Schlumberger Technology Corporation

Oliden Technology, LLC

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Jian Yang

Jean P Seydoux

Qiming Li

Jacques R Tabanou

Reza Taherian

Emmanuel Legendre

David Lee Alumbaugh

James P Brady

Andrew Hawthorn

John Paul Horkowitz

Dzevat Omeragic

Gerald N Minerbo

Sofia N Davydycheva

Jan Smits

Mark A Fredette

Helene Claire Climent

Chengbing Liu

Libo Yang

Mark Kuchenbecker

Bernadette Tabanou, Legal Representative

Yanqing Zeng

The present disclosure describes various antenna assemblies, each antenna coil being disposed about a tool body section in an antenna pathway. The antenna pathway passes through alternating grooves and lands. In each embodiment, at least one of the grooves is disposed in the tool body section at a non-axial direction relative to the longitudinal axis of the tool body section. In an embodiment, the antenna coil is an axial coil or a tilted coil. Additional grooves oriented at axial direction may be disposed on the tool body section. Each of the antenna assemblies disclosed may be employed in an electromagnetic logging tool for providing directional measurements while drilling.

Antenna, tool, and methods for directional electromagnetic well logging

A downhole electromagnetic logging tool having two or more antenna groups spaced along a longitudinal axis of the logging tool, each antenna group having one antenna or multiple antennas proximally located or collocated, each antenna group having at least one tilted antenna, at least one antenna group having, in addition to the tilted antenna, at least one transverse or axial antenna, and any given pair of antenna groups comprising at least four antennas is disclosed. The logging tool is disposed in a wellbore penetrating a formation and, while rotating, measures a tool rotation angle, transmits an electromagnetic signal from one antenna group, and receives the electromagnetic signal with another antenna group. Elements of an electromagnetic coupling tensor are determined using the received electromagnetic signal and the measured tool rotation angle, and properties of the formation using one or more elements of the determined electromagnetic coupling tensor are inferred.

Determining a full electromagnetic coupling tensor using multiple antennas

A downhole electromagnetic modular system has two or more antenna modules incorporated into a drill string, each antenna module comprising an antenna sub and an antenna. The antenna modules may be spaced apart by one or more spacer modules, battery modules, spacer-battery modules, and/or downhole tools. The connected modules (and/or downhole tools) provide an electrical pathway throughout the modular system. An antenna module may have an inner connector formed on its antenna sub between the antenna of that antenna module and a retainer of that antenna sub. An antenna module may have two antenna groups located towards opposite ends of the antenna module and spaced apart by more than half the length of the antenna module. If an antenna group has more than one antenna, those antennas may be co-located or in proximity to one another. A probe may be held fixed by the retainer of the inner pin connector.

Modular system for geosteering and formation evaluation

The present disclosure describes various antenna assemblies, each antenna coil being disposed about a tool body section in an antenna pathway. The antenna pathway passes through alternating grooves and lands. At least one of the grooves is disposed in the tool body section at a non-axial direction relative to the longitudinal axis of the tool body section. The antenna coil may be an axial coil or a tilted coil. Additional grooves oriented at axial direction may be disposed on the tool body section. Various methods include acquiring a plurality of data pairs using one or more antenna coils, each data pair comprising an induced signal at a receiver and a corresponding toolface angle using a tool including at least one antenna assembly, to generate a measurement including obtaining information about the directionality of the formation by calculating areas of an induced signal function approximated by the plurality of data pairs.

Method and tool for directional electromagnetic well logging

Formation properties in a vertical section of a wellbore are determined by considering the vertical section as consisting of one or more segments. Measurements are obtained with a directional resistivity tool at two or more measurement stations within each segment for which the complex 0harmonic coefficients for the obtained measurements are non-trivially different from one another. For each such segment, the phase shift and attenuation are determined using the complex 0harmonic coefficients obtained for that segment and an inversion is performed for the formation properties using the determined phase shift and attenuation for that segment. Formation properties for that segment may be output to a display or memory storage device. For certain segments, one or more gain factors may be obtained. The gain factors are used to correct the measured voltages for certain neighboring segments and the corrected voltages inverted to obtain anisotropy and formation structure.

Determining resistivity anisotropy and formation structure for vertical wellbore sections

The present disclosure relates to a method to produce an image of a subsurface formation using directional measurements. A downhole logging tool having one or more transmitters and one or more receivers, and being capable of making directional measurement, is used to measure the voltage in a particular receiver due to a particular transmitter for one or more transmitter/receiver pairs, at least one of those voltage measurements being a directional measurement. The complex (phasor) voltage recorded on a receiver coil is divided by the complex voltage recorded at another reference receiver coil. Alternatively, we can use the ratio of a receiver voltage at a particular rotation angle of the tool divided by the voltage on the same receiver when the tool has rotated by an angle of 180 degrees. The information in those ratios is combined to produce images of the resistivity of the subsurface formation surrounding the tool.

Imaging using directional resistivity measurements

A method for logging subsurface formations penetrated by a wellbore include measuring electromagnetic properties of the formations using electromagnetic fields having a magnetic dipole axis parallel to a logging tool axis Electromagnetic properties of the formations are also measured using electromagnetic fields having a magnetic dipole axis oblique to the logging tool axis. A horizontal resistivity of the formations is determined from the parallel dipole axis measurements. A vertical resistivity, formation layer boundaries and a dip angle of the formations are determined from the oblique dipole axis measurements.

Anisotropy processing in low angle wells

A directional antenna, system and method are provided. The methods include acquiring a plurality of data pairs, each data pair comprising an induced signal at a receiver and a corresponding toolface angle using a tool including at least one antenna assembly, as described herein. It further discloses a method to generate a measurement containing information about the directionality of the formation by calculating areas of an induced signal function approximated by the plurality of data pairs.

A technique provides a methodology for improving surveys of subterranean regions. The methodology comprises estimating macro anisotropy and an intrinsic or micro anisotropy of an overburden. A surface electromagnetic survey is conducted, and the data from the survey is inverted based on or including information gained from estimating the macro anisotropy and/or intrinsic anisotropy. A processor system can be used to conduct the inversion with the adjustments for anisotropy to improve the information provided by the survey.

System and method for improving surface electromagnetic surveys

The present disclosure relates to a method to determine the phase of a signal when transmitter and receiver circuits use separate clocks. A discrepancy between the separate clocks is determined, as is a correction factor between the separate clocks. The phase is determined using a measured time of arrival of the signal, the determined discrepancy, and the determined correction factor. A drift factor and an expected start time of a pulse sequence may be used to determine the discrepancy. A start time of a pulse within the pulse sequence is determined and used to determine the correction factor. The method works by either absolute synchronization of the separate clocks, or by making the measurements independent of clock synchronization.

Measuring the phase of received signals

A method and a downhole tool determine one or more parameters of a formation traversed by a borehole where at least a portion of the formation has substantially parallel boundaries. A tool is disposed in the borehole that includes a transmitter having a dipole moment at an angle &#x3b8;with respect to a longitudinal axis of the tool, a receiver having a dipole moment at an angle &#x3b8;with respect to the longitudinal axis of the tool and a rotational position indicator. The transmitter-receiver pair transmits an electromagnetic signal while rotating the tool, receives the electromagnetic signal to produce a measured signal, and determine(s) the formation parameters for the portion of the formation having substantially parallel boundaries based on the measured signal.

Determining formation parameters using electromagnetic coupling components

A system and method to determine earth formation properties by positioning a logging tool within a wellbore in the earth formation, the logging tool having a tool rotation axis and a first, a second, and a third tilted transmitter coil, and a tilted receiver coil; rotating the logging tool about the tool rotation axis; energizing each transmitter coil; measuring a coupling signal between each transmitter coil and the receiver coil for a plurality of angles of rotation; determining a coupling tensor; and determining the earth formation properties using the coupling tensor.

Determining properties of earth formations using the electromagnetic coupling tensor

The present disclosure relates to a method to produce an image of a subsurface formation using directional measurements. A downhole logging tool having one or more transmitters and one or more receivers, and being capable of making directional measurements, is used to measure the voltage in a particular receiver due to a particular transmitter for one or more transmitter/receiver pairs, at least one of those voltage measurements being a directional measurement. The complex (phasor) voltage recorded on a receiver coil is divided by the complex voltage recorded at another reference receiver coil. Alternatively, we can use the ratio of a receiver voltage at a particular rotation angle of the tool divided by the voltage on the same receiver when the tool has rotated by an angle of 180 degrees. The information in those ratios is combined to produce images of the resistivity of the subsurface formation surrounding the tool.

Growing community of inventors

Sugar Land, TX, United States of America

Jian Yang