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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

基本信息

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

项目摘要

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，约3万亿桶重油和焦油砂，其中阿尔伯塔省和萨斯喀彻温省厚度小于10 m的薄产层蕴藏有大量API为15-20°的重油。用热法从如此薄的产层中开采稠油是一项具有挑战性的任务，这要么是因为上覆岩层和下伏区域的大量热量损失，要么是由于以低垂直渗透率但高水平渗透率为特征的储层非均质性高。溶剂注入为开发这些薄稠油油藏提供了新的机遇。实验室研究证明，与连续溶剂注入相比，水交替溶剂工艺对于提高稠油采收率更有效。这主要归因于注水和延迟溶剂突破而提高了波及效率。然而，水和溶剂的低粘度仍然使得注入物和稠油的流度比不理想，并且油藏中的溶剂覆盖仍然是问题。在这项拟议的研究中，将探索一种新工艺，即表面活性剂-交替-溶剂泡沫工艺，以研究其改善流度控制、减少溶剂覆盖效应、从而提高稠油采收率的潜在机制。所提出的表面活性剂-溶剂交替泡沫工艺的新颖性在于两个重要机制：（1）重油中溶剂的溶解导致油溶胀并降低其粘度； (2)除了水交替溶剂工艺之外，泡沫的产生还进一步降低了流动性，并且通过减轻储层中的气体覆盖效应来提供更好的一致性控制。这两个基本机制预计将导致较低的残余油饱和度。该提案将进行实验和理论研究，探讨影响表面活性剂-溶剂交替泡沫过程的恢复性能的基本机制。这项研究的结果将为提高薄稠油油藏的石油采收率提供重要的见解和实用的方法。