Three operating fluids including highdensity brine，gellant and over-displacing fluids were used for this technique.
The gellant is instant soluble in acid, and it has good thermal stability, antishearing property and salt resistance, etc.
A special oil-based gelled fracturing fluid,Which combines gellant,crossing-linking agent,surfactant,exciting agent and breaker is presented and tested.
AMPS is chosen as the anionic monomer, and by its compounding with one or two kinds of non-ionic invert emulsions,a polymer gellant with high solids content and molecular weight is prepared.
The vital factor which influence the performance of frac fluid is the compatibility of crude oil with gellant, while the composition of crude oil from different field varied greatly.
Its formula constitutes HPAM, intermediate compounds of gellant, catalyst, retardant.Its advantages are good quality for injection, forming gel at low temperature and the adjustable time of gelling.