METHOD FOR PREVENTION OF BOTTOM WATER INFLUX TO PRODUCING OIL WELL Russian patent published in 2017 - IPC E21B43/32 E21B33/138 C09K8/42 C09K8/504 

FIELD: oil and gas industry.

SUBSTANCE: method involves three cycles of pumping a water-swellable polymer slurry into the isolated formation and installing a mobile viscoelastic barrier. Prior to the start of the producing oil well, a perforator on oil-well tubing is lowered for operation down to the oil water contact level. The perforation of the production string is done at 1.5 m below and above the OWC level. After lifting the perforator, the tubing strings are lowered to the perforations. Then, the first portion of the composition based on unifloc and CuSO₄ with the following ratio of components, wt %: 1% (wt.) unifloc solution + 5% (wt.) CuSO₄. Then the second portion of the composition is pumped in with the following ratio of the components, wt %: 1 (wt.) unifloc solution + 10% (wt.) CuSO₄ + ethyl silicate-32 (the volume ratio of ethyl silicate-32 is CuSO₄ = 0.33: 0.17). Then the third portion of the composition is pumped in with the following ratio of components, wt %: 2 (wt.) unifloc solution + 10% (wt.) CuSO₄ + ethyl silicate-32 (the volume ratio of ethyl silicate-32 is CuSO₄ = 0.33:0.17). After the third portion is pumped in, a microcement solution on the basis of EFDB "Mikrodur" in order to reinforce the waterproof barrier. For this purpose a microcement plug is built up to the pay top. Then, the tubing string is lifted, and the microcement is expected to solidify. After the microcement plug has been drilled up to the top of the barrier, a perforator on the tubing is lowered into the oil zone of the formation. The perforation of the formation, well development and its commissioning are performed.

EFFECT: increased efficiency of waterproofing works by creating a reliable extended waterproof barrier in the OWC zone.

2 tbl, 4 dwg