Pipe Viscometer for Continuous Viscosity and Density Measurement of Oil Well Barrier Materials

Summary A pipe viscometer system equipped with differential pressure sensors and a Coriolis flow meter was integrated into a small-scale batch mixer to develop a novel concept for continuous slurry characterization. Previous studies have shown that cement slurries can exhibit particle migration away from pipe walls, which will impact the measured friction pressure loss and equivalently the wall shear stress particularly in small-diameter pipes. The focus of this research is to probe the possible impact of particle migration within the current setup, comparing measurements with those acquired using a scientific rheometer. The research approach involves comparing flow curves derived from pipe viscometer readings with offline measurements conducted using a rheometer equipped with a concentric cylinder geometry using a rotor with either smooth or grooved surface. To facilitate this comparison, differential pressure and flow rate data were converted into shear stress and shear rate values, following the Mooney-Rabinowitsch relationship. Experiments were performed using a simulated fresh cement paste suspension prepared by mixing an aqueous xanthan gum solution with silica powder. Steady-state viscosity measurements from both the pipe viscometer and rheometer produced consistent results, emphasizing the similarity in the shape and slope of the flow curves. Notably, rheometer measurements acquired using the smooth cylinder geometry closely resembled the measurements from the pipe viscometer for all solutions and suspensions tested, and also aligned well with the conventional viscometers employed in field applications. For pure xanthan gum solutions, we observed a close agreement between the geometries considered in the rheometer measurements and the pipe viscometer. On the other hand, the analysis revealed particle migration effects when comparing smooth and grooved cylinder geometries and testing dispersed silica suspensions. These discrepancies were more pronounced with increasing silica particle content and, therefore, should be duly considered when employing the proposed pipe viscometer system for the continuous characterization of fresh cement paste. The novelty of this approach lies in the comprehensive evaluation of the pipe viscometer setup, examining factors that could potentially influence viscosity measurements. This investigation aims to ensure precise control when implementing the system into a full-scale batch mixer for automated fluid characterization or continuous ("on-the-fly") mixing of cement paste.

This work presents a novel technique to measure viscosity in-situ and in real time in engine component interfaces by means of an ultrasonic technique. Viscosity is a key parameter in the characterization of lubrication regime in engine parts because it can be related to friction in the contact, and to the lubricant film thickness. Ultrasound is a non-destructive and non-invasive technique that is based on the reflection of sound from interfaces. The reflection from a solid-air boundary can identify, for instance, the presence of a crack in a material, while reflection from a solid-liquid interface can help detecting the properties of the liquid sample. Reflection of longitudinal waves measures fluid film thickness and chemical composition, while the reflection of ultrasonic shear waves measures the fluid viscosity. The viscosity measurements based on ultrasonic reflection from solid-fluid boundaries are referred to as reflectance viscometry techniques. Common ultrasonic reflectance viscometry methods can only measure the viscosity of Newtonian fluids. This work introduces a novel model to correlate the ultrasonic shear reflection coefficient with the viscosity of non-Newtonian oils by means of the Maxwell model analogy. This algorithm overcomes the limitation of previous models because it is suitable for the analysis of common engine oils, and because it relies only on measurable parameters. However, viscosity measurements are prohibitive at the metal-oil interfaces in auto engines because when the materials in contact have very different acoustic impedances the sound energy is almost totally reflected, and there is very little interaction between the ultrasonic wave and the lubricant. This phenomenon is called acoustic mismatch. When acoustic mismatch occurs, any valuable information about the liquid properties is buried in measurement noise. To prove this, the common reflectance set-up was tested to measure the viscosity of different lubricants (varying from light base oils to greases) using aluminium as solid boundary. More than 99.5% of the ultrasonic energy was reflected for the different oils, and accurate viscosity measurement was not possible because the sensitivity of the ultrasonic measurement at the current state of the art is of ±0.5%. Consequently, the discrimination by viscosity of the oil tested was not possible. In this study a new approach is developed. The sensitivity of the ultrasonic reflectance method is enhanced with a quarter wavelength matching layer material. This material is interleaved between metal and lubricant to increment the ultrasonic measurement sensitivity. This layer is chosen to have thickness and mechanical properties that induce the ultrasonic wave to resonate at the solid-liquid interface, at specific frequencies. In this work, resonance is associated with the destructive interaction between the wave that is incident to the matching layer and the wave that is reflected at the matching layer-oil interface. This solution brings a massive increment in the ultrasonic measurement sensitivity. The matching layer technique was first tested by enhancing the sensitivity of the aluminium-oil set-up that was affected by acoustical mismatch. A thin polyimide layer was used as a matching layer between aluminium and the engine oil. This probe was used as ultrasonic viscometer to validate the sensing technique by comparison with a conventional viscometer and by applying a temperature and pressure variation to the samples analysed. The results showed that the ultrasonic viscometer is as precise as a conventional viscometer when Newtonian oils are tested, while for Non-Newtonian oils the measurement is frequency dependent. In particular, it was noticed that at high ultrasonic frequency only the viscosity of the base of the oil was measured. The ultrasonic viscometer was used to validate the mathematical model based on the Maxwell analogy for the correlation of the ultrasonic response with the liquid viscosity. At a second stage, this technique was implemented in a journal bearing. The ultrasonic viscometer was mounted in the shaft to obtain the first viscosity measurement along the circumference of a journal bearing at different rotational speeds and loads. The ultrasonic viscometer identified the different viscosity regions that are present in the journal bearing: the inlet, the regions characterized by the rise in temperature at the contact and the maximum loaded region were the minimum film thickness occurs. The results were compared with the analytical isoviscous solution of the Reynolds equation to confirm that the shape of the angular position-viscosity curves was correct. Finally, the method was preliminarily tested on a coated shell bearing to show that the coating presents in bearing, like iron-oxide or babbit, is a good matching layer for the newly developed ultrasonic viscometer technique. This means that ultrasonic transducers, with sizes as small as a pencil tip, have the potential to be mounted as viscometers in real steel bearings where the coating layer in contact with the fluid acts as a matching layer. Overall, the results obtained showed that this technique provides robust and precise viscosity measurements for in-situ applications in engine bearings.

A high-precision microfluidic viscometer with a microfluidic channel array composed of 100 indicating channels is demonstrated in this study. The relative viscosity of the sample fluid could be measured by simply counting the number of the indicating channels occupied by the sample and the reference fluids. Using lumped parameter modeling, an analytical solution of the relative viscosity is derived. In order to evaluate the performance of the developed microfluidic viscometer, the viscosity values obtained by the microfluidic viscometer are compared with the ones obtained by a conventional viscometer. In Newtonian fluid (sodium dodecyl sulfate [SDS] solution) tests, the normalized differences in the viscosities measured by two methods are less than 2.5%. In non-Newtonian fluid (whole blood, 45% hematocrit) tests at various shear rates, the viscosities measured by two methods are evaluated by a regression analysis via power law (). The k values for both the microfluidic viscometer and the conventional viscometer are 12.953 and 13.175, respectively; the n values are 0.797 and 0.807, respectively. The normalized differences in two parameters measured by two methods are less than 2%. Thus, it could be concluded that the microfluidic viscometer developed in this study is capable of measuring viscosity of both Newtonian fluid (SDS solution) and non-Newtonian fluid (whole blood) with a relatively high accuracy in a continuous and near real-time fashion. Furthermore, the viscometer could be potentially employed in cardiopulmonary bypass procedures by continuously monitoring viscosity changes due to blood damages and hemodilution.

Ensuring permanent zonal isolation in plug and abandonment (P&A) operations is critical to preventing fluid migration between subsurface formations and the environment. Failure in zonal isolation can result in groundwater contamination, sustained casing pressure, and formation charging, leading to operational risks. This study introduces a methodology to mitigate risks in cementing operations by developing representative downhole testing setups for barrier materials. Specifically, it investigates the integration of an inline pipe viscometer for real-time viscosity and density measurements of conventional Class G cement slurry and presents the Well Barrier Test Sub (WBTS), designed to replicate downhole conditions for barrier material evaluation. A 9 ⅝-inch WBTS cell was developed with a pressure-tight system to facilitate platform piston control, gas seepage tests, and real-time temperature monitoring using a PT100 or fiber optic sensor. The system was deployed at the Ullrigg Test Centre, interfacing with the wellhead via a 10 ¾-inch casing hanger flange. Cement slurry preparation followed offshore protocols, with viscosity and density assessed using an inline pipe viscometer and a Coriolis flow meter. Comparative analyses were conducted using conventional methods, including the FANN 35 rotational viscometer and a mud balance. The cement was subsequently pumped through coiled tubing to form a 5-meter plug, cured under 20 bar for 24 hours. A gas seepage test was then performed by lowering the WBTS piston while maintaining downhole pressure, using a precision gas tester to monitor gas flow. Results demonstrate the effectiveness of the proposed methodology for testing barrier materials under realistic conditions. The inline viscometer system provided flow curves consistent with those obtained using the FANN 35 rotational viscometer. The WBTS system functioned effectively in all test phases, from piston operation to gas seepage assessment. The seepage test established a direct correlation between injected and captured gas volumes, confirming the setup’s applicability for evaluating casing annuli, P&A plugs, and complex scenarios such as tubing left in the hole.

An Electric Submersible Pump (ESP) is studied experimentally with oil-water emulsion. Emulsion rheology inside the ESP is also studied and modeled at different oil and water fractions, ESP rotational speeds and temperatures, using a dimensional analysis on a set of parameters contributing to the emulsion rheology. Density and mass flowrate are measured using the mass flowmeter, while the emulsion effective viscosity is initially derived from the pipe viscometer (PV) installed downstream of the ESP. Effective viscosity values at the stage condition are corrected using an oil of known viscosity by correlating its viscosity to ESP average temperature. Watercut at the inversion point increases in case of contamination presence which directly affects the interfacial tension. Modeled effective viscosity values for emulsion with medium viscosity are within 5% deviation from the experimental values. However, when low oil viscosity is used, the deviation becomes larger, mainly due to the instability of the emulsion which leads to inaccurate measurement of the effective viscosity at the PV. Instability is confirmed from the PV results, density measurements and visual observation through the transparent pipe or during sampling. Further improvement of the model is needed by changing the parameters in a wider range, and possibly by including non-considered parameters such as salinity. Most of the parameters affecting the emulsion rheology are combined in one term which can be considered as a factor that corrects the effective viscosity of the emulsion.

High viscosity is a major concern in the recovery of heavy oil and bitumen. Viscosity reduction could be achieved by mixing bitumen with solvents. Cragoe(1) and Shu(2) have developed widely used methods for liquid mixture viscosity predictions. However, in these two models, the viscosities or densities of the heavy oil/bitumen and solvents have to be known at some reference condition. Low field nuclear magnetic resonance (NMR) relaxometry is an effective, non-destructive alternative for determining the petrophysical properties of oil reservoirs. It has also been shown to successfully predict the viscosity of conventional oils, heavy oils, and mixtures of oils with solvents. In this paper, a regression model of experimental data, Cragoe(1), Shu(2), and NMR models are compared with experimental data which were obtained from four heavy oil/bitumen samples mixed with six solvents in different ratios. NMR-based predictions are found to be similar to those of the Shu(2)model and superior to the predictions of the Cragoe(1) model. Introduction Viscosity and density reduction of a heavy oil or bitumen could be achieved by mixing it with a solvent. The information about the viscosity of a heavy oil/bitumen-solvent mixture is vital for designing solvent floods and for input into reservoir simulators, both for recovery processes and reserves assessment. Several correlations have been proposed for estimating the viscosity of a mixture of liquids. Cragoe(1) and Shu(2) have developed two widely-used methods for mixture viscosity predictions. In both of the models, viscosities of the heavy oil or bitumen and solvents have to be known for prediction. Sometimes, it is hard to measure the viscosity accurately using conventional viscometers when it is too high or too low, and a conventional viscometer is not a convenient method for in situ measurements. Low field nuclear magnetic resonance (NMR) relaxometry is an effective, non-destructive alternative for determining the petrophysical properties of an oil reservoir. It was also shown to successfully predict the viscosity of conventional oils(3) and heavy oils(4). The greatest advantage of NMR is its potential to translate these density and viscosity measurements to in situ measurements, which could be implemented in a logging tool, allowing density and viscosity to be estimated without having to extract oil samples in the lab. The NMR viscosity model is especially significant for use in designing a solvent injection process for heavy oil recovery. Experimental Procedure Four oils were used in the solvent experiments(5). They were from Peace River, Cold Lake, Edam, and Atlee Buffalo, and have viscosities of 670,000 mPa's, 130,000 mPa's, 14,000 mPa's, and 6,000 mPa's, respectively, at 25 °C. Kerosene, toluene, naphtha, heptane, hexane, and pentane were added to the oils in several predefined mass fractions: 100% oil, 99%, 96%, 93%, 90%, 85%, 80%, 70%, 50%, 30%, and 0% (100% solvent). The samples were slightly heated and mixed by stirring, and the resulting solventoil mixtures were cooled. NMR spectra were measured at 25 °C using an Ecotek FTB bench top relaxometer.

It is extremely important to gather the viscosity behavior of fluids accurately for industries and academia. There is no better method than viscosity measurement to detect changes in the specific characteristics of the materials. However, viscosity measurement is indeed a very sensitive process. In nature, fluids are involved in widely various containers, and they are affected by serious temperature deviations. It is a necessity for viscometers to have the capability to obtain accurate data from all types of containers of fluids even in serious temperature variations in order to understand the natural phenomena inside the fluids. Conventional viscometers mainly neglect the effect of sudden temperature deviations inside the fluids, or they need to use very expensive water bath systems that stabilize the temperature around the test fluids, which is not feasible at all. In this research, the effects of non-uniform temperature fields are analysed detailly to confirm that even in extremely limited amounts, serious viscosity and temperature deviations may occur. Experiments were performed in two parts. The first part was conducted using several thermocouples with different test fluids to find out the effects of thermal conduction and convection. For the second part, particle image velocimetry (PIV) was utilized to comprehend the flow movement within the test fluids. It was shown that even for small volumes and even in very controlled environments, an almost 35% viscosity measurement error (VME) occurs. Finally, as a solution to this problem, a new non-dimensional parameter called the Akpek number was proposed. The Akpek number enables the estimation of VMEs in any possible case. VME is a very crucial obstacle that has urgency to be illuminated by researchers and scientists to improve fluid characteristics. The main goal of this research is to illuminate the importance of this problem and offer a potential solution. The final results are supported by experimental data and numerical simulations using OpenFOAM.

Summary In oil and gas and geothermal well construction, a cementitious material is pumped in the wellbore to provide zonal isolation and support the casing during the life cycle of the well. Thus, the cementitious barrier materials must be durable in terms of chemical and mechanical properties and have chemical compatibility with casing pipe. The complex region of casing-cement interface is considered a key parameter to fulfill long-term zonal isolation. This interface must be chemically stable and impermeable to block unwanted formation fluid communication. Shortcomings of conventional Portland cement under operational conditions and increasing sensitivity to its carbon footprint are motivations for a green alternative. Bond strength and sealability of cement with steel surface have been measured previously. But few research works cover surface characterization and morphological analysis of barrier materials and the connected steel surface. This study provides a full picture of selected alternative materials in terms of shear bond strength, hydraulic sealability, and interface morphology analysis of the materials. Materials include API Class G cement, an industrial expansive cement, noncement-based pozzolanic material, geopolymer, and thermosetting resin. Also, clean and rusted steels were considered as a representative for the casing pipe in the field. The samples were prepared under elevated pressure and temperature. The results proved that higher shear bond strength is not an indication of good sealability, and the ingredients used to mix slurries have a critical role in the structure of the interfacial zone between casing and barrier material.

Portland cement is the prime zonal isolation material used in hydrocarbon wells and its utilization has been extended to geothermal, carbon sequestration and gas storage wells. Despite the vast quantity of research activities and publications, well integrity reports show shortcomings associated with Portland cement at specific conditions of pressure, temperature, chemical environment and geographical locations. In this experimental study, four alternative barrier materials have been selected for further experiments at laboratory scale: an industrial class of expansive cement, a non-cement pozzolanic slurry, a rock-based geopolymer and an organic thermosetting resin. Neat class G cement was used as reference material for comparing the results.The study includes the rheological behavior of the candidate materials, static fluid-loss and pumpability at both atmospheric and elevated pressures. All of the materials at the liquid phase showed an acceptable viscosity profile at the operational shear rates. The consistency curve of the slurries showed that the barrier materials are pumpable for the desired period with the right-angle set (RAS), except for the pozzolanic slurry, which was not able to make gel up to 24 h at dynamic conditions.Mechanical properties of the candidate barrier materials including uniaxial compressive strength (UCS), modulus of flexibility, sonic strength development and tensile strength of the samples were characterized up to 28 days of curing. The UCS test results showed that the thermosetting resin has an extremely high compressive strength compared to the other materials, while the geopolymer and the pozzolanic slurry are more ductile. The tensile strength of the materials experienced no significant change over time; however, for the neat class G cement, it is reduced after 28 days.

The presence of formation water throughout the oil well production lifetime is inevitable and consequently forming the dispersion or the emulsion due to the immiscibility of those two phases and the strong shear force acting in a rotating ESP. The formation of stable emulsion close to the inversion point will significantly increase the effective viscosity of an emulsion. This paper will present an experimental investigation of emulsion rheology inside the ESP and its effect on ESP performance under various oil viscosities and different water cuts (WC). Multi stages radial type ESP were assembled into a viscous flow loop which was initially developed by Zhang (2017). Emulsions at each WC formed from different oil viscosities, similar oil density, and surface tension. Multistage ESP was used to circulate oil/water emulsions in a close flow loop. Mass flowmeter measures both mass flow rate and fluid density, and the effective emulsion viscosity derived from an in-line pipe viscometer (PV) which locates downstream of the ESP discharge. The pressure transmitter is occupied in each pump stage to measure the pressure increment. The experiment results present in terms of pump boosting pressure at each water cut and the flow rate delivered by the pump. A Single-phase oil experiment was run at a different temperature to validate the accuracy of the PV. The data discrepancy of PV's viscosity and rotational viscometer is ±6%. The experiment results captured the emulsion's effective viscosity trend as a function of WC. A significant increase of effective viscosity close to the inversion point was observed, and it occurs due to a higher number of water droplets and hydrogen bonds which lead to an increase in hydrodynamic forces thus generating a tight emulsion. The experiment results reveal that a higher oil viscosity 70 cp reaches an inversion point at 30% - 35% WC. Meanwhile, for lower oil viscosity 45 cp reaches the inversion point at 35% - 40% WC since the turbulence increases with the decrease of oil viscosity. The increasing of effective viscosity in the water-oil emulsion induces higher pressure loss in the pump due to high friction loss, and it deteriorates the pump head. Nevertheless, as the WC increases further, the pump head will advance close to the single-phase water performance since the water turns as the continuous phase. Eventually, we can observe a prudent relationship in the pump performance in the change of emulsions effective viscosity as a function of WC. The inversion point phenomena occur at a different range of WC for different oil viscosity. Therefore, it is vital to set the possible range of operational conditions away from the inversion point. A better understanding of these aforementioned issues will lead to an accurate ESP design for optimum well performance.

This article describes a method for measuring the viscosity of oils that behave as Newtonian at low shear rates, by using only 80 μl of oil. This method is particularly useful when only such small quantities of oil are available—for example, when oil is extracted from grease taken from bearings. The method consists in placing an oil drop on blotter paper where an oil stain will grow in time. The rate of growth is then a measure of viscosity. Master curves were generated expressing the relation between viscosity and oil stain growth, both at a given time and as a function of time, each with its own accuracy. The viscosity measurements with this method were compared with those obtained in a conventional viscometer using poly-alpha-olefin (PAO), ester, and mineral oils.

A novel ultrasonic viscometer intended for in-situ applications in lubricated components is presented. The concept is based on the reflection of a shear wave at a solid–liquid boundary that depends on the viscosity of the liquid and the acoustic properties of the solid. Very little ultrasound energy can propagate into the oil at a metal–oil interface because the acoustic mismatch is great, and this leads to large measurement errors. The method described in this paper overcomes this limitation by placing a thin intermediate matching layer between the metal and the lubricant. Results obtained with this technique are in excellent agreement with expected values from conventional viscometers when Newtonian mineral oils are analysed. When complex non-Newtonian mixtures are tested, the viscosity measurement is frequency dependent. At high ultrasonic frequencies, over 1 MHz, it is possible to shear only the base oil, while to obtain the viscosity of the mixture it is necessary to choose a lower excitation frequency to match the dispersed polymer relaxation time.

A simple and quick in situ measurement technique for liquid viscosity is expected to enhance the quality of products and the production efficiency in many fields of engineering such as food production, film coating, medical application, and so on. For example, the in-process viscosity measurement is required to determine the economic feasibility of recovering hydrocarbon from subterranean strata. The real-time viscosity monitoring of organic liquid thin films can realize the control of the rheological and morphological characteristics of film-devices as well as the quality of film. Furthermore, the simple and fast measurement of blood viscosity realizes a diagnosis of cardiovascular disorders with new perspective. Therefore, in situ viscosity measurement could provide a breakthrough in sensing under specific conditions. However, conventional viscometers are inapplicable to in situ measurement because the contact-manner is utilized in these methods, and these methods require a long time for measurement. In the present study, a novel optical hand-held viscosity sensor (OHVS) has been developed to realize in situ viscosity measurement. The proposed sensor enables non-contact and high-speed viscosity measurement based on the optical measurement method called laser-induced capillary wave method. In order to robustly detect the optical signal which contains the information of the viscosity under hand-held condition, we developed the incident angle control system and integrated on the compact handy sensor. Through the experimental study, the irradiation angle was stabilized vertically under hand-held condition by the incident angle control system, and the standard deviation of the irradiation angle during control was smaller than 0.03 degrees that was enough to detect the viscosity signal. Finally, the optical signal which contains the information of viscosity has been observed by OHVS under hand-held condition. The applicability of the proposed sensor for the simple and quick measurement was verified.

A technique to measure fuel oil viscosity in a fuel power plant

The viscosity of the oil in the reservoir is one of the properties thatinfluence its movement through the sand to producing wells. Measurements ofviscosity, therefore, are pertinent to problems associated with well behaviorand with the estimation of recoveries, and afford an indirect means for partialevaluation of various methods of controlling reservoir behavior. The effect ofdissolved gases on the viscosity of crude oil has been determined, but no datahave been published on the viscosity of representative samples of reservoiroils, This paper describes a simple instrument that has been used to determinethe viscosities of a number of subsurface oil samples at the temperatures andpressures existing in the reservoirs, and presents the results of thedeterminations for typical fields. Construction of the Apparatus The principal requirements of any instrument used for the examination ofsubsurface samples are that it be strong and simple both in design and inmethod of operation. Accuracy beyond that of the degree of reproducibility ofsubsurface samples from various wells in a reservoir or exceeding that of thecommon measurements of reservoir temperatures and pressures is not required.Because of the expense of procuring subsurface samples, it is necessary alsothat the instrument operate on a relatively small fraction of a sample, leavingthe remainder for other tests, and that there be few or no failures of the equipment to cause undue delay orloss of a sample. After preliminary experiments with a falling bullet, the results of which werenot satisfactory, a simple viscosimeter was built of the rolling ball typefirst proposed by Flowers and later used by several investigators. Theapparatus consists essentially of a removable, accurately bored cylindricalbarrel of 1/4-in. nominal internal diameter, 8 in. long, in which a closely fitting steel ball rolls through the oil with thebarrel inclined at a definite angle, The ball makes contact at one end of thebarrel with an insulated electrode, closing an electrical circuit, whichactuates a buzzer. The measurements consist essentially in determining the timerequired for the ball to travel the length of the barrel. The details of the construction are shown in Fig. 1. The barrel in which theball rolls was made from a section of 2s-caliber blank rifle barrel, speciallybored to an exact uniform diameter and polished. The barrel slides snugly intoa hole bored in a solid stainless-steel cylinder, an upper external shoulder ofthe barrel compressing a small spring, and is held in place by a hollow nut.The spring prevents the barrel from seating against the bottom of the boredhole in the cylinder, while narrow external longitudinal slots in the barrelpermit fluid to flow around it and through the bottom. T.P. 1220