Study On High Temperature Polymer Gel Profile Control Ggent

In the exploration process,reservoir is influenced by the heterogeneity,so that the subsequent water often flowed into high permeability layer,resulting in water recycle ineffectual.At present,the development of reservoir extends to more complex zones of high-temperature and-salt formation,and the current profile control agent has weak gel strength and poor stability under the condition of high-temperature and-salt.This paper performed following study on high temperature-resistance profile control agent for suitable for high temperature reservoirs.In order to achieve high temperature resistance of 200℃and stable for more than7 days,a polyacrylamide gel system and an acrylamide gel system were developed.Based on the single variable method,the formulation optimization experiment of high temperature profile control system was carried out.The effects of different types and concentrations of polymer,crosslinker,stabilizer,temperature resistant particles and initiator on the gelation performance of the gel system were studied.At the same time,the effects of external factors such as temperature,p H and salinity on the gelation performance were studied.The rheological properties of the gel system were studied by rheometer.The strength and temperature resistance of the high temperature resistant gel were evaluated by gel visual code method.The microstructure of the gel system was studied by environmental scanning electron microscopy（ESEM）.The experimental results show that the optimal formulation of the polyacrylamide gel system is:0.75%S01+0.75%S02+4.5%phenolic resin+2%crosslinker+1%calcium silicate+0.1%stabilizer,the gel can be stably present at 200℃for 7 days,and the viscosity after gelation reaches 200 Pa·s at a shear rate of 1.5 s^-1.The gel has a modulus of elasticity greater than the viscous modulus and is a viscoelastic colloid mainly composed of elasticity.The gel has a three-dimensional network structure,and most of the temperature-resistant particles are selectively adsorbed onto the gel skeleton to make the microscopic network structure more stable.The optimum formulation of the acrylamide gel system is:8%（20%AM+60%AMPS+20%SMDT）+1%N-methylol acrylamide+zirconium acetate（9%of monomer）+KPS（0.5%of the monomer amount）+1%temperature resistant particles,the gel is stably present at a high temperature of 200℃for more than 7 days,and the viscosity after gel formation is as high as 400 Pa·s at a shear rate of 1.5 s^-1.The gel system is also a viscoelastic colloid mainly composed of elasticity,and the viscoelasticity is significantly higher than other gel systems,the elastic modulus is as high as 1000 Pa,and the viscous modulus is about100 Pa.The gel system forms a compact spatial network structure,which is shaped like a honeycomb.The diameter of the three-dimensional network structure is about 5microns.The crosslink density inside the gel is very large,and the temperature resistance at high temperature is significantly higher than other Gel system.