Cyclic Hot Solvent Injection (CHSI) Process for Enhanced Heavy Oil Recovery in Thin Reservoirs

我的研究计划的长期目标之一是开发有效和高效的技术，以环境可持续的方式解锁加拿大西部的重油资源。加拿大西部拥有世界第二大石油资源。90%以上是重油和沥青。其中，约有320亿吨重油沉积在鄂尔多斯地区。大庆油田稠油油藏具有产层薄（平均3-5 m）、含油饱和度高（平均85%）、渗透率高（平均2D）、粘度高（1000 ~ 12000 cp）等特点。稠油出砂冷采是该地区主要的开采方式。然而，只有10-15%的石油可以用CHOPS生产。即使是稠油油藏，也迫切需要提高采收率的方法。目前的提高稠油采收率的方法没有一种是商业上可行的。 本研究计划提出一种新的混合工艺--循环热溶剂注入工艺，并进行基础研究和应用研究。新发明的CHSI工艺是基于单井的工艺，其中在其接近露点的温度下加热的溶剂用作注入流体。在CHSI工艺的每个循环中，与CSI工艺类似，也有三个阶段：溶剂注入、浸泡和生产。用于CHSI工艺的溶剂是丙烷或丁烷。注入的溶剂可以加热到50-100 ℃，这取决于使用哪种溶剂。 井眼应隔热，以防止通过井眼的热损失和井眼中溶剂的冷凝。在注入和浸泡期间，储层中发生热量和质量传递。由溶剂携带的潜热和显热将被传递到储层/烃系统，并且溶剂将溶解到重油中。由于储层温度的升高和溶剂的溶解，油的粘度将降低。在采油期，储层的压力和温度都将逐渐降低。泡沫油渗流、溶解气驱和重力作用是油气田开发的主要驱动机制。CHSI过程是一个新的过程，尚未被其他研究人员研究过。在过去的两年里，通过我的NSERC发现发展赠款，对CHSI过程进行了初步评估，并取得了可喜的成果。正在申请专利以保护本发明的知识产权。该研究计划旨在评估CHSI过程的性能，更好地了解CHSI过程在不同压力和温度效应下的基本物理，并测量现场规模评估该过程性能所需的基础数据。

One of the long-term goals of my research program is to develop effective and efficient techniques to unlock Western Canada's heavy oil resources in an environmentally sustainable way. Western Canada has the second largest oil resource in the world. Over 90% is heavy oil and bitumen. Among them, about 32 billion of heavy oil is deposited in Lloydminster area. The heavy oil reservoirs in Lloydminster are featured with thin pay-zone (in average 3-5 m thick), high oil saturation (average 85%), high permeability (average 2D), and high viscosity (1000 12,000 cp). Cold Heavy Oil Production with Sand (CHOPS) is the main recovery method in this area. However, only 10-15% of oil can be produced with CHOPS. Even though enhanced oil recovery method is strongly needed for Lloydminster heavy oil reservoir. None of current enhanced heavy oil recovery method is commercially viable. This research program is proposing a new hybrid process, Cyclic Hot Solvent Injection (CHSI) process and both fundamental and application studies will be conducted. The new invented CHSI process is a single well based process where heated solvent in its near dew point is employed as injection fluid. In each cyclic of the CHSI process, similar to CSI process there have three periods: solvent injection, soaking and production. The solvent used for CHSI process is propane or butane. The injected solvent can be heated to 50-100 C, depending on which solvent is used. The wellbore should be insulated in order to prevent heat loss through the well bore and condensation of solvent in the wellbore. During the injection and soaking periods, both heat and mass transfers occur in the reservoir. The latent heat and sensible heat carried by the solvent will be transferred to the reservoir/hydrocarbon system and solvent will dissolve into the heavy oil. The oil viscosity will be reduced due to the increased reservoir temperature and the dissolved solvent. In the oil production period, both pressure and temperature of the reservoir will be decreased gradually. Foamy oil flow, solution gas drive and gravity effects are the main driving mechanisms of the oil production. The CHSI process is a new process and has never been investigated by other researchers yet. During the past two years, through my NSERC Discovery Development Grant preliminary assessment of CHSI process has been conducted and promising results have been obtained. Patent application is in the process to protect the Intellectual Property of this invention. The proposed research program is to evaluate the performance of CHSI process, better understand the fundamental physics of CHSI process under different pressure and temperature effects and measure fundamental data which needed to evaluate the performance of this process in field scale.