垂直水平フラクチャー型油層における有機溶剤抽出プロセスによる重質油増進回収 Improved Heavy Oil Recovery by VAPEX Process in the Presence of Vertical and Horizontal Fractures
重質油回収の手法としてSAGD（Steam Assisted Gravity Drainage）を含む水蒸気攻法と比べ，水蒸気生成や燃料油ガス使用の少ないことからコストの点で勝ると想定されるエチレン，プロパン等の有機溶剤を用いたVAPEX（Vapor Extraction）法につき，水平垂直フラクチャーを設定したセルおよび設定していないセルを用いた実験的手法により圧力およびフラクチャー密度が原油回収に与える影響に関する検討を実施した。<br>その結果，圧力が高いほど原油回収量は増大すること，有機溶剤の露点以下の圧力では回収率が急激に低下すること，さらにはフラクチャーの存在により油層のマトリックス部における溶剤と原油の接触が促進されることにより原油回収が増大することが確認された。
Vapor extraction (VAPEX) is an important process for recovery of heavy oil and bitumen. In this work, the VAPEX process is studied experimentally in a rectangular physical model. The setup was constructed in a manner allowing experiments in both fractured and non-fractured systems. Propane was used as the solvent in all experiments. The experiments were conducted with pure solvent and different configurations of fracture-matrix contacts. Effects of pressure and number of side fractures were studied in this work. Results showed that the oil recovery increased with pressure. In addition, we found for the first time that there is a pressure range below the solvent dew point that the process can be performed efficiently. This has an advantage to the process and prevents any pore space blocking in the system due to solvent condensation caused by sudden pressure drops in the connecting lines, as the solvent has the tendency for condensation at conditions near to its dew point pressure. It was also found that the fractures can enhance heavy oil recovery during VAPEX process by improving the contact between solvent and oil contained in the matrix block, increasing the cross flow of solvent and oil between matrix and fracture, and also by providing more area for solvent diffusion into the heavy oil. These findings increase industry confidence for application of VAPEX process in both conventional and fractured reservoirs for exploitation of heavy oil resources.
- Journal of the Japan Petroleum Institute
Journal of the Japan Petroleum Institute 50(6), 340-348, 2007-11-01
The Japan Petroleum Institute