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Laboratory and Modeling Study of Formation Injectivity Decline Due to Mineral Scale Deposition in Water Injection in one of Iranian Oil Resrvoirs

Hashemkhani, Mohammed | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49672 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Masihi, Mohsen; Ghazanfari, Mohammad Hossein
  7. Abstract:
  8. Scale deposition is one of the reasons of formation damage during water injection process. This phenomenon often ocuures when two incompatible waters that interact chemically and precipitate minerals, mix within the reservoir. A typical example is sea water, with high concentration of sulfate ion and formation water, with high concentrations of calcium and/or barium ions. Mixing of these waters, therefore, can cause precipitation of calcium sulfate and/or barium sulfate. This study was conducted to investigate the permeability reduction caused by deposition of calcium and barium sulfates in carbonate cores from mixing of injected sea water and formation water in two flow rates and two temperatures. Effect of a sulfonated inhibitor and nanosilica particles for improving rock permeability have been investigated. Also conductivity changes during mixing formation waters and sea waters, have been studied. A simple model is presented for predicting permeability decine along the core due to barium sulfate precipitation. The static results showed thatconductivity decreases as sea water is added to the formation water. Also, sulfonated inhibitor and nanosilica particles can improve the conductivity and so decrease the amount of scales. Effect of these inhibitors is better for calcium sulfate. Dynamic results showed that injection of sea water into the cores saturated with formation water, cause serious damage to the permeability of the rock. At higher flow rates, the amount of formatin damage increases. At higher temperature than room temperature, the deposition of CaSO4 scales increases and the deposition of BaSO4 scale decreases. The deposition of CaSO4and BaSO4 scales before and after the dynamic scale experiments was shown by Scanning Electron Microscopy micrographs. The presented model showed that the use of nanosilica particles can decrease the formation damage coefficient and kinetic coefficient which shows reduction of damage to the cores
  9. Keywords:
  10. Inhibitor ; Formation Damage ; Electrical Conductivity ; Water Injection ; Mineral Precipitation ; Scale Formation ; Iranian Oil Reservoirs

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