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.