This book is devoted to the most important and urgent problems arising during the operation of underground gas storage facilities (UGS) and associated with the destruction of the reservoir and sand production into the wells. UGS facilities play a special role in ensuring high reliability of stable and guaranteed gas supplies to consumers. However, despite many years of experience in UGS well operation, there is still no sufficiently substantiated geomechanical model of reservoir failure and a mathematical description of the processes occurring in the reservoir-well system, taking into account the peculiarities of the mechanical behavior of reservoir rocks during cyclic injection and extraction of gas. As a result, there are no reliable criteria for establishing a rational regime for the operation of an UGS wells in conditions of a possible destruction of reservoir rocks. Further development of underground gas storage direction requires the introduction of innovative technologies that can be used both in the design of new UGS facilities and to extend the safe and efficient operation of existing underground gas storage facilities. To solve these problems, the most promising technologies, taking into account their efficiency, relatively low cost and environmental safety, are those based on the geomechanical approach.
The book is addressed to specialists in the development and operation of underground gas storage facilities, as well as specialists in geomechanics of oil and gas fields. It can be useful for students and graduate students studying in the speciality "Development of oil and gas fields".

Chapter 1: Analysis of existing approaches to solving the problem of sand production during the operation of UGS wells.- Chapter 2: Experimental facilities for studying the deformation and strength properties of rocks and geomechanical modelling.- Chapter 3: Methodology for performing TILTS experiments to study the deformation, strength and filtration properties of rocks.- Chapter 4: Results of TILTS testing of the deformation, strength and filtration characteristics of reservoir rocks at uderground gas storage facilities based on triaxial tests.- Chapter 5: Geomechanical modelling of the stress-strain state in UGS reservoirs during cyclic changes in reservoir pressure and downhole pressure.- Chapter 6: Physical modelling programs of rock deformation and fracture in the near-wellbore zone of USG during gas injection and extraction.- Chapter 7: Results of physical modelling of deformation and filtration processes in the bottomhole zone of ugs wells during gas extraction and injection.- Chapter 8: Rationale for the possibility of using the directed unload reservoir method (DUR method) to increase rock permeability in the bottomhole zone of UGS wells.- Chapter 9: Justification of predictive recommendations for maximum and minimum allowable drawdowns, well flow rates and prevention of sand production.

Karev Vladimir, Doctor of Engineering. His research interests are geomechanics, theory of filtration, and fracture of geomaterials. Belgian Award "Merite de L'invention' for merits in invention. V.Karev is a member of the Presidium of the National Committee of Theoretical and Applied Mechanics, Scientific Secretary of it. He is the author of more than 150 works, including in the journals Q1, Q2 and 10 patents.

Kovalenko Yuri, Doctor of Physics and Mathematics, a prominent specialist in the field of geomechanics. His research interests are geophysics, geomechanics, theory of filtration, and fracture of geomaterials. Yu. Kovalenko is an expert in the field of mechanics of solids, the author of more than 150 scientific publications, including in the journals Q1, Q2.