Schlumberger Technology Corporation

David Linton Johnson

Jahir A Pabon

Bikash Kumar Sinha

Peter T Wu

Ralph Michael D'Angelo

Alain M Dumont

Pierre Henri Campanac

Toru Ikegami

Sergio Kostek

Oliver Clinton Mullins

Chung Lung Chang

Tarek M Habashy

Henri-Pierre Valero

Smaine Zeroug

Takeshi Endo

Hitoshi Sugiyama

Lucian K Johnston

Hiroshi Hori

Kambiz A Safinya

Raghu Ramamoorthy

Andrew Hawthorn

Gale Hyslip Gustavson

Bertrand Du Castel

Abderrhamane Ounadjela

Toshihiro Kinoshita

William F Murphy

Kenneth William Winkler

Vivian Pistre

Christoph Klieber

Jayanth R Banavar

Brian E Hornby

David P Madio

Sidney Robert Nagel

Romain C A Prioul

Atsushi Saito

Martin G Lüling

Andrew Norris

Chuar-Jian Hsu

Donald C Schumacher

A downhole tool system may include a Stoneley wave emitter, located in a downhole tool, designed to emit Stoneley waves into a borehole. The downhole tool system may include one or more Stoneley wave sensors, located in the downhole tool, and a processor. The processor may be designed to receive signals from the one or more Stoneley wave sensors based on the detection of the Stoneley waves. The processor may use the signals to obtain a temporal measurement of the Stoneley waves. Based at least in part on the temporal measurement, the processor may calculate a distance from the downhole tool or a bottom-hole assembly to the bottom of the borehole.

Systems and methods for using Stoneley waves for bottom-hole proximity detection

A downhole acoustic logging tool includes at least one acoustic transmitter and first and second arrays of acoustic receivers deployed on a tool body. The first array of acoustic receivers includes a plurality of axially spaced apart acoustic receivers and the second array of acoustic receivers includes a plurality of circumferentially spaced apart acoustic receivers. A method for making downhole acoustic logging measurements of a subterranean formation includes causing an acoustic logging tool to obtain axial acoustic logging measurements and circumferential acoustic logging measurements. The axial acoustic logging measurements and the circumferential acoustic logging measurements are then processed to compute each of five elastic constants of a transversely isotropic medium.

Downhole elastic anisotropy measurements

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

Methods and apparatus to determine slowness of drilling fluid in an annulus are described. An example method of determining slowness of drilling fluid in an annulus of a borehole in a formation includes obtaining a first slowness of the drilling fluid in the annulus and measuring with a downhole tool slownesses of the formation based on the first slowness. The example method also includes determining a first compressibility of the formation based on the slownesses of the formation and a first density of the formation and calculating a second density and a second compressibility of the drilling fluid in the annulus based on the first density and the first compressibility. The method also includes calculating a second slowness of the drilling fluid in the annulus based on the second density and the second compressibility.

Methods and apparatus to determine slowness of drilling fluid in an annulus

Methods and apparatus to optimize parameters in a downhole environment are described. An example downhole tool includes a transmitter to transmit a signal into a subterranean formation and one or more receivers to receive at least a portion of the acoustic signal. The downhole tool also includes a processor configured to determine slownesses of different acoustic modes at a frequency of the signal received. Each of the slownesses is associated with a first parameter and a second parameter. The different acoustic modes have substantially different sensitivities to at least one of the first parameter or the second parameter. The processor to invert the determined slownesses of the different acoustic modes to determine an optimized value of the first parameter and an optimized value of the second parameter.

Methods and apparatus to optimize parameters in a downhole environment

A method for estimating formation permeability from measured sonic wave Stoneley attributes and particularly the Stoneley attributes of slowness (DTst) and attenuation (ATTst), taking into consideration the existence of a heavy walled drill collar at the end of the drill string and the relative lack of borehole mud cake during a drilling operation. In the subject LWD application a real-time qualitative indication for fracture and permeable zones is estimated from Stoneley measurements. This information is useful to a driller to make important timely decisions about drilling and completion programs.

Method for permeable zone detection

A method for determining on a real time logging while drilling (LWD) basis gas within earth formations traversed by a borehole. Continuous LWD acoustic measurements are recorded and processed including coherent energy and attenuation attributes to detect downhole gas zones and kick during drilling operations.

Method for gas zone detection using sonic wave attributes

A method and system for fluid characterization in an underground formation surrounding a borehole are provided. Acoustic signals are transmitted and received in the borehole. The received acoustic signals are processed to obtain at least one attribute of formation mobility. Formation fluid is characterized based on a change of the at least one attribute. A decision is made based on the characterization output.

Fluid characterization from acoustic logging data

Certain embodiments are directed to devices, systems and methods for determining a penetration depth of an induced oscillation in a porous medium. In certain examples, the devices, systems and methods are designed to detect a magnetic resonance signal in the presence of an induced oscillatory fluid flow in a porous medium to determine penetration depth of the induced oscillation in the porous medium. In some examples, the mobility of a fluid in the porous medium may be determined from the determined penetration depth.

Devices, systems and methods for assessing porous media properties

An acoustic logging tool sleeve with a preferably discontinuous, alternating structure that is acoustically opaque in some zones, and acoustically transparent in others. The sleeve may be modular, with several stages connected together. The multiple stages provide a sleeve that may be useful with a variety of borehole logging tools to reduce or eliminate the transmission of noise to the receiving elements.

Acoustic logging tool sleeve

Tube waves are used to locate and characterize a solids deposit inside a fluid-filled pipe. An acoustic tube wave pulse is transmitted along the pipe. On encountering a solids deposit, the tube wave pulse is perturbed and partially reflected by changes in the boundary conditions between the fluid and the pipe to produce two deposit-modified acoustic waves. One is a perturbed wave travelling in the same direction as the tube wave pulse. The other is a reflected wave travelling in the opposite direction. One of these deposit-modified acoustic waves is received to produce an acoustic signal. Accumulated acoustic signals are processed by Fast-Fourier Transform to produce frequency-based digital data. Phase data from the frequency-based digital data is inverted to produce slowness spectrum data. Power data from the frequency-based digital data is inverted to produce attenuation spectrum data. Spectrum data is used to locate a solids deposit in the pipe. Inversion model processing of the spectrum data is used to estimate solids deposit thickness and type.

Assessing a solids deposit in an oilfield pipe

An acoustical method of determining the spherical, or vuggy, porosity in carbonate rock formations, as a function of shear modulus. Total porosity and shear modulus of the formation is measured. Then the intrinsic granular porosity, dry bulk modulus, and spherical porosity are calculated. The carbonate rock is modeled, consisting of a primary host medium composed of carbonate grains with intergranular porosity between them. The model is easily modified to account for the case of intercrystalline microporosity existing within the grains, in addition to the intergranular porosity between them.

Porosity estimation method in carbonate rock

An attenuator for use in attenuating tube waves in a borehole includes a body formed from a permeable material having a rigid matrix which can be saturated with fluid. In its simplest form, the attenuator is one or more cylindrical bodies as part of a borehole acoustic logging system. Alternatively, the shape, particularly at the end regions, can be modified to reduce the amount of reflection of tube waves in the borehole. Another attenuator includes a body for placement in a borehole formed from an attenuating material, the shape of the body being selected such that the change in impedance experienced by acoustic waves in the borehole is gradual rather than abrupt. One particularly preferred shape for the body comprises one in which the diameter is greatest towards the center of the body, for example the shape formed by two cones placed base to base, or a cylinder having conically tapered ends. A number of bodies can be used where appropriate.

Attentuator for borehole acoustic waves

Methods and apparatus are provided for determining an indication of a nonlinear property of the formation. A sonic tool is used in a borehole to generate a signal having multiple cycles of a wave of a predetermined frequency. The amplitude of a tube wave resulting from the signal is measured. The measured amplitude is then used to determine an indication of the nonlinearity of the formation according to a relationship which relates the measured amplitude to the amplitude of a second harmonic tube wave which is generated in the borehole by the tube wave of the predetermined frequency due to the nonlinear property of the formation. The indication of nonlinearity may then be utilized to give an indication of the relative consolidation of the formation surrounding the borehole.

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Somerville, MA, United States of America

David Linton Johnson