Baker Hughes Corporation

Geomechanics International, Inc.

Gamal A Hassan

Philip Lawrence Kurkoski

Phil L Kurkoski

Daniel T Georgi

Daniel Moos

David A Castillo

Gavin Lindsay

William Madigan

John Fabian

James V Leggett, Iii

Pingjun Guo

Andrew Kirkwood

Eric Molz

Philip L Kurkoski

James V Leggett

A system, method and computer-readable medium for developing an earth formation is disclosed. A tool conveyed in a borehole induces a stress in the earth formation proximate a borehole. A sensor assembly obtains a measurement of a physical property of the borehole at a plurality of azimuthal locations in the borehole. The values of the physical property are indicative of the induced stress in the formation. A processor forms an image of the borehole using the obtained measurements of the physical property, estimates an azimuthal variation with borehole depth of the induced stress in the formation from the formed image, and alters an operational parameter of a device for developing the earth formation using the estimated azimuthal variation with depth of the induced stress in the formation.

System and method for stress field based wellbore steering

A system and method for the geomechanical steering of the orientation of a wellbore is disclosed. In one embodiment, any available a priori data regarding the stress characteristics of a region of interest are used to develop a preliminary stress model for the region. A geosteered drilling operation is thereafter commenced, with the trajectory being steered in a direction relative to the stress model of the region. While drilling, real-time data is obtained from conventional down-hole instrumentation. The real-time data is used to refine the stress model for the region, such that the trajectory can be guided on an ongoing basis to achieve an optimal relationship with the measured stress characteristics of the region.

Caliper measurements made during rotation of an imager on a logging string are processed to estimate the location of the imager, and size and shape of the borehole. A piecewise elliptical fitting procedure may be used. These estimates may be used to correct measurements made by a standoff-sensitive formation evaluation sensor such as a neutron porosity tool. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Formation evaluation using estimated borehole tool position

Harmonics and subharmonics of acoustic measurements made during rotation of a sensor on a downhole are processed to estimate the location of the imager, and size and shape of the borehole. A piecewise elliptical fitting procedure may be used. These estimates may be used to correct measurements made by a standoff-sensitive formation evaluation sensor such as a neutron porosity tool.

Multi-resolution borehole profiling

The present invention provides a method and apparatus for logging an earth formation and acquiring subsurface information wherein a logging tool is conveyed in borehole to obtain parameters of interest. The parameters of interest obtained may be density, acoustic, magnetic or electrical values as known in the art. The parameters of interest may be transmitted to the surface at a plurality of resolutions using a multi-resolution image compression method. Parameters of interest are formed into a plurality of Cost Functions from which Regions of Interest are determined to resolve characteristics of the Features of interest within the Regions. Feature characteristics may be determined to obtain time or depth positions of bed boundaries and borehole Dip Angle relative to subsurface structures, as well borehole and subsurface structure orientation. Characteristics of the Features include time, depth, and geometries of the subsurface such as structural dip, thickness, and lithologies.

Apparent dip angle calculation and image compression based on region of interest

A logging-while-drilling density sensor includes a gamma ray source and at least two NaI detectors spaced apart from the source for determining measurements indicative of the formation density. An analytic function based on a heuristic model is used to predict the measured response as a function of offset, mud density and formation density. The model may be used to provide a caliper measurement where acoustic caliper data are unreliable.

Compensated caliper using combined acoustic and density measurements

Caliper measurements made during rotation of a bottomhole assembly are processed to estimate the location of the BHA, and size and shape of the borehole. A piecewise elliptical fitting procedure may be used. These estimates may be used to correct measurements made by a standoff-sensitive formation evaluation sensor such as a neutron porosity tool.

A method for measuring radiation in a borehole, the method including placing a detector comprising a scintillator and a plurality of photodetectors in the borehole; detecting a radiation interaction with a first photodetector; detecting the radiation interaction with at least a second photodetector; and determining a location of the interaction from the detecting; wherein the location provides information regarding formations surrounding the borehole.

High resolution gamma measurements and imaging

A data compression technique for MWD applications uses feature detection, extraction, followed by image compression for only the region(s) of interest. The detection approach processes data in real time. It triggers on the start and end of a feature without processing any further features. This provides feature detection with zero latency. Compressing only the region of interest provides data compression with both higher resolution and higher compression ratio.

The present invention provides a method and apparatus for logging an earth formation and acquiring subsurface information wherein a logging tool is conveyed in a borehole to obtain parameters of interest. The parameters of interest obtained may be density, acoustic, magnetic or electrical values as known in the art. As necessary, azimuths associated with the measurements are obtained and corrections applied. The corrected data may be filtered and/or smoothed. The parameters of interest associated with azimuthal sectors are depth matched, resolution matched and filtered, and the acquisition effects removed. The data are denoised using a multi-resolution wavelet transform. The data acquired with separate transducers are resolution matched to obtain a resolution matched data series. Subsequently the resolution matched data may be further denoised using a multi-resolution wavelet transform.

Enhancing the quality and resolution of an image generated from single or multiple sources

The present invention provides a method and apparatus for logging an earth formation and acquiring subsurface information wherein a logging tool is conveyed in borehole to obtain parameters of interest. The parameters of interest obtained may be density, acoustic, magnetic or electrical values as known in the art. The parameters of interest are acquired with a plurality of sensors. For time based image data, the time separation values between signals acquired from separate sensors for individual subsurface features are determined. The time separation values may be determined using correlation or other methods illustrated herein or as known in the art. Using known sensor spatial separations and time separation values a drill rate is determined and an incremental depth for the subsurface feature is defined. The geometries of subsurface features in incremental depth relative to the well bore may be accurately determined, including extremely accurate dip and azimuth structural information relative to the borehole.

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Houston, TX, United States of America

Gamal A Hassan