Use of Nano-Metal Particles for Promoting Aquathermolysis Reaction during Cyclic Steam Stimulation

  • Author / Creator
    Yi, Siyuan
  • Cyclic steam stimulation (CSS) is one of the commonly used thermal extraction methods for heavy oil and bitumen. However, CSS is still daunted by the lower oil recovery factor compared with other thermal recovery methods, such as steam-assisted gravity drainage (SAGD). Nano-metal particles, due to a high surface to volume ratio, can catalyze the reactions and in-situ upgrade heavy oil, which could potentially help to increase the oil recovery factor in CSS. This thesis aims to investigate the catalytic effect of different types of nano-metal particles on oil recovery factor. A series of recovery experiments simulating the CSS process were first conducted using nickel nanoparticles. The optimum nickel nanoparticle concentration, the effect of the particle’s penetration depth on oil recovery, and the performance of the particles at lower temperatures were investigated in detail. Experimental results show that the best concentration of nickel nanoparticle, which gave the highest ultimate oil recovery factor (RF), was 0.20 wt% of initial oil in place (IOIP) under 220°C, whereas the nickel concentration of 0.05 wt% provided the highest RFs at the early stages. A lower temperature of 150°C provided a much-lower RF than 220°C, which was mainly because of a lower level of aquathermolysis reactions. By analyzing the compositions of produced oil and gas samples with saturates-asphaltenes-resins-aromatics (SARA) test and gas-chromatography (GC) analysis, we confirm that the major reaction mechanism during the aquathermolysis reaction is the breakage of the carbon/sulfur (C/S) bond; the nickel nanoparticles can act as catalyst for the aquathermolysis reaction; and the catalytic effect becomes less remarkable from cycle to cycle. One run of the experiment to test the effect of particle-penetration depth revealed that the nickel nanoparticles distributed near the injection port greatly contributed to the ultimate RF. Next, a series of CSS experiments with the use of nickel and iron oxide nanoparticles were conducted under 220°C to compare their performance in promoting the aquathermolysis. During the experiments, we monitored the variations of oil recovery factor, produced-oil viscosity, produced-gas composition, and water production. The experimental results show that both nickel and iron oxide nanoparticles can act as catalyst for aquathermolysis reactions and reduce the viscosity of heavy oil. However, their catalytic effect differs dramatically. Nickel nanoparticle can break C-S bond more effectively than iron oxide nanoparticle, together achieving a higher ultimate oil recovery factor. Along with the boosted oil production, the water production was also increased from the very first cycle after introducing the nano-metal particles in CSS. The GC analysis and the pressure data recorded during each soaking period revealed that a higher amount of evolved gas was generated in the early stage, which increased the reservoir pressure and forced more condensed water produced from the sandpack. The last part of this thesis mainly focuses on how to achieve stabilized nickel nanoparticle suspensions. To stabilize the nickel nanoparticle suspension, Xanthan gum polymer and surfactant (SDS, CTAB or Hypermer KD-2) were introduced into the nickel nanoparticle suspensions. Visual tests were then conducted to observe how the nickel nanoparticles would settle in the suspensions; factors, including polymer concentration, surfactant type, surfactant concentration, were considered in the tests. Zeta potentials of the suspensions were also measured. The following three nickel nanoparticle suspensions recipes were found to be most stable: 1. 1 wt% Ni/0.35 wt% SDS/0.045 wt% Xanthan; 2. 1 wt% Ni/0.35 wt%/Hypermer KD-2/0.045 wt% Xanthan; and 3. 2 wt% Ni/0.5 wt% SDS/0.06 wt% Xanthan. Micromodel-based visualization tests were conducted on the three suspensions to reveal how the nickel nanoparticles would travel and distribute in the porous media when being injected into the porous media. Test results showed that most nickel nanoparticles were able to pass through the gaps between the sand grains; only a small amount of the nickel nanoparticles became attached to the grain surface. A higher nickel concentration in the suspension could lead to agglomeration of nickel nanoparticles in the porous media, while a lower concentration could mitigate this problem. Moreover, clusters tended to form when the nickel nanoparticle suspension carried an electrical charge opposite to that of the porous media. Follow-up water flooding was initiated after the nanofluid injection. It was found that the water flooding could not flush away the nanoparticles remaining in the micromodel.

  • Subjects / Keywords
  • Graduation date
    Fall 2017
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.