METHOD FOR LIQUIDATING COMPLICATIONS IN WELLS Russian patent published in 2004 - IPC

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes pumping of fresh water buffer into the well, dispersing water-swelling polymer in fresh water, pushing by fresh water and delay, buffer of fresh water should be in amount no less than amount of water-swelling polymer dispersion, after delay cementing solution is additionally pumped, and concentration of water-swelling polymer in percents in said dispersion is determined in accordance to acceleration of length with complication to be isolated, which is characterized by excessive pressure in MPa at said length when pumping fresh water buffer with productiveness 20 m³/h, accordingly, MPa-% : (15-12)-(0.2-0.3); (12-8)-(0.3-0.5); (8-6)-(0.5-1); (6-2)-(1-5); (2-1)-(5-10); (0.5-1)-(10-30). If length to be isolated contains cracked, cavernous and porous environments and also is subject to excessive pressure of 1-12 MPa filler is additionally injected into cementing solution while pressure on well mouth is constant. Said dispersion of polymer and fresh water for pushing may additionally be injected with filler while pressure on well mouth is constant. Pumping may be performed via tubing pipes, with behind-pipe space closed in the moment of outlet of cement determined by equality of pressure in tubing pipes and behind-pipe space. When isolating a length of low-porous and low-cracked environments with excessive pressure of 15 MPa said water-soluble gelatinous polymer may be used. When isolating watered complications, additionally after buffer of fresh water dispersion of water-soluble polymer in liquid inert to it may be pumped with pumping before or after it of dispersion of first and second buffers of liquid also inert to it, while second buffer contains filler - rubber crumb. When several watered portions are present in layers, multiple pumping of fresh water dispersions of water-swelling polymers is performed and of inert liquid with appropriate buffers.

EFFECT: higher efficiency.

7 cl, 5 ex