Carvalho Raíssa Takenaka Rodrigues, de Freitas Neimar Paulo, Francisco Agatha Densy Dos Santos, Palermo Luiz Carlos, Mansur Claudia Regina Elias
Instituto de Macromoléculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, Rio de Janeiro CEP 21945-970, Brazil.
LRAP (Enhanced Oil Recovery Lab), COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro CEP 21941-853, Brazil.
ACS Polym Au. 2025 Feb 3;5(2):134-144. doi: 10.1021/acspolymersau.4c00075. eCollection 2025 Apr 9.
The objective of this study was to develop an innovative biopolymer, cassia gum, for enhanced oil recovery (EOR) applications. The gum was extracted from the seeds of , a native Brazilian tree, using a novel method that achieved an average yield of 24.4 ± 1.7 wt %. Structural characterization identified cassia gum as a nonionic galactomannan with an average molar mass (Mw) of 8.07 × 10 ± 1.44 × 10 g/mol and an organic matter content of 80.32%. A cassia gum-saline solution at 3,000 mg/L, prepared using injection water containing 29,711 mg/L of total dissolved solids, exhibited shear-thinning rheological behavior and viscoelastic properties, with a viscosity of 21.38 cP at 60 °C, closely matching crude oil viscosity. Viscoelastic testing revealed a transition from viscous to elastic behavior, enhancing EOR efficiency by improving sweep and microscopic oil displacement. Contact angle tests with API 25 oil demonstrated that cassia gum could alter carbonate rock wettability from oil-wet to intermediate-wet. Coreflooding experiments under reservoir conditions showed that cassia gum-saline fluid achieved an additional oil recovery of 13.6% OOIP, following 38.5% OOIP recovery during waterflooding. These results establish cassia gum as a promising biopolymer for EOR applications.
本研究的目的是开发一种用于提高采收率（EOR）应用的创新型生物聚合物——决明胶。该胶是从一种巴西本土树木的种子中提取的，采用了一种新颖的方法，平均产率达到24.4±1.7 wt%。结构表征确定决明胶为一种非离子半乳甘露聚糖，平均摩尔质量（Mw）为8.07×10±1.44×10 g/mol，有机物含量为80.32%。使用含有29711 mg/L总溶解固体的注入水配制的3000 mg/L决明胶盐水溶液表现出剪切变稀的流变行为和粘弹性特性，在60°C时粘度为21.38 cP，与原油粘度非常匹配。粘弹性测试揭示了从粘性到弹性行为的转变，通过改善波及系数和微观驱油提高了EOR效率。与API 25油的接触角测试表明，决明胶可以将碳酸盐岩的润湿性从油湿改变为中间润湿性。油藏条件下的岩心驱替实验表明，决明胶盐水流体在水驱采收率达到38.5% OOIP之后，额外采收率达到13.6% OOIP。这些结果表明决明胶是一种有前途的用于EOR应用的生物聚合物。
