油藏堵水和调剖的效果在很大程度上取决于冻胶溶液的动态成胶性。本文针对一类聚合物冻胶溶液,分别通过瓶试成胶实验、岩心流动实验和机械旋转剪切实验,研究了岩心中的稀释作用、滞留作用和剪切作用对冻胶溶液成胶性和成胶强度的影响。结果表明,冻胶溶液(3000mg/L聚丙烯酰胺+3%交联剂+3‰助剂)在静态65℃条件下,可以形成中等强度冻胶。冻胶溶液注入到岩心后,在与地层水接触的前缘附近,受地层水稀释、孔隙中滞留和剪切三种因素的综合影响,溶液黏度损失率约95%,不能成胶;向采出液中另加入1.5%交联剂和1.5‰助剂,仍不能成胶。在注入端与冻胶溶液前缘之间,受孔隙中滞留和剪切两种因素的影响,冻胶溶液黏度损失率约70%,另加入1.5%交联剂和1.5‰助剂,可以成胶。在注入端附近,受多孔介质剪切作用的影响,冻胶溶液黏度损失约35%,可以成胶,所形成的冻胶强度降低。地层水稀释和孔隙中的滞留是影响该类冻胶溶液在油藏深部成胶的关键因素。对比无前置保护段塞、前置分子膜段塞和前置聚合物溶液段塞条件下,冻胶溶液在多孔介质中的成胶性发现,前置聚合物段塞可以减少地层水稀释和滞留对冻胶溶液组成的影响,有助于改善其成胶性。图8表2参11
The reservoir's water plugging and profile control effect largely depended on the dynamic gelling properties of one gelling solution. For a kind of polymer gelling solution, the effects of formation dilution, retention and shear action in core on the gelation and gel strength were studied by bottle tests, core flow experiments and mechanical rotary shear experiments, respectively. The results showed that a moderate intensity gel formed by gelling solution contained 3000 mg/L polyacrylamide, 3% cross linker and 3‰ additives in static condition at 65 ℃. When the gelling solution was injected into the core, near the front edge contacting formation water, three factors like water dilution, retention and shearing action had their influence on viscosity and gelation of gelling solution, which caused the viscosity loss rate of produced liquid was about 95%. If 1.5% cross linker and 1.5‰ additives were added to the produced liquid, it still couldn't form gel. Between core inlet and front edge of gelling solution, under the influence of retention and shearing action, the viscosity loss rate of produced liquid was about 70%, and it couldn't form gel before adding 1.5% cross linker and 1.5‰ additives. Near core inlet, influenced by shear action, the viscosity loss rate of produced liquid was about 35%. However, it could form gel with reducing gel strength. Water dilution and retention were key factors that affected the deep gelation of this kind of gelling solution in reservoir. For gelling solution through porous media, pre-flush polymer solution plug effectively reduced the concentration loss resulted from formation water dilution and retention, and help gelation, in contrast to no pre-flush protective slug and pre-flush plug of molecular deposition film.