Steam assisted gravity drainage (SAGD) has been known as a commercially proven high ultimate recovery process for bitumen and heavy crudes. It is an energy intensive process, which is economical when oil price is above certain value. When the oil price goes below the economic threshold of project, steam injection can be decreased or completely stopped for a certain period of time, and can resume thereafter when the condition alters. The objective of this study is to provide comprehensive information about the effect of steam injection interruptions on thermal project performance. An optimization strategy for the SAGD process, in cases where steam injection interruption occurs, is discussed using actual reservoir models of different geological formations. An economical model is used to evaluate operating strategy effect on the net present value (NPV) of the project. The parameters, like shut‐in period, initial steam injection period, etc, are optimized for Athabasca type oil sand reservoirs. The results show several key mechanisms exist in the life cycle of the SAGD process that must be included to reflect the field scale behaviour; otherwise, the mechanistic simplicity of the models could lead to directional and semi‐quantitative conclusions. Among the mechanisms, temperature effect on basic petrophysical properties of reservoir rocks was found to have an important role in the oil recovery, and considerably impacts the results of optimization. When the steam injection is interrupted, an optimum shut‐in period can be determined to maximize the oil recovery. The optimum length of steam injection interruption depends on the initial steam injection period.

中文翻译：

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低油价的优化策略及其对SAGD长期项目的影响

蒸汽辅助重力排水（SAGD）已被公认为是沥青和重质原油的高最终回收率工艺。这是一个能源密集型过程，当油价高于一定值时，这是经济的。当油价低于项目的经济阈值时，可以在一定时间内减少或完全停止注汽，然后在情况发生变化时恢复喷注。这项研究的目的是提供有关蒸汽注入中断对热工项目绩效影响的综合信息。在使用蒸汽注入中断的情况下，使用不同地质构造的实际储层模型讨论了SAGD工艺的优化策略。经济模型用于评估运营策略对项目净现值（NPV）的影响。对于阿萨巴斯卡型油砂储层，优化了诸如关闭期，初始蒸汽注入期等参数。结果表明，SAGD过程生命周期中存在几种关键机制，必须包括这些机制才能反映出油田规模行为。否则，模型的机械简单性可能导致方向性和半定量结论。在这些机理中，温度对储层岩石基本岩石物理特性的影响被发现在采油中起着重要作用，并极大地影响了优化结果。当蒸汽注入中断时，可以确定最佳关闭时间，以最大程度地回收油。