METHOD OF PRESSURISATION OF WELL WALLS Russian patent published in 2009 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas industry, particularly to methods of pressurisation of cased column and isolation of beds. The method consists in lowering a patch into interval of well installation; the patch is made in form of a smooth metal branch with elastic gaskets on ends and an anchor located beneath and made in form of an elongated corrugated branch; when corrugations are stretched, the external diametre of this branch is not less, than the internal diametre of the well in the interval of installation; then the method consists in creating excessive pressure inside the patch till corrugations of the anchor are stretched and tightly pressed to walls of the well; in transmitting rotation to a setting tool with an expanding mandrel; the latter extends the walls of the patch and presses them tightly and leak proof to the walls of the well; further, the setting tool and expanding mandrel are extracted to the surface. The lowering of the patch is performed on the flow string equipped from beneath with a hollow plug connected along perimeter to the upper end of the patch with leak proof overlapping; the lower end of the patch is overlapped pressure tight with a shoe; after setting the anchor the plug is detached from the anchor and is extracted from the well. Before expanding the setting tool is lowered; it is made in form of expanding head with alternative roller extension. At expanding an additional axial displacement is transmitted to the setting tool and lower end of the patch is depressurised.

EFFECT: increased reliability, simplification and reduction of cost of method.

3 cl, 3 dwg