Sustained Annulus Pressure Diagnostics in Offshore Wells by Multisensory Spectral Acoustics

The monitoring of sustainable annulus pressure (SAP) in offshore wells plays an important role in the development of an oil reservoir with a massive gas cap. The method of spectral noise logging and high-precision temperature logging used to identify SAP source presented in work (Shtun 2020) proved to be good in determining the intervals of gas movement, however, the method is limited in answers. The most significant limitation of the spectral noise logging method is associated with the impossibility based on power spectrum to distinguish the zones of gas flow in the annular space and gas inflow zones from reservoir contributing SAP. This information is critical for proper workover planning to eliminate SAP. This limitation relates to the fact that the amplitude and frequency of the resulting signal depend on not only the aperture of space fluid flow through and depend on the turbulence of the fluid flow. The paper describes a novel technology of multisensory passive acoustics of radial location that is designed to differentiate far and near acoustic sources in wells to accurately define the sources of SAP. The results of laboratory and field cases in offshore oil wells were presented in this paper as well as the comparison between single sensor spectral noise logging and multisensory passive acoustics of radial location answers was given at the end of the paper based on real case studies. As shown in the paper the described technology provides a more accurate determination of the source of SAP and the geometry of fluid movement in the near-wellbore zone.

Black Sea Methane Flares From the Seafloor: Tracking Outgassing by Using Passive Acoustics

The Black Sea bottom is well known to be earth’s largest anaerobic methane source, hosting a huge amount of cold seeps releasing significant volumes of methane of both thermogenic and biogenic origin. Taking into account the well-known effects of methane concerning global warming, including the warming up of the oceans, an effective monitoring of its output from the Black Sea is nowadays an essential target for interdisciplinary studies. We discuss the results achieved during monitoring campaigns aimed to detect and track methane flares from the seafloor of the Romanian sector of the Black Sea, in order to better constrain the possible mechanisms responsible for its injection from the marine sediments, through the water column, into the atmosphere. In the mainframe of the ENVRI-Plus project, we deployed a multidisciplinary seafloor observatory for short, mid and long time monitoring and collected samples of the water column. The multidisciplinary seafloor observatory was equipped with probes for passive acoustic signals, dissolved CH4 and chemical-physical parameters. The collected data showed a high concentration of dissolved methane up to values of 5.8 micromol/L. Passive acoustics data in the frequencies range 40–2,500 Hz allow us to discriminate different degassing mechanisms and degassing styles. The acoustic energy associated with gas bubbling is interpreted as a consequence of the gas dynamics along the water column while the acoustic range 2–20 Hz reveals vibration mechanisms generated by gas dynamic’s along the cracks and inside the sediments.

Applications of Variable Acoustics

This research investigates the use of variable acoustics and active acoustics system to improve the acoustics of the Paul H. Cocker Architecture Gallery at Ryerson University. These modifications can help the gallery become a multifunctional space in regards to acoustical characteristics of the room. Variation in acoustical response of a room requires use of different devices and material to change the reverberation and articulation time conveniently. Acoustical measurements were done in multiple locations at four multi-use auditoria with different variable acoustics features. These auditoria are Roy Thompson hall, Koerner Hall, Glenn Gould Studio and LiveLab at McMaster University. These case studies are used to better understand the acoustical responses of the auditoria with different configurations and use the data for the acoustical improvements of the Paul H. Cocker Architecture Gallery. After these evaluations were performed, results show that the acoustical poster board panels can be used to change the reverberation time of the Gallery based on the different uses. Keyword: acoustics, variable acoustics, reverberation time, active acoustics system, passive acoustics systems

Applications of Variable Acoustics

This research investigates the use of variable acoustics and active acoustics system to improve the acoustics of the Paul H. Cocker Architecture Gallery at Ryerson University. These modifications can help the gallery become a multifunctional space in regards to acoustical characteristics of the room. Variation in acoustical response of a room requires use of different devices and material to change the reverberation and articulation time conveniently. Acoustical measurements were done in multiple locations at four multi-use auditoria with different variable acoustics features. These auditoria are Roy Thompson hall, Koerner Hall, Glenn Gould Studio and LiveLab at McMaster University. These case studies are used to better understand the acoustical responses of the auditoria with different configurations and use the data for the acoustical improvements of the Paul H. Cocker Architecture Gallery. After these evaluations were performed, results show that the acoustical poster board panels can be used to change the reverberation time of the Gallery based on the different uses. Keyword: acoustics, variable acoustics, reverberation time, active acoustics system, passive acoustics systems

Soundscape of protected and unprotected tropical Atlantic coastal coral reefs

Behavioural patterns and distributions of crustaceans, fish and mammals can be inferred from acoustic recordings of the extremely noisy marine acoustic environment. In this study, we determined the soundscape of protected and non-protected marine areas between January and April 2016. Sonobuoy (a device for sound monitoring) recordings began at sunset and lasted approximately 12 hours per day. The results show a complex soundscape dominated by biological sounds produced by crustaceans and fish. Six fish chorus-dominant frequencies between 200 and 1000 Hz occurred at a similar time each day, except for chorus I. The choruses consisted of high-energy callings after the last reef line within the protected area. However, fish choruses showed low energy levels in unprotected areas. The results show the importance of protected areas for fish populations and the usefulness of passive acoustics to monitor biodiversity of sounds of commercial fish in Brazilian tropical costal reefs.

Implementation of the Advanced Passive Acoustics Hardware and Software Complex for Well Integrity Diagnostics

To ensure operational stability of the unified gas supply system depending on the seasonal gas demand fluctuations, the underground gas storage facilities are effectively used. Well integrity diagnostics using the advanced logging techniques facilitate timely identification of potential problems (pinpointing cross-flows behind casing, detecting leaks in production casing and other well construction components, locating sustained annulus pressure sources etc.), and, thereby extension of the safe operation life of functioning of the underground gas storage facilities. The results of the complex of field and geophysical studies in several underground gas storage wells are given in this article. Different types of the underground gas storages are reviewed: the ones located in an aquifer, salt dome, and mature field. The diagnostics was carried out based on the complex of downhole logging including a passive acoustic tool. The passive acoustics hardware and software technology can capture and interpret acoustic signals generated by the wellbore or reservoir flows. To recognise and interpret the captured signals, the temporal coherence algorithms, data wavelet filtration, and neural networks are used. The use of this technology allows to significantly improve the safety of well operation. The information obtained is used both in the preparation of industrial safety expert reports and for the development of effective programs for major repairs of the underground gas storage wells located in the depleted gas and water fields, as well as in the salt caverns. Hardware and software technology of passive acoustics is being used in almost all the major oil and gas provinces in the world, receiving recognition from the largest domestic and foreign companies, however, this is the first time that underground gas storage facilities are used to check the technical condition of the wells.