Study On Elastic Crosslinked Polymer

The formation temperature of the western T oilfield is 130℃,the salinity is 22×10~4 mg·L~-1,the fractures and caves in the formation are fully developed,and the water channeling is serious during the water injection development process.In this paper,high-strength cross-linked polymers for water shutoff and cross-linked polymer particles for water injection channel adjustment are developed.High-strength plugging agent is required as a sealing slug in the process of water plugging to prevent the plugging agent from returning during oil well production.Polyacrylamide is used to prepare the sealing gel.Due to the high molecular weight of polyacrylamide,it is difficult to configure a high-quality gellant,so the strength of the formed gel cannot meet the requirements.Polyvinyl alcohol has a low molecular weight,and high-strength cross-linked polymers can be prepared after being configured into a high-quality gellant.Traditional cross-linked polyvinyl alcohol is formed by polyvinyl alcohol and aldehyde cross-linking agent under the catalysis of strong acid.The gelation time is relatively fast,and it is difficult to meet the requirements of high temperature deep well injection.In this paper,by adding a latent acid or organic acid as a catalyst,and taking the product’s storage modulus and dehydration rate as evaluation indicators,the best performance slow-crosslinking high-strength gel formula was selected.The research results show that the gellant is prepared with 7%polyvinyl alcohol,0.4%crosslinking agent(aldehyde crosslinking agent),4%bentonite particles,and 0.25%latent acid.The gel forming time at 130°C is more than 2 hours.The obtained gel was evaluated for 3 months at high temperature,and the gel still maintained high strength.As the particles used for flow channel adjustment in fractured-cavity reservoirs,rubber particles have problems such as high density and poor deformability,as well as serious dehydration of cross-linked polyacrylamide particles under high temperature and high salt conditions.The topic chooses to use non-ionic polymer polyvinyl alcohol to react with aldehyde cross-linking agent to prepare temperature-resistant and salt-resistant cross-linked polymer,which is crushed to form elastic particles to provide support for the adjustment of flow channels in high-temperature and high-salt fracture-cavity reservoirs.The focus of the subject is to improve the temperature and salt tolerance of cross-linked polyvinyl alcohol particles by adding sulfonated phenolic resin and urotropine to the polyvinyl acetal system.The results of the study show that 8%polyvinyl alcohol,0.4%crosslinking agent(aldehyde crosslinking agent),4%bentonite particles,0.8%latent acid,1.5%sulfonated phenolic resin,and 0.3%urotropine are used to form a gel.The gel forming time is more than 2 hours at 60°C,which meets the needs of industrial production;the synthetic cross-linked polymer wet particles are evaluated at high temperature for 3 months and still maintain good elasticity.