METHOD FOR RESTRICTING BOTTOM WATER AND ANNULUS BLOWOUTS IN PRODUCTION WELLS Russian patent published in 2001 - IPC

FIELD: oil and gas production. SUBSTANCE: in a method including washing well and portionwise injecting water, cement mortar, and calcium chloride solution, distinguishing feature is that calcium chloride solution, followed by water and then sodium or potassium naphthenate solution or their mixture are at least three times injected through opened filter, after which water-tempered cement mortar with water-to-cement ratio 0.2-0.6 is injected in volume 0.5-2 cu.m per 1 m of the thickness of formation, to which mortar 0.5 to 10 vol % of additional solution of sodium or potassium naphthenate or their mixture with naphthenate-to-water ratio 1:2 is added (1-2 cum per 1 m of the thickness of formation). Well is further washed, wellhead sealed, and well is maintained under pressure during 24 h. EFFECT: increased oil recovery due selective insulation of water inflow channels.