Halliburton Energy Services, Inc.

Bp Corporation North America Inc.

Brian Edward Hornby

Ruijia Wang

Mark Vincent Collins

Raymond Lee Abma

Kristoffer Thomas Walker

Baichun Sun

Sverre Brandsberg-Dahl

Min Zhou

Joonshik Kim

David John Howe

John Naranjo

Mark A Roberts

A borehole sonic logging tool and method for imaging. The borehole sonic logging tool may comprise a transmitter configured to transmit a sonic waveform into a formation, wherein the transmitter is a dipole, and a receiver configured to record a reflected wave as waveform data, wherein the receiver is a quadrupole. A method may comprise disposing a downhole tool into a borehole, selecting a frequency range for the transmitter to a horizontally-polarized shear formation body wave, broadcasting the sonic waveform as the horizontally-polarized shear formation body wave into the formation penetrated by the borehole with the transmitter, recording a reflected wave on the receiver as waveform data, wherein the reflected wave is the horizontally-polarized shear formation body wave reflected from a reflector, and processing the waveform data with an information handling system.

Single-well reflected horizontal shear wave imaging with mixed types of transmitters and receivers

A method and system for estimating a full elastic tensor. The method may comprise taking a measurement for compressional wave sonic data and cross-dipole shear data with a sonic logging tool at a first location as cross-dipole data, processing the compressional wave sonic data to produce a compressional wave slowness (P), and processing the cross-dipole shear data to produce a fast horizontal polarized shear wave slowness (SH) and a slow quazi-vertical shear wave slowness (qSV) as a function of depth. The method may further comprise setting an initial guess for at least five constants of the full elastic tensor for Vertical Transversely Isotropy (VTI) symmetry, determining a modeled slowness surfaces from the full elastic tensor, and comparing the modeled slowness surfaces with measured values of the P, the SH, and the qSV. The method may be performed by a system comprising a sonic logging tool and an information handling system.

Depth-continuous estimation of the elastic tensor using single depth borehole sonic measurements

A method and system for locating a reflector in a formation. The method may comprise broadcasting a sonic waveform as a shear formation body wave or a compressional formation body wave into the formation, recording a reflected wave from a reflector with the one or more receivers as dipole data by the dipole receiver and quadrupole data by the quadrupole receiver, and processing the dipole data and the quadrupole data with an information handling system to determine a location of the reflector from the borehole sonic logging tool. The system may comprise a borehole sonic logging tool and an information handling system. The borehole sonic logging tool may comprise one or more transmitters configured to transmit a sonic waveform into a formation and one or more receivers configured to record a reflected wave as a dipole receiver for dipole data and a quadrupole receiver for quadrupole data.

Imaging with both dipole and quadrupole receivers

A method evaluating borehole subsurface geologies can include receiving a total response signal by a sensor array disposed in a borehole, the response signal represents a pressure wave propagating in the borehole. A secondary signal can be extracted from the total response signal and a depth location for at least one secondary source that corresponds to the secondary signal is determined. An estimated reflectivity response for the secondary signal as a function of frequency is determined and the estimated reflectivity response is inverted to determine the secondary source includes at least one of a potential fracture or a potential washout. The at least one of a fracture conductivity or a washout volume for the secondary source is compared to one or more borehole images corresponding to the depth location of the secondary source to determine the potential fracture is an actual fracture or the potential washout is an actual washout.

Techniques for evaluating borehole subsurface geologies using Stoneley waves

A portion of an anisotropy formation through which a wellbore is formed can be identified. An estimate of an elastic anisotropy parameter for the portion can be adjusted based on a first quality control analysis using the elastic anisotropy parameter for the portion. The first signal representing the elastic anisotropy parameter for the portion. The estimate of the elastic anisotropy parameter for the portion can be adjusted based on a second quality control analysis using estimates for the elastic anisotropy parameters for two or more portions of the anisotropy formation.

Verifying measurements of elastic anisotropy parameters in an anisotropic wellbore environment

An acoustic logging method that may comprise acquiring waveforms for multiple acoustic wave modes as a function of tool position in a borehole; deriving position-dependent mode dispersion curves from the waveforms; accessing a computed library of dispersion curves for a vertical shear slowness (s) and a Thomsen gamma (&#x3b3;) of a given acoustic wave mode as a function of frequency; interpolating dispersion curves in the computed library to an assumed known compressional wave slowness, a borehole radius, a formation density, a mud density, and a mud slowness; computing an adaptive weight; and inverting dispersion curve modes jointly for a shear wave anisotropy, a vertical shear wave slowness, an inverted mud slowness, and an inverted mud density as a function of depth. An acoustic logging system may comprise a logging tool, a conveyance attached to the logging tool, at least one sensor, and at least one processor.

Depth-dependent mud density determination and processing for horizontal shear slowness in vertical transverse isotropy environment using full-waveform sonic data

A method for use in vertical seismic profiling includes: independently and simultaneously shooting a plurality of seismic sources in a plurality of shooting areas to impart seismic signals into a water bottom: receiving reflections of the seismic signals from a subterranean formation beneath the water bottom at a plurality of seismic receivers; and recording the received reflections; wherein, one of the seismic sources and the seismic receivers are disposed in a wellbore in the water bottom.

Independent simultaneous shooting acquisition with vertical seismic profile recording

According to a preferred aspect of the instant invention, there is provided herein a system and method for imaging complex subsurface geologic structures such as salt dome flanks using VSP data. In the preferred arrangement, a receiver wave field will be downward continued through a salt flood model and a source wave field will be upward continued through a sediment flood model until they 'meet' at the subsurface locations of the VSP receivers. The source and receiver wave fields will be cross correlated as an imaging condition at each depth interval.

System and method of 3D salt flank VSP imaging with transmitted waves

The methods described herein are conceptually similar to classical migration/imaging for surface seismic data. However, instead of using computed (estimated) Green's functions in the imaging process, the instant invention utilizes measured (near-exact) Green's functions from VSP data to image the surface seismic data. Although the instant invention is best utilized where the velocity profile is approximately 1D (i.e., v(z)), the methods disclosed herein can also be extended to instances where there are some lateral velocity variations. Under these conditions, the instant invention allows for imaging surface seismic data and 'self-imaging' VSP data without first having to estimate a velocity model. The measurements obtained from the VSP data can also be used as a tool for calibrating computed Green's functions and migration operators.

Seismic imaging with natural Green's functions derived from VSP data

There is provided herein a system and method for the imaging and monitoring of hydrocarbon reservoirs and other subsurface features preferably using seabed or surface sensors in conjunction with one or more downhole sensors. In one preferred embodiment, recordings will be simultaneously made using both seabed and downhole receivers. The energy source might be either a controlled seismic source or ambient noise. In one embodiment, the data will be used to compute a virtual VSP, checkshot, or similar survey by cross correlating a trace recorded at the surface with a trace recorded at depth. In another embodiment, the surface and well sensors will be permanently emplaced and repeated recordings over time will be used to form a time-varying (4-D) image of the subsurface.

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Katy, TX, United States of America

Brian Edward Hornby