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Hochleiten油田是一个边际油田,位于维也纳北部,该油田的原油被高度隔离封存并且很黏稠,极具挑战性。主要油层深度约为1000m,仅在该储层的部分区域进行了水驱,观测到油层连通差并且整个油田的压差大。在筛选开采未波及到原油的工艺过程中,证明用CO2作为选择介质进行注气是最有前途的方法。选择了中部隔离区作为先导性试验区,因为到目前为止没有在该试验区进行水驱。最初估算最终采收率约为25%,由于在目标区采用EOR方法能够使最终采收率再提高5%。以吞吐方式注CO2,同时对周围井进行监测。正如所预计的那样,注入井和一口邻井之间的断层不密封,因此出现了早期气突破。CO2提高了注入井的注入能力,但是见效井的增油量幅度却很小。为了拟合该储层的实际效果,必须调整储层模型。为了证实现有的储层描述,进行了N2示踪试验以便找出油层最佳连通通道。最后得出结论,注气过程中的关键是油藏描述、数据准备、与技术顾问的交流和油藏监测试验结果。
The Hochleiten oil field is a marginal oil field located in the northern part of Vienna. The oil in this field is highly isolated, sequestered and very viscous, challenging. The main reservoir depth is about 1000 m. Only water flooding has been carried out in parts of the reservoir, poor reservoir connectivity is observed, and the pressure differential across the field is high. It is the most promising approach to demonstrate gas injection with CO2 as the selection medium during the screening process that does not affect crude oil. The Central Quarantine was chosen as a pilot area because so far no water flooding has been carried out in this area. The initial estimated final recovery rate was about 25%, since the final recovery rate can be increased by 5% due to the EOR method in the target zone. CO2 injection through the huff and puff, and monitoring the surrounding wells. As expected, faults between the injection well and a neighboring well were not sealed and an early gas breakthrough occurred. CO2 has increased the injection capacity of injection wells, but the effective oil production has only marginally increased. In order to fit the actual effect of the reservoir, the reservoir model must be adjusted. In order to confirm the existing reservoir description, an N2 tracer test was conducted to find the best communication path for the reservoir. Finally, it is concluded that the key points in gas injection process are reservoir description, data preparation, communication with technical advisors and reservoir monitoring test results.