Schlumberger Technology Corporation

Tom R Bratton

Bikash Kumar Sinha

Randy Koepsell

Tom Olsen

Benjamin Peter Jeffryes

Peter T Wu

Roberto Suarez-Rivera

Andrew Hawthorn

Thomas J Plona

John Walsh

John Adam Donald

Richard Anthony Birchwood

Claude Signer

Samer Alatrach

Romain C A Prioul

Randolph Koepsell

Peter Kaufman

J Adam Donald

Adam Donald

A method for performing wellbore operations of a field having a subterranean formation. The method includes determining, based on an image log of a wellbore penetrating the subterranean formation, a plurality of interpreted geological surfaces, identifying a plurality of estimated slickensides from the plurality of interpreted geological surfaces based on at least one pre-determined criterion, calculating, using a processor, a differential stress using a curvature model representing at least one mechanical unit defined by the plurality of estimated slickensides, generating a stress model using the differential stress, identifying a modeled wellbore stress-induced failure in response to a total stress value in the stress model exceeding a strength property of the subterranean formation, determining a difference between the modeled wellbore stress-induced failure and an observed stress-induced failure in the subterranean formation, and updating the stress model by adjusting the plurality of estimated slickensides to, in turn, adjust the difference.

Determining differential stress based on formation curvature and mechanical units using borehole logs

To determine properties of a subterranean structure, information relating to dipole compressional data is collected based on measurements by a logging tool in a borehole. The information relating to the dipole compressional data is analyzed in multiple dimensions (e.g., multiple borehole axial planes) to determine the properties of the subterranean structure through which the borehole extends.

Method of using dipole compressional data to determine properties of a subterranean structure

A method for performing field operations is disclosed. The method includes obtaining a first set of acoustic radial profiles of a subterranean formation prior to induction of a fracture disposed about the wellbore, obtaining a second set of acoustic radial profiles of the subterranean formation subsequent to the induction of the fracture, comparing the first set of acoustic radial profiles and the second set of acoustic radial profiles based on a pre-determined criterion to generate a comparison result, determining, based on the comparison result, an orientation of one or more portions of the fracture, and adjusting the operations of the oilfield based on the orientation.

Determining fracture orientation using wellbore acoustic radial profiles

A method for determining properties of a subterranean formation. The method includes determining at least one characterization parameter based on wave velocity measurement data, determining a plurality of elastic coefficients based on the at least one characterization parameter using a plurality of equations, determining an anisotropic stress profile of the subterranean formations based on the stiffness matrix of the subterranean formation comprising the plurality of elastic coefficients wherein the elastic coefficients are approximated using the plurality of equations, and displaying the anisotropic stress profile of the subterranean formations.

Estimating horizontal stress from three-dimensional anisotropy

A method is disclosed for generating a wellsite design, comprising: designing a workflow for an Earth Model; building an initial Earth Model based on the workflow adapted for modeling drilling and completions operations in a hydrocarbon reservoir; calibrating the initial Earth Model thereby generating a calibrated Earth Model; and generating the wellsite design using the calibrated Earth Model.

Method for designing and optimizing drilling and completion operations in hydrocarbon reservoirs

A technique involves facilitating fracturing operations along a wellbore extending through a subterranean formation. A stress device is deployed in a wellbore and activated to engage a surrounding wall. The stress device can then be manipulated to create a reduced stress region in the formation at a desired location along the wellbore. The reduced stress region facilitates the controlled formation of a fracture in the formation at the desired location. Furthermore, the stress device can be moved and the process repeated at multiple locations along the wellbore.

Rock stress modification technique

Fracture- and stress-induced sonic anisotropy is distinguished using a combination of image and sonic logs. Borehole image and sonic logs are acquired via known techniques. Analysis of sonic data from monopole P- and S-waves, monopole Stoneley and cross-dipole shear sonic data in an anisotropic formation are used to estimate at least one compressional and two shear moduli, and the dipole fast shear direction. Fracture analysis of image logs enables determination of fracture types and geometrical properties. Geological and geomechanical analysis from image logs provide a priori discrimination of natural fractures and stress-induced fractures. A forward quantitative model of natural fracture- and stress-induced sonic anisotropy based on the knowledge of fracture properties interpreted from image logs allows the computation of the fast-shear azimuth and the difference in slowness between the fast- and slow-shear. The misfit between predicted and observed sonic measurements (i.e. fast-shear azimuth and slownesses) is then optimized in order to discriminate depth zones with an elastic medium as being influenced by the presence of open natural fractures, closed natural fractures and fractures induced by non-equal principal stress effects.

Discriminating natural fracture- and stress-induced sonic anisotropy using a combination of image and sonic logs

A method of characterizing shear wave anisotropy in a formation includes obtaining crossed-dipole waveforms from a borehole penetrating the formation over a range of depths and frequencies, determining far-field slowness in a fast-shear and slow-shear direction using a low-frequency portion of the crossed-dipole waveforms, and determining near-wellbore slowness in the fast-shear and slow-shear directions using a high-frequency portion of the crossed-dipole waveforms. The method also includes marking a selected depth of the formation as having intrinsic anisotropy if at the selected depth the far-field slowness in the fast-shear direction is less than the far-field slowness in the slow-shear direction and the near-wellbore slowness in the fast-shear direction is less than the near-wellbore slowness in the slow-shear direction. The selected depth is marked as having stress-induced anisotropy if the far-field slowness in the fast-shear direction is less than the far-field slowness in the slow-shear direction and the near-wellbore slowness in the fast-shear direction is greater than the near-wellbore slowness in the slow-shear direction.

Method for characterizing shear wave formation anisotropy

A method for obtaining high-quality well logging data acquired during a drilling operation includes acquiring well logging data during a pump-off period when a mud pump is turned off; and extracting a subset of data from the acquired well logging data, wherein the subset of data corresponds to a quiet period within the pump-off period, wherein the quiet period is substantially free of interference from turning the mud pump on or off.

Pump off measurements for quality control and wellbore stability prediction

Systems and methods for determining a formation property related to formation strength and stresses are disclosed. A method for determining a formation strength includes obtaining radial formation property measurements at different wellbore pressures; generating a radial stress profile based on a formation model; generating a radial stress function from the radial stress profile; and comparing the radial formation property measurements with the radial stress function to determine the formation strength. A method for determining a formation stress profile includes deriving formation parameters from a formation radial profiling; obtaining formation log data that comprise formation density data; estimating formation stresses from the formation log data; and deriving a radial stress profile based on a formation model, the derived formation parameters, and the estimated formation stresses.

Methods and systems for determining formation properties and in-situ stresses

A method is disclosed for determining a diameter of a wellbore. The method includes inducing an electromagnetic field in the wellbore and a formation surrounding the wellbore from a first location along the wellbore. At a first time, a phase is measured, with respect to the field at the first location, of a signal induced by the electromagnetic field at a second and at a third location axially spaced apart from the first location and from each other. The measuring is repeated at a second time, and a resistivity of the formation, and the wellbore diameter at the first time and at the second time are determined from the measurements of phase made at the first and at the second times. Any ambiguity in the resistivity is resolved by using resistivity determined from the measurements made at the first time.

Growing community of inventors

Littleton, CO, United States of America

Tom R Bratton