Mechanistic Study of Surfactant-Alternating-Solvent Foam Process for Improving Heavy Oil Recovery

表面活性剂-溶剂交替泡沫工艺提高稠油采收率机理研究

• 批准号: RGPIN-2014-05394
• 负责人: Li, Huazhou
• 金额: $ 1.53万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=657446
• 关键词: Mechanistic; Study; Surfactant; Alternating; Solvent

Canada has the largest heavy oil reserves worldwide with around 3 trillion bbls of heavy oil and tar sands, among which a large amount of heavy oil with 15-20°API is contained in thin payzones with thickness less than 10 m in Alberta and Saskatchewan. It is a challenging task to recover heavy oil from such thin payzones with thermal methods either because of the extensive heat loss to overburden and underlying zones or due to high reservoir heterogeneity characterized with low vertical permeability but high horizontal permeability. Solvent injection provides new opportunity for developing these thin heavy-oil reservoirs. Water-alternating-solvent process is proven by laboratory study to be more effective for improving heavy oil recovery compared to continuous solvent injection. This is mainly attributed to the improved sweep efficiency due to water injection and delayed solvent breakthrough. However, the low viscosity of water and solvent still makes the mobility ratio of injectant and heavy oil undesirable, and solvent overriding in a reservoir can still be problematic. In this proposed research, a new process, i.e., the surfactant-alternating-solvent foam process, will be explored to examine its underlying mechanisms for improving mobility control, reducing solvent overriding effect, and hence enhancing heavy oil recovery. The novelty of the proposed surfactant-alternating-solvent foam process lies on two important mechanisms: (1) dissolution of solvent(s) in heavy oil leads to swelling the oil and reducing its viscosity; and (2) the foam generation offers a further mobility reduction in addition to that given by water-alternating-solvent process, as well as a better conformance control by mitigating gas overriding effect in the reservoir. These two fundamental mechanisms are expected to result in lower residual oil saturation. This proposal will conduct experimental and theoretical studies to explore the fundamental mechanisms that affect the recovery performance of surfactant-alternating-solvent foam process. The findings from this research will provide critical insights and pragmatic methods for enhancing oil recovery in thin heavy oil reservoirs.

加拿大拥有全球最大的重油储量，其中约3万亿英里的重油和焦油砂，其中大量的重油含有15-20°API的薄薄薪水，厚度小于10 m，艾伯塔省和萨斯喀彻温省的厚度小于10 m。通过热方法从这样的薄薪资区中回收重油是一项挑战任务，这是因为对覆盖层和下层区域的热量损失很大，或者是由于具有低垂直渗透性但水平较高的渗透率的高晶状体异质性。溶剂注入为开发这些薄层厚油的储量提供了新的机会。与连续溶剂注入相比，实验室研究证明了水抗溶剂的过程对改善重油的回收率更有效。这主要归因于由于注水和延迟溶剂突破而提高的扫描效率。但是，水和解决的低粘度仍然使注入和重油的迁移率不受欢迎，并且在储层中解决的压倒力仍然可能是有问题的。在这项拟议的研究中，将探索一个新的过程，即潜在的溶剂泡沫工艺，以检查其改善移动性控制的基本机制，减少解决的压力效应，从而增强重油的回收率。所提出的基础抗溶剂泡沫工艺的新颖性在于两个重要机制：（1）溶液在重油中的溶解导致吞咽油并降低其粘度； （2）除了通过水的溶剂过程给出的泡沫生成外，泡沫生成还提供了进一步的迁移率，以及通过减轻储层中的气体压力效应来更好地控制。预计这两种基本机制将导致剩余的油饱和度降低。该提案将进行实验和理论研究，以探索影响表面活性剂 - 抗溶剂的泡沫工艺的恢复性能的基本机制。这项研究的发现将提供关键的见解和务实方法，以增强稀薄的石油储层中的油回收率。