ACID-SOLUBLE LIGHTWEIGHT PLUGGING MATERIAL TO LIQUIDATE ABSORPTION IN PRODUCTIVE FORMATIONS Russian patent published in 2016 - IPC C09K8/473 

FIELD: oil and gas industry.

SUBSTANCE: plugging material comprising a binding, lightweight additive, filler and water, additionally contains a water-binding additive, fibrous filler and bischofite. As the binding material this contains caustic magnesite, and the filler is a carbonate filler, i.e. marble chips, as the lightweight additive aluminosilicate microspheres or hollow glass microspheres are used at the following content of the components in parts weight: caustic magnesite - 40-55; the said lightweight additive - 20-50; water-binding additive - 0.1-0.3; the said carbonate filler - 0.01-30; the said fibrous filler - 0.01-0.5; bischofite - 14.9-35; water - 58.3-90.8, wherein the total content of magnesia cement, lightweight additive and carbonate filler is 100 parts weight, and bischofite is contained in the form of a water solution with the density of 1.18-1.3 g/cm³.

EFFECT: provision the material with colmatage properties, strength, force of adhesion with rocks necessary under conditions of disastrous lost circulation, upon the presence in the formation of pores and cracks with opening up to 1 mm upon the simultaneous provision of destruction properties under acid effect for one hour of at least 80% of formed cement stone, and its complete destruction for 2-3 h.

3 cl, 4 tbl, 1 dwg