Study on Composite Polyelectrolyte Solution Used in Water Base Fracturing Fluid

Composite polyelectrolyte solution is studied for its use in fracturing fluid as thickening agent.It was found that stable homogeneous composite polyelectrolyte can be obtained by adjusting the molecular weights of anionic and cationic polyelectrolytes, and the cationic degreeof cationic polyelectrolytes.A cationic polymer with molecular weight of 800, 000 and cationic degree of 9.1%, when mixed with an anionic polymer with molecular weight of 22, 000, 000, produces a composite polyelectrolyte with high viscoelasticity, Study of the composite polyelectrolyte with SEM shows that network structures are generated in polyelectrolyte formed through Coulomb force, and the network structures vary with different polyelectrolyte morphology.Analyses of the rheology of the solution of a composite polyclectrolyte used in fracturing fluids show that it has excellent viscoelasticity, and the storage modulus is far greater than the loss modulus at a frequency of 0.1 Hz.Viscosity- temperature curves show that at shear rate of 170 s^-1 and 130℃, the composite polyelectrolyte solution still retain viscosity that is greater than 40 mPa·s.Homogeneous composite polyelectrolyte is expected to be used to prepare a new fracturing fluid system,