| This paper studied a CDG system (colloidal dispersion gels) of HPAM/ AlCit, based on formation characteristics and formation fluid characteristics of Daqing oilfield. The system can be gelling in the concentration ratio of 10 : 1～40: 1(the polymer/aluminum) and the gelling time can be controlled by adjusting the concentration ratio . At the same time, the gelling conditions, such as the polymer concentration, the concentration ratio of the polymer/aluminum, the HCO3- concentration, the base gel viscosity shearing degradation, ionic strength, and PH, were discussed. The gel strength was scored by the transition pressure and viscosity.Based on the relation of ultraviolet differential spectrum characteristic absorption peaks vs. time, and by means of the optical microscope and scanning electron microscope, the shape of CDG was analysed. The 1st and 2nd critical polymer concentration of CDG were defined. Under the 1st critical polymer concentration, the crosslinking reaction is took place only inside the molecule. Under the 2nd critical polymer concentration, the system is called colloidal dispersion gels. If the polymer concentration is higher then the 2nd one, the system will become the bulk gel.The anti-shearing and viscous-elastic behaviors of CDG system are related to the polymer concentration and the salinity of water that is one composition of the system. At the low salinity, the viscosity of system will become lower with shearing. When the polymer concentration is low, the viscosity of system nearly doesn't change with shearing at the high salinity. The crosslinking reaction of enhances its viscous-elastic behaviors.The rule of static isothermal absorption of CDG system is departure from Langmuir absorption law. The absorbance of HPAM in the CDG system is approximate 2 times that in the pure HPAM system, and the absorbance of AlCit in the CDG system is only one tenth ofthat in the pure AlCit system. In formation, the absorption of CDG is a accumulating process, in which...
|
PDF Full Text Request