Improvement of the "Slowness-Time Coherence" Method of Processing Borehole Acoustic Data Arrays

Introduction. The study of borehole acoustic waves is an important stage in geophysical well research. The main acoustic parameters are P-wave velocity of compression, S-wave velocity of shear, L-wave velocity of Stoneley along the boundary between the rock and the well fluid. The "Slowness-Tim...

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Main Authors: Sergii Lavreniuk, Yevhen Nazarenko, Daria Tulchynska, Petro Tulchynskyi
Format: Article
Language:English
Published: V.M. Glushkov Institute of Cybernetics 2024-12-01
Series:Кібернетика та комп'ютерні технології
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Online Access:http://cctech.org.ua/13-vertikalnoe-menyu-en/657-abstract-24-4-5-arte
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Summary:Introduction. The study of borehole acoustic waves is an important stage in geophysical well research. The main acoustic parameters are P-wave velocity of compression, S-wave velocity of shear, L-wave velocity of Stoneley along the boundary between the rock and the well fluid. The "Slowness-Time Coherence" (STC) method of estimating the velocity (slowness) is based on the coherence of signal arrays on 2 or more receivers of the well sonic tool. Compared with traditional acoustic logging, the main advantage of STC method is the automation of processing. The main disadvantages of STC method are the high cost and complexity of operating multi-channel sonic tools, and low quality of STC method in layers of high anisotropy, high fracturing, carbonate deposits, in horizontal wells. These disadvantages caused STC method spread slowly until the last decade. However, at present, the world's leading geophysical service companies (Halliburton, Schlumberger, etc.) use sonic tools with 8-12 receivers and 4 modes of the source signal. Over the past decade, the quality of tools and processing technologies has improved, but the problem of the high cost of using modern tools remains extremely relevant in Ukraine. The purpose of the article is – to investigate modern methods of data processing of the well sonic tools; to identify the features of the "Slowness-Time Coherence" (STC) algorithm; to propose improvements to the STC method; to implement, to test, and to integrate into production the acoustic data processing technology based on improved STC algorithm. Results. Improved "Slowness-Time Coherence" (STC) algorithm for calculating the velocity (slowness) of an acoustic wave in geological deposits. In the software package "GeoPoshuk" STC technology has been developed for the processing of acoustic waves. The technology based on the basic and improved STC algorithms. A methodology for comparing the improved STC algorithm with the basic STC algorithm has been developed. Statistical data show the advantage of the improved STC algorithm over the basic one. Conclusions. The use of the improved STC algorithm provides better automatic data processing compared to the basic STC algorithm.
ISSN:2707-4501
2707-451X