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

我的研究项目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320亿英镑的重油沉积在劳埃德明斯特地区。lloyd dminster稠油油藏具有产层薄（平均厚度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）的特点。冷稠油带砂采油是该地区的主要采油方式。然而，只有10-15%的石油可以用排骨开采。尽管劳埃德明斯特稠油油藏迫切需要提高采收率的方法。目前的提高稠油采收率方法在商业上都不可行。本研究项目提出了一种新的混合工艺——循环热溶剂注入（CHSI）工艺，并将进行基础和应用研究。新发明的CHSI工艺是一种基于单井的工艺，在其露点附近加热溶剂作为注入流体。在CHSI工艺的每个循环中，与CSI工艺类似，有三个阶段：溶剂注入、浸泡和生产。CHSI法所用溶剂为丙烷或丁烷。注入的溶剂可以加热到50-100°C，具体取决于使用哪种溶剂。井筒应隔热，以防止热量通过井筒散失，防止溶剂在井筒中凝结。在注入和浸泡期间，储层中同时发生传热和传质。溶媒携带的潜热和显热向储层/烃系统传递，溶媒溶入稠油。由于储层温度的升高和溶剂的溶解，油的粘度会降低。在采油过程中，储层压力和温度都会逐渐降低。泡沫油流、溶气驱动和重力效应是主要的驱油机理。CHSI工艺是一种新工艺，尚未被其他研究人员研究过。在过去的两年里，我通过国家科学研究委员会的发现发展基金对CHSI过程进行了初步评估，并取得了令人鼓舞的结果。为保护本发明的知识产权，正在申请专利。拟开展的研究项目是评价CHSI过程的性能，更好地了解不同压力和温度效应下CHSI过程的基本物理特性，并在现场尺度上测量评价CHSI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.