ultrasound pulse into the drilling fluid in a borehole using a first ultrasound transducer (); detecting the ultrasound pulse after the ultrasound pulse has traveled a distance (d); determining a travel time (t) required for the ultrasound pulse to travel the distance (d); and determining the velocity of ultrasound propagation from the known distance (d) and the travel time (t). An apparatus for determining a velocity of ultrasound propagation in a drilling fluid in a downhole environment includes a first ultrasound transducer () disposed on a tool; and a circuitry () for controlling a timing of an ultrasound pulse transmitted by the first ultrasound transducer () and for measuring a time lapse between ultrasound transmission and detection after the ultrasound pulse has traveled a distance (d).

Method and apparatus for ultrasound velocity measurements in drilling fluids

A borehole caliper tool includes a tool body, a bow spring flexibly coupled to the tool body, a target coupled to the bow spring, and an ultrasonic transducer coupled to the tool body, wherein in operation the ultrasonic transducer transmits an acoustic pulse to the target and receives an echo of the acoustic pulse from the target.

Borehole caliper tool using ultrasonic transducer

Methods for processing ultrasonic signal data to evaluate subsurface properties and tool orientation. Acoustic signals are transmitted into a plurality of azimuthal borehole positions. Formation echo signal transit time distributions are then determined in a plurality of azimuthal sectors for the acoustic signals. Front face echo signal transit times are also measured and farther-mode and closer-mode transit times are determined for the distribution of formation echo signals. Farther and closer tool standoffs are determined for the azimuthal sectors and a borehole diameter is determined from a summation including standoffs in opposing sectors. The standoffs are also used to determine a preferential tool position.

Subsurface borehole evaluation and downhole tool position determination methods

An ultrasonic sensor assembly for measuring the diameter of a well while it is being drilled is provided. The sensor assembly includes a stack including an inner sound absorbing backing element, a piezoelectric ceramic disk transducer stacked outwardly adjacent the backing element, and a matching layer, preferable made of PEEK and disposed outwardly adjacent the transducer. The layers of the stack are provided within a cavity of a metal cup and are maintained in position by a flexible diaphragm preferably made of PEEK. The diaphragm is sealed with an O-ring. A window, also preferably made of PEEK, is provided against the diaphragm and is held against the diaphragm by a spring. This arrangement acoustically couples the diaphragm to the stack and improves signal recovery. The diaphragm and O-ring form a hydraulic seal between fluid/mud in the well and the stack, and operate to retain the layers of the stack. Also, the diaphragm deforms to permit the stack to move when transmitting or receiving, and maintains an acoustic coupling between the stack and the window.

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Katy, TX, United States of America

Miguel F Pabon