Effect of Nanoparticles on the Performance of Drilling Fluids
283
3 Enhancement in Drilling Fluid Properties Due
to Nanoparticles
Nanoparticles enhance the rheological properties of the drilling fluids using various
mechanisms which mostly depends on the concentration, physical and chemical
properties of nanoparticle and continuous phase of drilling fluids.
3.1 Effect of Nanoparticles on Rheology
Since drilling fluid is a combination of solids and fluids, controlling the rheological
properties deep under the earth under high pressure and temperature is always a crucial part. Rheological properties are the basics for all analysis of wellbore hydraulics
and to assess the functionality of the mud system. The rheological characteristics
of drilling mud include apparent and plastic viscosity, yield point and gel strength.
Researchers found that addition of various types of nanoparticles to the drilling mud
modified or enhanced the rheological properties. Addition of nanoparticles to the
drilling mud enhanced the plastic and apparent viscosity and maintained the yield
point and gel strength.
The increment in rheological property of the bentonite-based mud by iron oxide
nanoparticles was studied by Jung et al. (2011). Iron oxide nanoparticle of concentration 0.5–5 wt% increased the yield stress and viscosity of the mud. The observed
enhancement in rheological properties is due to the fact that the nanoparticles got
embedded in randomly distributed pore structure on the surface of clay particle in
mud and confers a link between bentonite suspensions and promotes gelation of the
mud. The increment in rheological properties is stable even at high temperature. At
high temperature of 99 °C, the ferric oxide nanoparticle displaces the dissociated
cations from clay and yields a different clay platelet microstructure and gives higher
yield stress value (Mahmoud et al. 2016). Barry et al. (2015) showed that iron oxide
clay hybrid and drilling fluid containing various concentration of iron oxide nanoparticle showed higher stresses at all shear rate compared to the bentonite-based drilling
mud. The nanoparticles can improve the rheological properties of the drilling mud
without the need of any rheological additives and this is also confirmed by Contreras et al. (2014). They used an oil-based drilling fluid prepared with iron oxide
nanoparticle and graphite as a lost circulation material (LCM) rheological additive.
The combination of both the nanoparticle and LCM reduced the yield point at high
graphite concentration. Figure 2a shows the rheogram of bentonite and iron oxidebased drilling mud. Addition of iron oxide nanoparticle to the bentonite-based mud
increased the shear stress with increase in temperature.
It is to be noted that higher temperature yielded higher yield stress of value 7.15 Pa
at 60 °C because higher temperature create continuous gel strength in the bentonite
suspension. The yield stress is calculated from the rheograms after extrapolating
the graphs to zero shear rate and fitted in Herschel–Buckley (HB) model; τ =
283
3 Enhancement in Drilling Fluid Properties Due
to Nanoparticles
Nanoparticles enhance the rheological properties of the drilling fluids using various
mechanisms which mostly depends on the concentration, physical and chemical
properties of nanoparticle and continuous phase of drilling fluids.
3.1 Effect of Nanoparticles on Rheology
Since drilling fluid is a combination of solids and fluids, controlling the rheological
properties deep under the earth under high pressure and temperature is always a crucial part. Rheological properties are the basics for all analysis of wellbore hydraulics
and to assess the functionality of the mud system. The rheological characteristics
of drilling mud include apparent and plastic viscosity, yield point and gel strength.
Researchers found that addition of various types of nanoparticles to the drilling mud
modified or enhanced the rheological properties. Addition of nanoparticles to the
drilling mud enhanced the plastic and apparent viscosity and maintained the yield
point and gel strength.
The increment in rheological property of the bentonite-based mud by iron oxide
nanoparticles was studied by Jung et al. (2011). Iron oxide nanoparticle of concentration 0.5–5 wt% increased the yield stress and viscosity of the mud. The observed
enhancement in rheological properties is due to the fact that the nanoparticles got
embedded in randomly distributed pore structure on the surface of clay particle in
mud and confers a link between bentonite suspensions and promotes gelation of the
mud. The increment in rheological properties is stable even at high temperature. At
high temperature of 99 °C, the ferric oxide nanoparticle displaces the dissociated
cations from clay and yields a different clay platelet microstructure and gives higher
yield stress value (Mahmoud et al. 2016). Barry et al. (2015) showed that iron oxide
clay hybrid and drilling fluid containing various concentration of iron oxide nanoparticle showed higher stresses at all shear rate compared to the bentonite-based drilling
mud. The nanoparticles can improve the rheological properties of the drilling mud
without the need of any rheological additives and this is also confirmed by Contreras et al. (2014). They used an oil-based drilling fluid prepared with iron oxide
nanoparticle and graphite as a lost circulation material (LCM) rheological additive.
The combination of both the nanoparticle and LCM reduced the yield point at high
graphite concentration. Figure 2a shows the rheogram of bentonite and iron oxidebased drilling mud. Addition of iron oxide nanoparticle to the bentonite-based mud
increased the shear stress with increase in temperature.
It is to be noted that higher temperature yielded higher yield stress of value 7.15 Pa
at 60 °C because higher temperature create continuous gel strength in the bentonite
suspension. The yield stress is calculated from the rheograms after extrapolating
the graphs to zero shear rate and fitted in Herschel–Buckley (HB) model; τ =