Mitsubishi Chemical Corporation

The Nippon Synthetic Chemical Industry Co., Ltd.

Takahiro Saka

Chizuko Furo

Tomoya Fujita

Norihito Sakai

Shusaku Mandai

Ryosuke Taniguchi

Yusuke Muramatsu

Yasuhiro Hirano

Yoshihito Yamauchi

Kazutoshi Tsuji

Masaya Nakai

An object of the present invention is to provide a diverting agent that can exhibit sufficient filling properties against a fracture in a well in an excavation method using a hydraulic fracturing method, and that is excellent in solubility after a predetermined period of time has passed. The diverting agent of the present invention contains a polyvinyl alcohol-based resin having an average polymerization degree of 1000 or more.

Diverting agent and method of filling fracture in well using same

A problem to be solved of the present invention is to provide a diverting agent which gradually dissolves in water. The present invention relates to a diverting agent containing a polyvinyl alcohol-based resin and a method of filling a fracture using the diverting agent.

Diverting agent and method of filling fracture in well using the same

A diverting agent is provided that exhibits sufficient filling properties against a fracture in a well because of swelling without complete dissolution for a certain period of time (about 30 minutes to 5 hours), and that quickly dissolves and can be removed even at a low temperature of 40° C. to 60° C. after a certain period of time has passed. Also provided is a diverting agent that contains a modified polyvinyl alcohol-based resin.

The diverting agent of the present invention contains resin particles of polyvinyl alcohol-based resin. The resin particles of polyvinyl alcohol-based resin are a particle mixture containing two or more types of resin particles having different particle diameters, and the diverting agent contains resin particles A of polyvinyl alcohol-based resin having a particle diameter of 1,700 &#x3bc;m or more in a range of 5 mass % to 95 mass % and resin particles B of polyvinyl alcohol-based resin having a particle diameter of 250 &#x3bc;m to 1,000 &#x3bc;m in a range of 5 mass % to 95 mass %.

A filling material for underground treatment of the present invention contains at least one polyvinyl alcohol-based resin of a modified polyvinyl alcohol-based resin and an unmodified polyvinyl alcohol, and a swelling ratio of the polyvinyl alcohol-based resin after immersion in water at a temperature of 80&#xb0; C. for 30 minutes is 250% to 900%. The filling material for underground treatment has enhanced swelling performance, is effective in preventing phenomena such as lost circulation, and has improved workability of filling a well drilled part with the filling material.

Filling material for underground treatment, underground treatment method and filling well wall method

A cement admixture includes a crosslinked product of a modified polyvinyl alcohol-based resin, wherein the dissolution rate of 1 g of the crosslinked product of a modified polyvinyl alcohol-based resin for 1 liter of water at 70&#xb0; C. is 50% or less.

Cement admixture

Disclosed is a dispersing agent for agrochemicals, said dispersing agent which comprises a modified polyvinyl alcohol-based resin containing a structural unit having a nonionic hydrophilicity group in side chain, and having a saponification degree of 95 mol % or more. The dispersing agent for agrochemicals can provide a dispersion in which a hardly water-soluble agrochemical active ingredient employed for a dispersoid is dispersed in a stable state even in the case where the dispersoid has a relatively large particle size.

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Tokyo, Japan

Takahiro Saka