METHODS OF ISOLATION OF THE PRODUCTIVE STRATA OVERLAPPED BY THE CASING STRINGS AND THE GROUTING MORTAR FOR ITS EXERCISE Russian patent published in 2007 - IPC C09K8/467 E21B43/32 

FIELD: petroleum industry; natural gas industry; methods of isolation of the productive strata overlapped by the casing strings and the grouting mortar for its realization at the productive strata overhaul repair.

SUBSTANCE: the invention is pertaining to petroleum industry and natural gas industry, in particular, to the productive strata overhaul repair conducted in the process of the fields operation and at elimination of the development wells, which have fulfilled their assignment. The method may find the greatest application at operation of the multi-layer oil-fields and at elimination of the wells of the complex construction, specially on the final stage of the realized works - in the direct proximity to the earth surface for protection, for example, of the potable water, brackish waters and of the permafrost area, where their boreholes are socket by 3-4 and more casing strings. The technical result of the invention is extension of the technological possibilities of the method at the increased efficiency of the isolationof the productive strata. The grouting mortar for isolation of the productive strata overlapped by the casing strings, including Microdur-261R-X and the water, additionally contains calcium chloride, aluminum sulfate, nitriletrimethylenephosphonic acid NTF at the following ratio of the components (in mass %): Microdur-261R-X - 10-30, calcium chloride - 20-50, aluminum sulfate - 0.5-3.0, NTF - 0.0-0.2, water - the rest. The method of isolation of the productive strata overlapped by the casing strings including installation of the isolation cement bridges provides, that one of the isolation cement bridges is installed in the production string by 10-30 m below the interval of works, then using the hydroabrasive perforator cut slits in the casing strings - in the operational string and the intermediate strings - the vertical slits (3-5 slits per one meter), by means of the hydroabrasive cutter below and above the interval of the vertical slots cut all the casing strings forming the horizontal slits and the local cavities, in the formed vertical and horizontal slits and in the local cavities press through the above-mentioned grouting mortar with location of the roofing of the isolation bridge by 10-20 m above the interval of the works, then install the control isolation cement bridge, the base of which is placed on the roofing of the isolation bridge.

EFFECT: the invention ensures extension of the technological possibilities of the method at the increased efficiency of the isolationof the productive strata.

2 cl, 2 dwg, 1 tbl