A Study of the Performance of Nanomaterials on Water Base Drilling Fluid

Abstract: This study is an attempt to investigate the effect of nanomaterials on the water base drilling mud properties. Two types of nano materials were investigated, are Multi Walled Carbone Nano Tube (MWCNT) and nano silicon oxide (SiO2).The investigated properties of drilling mud with the rheological properties (Plastic viscosity, yield point, Apparent viscosity and Gel strength), filtration ,and lubricity test are investigated. In addition, effects of high temperature on these properties were studied. All tests are conducted according to API specification and proceed in Petroleum Research and Development Center (PRDC). The experimental results show that a significant improvements in the lubricity test and the rheological properties such as yield point, filtration properties of the MWCNT and nano silicon oxide modified drilling fluid compared with the base drilling fluid. Also a significant improvement in the rheological properties at using combined of nanomaterials (MWCNT and nanoSio2) and reduction of filter loss at using nanosilicon oxide compared with fluid loss reducer.


No.23-(6) 2019 Journal of Petroleum Research & Studies (JPR&S)
E87 Introduction: Drilling Fluids: Drilling deeper, longer and challenges in wells have been made possible by improvements in drilling technologies, including more efficient and effective drilling fluids. Drilling fluids, also referred to as drilling mud, are added to the wellbore to facilitate the drilling process by suspending cuttings, controlling pressure, stabilizing exposed rock, providing buoyancy, and cooling and lubricating [1].

Nano-Technology:
Nanotechnology is becoming a widely popular in every aspect of science and technology.
It involves using particles which are of 1-100 nm in size. It can play a major role in solving some of the most common problems encountered by drilling [2]. Amanullah and Al-Tahini [Amanullah and Al-Tahini, 2009] classified the nano-fluids as simple or advanced nano-fluids based on the nanoparticles concentration in the drilling fluid.
Nano-particles can be customized for achieving single or multiple functionalities. Nanoparticles have a very high surface area to volume ratio which increases the reactivity of the nanoparticles as shown in Figure (1). Due to this fact, the amount of nanoparticles required for any application is much less which reduces the cost to a great extent [3].
The smart fluid containing multifunctional nano-particles can be customized to form a thin layer of non-erodible and impermeable nanoparticle membrane around the wellbore which prevents some of the most common problems like shale swelling, spurt loss and mud loss due to lost circulation. This simple process eliminates the addition of fluid loss additives, shale inhibitors, rheology modifiers, formation strengthening materials etc. [4].
These nano-particle membranes are very useful during drilling application and can be removed easily during clean-up before the completion process. This is very helpful in deviated, horizontal and extended reach wells. The smart fluids can be used in reducing the torque and drag in the drilling process. The nano-particles form a continuous thin film around the drill-pipe,This provides lubrication and thus reduces the torque and drag problems. The same concept can be used to reduce the differential pipe sticking problem. [5].

Effect of NANO FLUIDS on Drilling:
Nanofluids can be designed by adding nanosized particles in low volumetric fractions to a fluid. The nanoparticles improve the fluid's rheological, mechanical, optical, and thermal properties. Suspensions of nanosized particles may provide the following advantages: (1) Nanosized particles can have enhanced stability against sedimentation since surface forces easily balance the gravity force, and (2) Thermal, optical, mechanical, electrical, rheological, and magnetic properties of nanoparticles, which depend significantly on size and shape, of these particles [6].

The Aim of The Study:
The aim of this study is to investigate the effect of nanomaterial by adding with water base drilling fluids to examine the performance of this nano material on the rheological properties, filter loss and lubricity test of water base drilling fluids. In this work, the nanomaterial uses MWCNT (Multiwall Carbone Nanotube) and nano Sio 2 (silicon oxide).

Nano material properties:
Good formulations of drilling fluid properties are required in drilling operations.
Selection of suitable drilling fluid additives are important criterion in formulating drilling fluid. Nanomaterial selected in this study due to its extremely high surface area to volume ratio and high thermal conductivity. This research is focused on use the multiwalled carbon nanotubes (MWCNTs) and nanosilicon materials to investigate the effect
Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, significantly larger than for any other material [7]. Nanotubes are categorized as singlewalled nanotubes (SWNTs), and multi-walled nanotubes (MWNTs) [8].
Single-walled nanotubes (SWNTs) have a diameter of close to 1 nanometer, with a tube length that can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping an oneatom-thick layer of graphite called graphene into a seamless cylinder [9].

Nano silicon
Silicon dioxide nanoparticles, also known as silica nanoparticles or nanosilica, are the basis for a great deal of biomedical research due to their stability, low toxicity and ability to be functionalized with a range of molecules and polymers [11].
Physical Properties: Silicon dioxide nanoparticles appear in the form of a white powder.
Density is 2.4 g/cm3 and molar mass is 59.96 g/mol.

Experimental work and Apparatuses:
In order to evaluate and enhance mud performance, many tests carried out in laboratory to investigate the effect of nanomaterial on the rehology, filter loss and lubricity of drilling fluids.
The nano silicon dioxide (SiO 2 ) and multiwalled carbon nano tube (MWCNT) as nano materials are used in this work.

Materials
Before going into the experiments, a brief description of all chemicals and additives used in this study listed below:

MWCNT (MULTI-WALLED CARBON NANOTUBES):
By generating better rheological properties in water-based drilling fluid Characterization of the MWCNT that use in this study are: Table (1)

Table (1) Characterization of MWCNT Silicon Dioxide (SiO 2 )
White powder used to improve the rheological properties and filter loss with OD >40nm.  A phenomenon known as "shear thinning" occurs when the effective viscosity is high at low shear rates and low at high or increased shear rate, this obvious at Figures (13, 14) for both MWCNT & nano SiO 2 . The results of Tables (3,4) were plotted as shown in

Combined effect of nano materials
In this test it prepared three samples of nanomud by mixing nano silicon oxide with multi In all samples, the aging for 16 hours by taking the measurements of viscosity, density, pH and filtration of the laboratory condition and the results are shown in Table (8).   The laboratory measurements included measuring mud weight, pH, viscosity, and standard API filter test at laboratory condition and the results were as follows:

Result of lubricity test:
Lubricity test was designed to simulate the speed of rotation of the drill pipe and the pressure with the pipe bears against the wall of the bore hole. Table (10) shows the result of lubricity test on base drilling fluids (blank) and adding of SiO 2 and MWCNT.

Table (10) Results of lubricity test
The nano-particles form a continuous thin film around the drill-pipe. This provides lubrication and thus reduces the torque and drag problems.

Conclusion
Based on this experimental study, several conclusions have been made: 1-An increase concentration in MWCNT and nano silicon oxide (SiO 2 ) resulted in higher plastic viscosity, yield point and gel strength for water base drilling fluid.
2-An increase in temperature of nanofluids in comparison with conventional fluid increase of plastic viscosity, yield point and gel strength for water base drilling fluid.
3-An addition of nanoparticles (MWCNT and nano silicon oxide (SiO 2 )) into water base drilling fluid give better results because the fluid loss and the filter cake thickness were reduced.
4-The nanoparticles (SiO 2 ) proved to be more effective in reducing the filtrate losses than conventional fluid loss reducer (PAC-LV).
5-An addition of nanoparticles (MWCNT and nano silicon oxide (SiO 2 )) into water base drilling fluid give better results by reducing the friction factor of drilling fluid compared with the conventional fluid.