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Effects of surface modified nanosilica on drilling fluid and formation damage

Hajiabadi, S. H ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.petrol.2020.107559
  3. Publisher: Elsevier B.V , 2020
  4. Abstract:
  5. Despite the fact that hydrophobic nanosilica can improve the stability of water/oil emulsion, there exist controversies pertaining to its influence on oil-based drilling fluid rheological behavior and the subsequent formation damage. The present study addresses the above using a surface modified nanosilica, where the particles were functionalized with different silane-based groups to alter their hydrophilicity: 3-glycidoxypropyl-triethoxy silane (GPTS) and combined GPTS and propyl silane (PGPTS). The NPs were characterized through FTIR analysis, particle size, and zeta-potential measurements followed by flow behavior experiments, core-scale mud flow tests, Computed Tomography (CT) scanning and SEM imaging techniques to determine the mud penetration depth. We found that, depending on the type of functionalized group and the size of NPs, the surface modification of NPs can enhance the rheological properties and mitigate formation-damage. The most desirable behavior, both in terms of the plastic viscosity and yield stress, was achieved with 15 nm size NPs. The functionalized NP with the 3-glycidoxypropyl-triethoxy silane (GPTS@SiO2), which is less hydrophilic compared with bare NP, improved plastic viscosity of the drilling fluid, however slightly deteriorated the yield stress. This was compensated for by adding a double amount of GPTS on the surface of NP (DGPTS@SiO2), which was shown to be more effective than merely increasing the GPTS content in the drilling fluid. Further improvement of rheological properties was made by combining GPTS and propyl silane (PGPTS@SiO2); implying the positive effect of reducing hydrophilicity on both the plastic viscosity and yield stress. It is noteworthy that surface modifications were identified to be efficient below an optimal concentration of 1 wt% of NPs due to the lack of particle agglomeration. Moreover, a decreasing trend in plastic viscosity was observed against increasing temperature as a result of lowering viscosity of the continuous phase. Meanwhile, the yield stress experienced greater changes versus temperature due to the larger dependency of the interactions between drilling fluids components on temperature. In addition, the results were further validated through a series of core-flow tests which showed that with the aid of the nano-based drilling fluids (NDFs) containing DGPTS@SiO2 and GPTS@SiO2 the penetration depth of mud, thus the degree of internal formation damage can be significantly reduced. © 2020 Elsevier B.V
  6. Keywords:
  7. Formation damage ; Functionalized nanosilica ; Nano-drilling-fluid ; Rheological behavior ; Computerized tomography ; Drilling fluids ; Emulsification ; Hydrophilicity ; Infill drilling ; Particle size ; Particle size analysis ; Rheology ; Silanes ; Silica ; Silicon ; Viscosity ; Increasing temperatures ; Oil-based drilling fluid ; Optimal concentration ; Particle agglomerations ; Plastic viscosity ; Rheological behaviors ; Rheological property ; Zeta potential measurements ; Yield stress ; Drilling ; FTIR spectroscopy ; Hydrocarbon reservoir ; Numerical model ; Scanning electron microscopy
  8. Source: Journal of Petroleum Science and Engineering ; Volume 194 , 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0920410520306306