Schlumberger Technology Corporation

Westerngeco L.l.p.

Cengiz Esmersoy

Brian Oliver Clark

Dzevat Omeragic

Annabelle Kania

Tarek M Habashy

Jahir A Pabon

Martin E Poitzsch

Edward Nichols

David Lee Alumbaugh

Anthony Louis Collins

Jean-Michel Hache

Ralph Michael D'Angelo

Raj Banerjee

William Brian Underhill

Pierre Henri Campanac

Peter Gerhard Tilke

Maurice Nessim

Andrew Hawthorn

Chaur-Jian Hsu

Lennox Reid

Ralf Heidler

Jeffrey Spath

Steven F Crary

Sudhendu Kashikar

Jianchun Dai

Ruvinda Gunawardana

Nader Dutta

R K Michael Thambynayagam

Gregory P Grove

Jeffrey B Aron

Ling Duan

Richard D Joyce

Christopher Hopkins

H Charles Straub

Darryl Grigor

A drill string is disposed in the borehole having a BHA and a drill bit advancing the borehole. Among other BHA components, including a telemetry unit and a data acquisition unit, in a surface-to-borehole configuration a receiver (or receiver array) is positioned immediately proximate the drill bit in the borehole, while a source (or source array) is positioned at the Earth's surface. Alternatively, in a borehole-to-surface configuration the source may be positioned immediately proximate the drill bit in the borehole while a receiver (or receiver array) is positioned at the surface. The surface-to-borehole, or borehole-to-surface, system enables an electromagnetic look about while drilling operations are underway.

Systems and methods for electromagnetic detection of a formation anomaly from a near bit location while drilling

Techniques for estimating velocity ahead of a drill bit include generating seismic waves at a surface from at least two different source positions in the vicinity of a borehole, receiving seismic waves reflected from a reflector ahead of the drill bit at one or more locations in the borehole, determining travel times of the seismic waves received at the one or more locations in the borehole, and inverting the travel times to determine a velocity of a formation ahead of the drill bit. One embodiment includes transforming the velocity into pore pressure of the formation.

Real-time velocity and pore-pressure prediction ahead of drill bit

A method for water monitoring about a deviated well is disclosed. The method includes positioning a series of electromagnetic (EM) receivers in a completed deviated wellbore, said receivers being spaced along substantially the length of the well located in a region of a reservoir to be monitored. The method also includes positioning an electromagnetic (EM) source at a first Earth surface location. Then the EM source is activated for a first survey measurement of the reservoir, and an EM field detected at each EM receiver is recorded. The EM source is moved to a second Earth surface location, and activated for a second survey measurement of the reservoir, and an EM field detected at each EM receiver is recorded. From the first and second survey measurements at each of the receivers, an inversion is performed to determine position of water about (and specifically below) the horizontal well.

Electromagnetic surface-to-borehole look around systems and methods of monitoring in horizontal wells

A method to predict tars and tar sands in petroleum exploration and production in a subsurface volume by building a viscoelastic property model of the volume using rock behavior including tars together with seismic inversion to derive a lithology volume identifying tars.

Tar estimation

A system and method for performing an adaptive drilling operation is provided. The method involves obtaining data prior to drilling, constructing a base model with a base model unit from data obtained prior to drilling, constructing an overburden posterior model with an overburden model unit using the base model and data obtained from overburden drilling, constructing a reservoir posterior model with a reservoir model unit using the overburden posterior model and the data obtained from reservoir drilling and updating drilling operation based on the models.

System and method for performing an adaptive drilling operation

Methods are disclosed to predict pore pressure ahead of the drill bit while drilling a borehole through subsurface regions.

Multi-physics inversion processing to predict pore pressure ahead of the drill bit

Techniques are presented for determining the drift of a clock adapted for subsurface disposal. Seismic signals are transmitted through the subsurface medium from an uphole location at selected times, acoustic signals associated with the transmitted seismic signals are received with acoustic sensors at identified downhole locations. First and second transit times for acoustic signals received at an identified downhole reference location are determined using the clock. A time difference between the first and second signal transit times at the reference point is calculated to determine the clock drift.

System and method for determining downhole clock drift

An electromagnetic well logging instrument is disclosed which includes at least one transmitter antenna oriented to have at least some magnetic dipole moment component transverse to an axis of the instrument. The instrument includes at least two receiver antennas oriented to have at least some magnetic dipole moment component transverse to the axis and parallel to the magnetic dipole moment component of the at least one transmitter antenna. The at least two receiver antennas are axially spaced apart from the transmitter antenna so that a response of the instrument to the transverse magnetic dipole moment component is axially substantially on one side of a more distant spaced one of the at least two receiver antennas.

Electromagnetic resistivity logging instrument with transverse magnetic dipole component antennas providing axially extended response

In one aspect, the invention involves an acoustic logging tool for performing acoustic investigations of subsurface geological formations. In one embodiment, the tool comprises a generally longitudinally extending tool body adapted for positioning in a borehole. At least one transmitter is mounted on the tool body to emit acoustic energy. At least one receiver is also mounted on the tool body at a location axially displaced from the at least one transmitter. The receiver is adapted to receive acoustic energy. An attenuator is also positioned along the body and includes at least one cavity having a plurality of particles disposed therein. The attenuator as disclosed herein may be applied to other logging tools for protecting tool components and enhancing measurement quality. Methods for attenuating acoustic energy transmitted through the body of an acoustic logging tool or other logging tools are also disclosed.

Structures and methods for damping tool waves particularly for acoustic logging tools

A clock system is disclosed which includes a dual mode oscillator crystal having a first output having a frequency related to a temperature of the oscillator crystal and a second output having a frequency substantially stable with respect to temperature. The clock includes a temperature maintenance device. The temperature maintenance device and the oscillator crystal are disposed in a thermally insulated chamber. The clock includes a processor operatively coupled to the temperature maintenance device and the oscillator crystal. The processor is adapted to operate the temperature maintenance device so as to maintain a temperature of the chamber within a predetermined range. The processor is adapted to calculate a substantially constant frequency clock signal from the second output and a ratio of the frequency of the first output with respect to the frequency of the second output.

Self-compensating ovenized clock adapted for wellbore applications

A method is disclosed for determining a position of a wellbore with respect to layer boundaries in earth formations. The method includes projecting a trajectory of the wellbore onto an initial model of the earth formations, selecting a segment of the trajectory and calculating along the segment expected responses of a well logging instrument. Differences between the expected responses and responses measured by the instrument along the segment are determined. The model is adjusted, the expected responses are recalculated and the differences are again determined. These are repeated until the differences fall below a selected threshold. In one embodiment, the trajectory of the wellbore can be adjusted to remain within a selected distance of a selected one of the layer boundaries.

Method for calculating a distance between a well logging instrument and a formation boundary by inversion processing measurements from the logging instrument

An apparatus for communication with a downhole tool includes uphole and downhole equipment. The uphole equipment includes a signal source (or array) coupled to a programmable triggering system and a precision clock. Optionally, the uphole equipment may include receivers for capturing reference signals near the source and may include telemetry equipment for receiving MWD signals from the downhole equipment. The downhole equipment includes one or more receivers, signal processing equipment, memory, and a precision clock. Optionally, the downhole equipment also includes MWD telemetry equipment for transmitting data to the surface. The methods of the invention include, but are not limited to, synchronizing the recordation of signals detected downhole with the firing of the signal source and processing the recorded signals to eliminate useless information. The methods of the invention present several techniques for true source signal recognition whereby actual signal information is extracted from the recordings of the receivers so that the ultimate stored data is compact and virtually 100% useful. This elimination of useless data conserves valuable telemetry time and/or enables longer operation of the apparatus before tripping out to retrieve stored data by using memory efficiently.

Method and apparatus for communication with a downhole tool

There are many natural pauses during rotary drilling operations where a portion of the drill string remains stationary. Pauses include drill pipe connections, circulating time, and fishing operations. These pauses are used to obtain formation evaluation measurements that take a long time or that benefit from a quiet environment, as opposed to the naturally noisy drilling environment. Various techniques that are sensitive to the mud flow, weight-on-bit, or motion of the drill string may be used alone or in combination to identify the drilling mode and control the data acquisition sequence.

Apparatus and method for determining a drilling mode to optimize formation evaluation measurements

Parametric inversion is used to advantage in a technique and apparatus for borehole logging to determine properties of anisotropic formations, and a dispersion function that varies with frequency is used in the modeling of the formations. An embodiment of the method includes the following steps: providing a logging device that is moveable through the borehole; exciting a sonic source at a transmitter location on the logging device to establish flexural waves in the surrounding formations; measuring at each of a plurality of receiver locations on the logging device, which are spaced at a respective plurality of distances from the transmitter location, orthogonal wave components of split flexural waves that have travelled through the formations; computing, for each of the plurality of distances and for multiple frequencies, model orthogonal wave components which would result from the superposition of model split-flexural waves having selected wave parameters including respective fast and slow model slownesses which are variable functions of frequency and model polarizations; determining an error value which depends on the differences, at each of the plurality of receiver locations, between measured wave components and the model composite waves; modifying the model parameters; iteratively repeating the computing, determining, and modifying steps to reduce the error; and storing the ultimately modified model parameters as being indicative of properties of the formations.

Dipole shear anisotropy logging

A technique is disclosed for determining properties of an anisotropic elastic medium, such as earth formations. Acoustic waves are established in the medium. At several spaced locations in the medium, there are measured at least two orthogonal components of acoustic waves which have propagated through the medium. For positions corresponding to a plurality of adjacent ones of the spaced locations, there are computed model composite waves which would result from the superposition of a plurality of model acoustic waves, each having selected model parameters. The model acoustic waves include a plurality of model acoustic shear waves and the model parameters include model velocities and model polarizations for each of the model acoustic shear waves. An error value is determined, the error value depending on the differences, at each of the plurality of adjacent ones of the locations, between measured wave components and the model composite wave. The model parameters are then modified. The computing, determining, and modifying steps are then iteratively repeated to reduce the error. The ultimately modified model parameters are stored as being indicative of properties of the medium in the region of at least one of the plurality of locations.

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Sugar Land, TX, United States of America

Cengiz Esmersoy