The oil and gas wells, which depleted their resources, must be abandoned. However, in the past not in all the wells the liquidating works were carried out (they were simply left) — this is so-called abandoned or unowned wells. However, even those wells where liquidating works were carried out, due to corrosion and destruction of the cement stone become outwear over time, and emergence of oil and gas on the surface is possible posing a threat to the population and the environment. It is required to introduce changes to regulatory-technical base concerning wells abandonment. Abandonment itself shall be carried out so that there was a safety guarantee for a long time. It is required to create special services, which are engaged in the development of the abandoned wells register, and, also the whole complex of works and measures on the issues of oil and gas well abandonment. Additional regulatory documents shall be developed, according to which the liquidating works in the wells are to be performed, that will guarantee safety of the population, safety of the environment, as well as construction works.
Carrying out liquidating works at the wells require big capital investments. Liquidating costs shall include expenses for physical liquidation of wells, for dismantling of land fixed business assets and earth re-cultivation. The experience of major foreign companies on accumulation of funds is of interest for liquidation of each individually abandoned well. At a certain operational stage of the well the deduction begins for liquidating works, and the necessary sum appears to be accumulated by the required moment of time.
It is possible that one of the methods of liquidation would become the method of consecutive small explosions inside the well within the range of shale which would destroy the obstacles from metal and the cement stone, and as a result, the shale would finally fill the well. In this case the time would work for increase in isolation tightness.