New Methodology for Quantitative Cement Evaluation Using Sonic Logging while Drilling: First Application in Middle East

2020 ◽  
Author(s):  
Abdullah Al-Fawwaz ◽  
Duaa Alsenan
Keyword(s):  
Middle East ◽  
Logging While Drilling ◽  
Sonic Logging

scholarly journals Influence of borehole-eccentred tools on wireline and logging-while-drilling sonic logging measurements

2013 ◽  
Vol 61 ◽  
pp. 268-283 ◽  
Author(s):  
David Pardo ◽  
Pawel J. Matuszyk ◽  
Carlos Torres-Verdin ◽  
Angel Mora ◽  
Ignacio Muga ◽  
...  
Keyword(s):  
Logging While Drilling ◽  
Sonic Logging

scholarly journals Reflection signals and wellbore scattering waves in acoustic logging while drilling

2020 ◽  
Vol 17 (3) ◽  
pp. 552-561
Author(s):  
Yue Pan ◽  
Xiao He ◽  
Hao Chen ◽  
Xiuming Wang
Keyword(s):  
Time Domain ◽  
Body Wave ◽  
Acoustic Signals ◽  
Wave Reflections ◽  
Wave Fields ◽  
S Waves ◽  
Scattering Effects ◽  
Apparent Source ◽  
Logging While Drilling ◽  
Sonic Logging

Abstract In sonic logging while drilling (LWD), it is difficult to extract reflection signals for the goal of geo-steering as the wave fields are so complicated. It is important to analyse the reflection and scattering effects based on the synthetic acoustic signals of the real LWD models, while considering the medium discontinuity at the end of the borehole. We numerically investigate the acoustic LWD responses to reflective boundaries out of the borehole. To simulate the received signals, the 3D finite difference in time domain method is implemented. Mode conversions between the collar and the Stoneley waves are revealed. Strong reflections are generated at the bottom of the well, which can be equivalent to an additional scattering source (i.e. an apparent point source). The scattering waves by the wellbore bottom are generally much stronger than the reflections from the layer interfaces of formations. By comparing the models with stratified interfaces of opposite inclination directions, the propagation mechanisms of two newly recognised reflection waves are revealed in addition to the traditional body wave reflections (P and S waves) in LWD models. The energy of the collar wave radiates outside the borehole and then reflects at the bedding boundaries; meanwhile, the scattering waves from the well bottom can generate reflections too. These reflection arrivals match well with the time predicted by ray theories, respectively. Finally, we propose a possible means to estimate the dipping directions of geological interfaces by reflection waves emitted from both LWD transmitters and the apparent source at the well bottom.

Frequency-domain simulation of logging-while-drilling borehole sonic waveforms

Geophysics ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. D99-D113 ◽  
Author(s):  
Paweł J. Matuszyk ◽  
Carlos Torres-Verdín
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Frequency Domain ◽  
Internal Structure ◽  
Adaptive Finite Element Method ◽  
Computational Domain ◽  
Mechanical Filter ◽  
Logging While Drilling ◽  
Sonic Logging

Numerical simulation of sonic logging-while-drilling (LWD) borehole measurements is challenging because of significant wave propagation effects due to the massive drilling collar occupying a large portion of the borehole. In addition, the internal structure of the LWD tool can have a significant impact on the measured dispersions of Stoneley and quadrupole modes. The collar is typically constructed with a set of inner periodic grooves, which act as a mechanical filter to attenuate undesirable collar modes. Reliable numerical simulation and interpretation of LWD sonic waveforms requires that all features and dimensions of the drilling collar be included in the simulation model. Furthermore, the presence of the drilling collar can prompt numerical instabilities due to backward propagating modes in the perfectly matched layer (PML) commonly used to truncate the computational domain. This problem can be circumvented with the implementation of artificial viscoelastic attenuation in the collar whenever the simulations are intended to reproduce only wave propagation within the surrounding rock formations. In addition, reliable modeling of borehole wave propagation in the presence of high contrasts in material properties and the internal structure of the LWD collar requires a numerical method capable of accurately and stably resolving all spectral scales present in the model. We implemented an automatic [Formula: see text]-adaptive finite-element method in the frequency domain combined with a PML technique to simulate LWD sonic logging measurements. Examples of the application verified the accuracy and reliability of the simulated borehole and formation propagation modes in the presence of casing and internal structures in the LWD collar. The presence of steel casing and quality of casing/formation bond significantly influence the propagation modes excited in a borehole. However, it is still possible to estimate the formation shear slowness using monopole and quadrupole sources regardless of the quality of cement bond in fast formations. Assessment of the formation compressional slowness was significantly impeded by the strong pipe mode. Estimation of formation shear slowness in slow formations is practically impossible due to the presence of casing and a strong annulus mode when the quality of casing bond is poor.

Logging while drilling shear sonic logging in very large boreholes

2019 ◽  
Vol 145 (3) ◽  
pp. 1768-1768
Author(s):  
Matthew Blyth ◽  
Naoki Sakiyama ◽  
Hiroaki Yamamoto ◽  
Atsushi Oshima ◽  
Eduardo Saenz
Keyword(s):  
Logging While Drilling ◽  
Sonic Logging
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