The permeability of higher permeability zones of a subterranean reservoir of heterogeneous permeability is reduced by injecting (1) an aqueous solution of a crosslinkable water-soluble polymer, a material capable under certain conditions of at least partially crosslinking the polymer to form a gelatinous precipitate, a water-soluble alkaline material in an amount sufficient to maintain the pH of the aqueous solution above the pH at which crosslinking occurs until the composition has passed a desired distance through the reservoir, and a water-soluble surface active agent; and (2) a gas mixture comprising an acid gas. A gelatinous foam forms in situ useful for blocking escape of fluids, both gaseous and liquid, into the higher permeability zones of the reservoir during enhanced recovery, typically by carbon dioxide flooding. The polymer-surfactant solution and the gas mixture can be injected in alternating slugs to enhance formation of the gelatinous foam and to allow for plugging of higher permeability zones progressively encountered during recovery operations.
通过注入 (1) 一种可交联
水溶性聚合物的
水溶液、一种在特定条件下至少能使聚合物部分交联以形成胶状沉淀的材料、一种
水溶性碱性材料(其用量足以使
水溶液的 pH 值保持在发生交联的 pH 值以上,直到该组合物通过储层达到所需的距离)和一种
水溶性表面活性剂,来降低异质渗透性地下储层较高渗透率区的渗透率;(2) 由酸性气体组成的混合气体。在提高采收率的过程中,通常通过
二氧化碳充注,在原地形成胶状泡沫,用于阻止气态和液态流体逸出,进入储层的高渗透区。聚合物-表面活性剂溶液和混合气体可以交替注入,以促进胶状泡沫的形成,并在采油作业过程中逐渐堵塞高渗透区。