Practical Acoustics with Techlog - Applications for Geomechanics and Petrophysics

Fundamentals of acoustic logging

• Overview acoustic logging and its applications in the oil & gas industry
• Fundamentals of borehole acoustics and wave propagation theory
• Understand sonic tool hardware with examples from different Wireline and LWD tools
• Understand the different acoustic data types (raw and filtered waveforms, slowness projections, etc).
• Import DLIS data containing sonic waveforms and use Techlog to assign tool-specific properties
• Visualize and QC acoustic data using different plots (waveform, spectrum, depth log). Perform slowness relabeling (when necessary) without reprocessing

Participants will have a short overview of acoustic logging, sonic tool hardware and the main uses of sonic data. They will learn the theory and basic techniques of sonic processing, and will be able to independently quality control the results of sonic processing delivered by a service provider. They will be able to spot problems in raw data, processed slownesses and make some corrections using slowness projections before finalizing the results.

Slowness processing workflows

• Theory of semblance processing and slowness estimation from array waveform data
• Non-dispersive slowness time coherence (STC) processing workflow
• The importance of dispersion analysis for identifying best processing parameters
• Dispersive STC (DSTC) for dipole data
• Quality control of slownesses using dispersion analysis tool and slowness frequency analysis (SFA) projections
• High-resolution (multiple shot) processing

Participants will learn how to perform the full processing workflow for obtaining slowness from Monopole, dipole and low-frequency sources. They will be able to appreciate the importance of dispersion analysis tool for selecting the optimal processing parameters as well as for quality control of the deliverables.

Sonic processing workflows

• Understanding Logging-While-Drilling sonic data deliverables (real-time and in memory-mode)
• Quadrupole shear and its applications
• Transmitter mode and Depth-Derived BoreHole Compensation (DDBHC)
• Processing slownesses in challenging environment: Leaky-P processing
• Quality control of slownesses using dispersion analysis tool and slowness frequency analysis (SFA) projections
• Case study for an exploration well: run the full P&S workflow, derive the best slownesses combining monopole and dipole results. 

Participants will learn how to perform the full processing workflow for obtaining slowness from Monopole, dipole and quadrupole sources in challenging environments using dispersion analysis and depth-derived borehole compensation.  They will be able to significantly improve the vertical resolution of the sonic logs by using multiple shot resolution based on multiple source firings. At the end of this session, they will be able to identify any poorly-processed intervals and recommend improved processing techniques.

Anisotropy analysis and its applications

• The concept of anisotropy in the earth and how it is measured
• The different mechanisms of acoustic anisotropy and their applications in the oil&gas industry
• Understand and apply the four-component rotation workflow using cross-dipole sonic waveforms (preprocessing, filtering, processing)
• Anisotropy analysis finalization and presentation (including angle swapping when necessary)
• Understanding the shale anisotropy and how to characterize it using sonic data
• Applications of anisotropy to Drilling and completion applications (stress direction, fractures, shale anisotropy, etc) 

Participants will learn how to perform the complete four-component rotation workflow using cross-dipole sonic data in order to identify zones exhibiting anisotropy. They will be able to derive several outputs (such as slowness anisotropy, time anisotropy and fast shear azimuth) for the anisotropic zones and comment on the dominant source of anisotropy by using dispersion analysis. 

Applications of Acoustic interpretation to Geomechanics, Geophysics and Petrophysics

• Case study for an exploration well: run anisotropy analysis on an exploration workflow and derive the main acoustic outputs for geomechanics and petrophysics applications.
• How to use acoustic outputs in the geomechanical workflows (mechanical earth model building, minimum and maximum horizontal stress estimation and fracture characterization)
• Petrophysics applications of sonic data (sonic porosity, Stoneley permeability, etc)
• Geophysics applications of sonic data

 Participants will apply all the methods learned in the course to an exploration well with a rich dataset. They will be able to conduct anisotropy analysis and use dispersion analysis to explain the dominant source of acoustic anisotropy by integrating sonic with petrophysics (ELAN) and wellbore image interpretation. They will also learn the different uses of sonic outputs to other domains, especially petrophysics and geomechanics.