Mud Viscosity Research Articles

Modeling cryogenic mud volcanism on Pluto

Subsurface ice cryofluids and ice interactions with ammonia for cryovolcanic materials give the potential ingredients for the formation of mud volcanoes on Pluto. In order to constrain the possible morphology from images acquired by the New Horizons spacecraft, we have modeled the formation of mud volcanoes, isostatic layers of ice overlain by denser material, from a series of possible solid-liquid “mud” compositions (methane and ammonia), as well as accounting for the full range of eruption variables (e.g., mud viscosity, conduit diameter, and eruption duration). We categorize them into nine specific scenarios based on the composition of the top ice layer and mud composition. From these scenarios, the maximum height of the potential mud volcano can be calculated. We find that ammonia mud sources produce smaller edifice heights and wider flow profiles compared to methane-dominant mud cryovolcanoes. Assuming certain preliminary parameters, we also propose the evolution and development of the edifice of Wright Mons in as little as 3.8 million years given a 10 wt% ammonia subsurface mud composition. If characterized on Pluto's surface, mud volcanoes would provide an interesting insight on the subsurface dynamics of solids and cryofluids on Pluto.

Experimental and numerical investigation of Gas–Liquid gravity displacement in a horizontal well intersecting a vertical fracture

This study focused on the gas–liquid gravity displacement phenomenon that occurs when a horizontal well intersects a vertical fracture. The phenomenon was first investigated through visual experiments, and the results revealed the influences of differential pressure and liquid viscosity on displacement behaviors. Subsequently, a numerical method was applied to examine the gas–liquid gravity displacement, which was then also validated experimentally. The numerically derived displacement behaviors under downhole conditions were consistent overall with the experimental behaviors, with the primary difference being the interface distribution in the annulus. The displacement phenomenon only occurred within a narrow differential pressure range, defined as the displacement window, and was demonstrated to be mainly determined by the fracture width. As the fracture width increased, the displacement window expanded, and the rates of mud loss and gas inflow increased significantly. Notably, the displacement phenomenon did not occur at microfractures. The increase in the mud loss rate exceeded the gas inflow rate as the difference between densities of mud and formation fluid increased. As the mud viscosity increased, mud loss and gas inflow rates decreased, and the displacement window narrowed. The effects of the downhole differential pressure and fracture width on the displacement behavior were more substantial than those due to density difference and mud viscosity. These results promote a better understanding of the gas–liquid gravity displacement phenomenon, ultimately benefitting the practice of horizontal drilling in fractured reservoirs.

Synthesis and performance evaluation of a novel polymeric fluid loss controller in water-based drilling fluids: High-temperature and high-salinity conditions

Fluid loss prevention is a crucial factor in oil and gas drilling operations. In water-based drilling fluids, often called drilling muds, the colloidal structure made by bentonite begins to thicken upon exposure to high salinity conditions, especially when an excessive temperature is encountered. The consequences are a considerable increase in the filtration volume and poor rheological properties. In this study, a novel terpolymer, AAV, was synthesized by acrylamide (AM), 2-acrylamide-2- methylpropane sulfonic acid (AMPS), and 1-vinylimidazole (VI) to be used as a fluid loss controller. AAV was characterized by the proton nuclear magnetic resonance (1H-NMR) and Fourier transform infrared spectroscopy (FTIR). Based on the thermal gravimetric analysis (TGA), AAV was thermally stable up to 300°C. The performance of AAV was explored according to API standard procedure. Under saturated-salt contamination, the bentonite-based fluid exhibited a fluid loss volume of 111 ml and 245 ml and a filter cake thickness of 2.7 mm and 2.9 mm at 26°C and 100°C, respectively. After thermally aging the muds even up to 180°C, AAV performed best in the filtration control, allowing filtration volume in the range of 1.4 ml–6.5 ml. It also left a much thinner filter cake, 0.21 mm–0.79 mm. SEM images showed a much smooth, uncracked, and compact filter cake for the mud samples treated by AAV. The addition of the terpolymer to bentonite dispersion decreased the value of the zeta potential by 5 mV, indicating an improvement in the stability of the dispersion. From the rheological analysis, AAV increased the viscosity of bentonite-based mud under saturated-salt contamination. The interaction between AAV and bentonite was revealed by FT-IR spectra. The filtration control mechanisms of AAV are hypothesized through the deflocculation of montmorillonite (Mt) particles, the formation of a chelate complex with cations, and surface adsorption of onto Mt particles.

Systematic sensitivity analysis of cuttings transport in drilling operation using computational fluid dynamics approach

Hole cleaning and cuttings transport play a vital role in the drilling operation. Various drilling problems such as a reduction in penetration rate, an increase in the torque and drag, and an increase in the potential of differential sticking are often related to poor cuttings transport from a wellbore. Multiple parameters, including the fluid rheology, mud velocity, cuttings size, and drill pipe inclination generally influence the cuttings transport performance. Although several experimental and modelling research works have been conducted in this area, the interactions among the parameters during cuttings transport have not been adequately investigated. This study focuses on interactions between the drilling parameters. Cuttings transport in the wellbore represents a solid-liquid multiphase flow phenomenon. In this research work, Computational Fluid Dynamics (CFD) model was employed to simulate the cuttings transport behaviours in a horizontal wellbore. The Eulerian-Eulerian multiphase flow model was adopted to describe the flow characteristics in the wellbore annular section. Design of Experiment (DoE) was used to systematically study the sensitivity and interactions among the operating parameters. It was observed that the mud viscosity, mud velocity, and drill pipe rotation have a positive impact, whereas an increase in cuttings size and eccentricity in annular clearance show a significant adverse effect on cuttings transport performance. According to the results, the cuttings between 1 mm to 2 mm are difficult to clean, compared to larger cuttings. The study also revealed important interaction effects between the parameters. Although both drilling mud viscosity and velocity show a positive effect, the interaction among them exhibits a negative influence on cuttings transport.

THE EFFECT OF SOME MATERIALS ON FUNNEL VISCOSITY READING IN WATER BASE MUD

Since Marsh funnel is the most famous and quick tool that used in field operations. When a crew get sample from the well and test it to show the effect of some materials on mud viscosity, it should take into consideration that there are many materials affect on the funnel viscosity like weighting materials, thinners, and polymers. Weightings material additives are essential to give adequate hydrostatic pressure to confirm borehole stability. Barium sulphate is the predominant weighting material. Many mud samples were prepared which involved freshwater, caustic soda, Bentonite, and weighting material. The weighting materials are added to mud distinctly alone to form the requisite mud density varieties between 8.7 ppg to 10 ppg. Likewise, a slight variance was detected in plastic and apparent viscosities. The experiments are done for another two substances like carboxy methyle cellulose and Lignite to show their effect on the funnel viscosity. Adding carboxy methyle cellulose led to increase the funnel viscosity, but adding Lignite led to reduce funnel viscosity. The results show that not only the viscosity affect on the funnel viscosity reading but also the density of drilling fluid have an effect on the funnel viscosity reading. The results show that when the solild percentage low about 1% or 2%, all the tested materials gave the same value of the funnel viscosity about (40–42) sec, that mean at low soild percentage we cannot know which material behind that change, so we should take that point into our consideration. Thus, it is concluded that mud density is another factor that affects funnel viscosity, and this point should be taken in consideration especially in-field testing and operations to avoid wrong interpretation for the tested field samples.

Study on the Influence of Mud Properties on the Stability of Excavated Face of Slurry Shield and the Quality of Filter Cake Formation

In the construction of subsea tunnels, the stability and control of the excavation surface are the main concerns of the engineering community. In this paper, the Xiamen Metro Line 2 is used as the study case. The filter cake formation of mud shields is experimentally studied, and the excavation surface is numerically simulated. It is found that the formation of filter cake does not require a large pressure difference, and can be formed under 0.06 MPa. With the increase of pressure, the quality of filter cake is further improved, and a small amount of seawater (volume ratio less than 3%) also has a significant effect on the viscosity of mud. Under different cross-section geological conditions, with the decrease of the support pressure of the excavation face, the vertical displacement and vertical (Y-direction) displacement of the excavation face dome gradually increase, the maximum longitudinal displacement is 9.7 mm, the maximum longitudinal displacement can reach 23.9 mm, and the growth trend is nonlinear. According to different stratum conditions, during the excavation of the tunnel, the plastic area of the excavation face is different.

Improving rate of penetration prediction by combining data from an adjacent well in a geothermal project

Drilling costs can account for more than 60% of the total cost of an Enhanced Geothermal System (EGS). Thus, drilling optimization is crucial for the success of EGS, especially with limited drilling data. In this study, the rate of penetration (ROP) was predicted using an Artificial Neural Network (ANN) model and drilling data from two wells situated 6 m apart at the surface in an EGS project. Ten drilling data cases that used either data from one or both wells were compared. The input parameters included depth, pore pressure gradient, equivalent circulating mud density, weight on bit, rotary speed, fraction of tooth worn away, mud density, flow rate, and mud viscosity. The lowest error was obtained for the case that combined a short data section located right before the prediction depth from the adjacent well with data resampled in a root-square-like manner before prediction in the predicted well. This arrangement led to a mean percent error of 18.5%. Besides highlighting the positive impact of root square data resampling, this assessment also showed the negative effect of including a data set from the adjacent well at the predicted depth during training.

Rheological behavior of a bentonite mud

Abstract Predicting drilling fluids rheology is crucial to control/optimize the drilling process and the gas extraction from drilling fluids in logging systems. A Couette viscometer measured the apparent viscosity of a bentonite mud at various shear rates and temperatures. The bentonite mud behaved as a yield-pseudoplastic fluid, and a modified Herschel-Bulkley model predicted the shear rate and temperature effects upon the shear stress. A pipe viscometer was built to seek a correlation between the mud flow rate and the pressure drop and thereby determine refined Herschel-Bulkley parameters. Coupling a rheological model to a pipe viscometer enables the continuous acquisition of apparent viscosities of Newtonian or non-Newtonian fluids at a rig-site surface.

Utilization of styrofoam waste as a lost circulation material in drilling mud

Lost circulation is a major problem that was often found in the well drilling process. This resulted in rock formations to become unstable, cause damage to wells, equipment, and workers. So to overcome this problem, drilling fluid will usually include lost circulation materials that act as connecting agents throughout the openings in rock formations, which physically close the formation of the opening by entering into the hole and prevent more fluid from coming out. The method used is laboratory research to test the rheology properties of sludge that has been treated with the addition of styrofoam (1 to 5 grams) under conditions of temperatures of 83 °F to 243 °F with intervals of temperature increase of 40 °F and testing using the Fann VG Meter. The measurement results are then compared with the standard. This test was carried out to see the effect of mass and temperature on the physical and rheological properties of drilling mud. The result of this research shows plastic viscosity, yield point, and gel strength of mud increases with increasing concentrations of styrofoam, and decreased when the temperature was increased. The combination of mud that best fits with the standard was addition with 1 gram of styrofoam.

Numerical investigation of gas‐liquid displacement between borehole and gassy fracture using response surface methodology

AbstractGas‐liquid displacement occurs often in fractured gas reservoirs, and can cause gas kick and mud leakage, resulting in a very high risk of losing well control. To analyze gas‐liquid displacement between borehole and gassy fracture, we used computational fluid dynamics to simulate its behaviors. We also used response surface methodology (RSM) to design numerical experiments. The effects of fracture width, bottom‐hole differential pressure, mud density, mud viscosity, and mud displacement were taken into account. We used RSM to determine the influence of the multifactor interaction of gas‐liquid displacement and established an empirical formula for the gas displacement rate. The results show that gas‐liquid displacement is proportional to fracture width, bottom‐hole differential pressure, mud density, and mud displacement; however, the displacement is inversely proportional to mud viscosity. The sensitivity sequence of the gas‐liquid displacement rate is fracture width > bottom‐hole differential pressure > mud viscosity > mud density > mud velocity. The impact of fracture width is clearly higher than that of the other factors, while the mud velocity has almost no impact. Our established empirical formula can be used to predict bottom‐hole gas kick and drilling mud leakage and to inversely predict the fracture width and formation gas pressure.

Investigation of temperature dependence of drilling mud viscosity with silica nanoparticles addition

An experimental study on the effect of silica nanoparticles addition on the viscosity of water-based mud at different temperatures was carried out. The mass concentration of clay was 5%, and the nanoparticles concentration varied from 0.5wt% to 3wt%. The nanoparticle size was 10 nm. Viscosity coefficient measurements were carried out in a wide temperature range.

Preparation and Properties of Green Environment-Friendly Drilling Polymer Mud

In this paper, a water-based green polymer mud is synthesized by simple compounding method. Effects of different kinds of tackifiers, their molecular weight on the viscosity of polymer mud and the effects of different fluid loss additives on mud fluid loss are studied. The results show that when polystyrene and anionic polyacrylamide with molecular weight of 8 ~ 10 million are used as the main thickening ingredient, polymer mud with high viscosity and high stability can be obtained. When the prepared polymer mud is formulated as NPAM: PEO: Hydroxypropyl cellulose(HPC) :Water = 42:10:10:100000 (unit: kg), the viscosity can reach 20.6 s, the filtration loss in 7.5 min is 24 mL, and the sand content is only 0.1%. Compared with traditional bentonite mud, the green environment-friendly polymer mud has the advantages of small amount of waste, low environmental pollution, and low pulping cost, and can meet the construction needs for most topography and geomorphology drilling engineering.

Experimental and modelling of the impact of quaternary ammonium salts/ionic liquid on the rheological and hydrate inhibition properties of xanthan gum water-based muds for drilling gas hydrate-bearing rocks

In this study, quaternary ammonium salts (QAS) and ionic liquid (IL) were used as additives in xanthan gum water-based muds formulations to investigate their rheological and hydrate inhibitive potentials in drilling gas hydrate sediment. The QAS/IL used were TMABr, TPrABr, TMACl, and EMIMCl. The mud rheological characterisation was performed at a controlled shear rate of 1 s−1 to 200 s−1 at -2 °C–40 °C. The hydrate test was conducted in a high-pressure reactor at 8 MPa and -2 °C. The hydrate nucleation onset time was predicted using the classical nucleation theory (CNT) model. The rheology and hydrate results confirmed the potential application of QAS/IL in drilling mud formulations for drilling hydrate sediments. The presence of QAS/IL in the base mud suitably reduced the mud viscosity and yield stress, which are desired properties for generating turbulent flow to enhance cuttings transport, especially in high angle wellbores. The rheological properties of water-based mud were found to be significantly controlled or affected by the cation, anion, and alkyl chain length type of QAS/IL. However, the anion effect is more dominant and exhibit a critical concentration depending on its respective ionic strength. Further FTIR analysis confirmed the presence of N–O stretching which supports the performance of TMA+ over EMIM+ to reduce the mud yield stress. In addition, the thermal degradation of the base mud was significantly reduced in the presence of QAS/IL. Amongst the studied additives, TMACl and TPrABr WBMs completely prevented hydrate plugs in the mud system. Furthermore, the CNT model accurately predicted the hydrate onset time with APE <2%. The QAS/IL in the WBM systems exhibited minimal to negligible disturbance (<0.5 K shift) on the methane hydrate phase boundary compared with commercial hydrate additives at 3 wt%. This study provides guidelines to design efficient QAS/IL WBMs for drilling gas hydrate rocks.

Appraising the impacts of SiO2, ZnO and TiO2 nanoparticles on rheological properties and shale inhibition of water-based drilling muds

In recent decades, utilizing of water-based muds (WBMs) in drilling oil and gas wells is ever increasing comparing to oil-based muds and synthetic-based muds due to the lower environmental issues. However, the main drawbacks with WBMs are rheological properties inefficiency and shale swelling which have caused attentions turn to improvement of WBMs’ rheological properties. In this study, the effects of various nanoparticles (NPs) namely titanium dioxide (TiO2), silicon dioxide (SiO2), and zinc oxide (ZnO) on improving rheological properties and shale recovery rate of a WBM sample at two temperatures (25 and 50 °C) were investigated. The concentrations of NPs in the base mud were set at 0.01, 0.05, 0.1 and 0.5 wt%. The results revealed that by adding NPs, the plastic viscosity (PV) of base mud was noticeably increased at the both temperatures. The optimum concentration of all NPs for increasing PV was found to be 0.01 wt%. Furthermore, by increasing concentration of ZnO and SiO2 NPs up to 0.5 wt%, the base mud yield point value was considerably risen to around 13.3%, while by increasing concentration of TiO2 NPs, the mud yield point values were reduced to 23.5 and 20.2 (lb/100 ft2) at 25 and 50 °C, respectively. The optimum ZnO, TiO2, and SiO2 NPs concentrations for this purpose were found to be 0.05, 0.01, and 0.1 wt%, respectively. Moreover, ZnO and SiO2 NPs at concentrations below 0.05 wt% had the best performances for filtration loss control. The related reason is higher stability of these NPs in the aqueous phase and consequently, better mud cake pores filling act by them which caused the mud cakes permeabilities were noticeably reduced. Besides that, SiO2 NPs caused the highest 10 s and 10 min gel strength values and ZnO and TiO2 NPs in order had the lowest 10 s and 10 min gel strength values at all applied concentrations and temperatures. Finally, by increasing concentrations of all NPs, shale recovery rates have noticeably risen comparing to the base mud. SiO2, ZnO and TiO2 NPs in order were successful additives for shale recycling.

A novel approach to enhance rheological and filtration properties of water–based mud using polypropylene–silica nanocomposite

Deeper drilling depths and high pressure high temperature (HPHT) wells require good well planning at minimum cost and unproductive time. Polymer nanocomposite has emerged as a promising additive to enhance the thermal stability of conventional water–based muds (WBMs). In this study, polypropylene–silica nanocomposite (PP–SiO2 NC) was synthesized using hot–emulsion sol–gel method. The performance of the PP–SiO2 NC in WBMs was critically examined and compared with that of partially hydrolyzed polyacrylamide (PHPA). Different characterization techniques were used to examine the morphology, structure information and thermal stability of the PP–SiO2 NC. The effect of 0.3 g, 0.6 g, 0.9 g, 1.2 g and 1.5 g each of PHPA and PP–SiO2 NC towards rheological properties, lubricity, filter cake thickness, and filtrate volume of WBM before and after thermal aging tests were studied. In addition, salt tolerance and cost analysis of the PP–SiO2 NC were evaluated. The results show that the PP–SiO2 NC has a spherical shape and a particle size distributed between 80 and 390 nm. The WBM with PP–SiO2 NC has better performance in controlling filtration and modifying rheological properties than the PHPA owing to the finely dispersed PP–SiO2 NC particles. With a concentration of 0.6 g after aging, the plastic viscosity of the PHPA mud decreased by 52.7% from 27.5 to 13 mPa s, while that of the PP–SiO2 NC mud reduced by 22.7% from 22 to 17 mPa s. Salt tolerance study showed that high concentration of potassium chloride affected the effectiveness of the PP–SiO2 NC in controlling HPHT filtrate volume. The cost analysis of the PP–SiO2 NC shows low cost of formulation. Hence, PP–SiO2 NC showed promising attributes for a good drilling mud.

A Study of Wave Dissipation Rate and Particles Velocity in Muddy Beds

The interactions between free surface waves and layers of cohesive sediments including wave height attenuation and mud movement are of great importance in coastal and marine engineering. In this study, the results from a new analytical model were compared with those from literature experimental works and analytical models in terms of wave height dissipation rate and mud velocity. It was found that the new model provided good agreements in the case of coexisting waves and currents, while the literature model of Ng (explained in Section 2 of the text) —assuming the mud layer as a highly viscous layer with high shear rates—matched well with the experimental data for high viscosity (mud viscosity, νm = O [0.01 m2/s]). In addition, it was found that the new model is able to successfully simulate particles velocity in the presence of co-current.

Bayesian prediction of rotational torque to operate horizontal drilling

Horizontal directional drilling is usually used in drilling engineering. In a variety of conditions, it is necessary to predict the torque required for performing the drilling operation. Nevertheless, there is presently not a convenient method available to accomplish this task. In order to overcome this difficulty, the current work aims at predicting the required rotational torque (RT) to operate horizontal directional drilling on the 7 effective parameters including the length of drill string in the borehole (L), axial force on the cutter/bit (P), total angular change of the borehole (KL), radius for the ith reaming operation (Di), rotational speed (rotation per minute) of the bit (N), mud flow rate (W), and mud viscosity (V). In this paper, we propose an approach based on the model selection criteria such as various statistical performance indices mean squared error (MSE), variance account for (VAF), root mean squared error (RMSE), squared correlation coefficient (R2), and mean absolute percentage error (MAPE) to select the most appropriate model among a set of 20 candidate ones to estimate RT, given a set of observed data. Once the most appropriate model is selected, a Bayesian framework is employed to develop the predictive distributions of RT, and to update them with new project-specific data that significantly reduce the associated predictive uncertainty. Overall, the results obtained indicate that the proposed RT model possesses a satisfactory predictive performance.

Experimental investigation of the effect of TiO2 nanofluid and KCl salt on polymeric water-based drilling fluid properties

In petroleum industries, nanofluids have the potential to improve the characteristics of the fluids used in drilling wells or Enhanced Oil Recovery (EOR) processes. In this study, a water based mud containing polymer was considered as the base fluid. Different concentrations of TiO2 nanoparticle (0, 0.5 and 0.75 wt%) and different concentrations of KCl salt (0, 0.5, 1.5, and 3 wt%) were added to the base fluid and exposed to different temperatures (30, 50, 70 and 90 °C) with 19 different shear rates for investigating the effects of nanoparticle concentration, salt concentration, temperature and shear rate on viscosity of the base mud. Presence of TiO2 particles enhanced not only the rheological behavior but also electrical and thermal conductivity of fluid up to 25% and 43%, respectively. Furthermore, the stability of the fluid containing salt and nanoparticle was investigated in these temperatures owing to the fact that the temperature could cause degradation of the fluid. For the purpose of investigating this phenomenon, the after cooling experiment was conducted. In addition, the data gathered in this investigation were examined by using three famous rheological models (Power law, Herschel-Bulkley and Herschel-Bulkley-Papanastasiou models) and the rheological parameters of each model were determined.

Shale inhibition by low-molecular-weight cationic polymer in water-based mud

The presence of oligomers possessing amine or ammonium functionality in drilling fluid plays an important role in stabilizing the shale formations during drilling with water-based mud. In this study, we have compared the activity of neutral to charged amine polymers towards shale stabilization. Low-molecular-weight polymer possessing charged moieties provided superior inhibitive capacity compared to that of the neutral amine functionality-based polymer. The polymer with cationic functionality (polyAETMAC) exhibited higher shale recovery, lesser shale swelling and lower capillary suction time compared to that of the neutral amine-based system (polyDMAPMA) supporting the above. Shale recovery in shale disintegration test improved from 92.3 to 98.7% for polyAETMAC concentration of 0.625 w/v% in water-based mud. The prodigious shale recovery is attributed to the strong interaction between the cationic sites of the polymer with the minerals present in the shale. The overall rheological properties of drilling fluids also improved in the presence of charged amine polymer before and after hot rolling. Apparent viscosity of mud increased by ~ 29% for polyAETMAC as compared to ~ 25% for polyDMAPMA at a concentration of 0.625 w/v%. Plastic viscosity and yield point of base mud were also improved by ~ 43% and ~ 15% at 0.0625 w/v% concentration of polyAETMAC and to a similar extent by polyDMAPMA for the same concentration. The decrease in API fluid loss after hot rolling of drilling fluid at 100 °C for 16 h was ~ 20% for polyDMAPMA and ~ 13% for polyAETMAC compared to base mud for the same concentration of the polymers. These polymers can be used as a potential shale stabilizer for water-based drilling fluids.Graphical abstract

Rheology of a colloidal suspension of carbon nanotube particles in a water-based drilling fluid

High-pressure and high-temperature rheology of a nanomud suspension is studied. The nanomud is prepared by dispersing a water-based drilling mud suspension with multi-walled carbon nanotubes (MWCNT). Effect of nanoparticle concentration, shear rate, pressure, and temperature are investigated. The pressure and temperature are independently varied from ambient conditions to 170 MPa and 180 °C respectively. The results presented show that the addition of CNT increases the viscosity of the drilling mud. A shear thinning non-Newtonian behavior is observed for the basemud and the nanomud samples at all pressures and temperatures. The basemud showed an increase in viscosity with an increase in pressure. However, with CNT particle addition this trend is observed to have reversed. For the basemud and the nanomud at lower concentrations, the viscosity values are observed to have initially increased with the increase in temperature and to have reduced beyond 100 °C. For a higher particle loading, a consistent decrease in viscosity with temperature is observed. The behavior of higher concentration nanomud samples with respect to pressure and temperature are seen to follow a similar trend to that of water. It is reasoned that an adequate addition of CNT nanoparticles helps retain the mud particles in a more homogenous and stable state, where they are held within the CNT chains. However, with further addition of CNT nanoparticles, the mud particles become agglomerated with the long chains of CNT, eventually separating water from the drilling fluid mixture.