METHOD AND COMPOSITION FOR SEALING A SUBSURFACE FORMATION

    公开(公告)号:US20190352556A1

    公开(公告)日:2019-11-21

    申请号:US15981998

    申请日:2018-05-17

    Abstract: A method for plugging and sealing subsurface formations using alkaline nanosilica dispersion and a delayed activation chemistry is disclosed. In accordance with one embodiment of the present disclosure, the method includes introducing a mixture with a first pH into the subsurface formation. The mixture comprises an aqueous solution, an alkaline nanosilica dispersion and a water-insoluble hydrolyzable compound. The method further includes allowing the water-insoluble hydrolyzable compound to hydrolyze in the subsurface formation to form an acid at 70° C. or greater, thereby acidizing the mixture to a reduced second pH and causing the alkaline nanosilica dispersion to gel into a solid and seal the subsurface formation. A composition for sealing a subsurface formation is also disclosed. The composition includes an aqueous mixture including water, an alkaline nanosilica dispersion, and a water-insoluble hydrolyzable compound.

    DEVELOPMENT OF RETARDED ACID SYSTEM
    129.
    发明申请

    公开(公告)号:US20180320063A1

    公开(公告)日:2018-11-08

    申请号:US16039525

    申请日:2018-07-19

    Abstract: In one embodiment, a retarded acid system comprises an aqueous acid and a retarding surfactant. The aqueous acid may comprise from 5 wt. % to 25 wt. % of a strong acid, that is, an acid having a Ka greater than or equal to 0.01. The aqueous acid may further comprise from 75 wt. % to 95 wt. % water. The retarding surfactant may have the general chemical formula R—(OC2H4)x—OH where R is a hydrocarbon having from 11 to 15 carbon atoms and x is an integer from 6 to 10. The retarding surfactant may have a hydrophilic-lipophilic balance from 8 to 16.

Patent Agency Ranking