ANALYSIS OF THE MECHANISMS OF DESTRUCTION OF PRECONVENT WELL ZONES WHEN OPERATING UNDERGROUND GAS STORAGES AND THE POSSIBILITY OF REDUCING INTENSITY THEIR DESTRUCTION
The paper presents the results of an analytical and numerical study of the formation of zones of concentration of destructive stresses in the bottomhole well zones in the operation of underground gas storage facilities. It is shown that within the framework of the theory of elastic deformation of rocks, such zones are the vicinities of perforation canals and, from the standpoint of their stability to fracture, it is expedient to use slotted hole perforation. It has also been established that when the reservoir pressure decreases, the peak value of shearing stresses on the casing wall falls on the contact line of the reservoir with its impermeable roof (sole). The reduction of such peak values will be facilitated by the formation of cemented caverns of a special cone-shaped shape. When extending the bottomhole zone of the well, it is advisable to make the shape of this enlarged zone at its upper part smoothed and extended upwards. The implementation of these measures in the construction of wells will increase the stability of their bottomhole zones to additional loads that develop during the cyclic nature of operation of underground gas storage facilities.