Method for sealing underground formations, particularly in the field of oil drilling, as well as corresponding applications and compositions

摘要

The invention relates to a new method for sealing and/or consolidating a permeable geological formation, particularly one passed through by a drilling well. The method according to the invention includes the following stages: a) insertion into the formation Z of an over-retarded gel composition GR comprising a gelling compound and a hardening agent, the setting time of which is much greater than the time for proper positioning of the composition, so that the latter runs into the formation from the well and over a notable distance, b) injection, behind a mechanical or fluid stopper, of a rapid-action gelling agent 1 so as to gel instantaneously the part of the over-retarded gel composition located in the immediate vicinity of the interface of the zone to be treated and of the drilling well, which stops the over-retarded gel composition from moving towards the inside of the formation. A gel is obtained which is strong and placed correctly. Application to the treatments of oil, gas, water and geothermal wells. IMAGE