Nano-scale study on mechanisms of low-salinity enhanced oil recovery toward high-efficiency production design

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06925
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Earth system and resources engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Liang Yunfeng 東京大学, 人工物工学研究センター, 特任准教授 (70565522)
• Co-Investigator(Kenkyū-buntansha): 松岡 俊文 公益財団法人深田地質研究所, その他部局等, 主席研究員 (10303851) ; 村田 澄彦 京都大学, 工学研究科, 准教授 (30273478) ; 増田 昌敬 東京大学, 人工物工学研究センター, 教授 (50190369)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 石油増進回収法 / 低濃度塩水 / ナノスケール / 分子動力学 / X-Ray CTR / 界面の吸着構造 / 資源開発 / 界面科学

Outline of Final Research Achievements

Enhanced oil recovery (EOR) with low concentration brine is increasing its application because it has less environmental impact and is more economical than EOR using conventional chemical agents. However, the mechanism that improves the oil recovery rate has not been fully elucidated. So, in this research, it aims at investigating the adsorption structure of oil on the mineral surface when changing salt concentration, and clarifying the EOR mechanism by low concentration brine from molecular level. We have performed X-Ray crystal truncation rod experiment, molecular dynamics simulations, and wettability measurement. In the case of clay mineral such as in sandstone reservoir, it is found that divalent Ca2+ ions play an essential role by forming cation bridging structure between acidic oil and minerals at high pH condition. In the case of calcite such as in carbonate reservoir, it is found that adsorption is stronger at low pH condition. The monovalent Na+ is found to be more important.

Free Research Field

工学・総合工学（地球・資源システム工学）

Academic Significance and Societal Importance of the Research Achievements

低濃度塩水による石油増進回収法(EOR)は従来の化学薬剤を用いるEORに比べて環境負荷が小さく経済的であることから、適用例が増えている。しかし、その油回収率を向上させるメカニズムは十分に解明されておらず、油田によってはその効果がほとんど見られない場合もある。実験やシミュレーションを含む分子スケールの研究を実行することによって、我々は低塩分濃度水攻法によるEORメカニズムに関する新しい理論を提供することができた。