Patents by Inventor Keietsu Kato

Keietsu Kato has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Composition and method for recovery of petroleum and gas
    Patent number: 5487425
    Abstract: The present invention provides a composition for recovery of petroleum and gas, which comprises (a) a copolymer having a molecular weight of 100,000 or more, composed of 30-75 mole % of N-vinylpyrrolidone unit, 5-70 mole % of (meth)acrylamide unit and 0-20 mole % of (meth)acrylic acid unit or a salt thereof, (b) a water-soluble aldehyde, (c) a phenol compound, and (d) water. This composition can form a gel in a required gelling time even at high temperatures and even in the presence of bivalent metal ions and accordingly can be used for efficient recovery of petroleum and gas.
    Type: Grant
    Filed: September 22, 1994
    Date of Patent: January 30, 1996
    Assignees: Nitto Chemical Industry Co., Ltd., Japan Petroleum Exploration Co., Ltd.
    Inventors: Takamasa Ohno, Keietsu Kato, Yoshiyuki Yamaguchi, Masami Murakami, Shogo Suzuki, Shoichi Kanda, Tsuyoshi Nakagawa