Experimental and Modeling Investigation of Wettability Alteration to Gas Wetting Condition in Gas Condensate Reservoirs

Erfani Gahrooei, Hamid Reza | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47465 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Ghazanfari, Mohammad Hossein
  7. Abstract:
  8. During production from gas condensate reservoirs, reservoir pressure decreses to lower than dew point pressure of the reservoir fluid. Consequently, condensates will form in near wellbore regions, which significantly decrease well productivity. One of the remediations that is recently proposed for solving this problem is wettability alteration of near wellbore region to gas wetting condition. In comparison to other methods, it provides a better permanency, which is its key advantage. The main purpose of this thesis is, quantitative, qualitative and modeling study of wettability alteration of rock to gas wetting condition and verification of modeling rsults for a reservoir rock sample. Also, a new hydrocarbon based chemical is proposed for this application for the first time.We have used SEM and EDX tests for evaluation of coating ability of proposed chemical on carbonate and sandstone surfaces, atomic analysis of formed layer and quality of coating.We performed some tests in thin-section and core scale with purpose of evaluating the proposed chemical ability in changing the wettability of rock, such as measuring static and dynamic contact angles, spontaneous imbibition and core flooding. In addition to proposed hydrocarbon based chemical, we used another water based nano-fluid, which was used in previous researches, for performing adsorption and stability tests. Dynamic contact angle measurement results show that, surface free energy and surface roughness of calcite was decreased significantly after coating with wettability alteration agent, that shows lower tendency to condensate. The results of air-water and air-kerosene spontaneous imbibition tests in core scale prove that, oil and water repellency was induced to rock surface after its treatment with chemical agents. Estimation of water capillary pressure for aforementioned experiments also demonstrates dramatic change of wettability of the rock. Core flooding experiments prove that mobility of the liquid phase have increased notably after wettability alteration. Proper functioning of proposed hydrocarbon based chemical, introduces it as a candidate for usage in gas condensate reservoirs for wettability alteration of reservoir rock to gas wettig condition
  9. Keywords:
  10. Gas Condensate Reservoirs ; Modeling ; Wettability Alteration ; Dynamic Contact ; Contact Angle ; Core Flooding ; Gas Wetting Condition

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