Vipulanandan Rheological Model Research Articles

Characterizing the thermal, piezoresistive, rheology and fluid loss of smart foam cement slurries using artificial neural network and Vipulanandan Models

Light weight cement slurries with foam additions are being used in multiple applications including onshore and offshore deep wells installed in varying geological formations with low strength rocks. Also, the foam cement has reduced thermal conductivity making it a better insulator. It is also important to model the behavior of the foam cement for real time monitoring with the artificial neural network (ANN) models for adaptation in machine learning for various applications. The investigation was on the performance of highly sensing foam added smart cement and verified with various behavior models. Added foam was characterized based on stability, half-life, electrical resistivity, oxidation-reduction potential (ORP), and pH. Highly sensing smart oil well cement with water to cement (w/c) ratio of 0.38 was modified by adding 5% and 20% foam by weight and was first characterized using the impedance–frequency response to identify the critical electrical property for monitoring. Based on the Vipulanandan Impedance Model, electrical resistivity was the monitoring property. Also rheological properties, fluid loss and piezoresistivity (slurry) were investigated. With the addition of 20% foam the density reduced by 45 the thermal conductivity reduced by 65%.With the addition of 20% foam the initial resistivity increased by 94% indicating a potential quality control parameter for monitoring in the field. The thermal conductivity and the initial resistivity were related to the density using the Vipulanandan Correlation Model. The slurries investigated were piezoresistive, when pressure was applied the electrical resistivity changed. The rheological behavior of the smart foam cement slurries have been quantified using the new Vipulanandan rheological model and compared with Artificial Neural Network (ANN) Model. The total fluid loss with the addition of 20% foam, reduced by about 90% and the Vipulanandan fluid loss model and the ANN model were used to predict the behavior. The slurry piezoresistivity model was used to predict the piezoresistive behavior and compared it to an ANN model. The accuracy of the all the model predictions were compared using the statistical parameters.

Different model approaches with residual errors to predict the short and long-terms fluid loss and rheological properties of clay bentonite modified with nano-montmorillonite

ABSTRACT In this study, the percentage of bentonite in the WBM was ranged from 2%-8% as a percentage of the weight of water. The percentage of clay Nanopowder Montmorillonite (NC) was ranged between 0% and 1% by mass of drilling mud. The tests were performed under various temperature conditions ranged between 25°C and 85°C. From the lab studies and numerical examinations, the electrical resistivity (ER) was identified as a sensing property of the WBM so that the rheological properties can be estimated during the construction. The additional 1% NC reduced the ER of the WBM by 15% to 36% depending on the composition of the drilling fluid and the temperature of testing. The nanoclay modification increased the yield stress (yield point) and shear stress limit tolerance of the WBMs measured using the Vipulanandan rheological model by 32% to 60%, and the outcome of the model prediction was related with Vocadlo model. The laboratory HPHT fluid loss tests were conducted on the drilling fluids based bentonite modified with NC using API standard test up to 420 minutes until the end of the fluid loss. Zero fluid loss was obtained when 8% of bentonite drilling mud modified with 1% of NC at 25°C. The Vipulanandan fluid loss model predicted the short- and long-term fluid loss and the upper limit of fluid losses very well.

Magnetic Field Strength and Temperature Effects on the Behavior of Oil Well Cement Slurry Modified with Iron Oxide Nanoparticles and Quantified with Vipulanandan Models

Abstract The focus of this study was to investigate the methods that could potentially be easy to adopt in field to modify cement slurry rheological properties in situ during the installation of oil and gas wells. In this study, we investigated the effects of magnetic field strengths and temperatures on the rheological properties of an oil well cement (Class H) modified with iron oxide nanoparticles (NanoFe2O3). Also, the sensitivity of using electrical resistivity in monitoring changes in the cement slurry was also investigated. The water-to-cement ratio used in this study was 0.38, since it is a popular ratio used in oil well cementing. The NanoFe2O3 contents (average particle size of 30 nm) in the cement slurry were varied up to 1 % by the weight of cement. The temperature was varied from 25°C to 85°C. The magnetic field strength was varied up to 0.6 T. The initial electrical resistivity of the cement slurry modified with NanoFe2O3 decreased by 6 % to 52 % based on the NanoFe2O3 content, temperature, and magnetic field strength. The shear thinning behavior of the cement slurry with and without NanoFe2O3 has been quantified using the Vipulanandan rheological model and compared to the Herschel-Bulkley model. The results show that the Vipulanandan rheological model predicted the shear thinning relationship between the shear stress and shear strain rate of the NanoFe2O3-modified cement slurry very well with the maximum shear stress tolerance. The rheological properties of the cement slurry modified with NanoFe2O3 under different magnetic field strengths have been correlated to the electrical resistivity of the cement slurry using a nonlinear resistivity and Vipulanandan property correlation models. Thus, the performance of the cement slurry with and without NanoFe2O3 can be characterized based on the electrical resistivity, which can be used as a real-time monitoring tool in the field.

Vipulanandan Constitutive Models to Predict the Rheological Properties and Stress–Strain Behavior of Cement Grouts Modified with Metakaolin

Abstract In this study, the effects of metakaolin clay (MK) on the rheological properties, setting time, compressive strength, and toughness of cement grouts with water-cement ratios (w/c) of 0.6 and 1.0 were investigated. Based on the information in the literature, the amount of MK used in various mix designs varied up to 10 % by the weight of cement. The compressive stress–strain behavior of cement grout modified with MK was investigated up to 90 days of curing. The addition of 10 % of MK increased the apparent viscosity of the cement grout from 20 cP to 62 cP and from 13 cP to 44 cP with w/c ratios of 0.6 and 1, respectively. Setting time of cement grout mixes with a w/c ratio of 1.0 had longer initial and final setting times than the grout mixes with a w/c ratio of 0.6. The addition of 10 % MK increased the compressive strength of the cement grouts with w/c ratios of 0.6 and 1 from 8 MPa (1,175 psi) to 30.1 MPa (4,366 psi) and from 2.4 MPa (348 psi) to 17.8 MPa (2,582 psi) after 90 days of curing, respectively. The addition of 10 % MK increased the toughness of the cement grouts with w/c ratios of 0.6 and 1 from 1.42 J·m−3 to 2.27 J·m−3 and from 0.94 J·m−3 to 1.38 J·m−3 after 90 days of curing, respectively. The Vipulanandan p–q model was used to predict the changes in stress-stain behavior with curing time. The Vipulanandan rheological model also has a limit on the shear stress were as the other model did not have a limit. Based on the Vipulanandan rheological model, the maximum shear stresses produced by the portland cement grouts with w/c ratios of 0.6 and 1 with 0 MK were 58 Pa and 33 Pa, respectively. The addition of 10 % MK to the Portland cement (PC) grouts increased the maximum shear stresses by 155 % and 136 % for w/c ratios of 0.6 and 1, respectively.

Zero fluid loss, sensitivity and rheological properties of clay bentonite (WBM) modified with nanoclay quantified using Vipulanandan models

To improve the performance, sensibility, rheological properties, fluid loss of the bentonite water-based drilling mud (WBM), and minimizing the fluid loss of the WBM. The impact of bentonite modified with nanoclay (NC) on the sensibility, rheological properties, and fluid loss of the WBM was investigated. Depend on the information collected from different research studies, the percentage of bentonite in the WBM was ranged from 2%-8% as a percentage of the weight of water. The percentage of NC was ranged between 0 and 1% by mass of drilling mud. The tests were performed under various temperature conditions ranged between 25 °C and 85 °C. From the lab studies and numerical examinations, the electrical resistivity (ER) was identified as a sensing property of the WBM so that the rheological properties can be estimated during the construction. The additional 1% NC reduced the ER of the WBM by 15% to 36% depending on the composition of the drilling fluid and the temperature of testing. The nanoclay modification increased the yield stress (yield point) and shear stress limit tolerance of the WBMs measured using Vipulanandan rheological model by 32% to 60%, and the outcome of the model prediction was related with Vocadlo model. The laboratory HPHT fluid loss tests were conducted on the drilling fluids based bentonite modified with NC using an American Petroleum Institute (API) standard test up to 420 min until the end of the fluid loss. Zero fluid loss was obtained when 8% of bentonite drilling mud modified with 1% of NC at 25 °C. The Vipulanandan fluid loss model predicted the short and long-term fluid loss and the upper limit of fluid losses very well.

Shear stress limit, rheological properties and compressive strength of cement-based grout modified with polymers

Grouting is a comprehensive technology used in the construction projects due to the rapid development of sub-surface urban infrastructures, the main reasons for grouting soils are strengthened the cohesion-less soils and increasing the shear stress (pure shear) of the grouted soils. Providing high flowability with high viscosity for the cement-based grout in the liquid stage (slurry) and high compressive strength of the cement-based grout in the hardened stage are significant challenges. In this study, the impact of two types of water reducer [polycarboxylate (PCE)] polymer on the rheological properties with the ultimate shear strength and compressive strength of cement-based grout with water-cement ratios (w/c) of 0.6 and 1.0 at two different temperatures 25 °C and 50 °C were studied. XRD and TGA were used to analysis the cement, polymers, and cement modified with polymers. The behavior of cement-based grout in the liquid phase (slurry) and hardened phase modified with different percentages of polymer up to 0.16% (by dry weight of cement) were investigated. The compressive strength of cement-based grout modified with polymer was tested from the young age up to 28 days of curing. Vipulanandan rheological model was used to predict the shear stress-shear strain behavior of cement-based grout slurry and compared to the Herschel–Bulkley (HB) model. The rheological and the compressive strength are increased with increasing the of PCE content. The polymer modification increased the yield stress, apparent viscosity and plastic viscosity of the cement grout by 19–136%, 32–319% and 58–367%, respectively based on the types of polymer, polymer content, w/c, and temperature. The compressive strength of the cement-based grout increased by 94–786% based on the types of polymer, polymer content, w/c and curing time. Increasing the temperature of cement-based grout slurry to 50 °C increased the maximum shear stresses by 110% and 107%, respectively. Effects of polymer content, w/c, curing time and the temperature of the plastic and hardened properties of cement-grout were modeled using a multiple nonlinear regression analysis.

TGA, rheological properties with maximum shear stress and compressive strength of cement-based grout modified with polycarboxylate polymers

Grouting is a comprehensive technology used in the construction projects due to the rapid development of sub-surface urban infrastructures, the main reasons for grouting soils are strengthened the cohesion less soils and increasing the shear stress (pure shear) of the grouted soils. Providing high flowability with high viscosity for the cement-based grout in the liquid stage (slurry) and high compressive strength of the cement-based grout in the hardened stage are significant challenges. In this study, the impact of two types of polycarboxylate (PCE) polymer on the rheological properties with the ultimate shear strength and compressive strength of cement-based grout with water-cement ratios (w/c) of 0.6 and 1.0 at two different temperatures 25 °C and 50 °C were studied. XRD and TGA were used to analysis the cement, polymers, and cement modified with polymers. The behavior of cement-based grout in the liquid phase (slurry) and hardened phase modified with different percentages of polymer up to 0.16% (by dry weight of cement) were investigated. The compressive strength of cement-based grout modified with polymer was tested from the young age up to 28 days of curing. Vipulanandan rheological model was used to predict the shear stress-shear strain behavior of cement-based grout slurry and compared to the Herschel-Bulkley (HB) model. The rheological and the compressive strength are increased with increasing the of PCE content. The polymer modification increased the yield stress, apparent viscosity, and plastic viscosity by 19–136%, 32–319% and 58–367%, respectively based on the types of polymer, polymer content, w/c, and temperature. The compressive strength of the cement-based grout increased by 94–786% based on the types of polymer, polymer content, w/c, and curing time. Based on the Vipulanandan rheological model, increasing the temperature of cement-based grout slurry to 50 °C increased the maximum shear stresses by 110% and 107% respectively. The unprecedented conclusions can be drawn in this study, which is the effect of the polymer content, water-cement-ratio and temperature effect on the plastic viscosity, yield points and shear stress limit in the fresh stage (slurry) of the cement-based grout and also, the impact of the polymer content, water-cement-ratio and curing time on the flexural with compressive strengths in the hardened stages of the cement modified with polymers were modeled.

Modification of the Vipulanandan rheological model with correlation for temperature and electrolyte effect on drilling muds

Modelling the flow of drilling muds requires the use of existing generic time-independent models with a number of parameters incorporated. While these parameters quantify the uncertainties surrounding the mud rheology, the tuning of each parameter for proper flow description can be challenging and time consuming. As such, the introduction of new parameters in describing additional reservoir conditions associated with drilling muds would only increase the complexity of the computational process. Therefore, the predictive capability of applied rheological models for the different flow regimes and reservoir conditions associated with drilling muds is still limited in scope. Existing procedure using generic rheological models would give a generalized approach to computing the performance of drilling muds when taking into account new factors such as temperature and electrolyte effects. Therefore, there is need to accurately model the rheology of drilling muds taking into account new conditions without necessarily introducing new fitting parameters to a particular model. In this work, a novel approach was employed where the time constant of the modified Vipulanandan model was related to reservoir conditions without introducing a new fitting constants or parameters. The selection of the Vipulanandan model among others was based on the conditions stated by Vipulanandan and Mohammed (2014) and the use of statistical validation tools based on best fit. Moreover, the Vipulanandan model represents the only model which can be modified to have a time constant in it.

Modeling the rheological properties with shear stress limit and compressive strength of ordinary Portland cement modified with polymers

In this study, the effect of two water reducer polymers on the thermal stability, rheology, and compressive strength of Gasin Ordinary Cement (GC) was investigated. The behavior of cement in the liquid phase (slurry) and hardened phase modified with two types of polymer varied from 0 to 0.06% (%wt) were investigated. XRD and TGA tests were conducted to identify the effect of polymers on the behavior of GC. The compressive strength of cement mixed with polymers was tested from the early aged of 1 days to 28 days of curing. The shear stress versus shear strain rate of cement slurry was modeled and the results of prediction using Vipulanandan rheological model were compared to the Vocadlo model. High reduction in the total weight loss of the GC at 800 °C when the cement modified with 0.06% of polymers detected using TGA test. The rheological properties of the cement slurry such as viscosity, yield stress, and the compressive strength of GC were increased significantly with increasing the polymer contents. Addition of polymers reduced the required water to reach the desired fluidity by about 43% based on the type of polymer. The results showed that the Vipulanandan rheological model predicted the shear-thinning relationship between the shear stress and shear strain rate of the cement slurry modified polymers very well. Also, the Vipulanandan rheological model has a maximum shear stress limit were as the Vocadlo model did not have a limit on the maximum shear stress. Based on the Vipulanandan rheological model the maximum shear stress produced by the cement slurry modified with 0% and 0.06% of polymers at the temperature of 25 °C were increased from 38.7 to 171.3 Pa and to 184.8 Pa respectively due to the addition of polymers. Nonlinear models were used to separate the effect polymer quantity, water–cement ratio, and curing time on the rheological properties and compressive strength of cement.

Predictive analytics for the Vipulanandan rheological model and its correlative effect for nanoparticle modification of drilling mud

Modelling the flow of nanoparticle modified drilling mud (or nano-drilling muds) requires the use of existing generic time-independent models with the addition of nanoparticle terms having a number of parameters incorporated. These parameters quantify the uncertainties surrounding nanoparticle contributions to drilling mud rheology. However, when the parameters in the overall model become too large, the tuning of each parameter for proper flow description can be challenging and time-consuming. In addition, the predictive capability of known models for the different regimes associated with the flow of nano-drilling muds is limited in scope and application. For example, computational analysis involving nano-drilling muds have been described using Herschel-Buckley, Power-Law, Bingham Plastic, Robertson-Stiff, Casson, Sisko, and Prandtl-Eyring. However, these models have been shown over time to have limited predictive capability in accurately describing the flow behavior over the full spectrum of shear rates. Recently, a new rheological model, the Vipulanandan model, has gained attraction due to its extensive predictive capability compared to known generic time-independent models. In this work, a rheological and computational analysis of the Vipulanandan model was carried out with specific emphasis on its modification to account for the effects of nanoparticles on drilling muds. The outcome of this novel approach is that the Vipulanandan model can be modified to account for the effect of interaction between nanoparticles and clay particles. The modified Vipulanandan show better prediction for a 6.3 wt% mud with R2 of 0.999 compared to 0.962 for Power law and 0.991 for Bingham. However, the R2 value was the same with Herschel Buckley model but the RMSE value show better prediction for the Vipulanandan model with a value of 0.377 Pa compared to the 0.433 Pa for Herschel Buckley model.

Research on the influence of sodium fatty alcohol polyoxyethylene ether sulfate on the microstructure and properties of Portland cement

Sodium fatty alcohol polyoxyethylene ether sulfate (AES), an anionic surfactant, which relieves the contamination of Portland cement slurry containing mineral oil based mud (MOBM) effectively. In this paper, by testing fluidity and compressive strength firstly in 25 °C and 90 °C after 1, 3, 7, 14 and 28 days of curing respectively, Vipulanandan rheological model was applied to analyze rheological behavior. We found AES could deteriorate cement’s fluidity and compressive strength as its content increasing. Additionally, cement stone would lose about 85% of compressive strength as low as 0.05%wt AES especially. We observed microstructure of cement containing AES by Environment Scanning Electron Microscope (ESEM), which proved that AES causes cement surface to form holes, and the reduction of cement hydration products was confirmed by X-ray diffraction (XRD). Finally, by comprehensively analyzing combining Zeta Potential and Contact Angle, we used mathematical models to explain the mechanism of AES’s affecting on the structure and performance of cement: (1) In the slurry, AES deteriorates fluidity by trapping the free water. (2) AES attaches on cement particles surface, via affecting “Dynamic Potential” to decrease mutual repulsion between cement particles to accumulate them, resulting in uneven distribution of cement particles in the cement slurry with appearing holes and the dropping of density. (3) Foaming and its stability of AES makes structure of cement structure porous, forming entangled network structures and bounded air bubbles.

Development of Nanofluids for Perdurability in Viscosity Reduction of Extra-Heavy Oils

The primary objective of this study is the development of nanofluids based on different diluent/dispersant ratios (DDR) for extra-heavy oil (EHO) viscosity reduction and its perdurability over time. Different diluents such as xylene, diesel, n-pentane, and n-heptane were evaluated for the formulation of the carrier fluid. Instability of asphaltenes was assessed for all diluents through colloidal instability index (CII) and Oliensis tests. Rheology measurements and hysteresis loop tests were performed using a rotational rheometer at 30 °C. The CII values for the alkanes type diluents were around 0.57, results that were corroborated with the Oliensis tests as asphaltenes precipitation was observed with the use of these diluents. This data was related to the viscosity reduction degree (VRD) reported for the different diluents. With the use of the alkanes, the VRD does not surpass the 60%, while with the use of xylene a VRD of approximately 85% was achieved. Dimethylformamide was used as a dispersant of the nanoparticles and had a similar VRD than that for xylene (87%). Subsequent experiments were performed varying the DDR (xylene/dimethylformamide) for different dosages up to 7 vol % determining that a DDR = 0.2 and a dosage of 5 vol % was appropriated for enhancing EHO VRD, obtaining a final value of 89%. Different SiO2 nanoparticles were evaluated in the viscosity reduction tests reporting the best results using 9 nm nanoparticles that were then included at 1000 mg·L−1 in the carrier fluid, increasing the VRD up to 4% and enhancing the perdurability based on the rheological hysteresis and the viscosity measurements for 30 days. Results showed a viscosity increase of 20 and 80% for the crude oil with the nanofluid and the carrier fluid after 30 days, respectively. The nanoparticles have a synergistic effect in the viscosity reduction and the inhibition of the viscoelastic network re-organization (perdurability) after treatment application which was also observed in the rheological modeling carried out with Cross and Carreau models as the reported characteristic relaxation time was increased almost a 20%. Moreover, the Vipulanandan rheological model denotes a higher maximum stress value reached by the EHO with the addition of nanofluids which is derived from the EHO internal structure rearrangement caused by the asphaltenes adsorption phenomenon.

Vipulanandan models to predict the electrical resistivity, rheological properties and compressive stress-strain behavior of oil well cement modified with silica nanoparticles

In this study, the effect of silica nanoparticles (NS) and temperature on the rheological properties with ultimate shear stress and weight loss of the oil well cement (class H) modified with NS were investigated. The NS content was varied up to 1% by the weight of the cement. The total weight loss at 800 °C for the oil well cement decreased from 6.10% to 1.05%, a 83% reduction when the cement was mixed with 1% of NS. The results also showed that 1% of NS increased the rheological properties of the cement slurry. The NS modification increased the yield stress (τo) and by 5% to 65% based on the NS content and the temperature of the cement slurry. The addition of 0.5% and 1% NanoSiO2 increased the initial electrical resistivity of the cement by 17% and 35% respectively. The shear thinning behavior of the cement slurry with and without NS has been quantified using the Vipulanandan rheological model and compared with the Herschel-Bulkley model. Based on the Vipulanandan rheological model the maximum shear stress produced by the cement slurry modified with 0% and 1% of NS at the temperature of 25 °C were 148 Pa and 179 Pa respectively hence an increase of 21% in the ultimate shear stress due to the addition of NS. The addition of 1% of NS increased the compressive strength of the cement by 14% and 42% after 1 day and 28 days of curing respectively. Effects of NS content and the temperature on the model parameters have been quantified using a nonlinear model (NLM). The NLM quantified the effect of NS treatment on all the model parameters.

Vipulanandan model for the rheological properties with ultimate shear stress of oil well cement modified with nanoclay

In this study, the effect of clay nanoparticles (NC) and temperature on the rheological properties with ultimate shear stress and weight loss of the oil well cement (class H) modified with NC was investigated. The NC content was varied between 0 and 1% by the weight of the cement. The total weight loss at 800°C for the oil well cement decreased from 6.10% to 1.03%, a 83% reduction when the cement was mixed with 1% of NC. The results also showed that 1% of NC increased the rheological properties of the cement slurry. The NC modification increased the yield stress (τo) and plastic viscosity (PV) by 5%–65% and 3%–16% respectively based on the NC content and the temperature of the cement slurry. The shear thinning behavior of the cement slurry with and without NC has been quantified using the Vipulanandan rheological model and compared with the Herschel-Bulkley model. The Vipulanandan rheological model has a maximum shear stress limit were as the Herschel-Bulkley model did not have a limit on the maximum shear stress. Based on the Vipulanandan rheological model the maximum shear stress produced by the 0% and 1% of NC at the temperature of 25°C were 102Pa and 117Pa respectively hence an increase of 15% in the ultimate shear stress due to the addition of NC. The addition of 1% of NC increased the compressive strength of the cement by 12% and 43% after 1day and 28days of curing respectively. The modulus of elasticity of the cement increased with the additional of 1% NC by 6% and 76% after 1day and 28days of curing respectively. Effects of NC content and the temperature on the model parameters have been quantified using a nonlinear model (NLM). The NLM quantified the effect of NC treatment on all the model parameters.