In this paper, the technical challenges in enhanced oil recovery using a sodium silicate solution as a multi-purpose chemical are introduced to enhance oil recovery by alkaline flooding and prevent channeling flows through high permeability layer/regime and geological storage of carbon dioxide (CO 2 ) . We have focused on the sodiummetasilicate-hydrates (Na 2 SiO 3 .9H 2 O; S -MS) from many types of chemicals. Firstly, oil properties with S -MS solution (pH12-13) are presented to carry out alkaline flooding based on measurement results of interfacial tension (IFT) , contact angle and emulsion formation with oil considering reservoir-water salinity. Secondary, in-situ gel formation using the reaction between S-MS solution and dissolved CO 2 is introduced as a blocking agent in high permeability owpasses in an oil reservoir with different permeability layers. Both of Raman and SEM -EDS spectroscopy revealed that the formed gel is a sodium carbonate type gel (SC -gel) . Physical characteristics of SC-gel were investigated in respect of S-MS concentration, temperature and CO 2 gas pressure. The blocking effect was evaluated by threshold pressure gradient and gas permeability by forming in-situ SC -gel in a sandstone core. Then the core ooding test using heterogeneous core consists from two sandstones cores with different permeabilities was carried out to nd improvements in oil recovery by alkaline ooding using S -MS solution and blocking effect by the in-situ gel formation with CO 2 gas injected. Furthermore, a new system (a kind of Carbon-dioxide capture, utilization and storage) using the S -MS solution is proposed for CO 2 capture, usage and geological storage into relatively shallow oil reservoirs or aquifers meet a safe and economical onshore CO 2 sequestration. Furthermore, it is also expected that the in-situ gel formation between S -MS solution and CO 2 gas emitted from res of peat layer or coal seam has a possibility to extinguish large scale res contributing global warming.
Keywords:Enhanced oil recover y, Alkaline flooding, Blocking, CO 2 sequestration, Sodium silicate solution, Gel formation, Shallow aquifer, CCUS * 令和 2 年 10 月 28 日,石油技術協会令和 2 年度学術大会開発・生産 部門シンポジウム「石油増進回収(EOR)の未来-多様性と持続性, 実証ステージへの展開-」にて,講演題名「油層内原位置ゲル生成 技術を用いた EOR と CO 2 固定」で講演 This lecture was presented at 2020 JAPT Development and Production Technology Symposium entitled "The Future of Enhanced Oil Recovery(EOR)-Development to the demonstration stage of diversity and sustainable EOR techniques" held on Oct. 25-31, 2020.