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Special Topics & Reviews in Porous Media: An International Journal
ESCI SJR: 0.259 SNIP: 0.466 CiteScore™: 0.83

ISSN Imprimer: 2151-4798
ISSN En ligne: 2151-562X

Special Topics & Reviews in Porous Media: An International Journal

DOI: 10.1615/SpecialTopicsRevPorousMedia.2017022164
pages 37-45

A STUDY OF GAS BUBBLE FORMATION MECHANISM DURING FOAMY OIL DEPLETION EXPERIMENT

Weifeng Lv
Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China; State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC, Beijing, China
Jiru Yang
State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC, Beijing, China
Ninghong Jia
State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC, Beijing, China
Zhibin Jiang
School of Geoscience and Technology, Southwest Petroleum University, Chengdu, China; Research Institute of Petroleum Exploration and Development, PetroChina Xinjiang Oilfield Company, Karamay, China
Tong Li
State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC, Beijing, China
Xu Chen
State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration and Development, CNPC, Beijing, China
Rong Wang
Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
Xiaoliang Wang
Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China

RÉSUMÉ

Solution gas drive is an effective way to yield oil recovery in some heavy oil reservoirs and is also identified as foamy oil, which shows the characteristics of low gas-oil production ratio, high production rate, and exceeds oil recovery prediction. Although many laboratory investigations and field observations were published, the mechanism of gas bubble motion remained an essential issue. In this study, a sandpack study is designed to investigate a foamy oil displacement mechanism by CT scanning. According to oil and gas production during the entire process, there are three stages corresponding to compressibility single oil flow, foamy oil flow, and channel gas flow. Combining oil saturation images and their histograms, the limit of minimal gas generation saturation and the critical gas saturation for gas phase to flow can be confirmed and a series of formulas is created to identify the size and volume of bubbles. The results indicated that the foamy oil stage takes the major contribution to the whole process, and gas presents as disconnected bubbles in this stage to better use the expansion energy of gas until the gas saturation broke through the critical gas saturation to form a continuous gas phase, which decreases the oil recovery.