Logging response characteristics and formation process of flushed zone in the Orinoco heavy oil belt, Venezuela

• 作者: CHEN Hao CHEN Heping HOU Qiuyuan HUANG Rui LI Changwen LI Jianping TIAN Congcong WANG Yusheng
• 来源期刊: 石油勘探与开发:英文版
• 学科: 工学
• 关键词: flushed zone asphalt crust crude oil thickening freshwater leaching foam oil flow Orinoco heavy oil belt
• 年，卷（期）: 2020,（3）
• 页码范围: 585-593
• 页数: 9页
• 分类号: TE151

摘要

The origins and logging responses of flushed zones in some blocks of Orinoco heavy oil belt, Venezuela are still unclear. To solve this issue, we examined the conventional logging, nuclear magnetic resonance logging, fluid viscosity, core analysis and oil field production data comprehensively to find out the logging responses and origins of the flushed zones. The results show that the main reason for the formation of flushed zone is surface water invasion, which leads to crude oil densification. The crude oil densification produces asphalt membrane(asphalt crust) which wraps up free water, causing special logging responses of the flushed zones. According to the different logging responses, we classified the flushed zones into two types and analyzed the formation processes of the two types of flushed zones. According to the characteristics of logging curves after water flush, we confirmed that the water flush began earlier than the reservoir accumulation.