Schlumberger Technology Corporation

Toru Ikegami

Bikash Kumar Sinha

Jahir A Pabon

David Linton Johnson

Fernando Garcia-Osuna

Shinji Yoneshima

Nicolas Goujon

Julian Edward Kragh

Emmanuel Coste

Shu-Kong Chang

Clement Kostov

Masafumi Fukuhara

Oeyvind Teigen

Vivian Pistre

Marwan Charara

Philip A F Christie

Tatsuki Endo

Yoko Morikami

Sogo Kuroiwa

Takashi Yoshikawa

Ryo Imai

A technique facilitates seismic exploration by identifying time differences between clocks employed during the seismic exploration. According to an embodiment, a seismic signal is output from a source and has an incident wave and a reflected wave. The seismic signal is received by at least one receiver which outputs data to a control system. The control system is employed to compare a symmetry of the propagation of the incident wave and the reflected wave. The symmetry data is then used to determine a temporal change of the time base of the at least one receiver.

System and methodology for identifying time differences between clocks during seismic exploration

A technique facilitates geophysical exploration by employing a tool wrapped with an optical fiber. Additionally, an orientation sensor is coupled to the tool and is operable to provide data regarding orientation of the tool. A processing system, which may include an optical interrogation system, cooperates with the optical fiber and with the orientation sensor to obtain acoustic data. For example, the processing system collects tool orientation data and also strain data obtained from a location along the wrapped optical fiber. The strain data results from excitation of an acoustic signal from a suitable acoustic source.

Downhole acoustic wave sensing with optical fiber

A technique facilitates geophysical exploration and comprises deploying an optical fiber in a borehole formed in a formation. A seismic signal, e.g. seismic waves, is excited into the formation, and an optical interrogation system is used to obtain data at a plurality of fixed, sampling locations along the optical fiber. The data is processed to determine features in the formation. Based on the processed data, updated sampling locations are selected along the optical fiber to enable further analysis of the features of interest.

Seismic sensing with optical fiber

A technique facilitates seismic wave detection with a seismic receiver. The seismic receiver has a tool body, a vibrationally isolated sensor package mounted in the tool body, and a plurality of contact shoes. The contact shoes are mounted around the sensor package in a distribution which enables three-point contact with a surrounding wellbore wall regardless of the azimuthal orientation of the sensor package.

Seismic detector

A seismic sensor for a downhole tool positionable in a wellbore penetrating a subterranean formation. The seismic sensor includes a sensor housing, a bobbin supported in the sensor housing along an axis thereof, at least one coil wound about the bobbin (the coil movably supportable within the sensor housing by at least one spring), at least one magnet positionable about the bobbin to generate a magnetic field with the at least one coil whereby seismic vibrations are detectable, and a filler fluid disposed in the sensor housing to buoy the at least one coil whereby gravitational effects may be neutralized.

Downhole seismic sensor with filler fluid and method of using same

A sensor array is positionable in a wellbore penetrating a subterranean formation. The sensor array includes a plurality of seismic sensors disposable about a perimeter of the wellbore and coupleable to a signal measurer with a configuration to provide three component seismic signal measurement within the wellbore. At least two of the seismic sensors are located at different azimuthal angles relative to one another and oriented tangentially to a longitudinal axis of the wellbore so as to receive tangential components of wellbore seismic signals to the exclusion of longitudinal and radial components of the wellbore seismic signals.

Wellbore signal monitor with tangential seismic sensors for tube-wave noise reduction

Methods and apparatus facilitating radial profiling of shear slowness are disclosed. According to some aspects of the invention, acoustic tool bias is accounted for in the calculation of radial profiles. According so some aspects, acoustic tool bias is accounted for by replacing acoustic tool structure with a resonance-impedance model. The resonance-impedance modeling according to principles of the present invention is applicable to vertical, deviated, and horizontal boreholes.

Use of an effective tool model in sonic logging data processing

Neutrally-buoyant tools for seismic data collection are provided that may range from several hundred meters to several kilometers in length and have integrated sensors which move along with the borehole fluid in response to a passing seismic wave. The disclosure also provides methods of deploying neutrally-buoyant tools, which includes using a tractor, adding a weight or both to the tool in order to overcome the difficulty of lowering a neutrally buoyant tool into a borehole, and optionally occasionally clamping the tool to the borehole to alleviate tension in the tool. This disclosure also provides methods of acquiring seismic data, which involves positioning a neutrally-buoyant tool in a borehole such that the tool is able to move relatively freely along with the borehole fluid in response to a seismic wave passing through the fluid, firing a seismic source, and using the sensors to collect seismic data generated thereby.

Neutrally-buoyant borehole investigation tools and methods

A method for in-situ calibrating acoustic receivers while the tool is in an open or cased borehole or during a logging run in a borehole. The method and system facilitate calibrating the acoustic receivers while they are mounted to a downhole acoustic tool. Calibrating the acoustic receivers in situ provides more accurate results than previously available. The method and system provide separate compensation factors for the acoustic receivers at different frequencies and for different transmission sources. The separate compensation factors facilitate more accurate signal acquisition over a wider range of conditions.

Methods and systems for calibrating acoustic receivers

A method and system for calibrating acoustic receivers (). The method and system facilitate calibrating the acoustic receivers () while they are mounted to a downhole acoustic tool (). Calibrating the acoustic receivers () in situ provides more accurate results than previously available. The method and system provide separate compensation factors for the acoustic receivers () at different frequencies and for different transmission sources. The separate compensation factors facilitate more accurate signal acquisition over a wider range of conditions.

A logging system has a sonde in a borehole, which transmits sonic waves with one or more dipole sources to optimally excite dipole flexural mode sonic waves in the borehole. The system first determines the Airy frequency of the borehole. Then, the dipole sources are fired at a dipole firing frequency selected based on the Airy frequency.

Growing community of inventors

Machida, Japan

Toru Ikegami