Downhole fluid control processes

A stable dispersion in a non-aqueous liquid of reverse phase polymerised, substantially spherical, absorbent polymer particles of which at least 90% by weight have a size below 10 .mu.m and in which the concentration of polymer is not greater than 5% by weight of the dispersion.

A downhole process for the reduction of the permeability to water of a microporous subterranean formation which has average permeability of not greater than 10 Darcy,

• the process comprising
• applying to the formation a dispersion in non-aqueous liquid of water swellable, reverse-phase polymerized, substantially spherical particles of absorbent polymer of which at least 90% by weight have a diameter less than 10 .mu.m, wherein the dispersion has a water content of not more than 20% by weight of polymer
• whereby the dispersion of the substantially spherical particles of which at least 90% by weight have a size below 10 .mu.m is injected into the micropores of the subterranean formation and the particles are allowed to swell on contact with water and cause the reduction in permeability.

A downhole process for the reduction of the permeability to water of a microporous subterranean formation which has average permeability of not greater than 10 Darcy,

• the process comprising
• applying to the formation a dispersion in non-aqueous liquid of water-swellable, reverse-phase polymerized, substantially spherical particles of absorbent polymer of which at least 90% by weight have a diameter less than 10 .mu.m, in which the non-aqueous liquid consists substantially only of filtered base diesel,
• whereby the dispersion of the substantially spherical particles of which at least 90% by weight have a size below 10 .mu.m is injected into the micropores of the subterranean formation and the particles are allowed to swell on contact with water and cause the reduction in permeability.

A stable dispersion in non-aqueous liquid of reverse-phase polymerized, substantially spherical, absorbent polymer particles of which at least 90% by weight have a size below 10 .mu.m in which the concentration of polymer is not greater than 5% by weight of the dispersion and the dispersion has a water content of not more than 20% by weight of polymer.