新型物理交联凝胶体系性能特点及调驱能力研究

Performance characteristic and profile modification research of new type physical cross-link gel system

关键词:  物理交联  高黏弹性  网络聚集体  抗剪切性  调驱性能

Key words:  physical cross-link  high viscoelasticity  network aggregate  shear resistance  profile modification performance

摘要:

针对目前化学交联凝胶和体膨体颗粒类堵剂存在的地下交联不易控制及和孔喉尺寸较难匹配的不足,通过在聚丙烯酰胺侧链上引入含有18个碳的季铵盐疏水性功能基团,设计合成了以分子间物理交联为主的新型调驱体系,并对体系的分子结构特点,在水溶液中的微观聚集形态和性能进行了表征和评价。研究结果表明,物理交联调驱体系疏水性功能基团在水溶液中自发聚集,产生物理交联,形成致密的网络聚集体,聚集体的网络尺寸为200～400 nm,相对于化学交联凝胶,具有更好的增黏性、黏弹性和抗剪切性,同时通过调整疏水性功能基团的含量,可调整体系的成胶时间。在地层存在大孔道的条件下,注入未交联的颗粒,颗粒能在岩心中产生物理交联,有效封堵高渗带。物理交联体系分子间的作用力没有化学交联的共价键强,体系在地层中有一定的运移能力,因此物理交联体系具有调驱性能,是一种比较有前景的新型高效堵调体系。 

Abstract:

In view of the current shortages of chemical cross-linking gel and bulk particle plugging agent, which are difficult to control gelling and match the formation pore size. By introducing quaternary ammonium salt hydrophobic functional group it has eighteen atoms of carbon to polyacrylamide side chain, a new type of profile modification gel system basing on inter molecular physical cross-link is designed. The characteristic of molecular structure, the micro-aggregation morphology and property in aqueous solution are characterized and evaluated. The results show that the hydrophobic functional group of physical cross-linking gel system aggregated spontaneously in aqueous solution, produced physical crosslinking, formed dense network aggregate, and the aggregate network size is between 200-400 nm. It is qualified with better viscidity, viscoelasticity and shear resistance compared with chemical cross-linking gel, at the same time by adjusting the content of hydrophobic functional group, formation colloid time can be adjusted. The non cross-linked particle is injected into strata where there is big pore, the particle can produce physical crosslinking in the core, which can plug the high permeability zone effectively. The intermolecular force of physical crosslink is weaker than covalent bond of chemical crosslink, so the system is qualified with certain ability of migration in the formation. The physical crosslink system has the properties of profile control and flooding. It is a new type of promising efficient plugging and profile control system.