Ultrasonic Slowness Images for Geological Interpretation: Investigating Field Test Examples of a New LWD Technology

Abstract Borehole images have long been used for various applications related to geological interpretation, geomechanics and well-placement objectives. Based on the physical measurement used, the resolution and detection limit of the image logs vary considerably thereby limiting or enhancing the applications envelope against specific objectives. A new logging-while-drilling (LWD) technology of pitch-catch (PC) ultrasonic is under development, that can also provide borehole images of compressional and shear slowness in anisotropic and / or heterogenous formations both in water and oil-based-mud. Geological application of these images (which have inch-scale resolution) is being assessed and investigated with respect to the already established ultrasonic pulse-echo (PE) LWD images. While PE images show details of the borehole wall and are thus subject to the effects of drilling practices, the PC images reflect the rock mechanical properties of the formation at the depth of investigation of the measurement, in the same fashion as density images. Two case-studies are presented to assess the quality and application of these images; with one vertical and one horizontal well. The PC images are shown to provide a lot of meaningful information in addition to PE images, though the PC images lose out on detailed information related to texture and subtle structural features. In fact, the gross geological features of bedding and some sedimentation sequences have been imaged with confidence, with manifestation of the features available across the entire azimuthal coverage with the new-technology images and confident dips with sinusoidal fits are picked for gross geological variations. The horizontal well PC images have picked up higher confidence low-angled features than the vertical well PC images due to the longer intersection with borehole wall. The slowness images are found to provide confident bed-boundaries, also some fracture-traces are visible only on the slowness images. However, major vertical fractures and drilling-induced fractures (DIF) are more prominent on the PE amplitude images. The results show that slowness images offer the capability to understand gross structural dip and facies variability at a better resolution than conventional LWD images of similar resolution, and with the benefit of not needing to utilize a chemical source in the drilling bottom-hole assembly (BHA) for density images. Although the slowness measurements azimuthally have been developed to investigate near wellbore geomechanical concerns, such as stress, heterogeneity, and anisotropy, it is clear that the resultant images also have geological applications that is demonstrated by the datasets shown. These applications mean that the images could offer a more sustainable geosteering capability if delivered in real-time.

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Оценка реальной чувствительности приемочного ультразвукового контроля рельсов

Дефектоскопия ◽

10.31857/s0130308220110020 ◽

2020 ◽

pp. 17-27

Author(s):

А.А. Шелухин

Keyword(s):

Ultrasonic Pulse ◽

Piezoelectric Transducers ◽

Acoustic Path ◽

Metallic Inclusion ◽

Inclusion Type ◽

The Real ◽

Rail Head ◽

Pulse Echo

In this article, the analysis of the acoustic path during the ultrasonic pulse echo testing of the rail head in production is carried out. The influence of the parameters of the applied piezoelectric transducers on the distribution of sensitivity for the sounding scheme used in the existing installations is estimated and the real sensitivity of detecting defects of the «non-metallic inclusion» type is estimated.

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X-ray Diffraction Analysis and Williamson-Hall Method in USDM Model for Estimating More Accurate Values of Stress-Strain of Unit Cell and Super Cells (2 × 2 × 2) of Hydroxyapatite, Confirmed by Ultrasonic Pulse-Echo Test

Materials ◽

10.3390/ma14112949 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2949

Author(s):

Marzieh Rabiei ◽

Arvydas Palevicius ◽

Amir Dashti ◽

Sohrab Nasiri ◽

Ahmad Monshi ◽

...

Keyword(s):

Young’S Modulus ◽

Young's Modulus ◽

Ultrasonic Pulse ◽

High Accuracy ◽

Unit Cell ◽

Deformation Model ◽

X Ray Diffraction ◽

Uniform Deformation ◽

X Ray ◽

Pulse Echo

Taking into account X-ray diffraction, one of the well-known methods for calculating the stress-strain of crystals is Williamson-Hall (W–H). The W-H method has three models, namely (1) Uniform deformation model (UDM); (2) Uniform stress deformation model (USDM); and (3) Uniform deformation energy density model (UDEDM). The USDM and UDEDM models are directly related to the modulus of elasticity (E). Young’s modulus is a key parameter in engineering design and materials development. Young’s modulus is considered in USDM and UDEDM models, but in all previous studies, researchers used the average values of Young’s modulus or they calculated Young’s modulus only for a sharp peak of an XRD pattern or they extracted Young’s modulus from the literature. Therefore, these values are not representative of all peaks derived from X-ray diffraction; as a result, these values are not estimated with high accuracy. Nevertheless, in the current study, the W-H method is used considering the all diffracted planes of the unit cell and super cells (2 × 2 × 2) of Hydroxyapatite (HA), and a new method with the high accuracy of the W-H method in the USDM model is presented to calculate stress (σ) and strain (ε). The accounting for the planar density of atoms is the novelty of this work. Furthermore, the ultrasonic pulse-echo test is performed for the validation of the novelty assumptions.

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Determination of the Elastic Tensor of a Textured Low-Carbon Steel

Textures and Microstructures ◽

10.1155/tsm.21.3 ◽

1993 ◽

Vol 21 (1) ◽

pp. 3-16 ◽

Cited By ~ 9

Author(s):

P. Spalthoff ◽

W. Wunnike ◽

C. Nauer-Gerhard ◽

H. J. Bunge ◽

E. Schneider

Keyword(s):

Carbon Steel ◽

Elastic Anisotropy ◽

Low Carbon Steel ◽

Elastic Stiffness ◽

Ultrasonic Pulse ◽

Grain Structure ◽

Maximum Deviation ◽

Low Carbon ◽

The Hill ◽

Pulse Echo

The components of the elastic stiffness tensor of hot rolled low-carbon steel were determined using an ultrasonic pulse-echo-method. They were also calculated on the basis of X-ray texture measurements using the Hill approximation. The maximum deviation between experimental and calculated values is 3.5%. An influence of the slightly anisotropic grain structure on the elastic anisotropy could not be seen.

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Prediction of flaw response in polycrystalline metals for an ultrasonic pulse echo simulation using Born approximation

Nondestructive Testing And Evaluation ◽

10.1080/10589750802422343 ◽

2009 ◽

Vol 24 (3) ◽

pp. 289-300 ◽

Cited By ~ 2

Author(s):

K.S. Aprameya ◽

R.S. Anand ◽

B.K. Mishra ◽

S. Ahmed

Keyword(s):

Born Approximation ◽

Ultrasonic Pulse ◽

Polycrystalline Metals ◽

Echo Simulation ◽

Pulse Echo

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Elastic properties ofGd5Si2Ge2studied with an ultrasonic pulse-echo technique

Physical Review B ◽

10.1103/physrevb.74.184105 ◽

2006 ◽

Vol 74 (18) ◽

Cited By ~ 8

Author(s):

O. Svitelskiy ◽

A. Suslov ◽

D. L. Schlagel ◽

T. A. Lograsso ◽

K. A. Gschneidner ◽

...

Keyword(s):

Elastic Properties ◽

Ultrasonic Pulse ◽

Pulse Echo

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The far-field scattering response of a side drilled hole in single/layered anisotropic media in ultrasonic pulse-echo setup

Wave Motion ◽

10.1016/j.wavemoti.2010.11.003 ◽

2011 ◽

Vol 48 (3) ◽

pp. 275-289 ◽

Cited By ~ 4

Author(s):

Jing Ye ◽

Hak-Joon Kim ◽

Sung-Jin Song ◽

Sung-Sik Kang ◽

Kyungcho Kim ◽

...

Keyword(s):

Anisotropic Media ◽

Ultrasonic Pulse ◽

Far Field ◽

Scattering Response ◽

Pulse Echo

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First approximations to the energy release of giant dikes at Cerberus Fossae, Mars

10.5194/egusphere-egu21-13008 ◽

2021 ◽

Author(s):

Sam Rivas-Dorado ◽

Javier Ruiz ◽

Ignacio Romeo

Keyword(s):

First Episode ◽

Aspect Ratios ◽

Cross Section Area ◽

Section Area ◽

Induced Fractures ◽

Seismic Moment Release ◽

Rock Mechanical Properties ◽

Lower Size ◽

Insight Mission ◽

Cerberus Fossae

Historical dike intrusions in the vicinity of volcanic edifices on Earth are known to produce swarms of seismic activity with cumulative seismic moments between 1&#183;1012 and 1&#183;1020 Nm, equivalent to moment magnitudes between 2 and 7. On Mars, long linear graben systems are likely to host giant dike complexes at depth, which possibly produced significant seismicity during their intrusion. Not only this, but dike intrusions are also candidates to produce crustal seismicity at present day, which may be detected during the lifespan of the InSight mission. In this work we infer the possible geometry of dikes underneath Cerberus Fossae, and make estimations of the energy released during their intrusion.We used cross section area balancing on topographic profiles orthogonal to several of the Cerberus Fossae graben to estimate proxies for the geometry of the underlying dikes (aperture, height, depth, etc.). This technique has already been used to approximate dike properties at the nearby Elysium Fossae, with successful results. At Cerberus Fossae, the obtained dike aspect ratios are consistent with sublinear scaling, which is characteristic of fluid-induced fractures (as expected for dikes). These results support the presence of giant dikes underneath Cerberus, which may be up to 700 m thick, 140 km long, and have heights of up to 20 km.Additionally, we used the inferred geometries and assumptions about the host rock mechanical properties to estimate various energy quantities related to dike intrusion, and compared them with the energy releases in terrestrial diking episodes. Two calculations are of special interest; Md, the energy associated to dike inflation, and Ms, an approximation to the cumulative seismic moment release. The obtained Md values are between 3.1&#183;1020 and 5.0&#183;1021 Nm, and are 1 to 2 orders of magnitude larger than the equivalent moments in terrestrial events. Ms was calculated from Md with two key assumptions; 1) that all aseismic energy was released by the dike, and 2) values of seismic efficiency (the percentage of seismic relative to the total energy released) based on terrestrial examples. The obtained Ms are between 6.3&#183;1019 and 2.2&#183;1021 Nm, which are equivalent to moment magnitudes of 6.5 and 7.9. These are comparable to, albeit slightly larger than, the cumulative moments of some of the largest terrestrial diking events, such as the first episode in the Manda-Hararo sequence (Ethiopia, 2005, Ms = 6.2) or the Miyake-jima event (Japan, 2000, Ms = 6.8).The Elysium volcanic province is thought to have been active until very recent times, and possibly even at present day. If this is the case, then intrusions in the lower size of the spectrum investigated at Cerberus, and smaller-sized events, may be detected by InSight as a series of crustal seismic events with cumulative moment magnitudes <6. Further research is needed to fully assess the validity of the comparisons between terrestrial and Martian events, and the possible energy releases of dike-induced marsquakes.

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