The invention provides a selective water plugging agent of thin
oil well as well as a preparation method and application of the selective water plugging agent. By taking the total weight of the selective water plugging agent as 100 percent, the selective water plugging agent is prepared from the following raw materials through the following dosage: 3 percent to 6 percent of soft
oil sludge, 2 percent to 4 percent of
ageing oil, 0.5 percent 1 percent of an
amide modified starch copolymer YX-I, 0.3 percent to 0.6 percent of
sodium alpha-olefinsulfonate, 0.2 percent to 0.5 percent of
sodium dodecyl sulfate, 0.2 percent to 0.4 percent of
sodium stearate, 0.3 to 0.5 part of
glyceryl stearate, 0.1 percent to 0.2 percent of sodium
pyrophosphate, 0.08 percent to 0.15 percent of
silicon dioxide, 0.15 percent to 0.25 percent of kaolin, 0.1 percent to 0.2 percent of
mica powder and the balance of water. The selective water plugging agent has good compatibility with a stratum; the plugging strength is great and
deep water plugging can be realized; the selective water plugging capability is high; the selective water plugging agent has no damages to an oil layer and does not pollute the stratum, so that the selective water plugging agent is completely suitable for an
oil well plugging technology of a thin-oil oil reservoir.