Investigating the Role of Nanoparticles and Chemicals on Wettability Alteration of Carbonate Rocks to Gas-Weting Condition and Analysis of Hystertic Behavior

Azadi Tabar, Mohammad | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50405 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ghazanfari, Mohammad Hossein
  7. Abstract:
  8. The purpose of this study was to investigate the experimental and modeling of the drop formation process on calcite rock and calcite aged in nano fluid surfaces in order to analyze size dependent contact angle and wettability modification. To do this, the calcite surfaces were prepared by cutting to an approximately size of 3*3*0.4 cm and grinded and polished to achieve different roughnesses. The purity and roughness of the samples were determined by X-ray diffraction and atomic force microscopy, respectively. In order to conduct the dynamic and static contact angle measurements on the calcite surface in vapor saturated condition, a small laboratory device was designed. The advanced contact angle measurement in sessile drop experiment method consist of three distinct region including: drilled hole, line tension and stick-slip behavior. In the first region, the contact angle increases with increasing droplet volume. Whereas in the second region, for positive line tension values, as drop volume is increased, the conract angle is deacresed. In the third region, the contact angle oscillates between two values which depend on the roughness and surface heterogeneity. The result showed that the duration of first region directly depends on the the hole diameter and the infinite contact angle of the drop on the calcite surface. The contact angle variation in the second region, which is due to line/psedo line tension effects, increases with increasing roughness. In the static contact angle studies section, surface energy of calcite and calcite aged in nano-fluid determined by geometric mean, arithmetic mean and Zisman plot show values between 30-40 mN/m, and polar forces overcome dispersion force. After aging calcite in the nano fluid, surface energy decreased to lower than 12 mN/m. Reduction of surface energy indicates an increase in the contact angle of the fluid on the surface of the aged calcite in the nano fluid. In order to determine the contact angle of symmetric or asymmetric drop, an algorithm for simultaneous detection of the drop profile and the three phase (fluid-rock-fluid) contact point with horizontal, inclined and curved surfaces is presented. Also the application range of the Cassie-Baxter equation for predicting the apparent contact angle of drop on rough surface has been investigated. The calculated contact angle of this method is compared with the value obtained from the developed numerical method, moreover the concept of the length fraction proposed by Yarslav and Miller is investigated. The length fraction and surface fraction obtained in this work show oscillation behavior around the Cassie-Baxter prediction. When the drop radius tends to infinity, both values of surface and length fractions approach to the Cassie-Baxter prediction. Investigating the rock surfaces not only can positively help to change the substrate properties but also determine the transport behavior and mobility of fluids through porous media. Thus, a deep understanding of these features may help to better design a successful wettability modifier to assist condensate recovery process
  9. Keywords:
  10. Nanoparticles ; Wettability Alteration ; Gas Wetting Condition ; Hysteresis Behavior ; Wetting ; Carbonate Resrevoirs ; Linear Tension

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