Effect of Temperature, Phase Change, and Chemical Additive on Interfacial Properties and Performance of Steam Applications

• Author / Creator

  Pratama, Randy A

• When considering the wettability state during steam applications, we find that most issues remain unanswered. Removal of polar groups from the rock surface with increasing temperature improves water wettability; however, other factors, including phase change, play a reverse role. In other words, hot water or steam shows different wettability characteristics, eventually affecting the recovery. Alternatively, wettability can be altered using steam additives. The mechanism of this phenomenon is not yet clear. The objective of this work is to quantitatively evaluate the steam-induced wettability alteration caused by phase change of water and chemical additives in different rock systems and qualitatively visualize the phenomenon by encompassing pore-scale micromodel to further investigate phase distribution and oil entrapment mechanisms in the porous media.

  All experiments were conducted at a temperature ranging up to 200°C using a high-temperature high-pressure IFT device and glass bead micromodel. To obtain a comprehensive understanding of this process, different factors, including the phase of water, pressure, rock-type, contact sequence, phase distribution, and oil entrapment were considered and studied separately. To study the effect of pressure on wettability, we started with maintaining the water in liquid phase and measured the contact angles between the oil and water at different pressures. Next, the contact angle was measured in pure steam by keeping the pressure lower than saturation pressure. The influence of contact sequence was investigated by reversing the sequence of generating steam and introducing oil during measurement; these measurements were repeated on different substrates.

  For micromodel visualization, the models were initially saturated with brine solution and then displaced the oil phase to maintain initial water and oil saturation. Hot-water was then constantly injected into the micromodels to evaluate the impact of phase change and wettability status on residual saturation development. Similar parameters were also evaluated in pure steam injection by elevating the temperature to match the steam temperature and maintaining pressure below saturation pressure. Different temperature resistant chemical additives including conventional chemicals additives—alkalis, surfactants, ionic liquid—and novel chemicals additives—biodiesel, Switchable-Hydrophilicity Tertiary Amines (SHTA), nanofluids (dispersed SiO2 and ZrO2), ethers, alcohols, and chelating agents—were added to the system.

  The results showed that wettability of tested substrates is not sensitive to pressure as long as the phase has not been changed. The system, however, was observed to be more oil-wet in steam than in water at the same temperature in the calcite test. The wettability state could be altered by utilizing chemical additives in certain ranges of concentration; moreover, the result of the experiments in the glass bead micromodel presented that phase distribution and wettability state were sensitive to steam phase (vapor yielded oil-wet or condensate yielded water-wet case). At any circumstances, wettability alteration with chemicals was possible. The shape and characteristics of the trapped oil with and without chemicals were identified through micromodel images and suggestions were made as to the conditions (pressure, temperature, and time to apply during the injection application) at which these chemicals show optimal performance.

  Analysis of the degree of wettability alteration induced by steam (or hot-water) and temperature was helpful to further understand the interfacial properties of the steam/bitumen/rock system, as well as proving useful in the recovery performance estimation of the steam injection process in carbonate and sand reservoirs, specifically in chemically enhanced heavy-oil recovery. According to this research, conventional steam additives can be altered by these novel chemicals that are both cheaper and more thermally stable, thus showing potential and appearing promising for steam wettability improvement and surface tension reduction in steam applications. In addition, the study and analysis of phase distribution and wettability change in micromodels during hot-water and steam applications provides useful data and understanding of interfacial properties, oil trapping mechanism, and the recovery performance of rock/bitumen/hot-water or steam system in the reservoirs. For practitioners, chemical additives were recommended, validated by visual images and thermal stability tests.

• Subjects / Keywords

  • Wettability alteration
  • Oil entrapment
  • Phase change
  • Nano materials
  • Chemical and nanofluid additives
  • Steam injection efficiency
  • Oil sands
  • Chemical additive
  • Grosmont carbonates
  • Steam injection
  • Residual oil
  • Interfacial tension
  • Wettability change
  • Micromodels
  • Phase distribution
  • Contact angle

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-m5e5-z008

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.