Research Of High Temperature And High Salinity Tolerant Weak Gel Profile Control System

Weak gel profile control and flooding is a kind of tertiary recovery technique develop from combining the best of technique of profile control and water plugging and technique of polymer flooding. Weak gel profile control and flooding not only could improve oil-water mobility ratio of high permeability, large pore or fracture formation plugging, more improve water flooding oil recovery provides a new direction,become one of main at the late stage of oilfield water injection development oil stabilization and water control.The formula of temperature resistant and salt resistant weak gel system was developed. Compared to four kinds of polymer based agent of different salinity, different temperatures of weak gel system, polymer AP-P4 has good resistance to temperature and salt effect; formaldehyde, phenol/hydrophobically associating polymer crosslinking system under high temperature and high salinity environment form weak gel system has good comprehensive properties,so choose choose phenolic aldehyde crosslinking agent;was synthesized in laboratory water soluble phenol aldehyde crosslinking agents, and to evaluate its performance. Optimization of weak gel system formula,and finally come to the polymer mass concentration is 2000 mg / L, phenol aldehyde crosslinking agent concentration selection over 800 mg/L, the thiourea as a stabilizer system, thiourea concentration is 200mg/L optimization formulation.Through the method of experiment, the indoor performance evaluation of the low temperature and salt resistance and weak gel system was evaluated. The result of evaluation shows that at 100 DEG C into 3558 mpa-s viscosity is, that the system has good thermal stability. The mineralization degree up to 160000mg/L and viscosity of can still achieve 3000mPa·s, so the weak gel system with high salt resistance; shear viscosity as a whole to be low but still be able to meet the requirements, the weak gel system has good resistance to shear; a gel polymer shear viscosity recovery time is short, the effect is good, the weak gel system has good shear recovery; when time is 100 D its viscosity for 3667mPa·s viscosity keep rate was 79.1%. So the weak gel system showed good long-term stability.Core plugging experiments and core displacement experiments were carried out on the low temperature resistant and salt resistant gel system. The results of core plugging experiment show that the weak gel system has good sealing performance. The results of core flooding experiment show that when the injection 0.3PV is improved by 7.35%.