Method of treating a wellbore having annular isolation system

摘要

A well treatment fluid containing a borated galactomannan gum such as guam is used to isolate a productive zone in a well having multiple productive zones. The fluid (27) is particularly useful in treatment of well bores containing a mechanical zonal isolation system (30) in the productive zone of interest. The fluid is pumped into the well in a substantially non-hydrated form. The well treatment fluid is therefore highly effective in preferentially sealing or blocking productive zones in the formation since delayed hydration of the fluid may be controlled for up to several hours. The isolated zones can then be treated by perforation and hydraulic fracturing to improve the production of the well.