Patents Examined by C. Melissa Bonnar
  • Well preflush fluid
    Patent number: 5082499
    Abstract: A thixotropic preflush fluid is employed in a well drilling operation to prevent loss of cement slurry to an air zone penetrated during the drilling operation. The preflush fluid comprises water, a cement, calcium sulfate, and a quick-hardening accelerator. Optionally, the preflush fluid also comprises a thickening agent.
    Type: Grant
    Filed: December 28, 1989
    Date of Patent: January 21, 1992
    Assignee: Union Oil Company of California
    Inventor: Jian-Chyun Shen
  • Hard coating compositions
    Patent number: 5021091
    Abstract: A hard coating composition comprising an organic silicon compound and inorganic submicron particles such as silica sol and antimony oxide sol is improved in curing properties and shelf stability by blending aluminum perchlorate as the curing catalyst.
    Type: Grant
    Filed: January 16, 1990
    Date of Patent: June 4, 1991
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Mitsuhiko Takarada, Kazuharu Sato, Kenji Yamamoto, Shigeru Mori