Rheological Properties Of Fluid Research Articles

A Novel Model for the Real-Time Evaluation of Hole-Cleaning Conditions with Case Studies

The main challenge in deviated and horizontal well drilling is hole cleaning, which involves the removal of drill cuttings and maintaining a clean borehole. Insufficient hole cleaning can lead to issues such as stuck pipe incidents, lost circulation, slow rate of penetration (ROP), difficult tripping operations, poor cementing, and formation damage. Insufficient advancements in real-time drilling evaluation for complex wells can also lead to drilling troubles and an increase in drilling costs. Therefore, this study aimed to develop a model for the hole-cleaning index (HCI) that could be integrated into drilling operations to provide an automated and real-time evaluation of deviated- and horizontal-drilling hole cleaning based on hydraulic and mechanical drilling parameters and drilling fluid rheological properties. This HCI model was validated and tested in the field in 3 wells, as it was applied when drilling 12.25″ intermediate directional sections and an 8.5″ liner directional section. The integration of the HCI in Well-A and Well-B helped achieve much better well drilling performance (50% ROP enhancement) and mitigate potential problems such as pipe sticking due to hole cleaning and the slower rate of penetration. Moreover, the HCI model was also able to identify hole-cleaning efficiency during a stuck pipe issue in Well-C, which highlights its potential usage as a real-time model for optimizing drilling performance and demonstrates its versatility.

H2S scavenging performance and rheological properties of water-based drilling fluids comprising ZIF-67

Exposure to the toxic hydrogen sulfide (H2S) gas during oilfield operations carries serious health and safety concerns, in addition to significant economic losses resulting from the corrosion and potential failures of the handling equipment. Although there are several H2S scavengers reported in the literature or commercially available, they have their own limitations in terms of efficacy, toxicity, and/or environmental impact, among others. Thus, we report herein, for the first time, the H2S scavenging performance of Zeolitic Imidazolate Framework-67 (ZIF-67) nanoparticles (NPs) and its effect on the rheological and fluid loss properties of water-based drilling mud. The synthesized ZIF-67 material was characterized using different characterization techniques. The incorporation of the ZIF-67 NPs into the drilling fluids was found to significantly enhance the H2S scavenging performance, where the breakthrough and saturation capacities in the presence of 1 wt.% ZIF-67 NPs were more than 2300 and 495%, respectively, higher than those obtained using the base drilling mud. The remarkable H2S scavenging performance of the ZIF-67 NPs in the drilling fluid can be attributed to their unique structural properties, abundant uncoordinated open metal (Co(II)) sites, high surface area, and the presence of active surface nitrogen functional groups. The fluid loss and rheological properties of the base drilling mud were not compromised by the addition of ZIF-67 NPs. Contrarily, the addition of ZIF-67 improved the plastic viscosity (PV), apparent viscosity (AV), yield point (YP), carrying capacity, and gel strength (GS) of the based mud. To the best of our knowledge, there are no published studies so far on H2S scavenging using any ZIF material while submerged in a liquid phase or incorporated into a drilling fluid, highlighting the novelty and significance of this work.

Semi-active structural vibration control with magnetorheological damper based on hybrid fuzzy sliding mode controller

Recently, structural vibration control has proved its capacity to save lives and keep structures safe during earthquakes. Furthermore, there is a wealth of research in both numerical and experimental studies. As a result, due to its simplicity and performance in mitigating structural vibrations generated by ground motions, semi-active control played a significant role in the majority of these studies. Nonetheless, the magnetorheological damper is the most often used semi-active device. In particular, the rheological fluid properties have gained adequate attention in earthquake energy dissipation and structural vibrations management, particularly in the civil engineering field. The semi-active control of three scaled excited structures is addressed in this study. A magnetorheological damper operated by a hybrid fuzzy sliding mode controller ensures the proposed control. However, to provide the appropriate current for the damper to operate, this proposed intelligent controller is combined with a clipped optimum algorithm. Otherwise, the numerical simulation results of the seismic excited scaled structure demonstrate the resilience of the suggested controller. As a result, four time-scaled seismic data are applied to the tested structure. Finally, the usefulness of the suggested semi-active control technique in mitigating earthquake structural vibration is demonstrated clearly in the compared controlled and uncontrolled responses.

Particle Image micro-Rheology (PIR) using displacement probability density function

We present a novel approach to perform passive microrheology. A method to measure the rheological properties of fluids from the Brownian motion of suspended particles. Rheological properties are found from the particles' mean square displacements (MSDs) as a function of measurement time lag. Current state-of-the-art approaches find the MSD by tracking multiple particles' trajectories. However, particle tracking approaches face many limitations, including low accuracy and high computational cost, and they are only applicable to low particle seeding densities. Here, we present a novel method, termed particle image rheometry (PIR), for estimating the particle ensemble MSD from the temporal evolution of the probability density function of the displacement as a function of measurement time lag. First, the probability density function (PDF) of the particle displacements for each time lag is found using a generalized ensemble image cross-correlation approach that eliminates the need for particle tracking. Then, PDFs are used to calculate the MSD from which the complex viscosity of the solution is measured. We evaluate the performance of PIR using synthetic datasets and show that it can achieve an error of less than 1% in passive microrheology measurements, which corresponds to a twofold lower error than existing methods. Finally, we compare the measured complex viscosity from PIR with bulk rheometry for a polymeric solution and show agreement between the two measurements.

A Methodical Approach to Scaling Up an Aerated Coaxial Mixer Containing a Shear-Thinning Fluid: Effect of the Fluid Rheology

The evolution of the rheological behavior of the fluid is one of the primary challenges encountered in the scale-up of the most aerated reactors. In fact, mixing efficiency diminishes because of the changes in the fluid rheological properties. Under these circumstances, it is challenging to keep the mass transfer constant upon scale-up. A thorough literature review revealed that no scale-up study of aerated coaxial mixers has considered the effect of varying fluid rheological properties. Therefore, to analyze the scale-up of these aerated mixing systems, the effects of the impeller speed and type, fluid rheology, and aeration rate on the gas hold-up, local mass transfer coefficient, bubble size distribution, hydrodynamics, and specific power consumption were explored. Electrical resistant tomography, dynamic gassing-in, and computational fluid dynamics methods were employed. For the first time, a systematic approach based on a constant volumetric mass transfer has been proposed for the scale-up of aerated coaxial reactors at different fluid rheological properties.

Fluid laminarization process and rheological properties of protein-stabilized high internal phase emulsions

Protein-based high internal phase emulsions (HIPEs) have gained tremendous attention in diverse fields, but their mechanism in the emulsification process remains elusive. In this article, HIPEs were stabilized directly by food-grade proteins, depending on a self-organized process featuring a fluid laminarization. We elucidated that the emulsification with the rotor-stator mixer is a typical non-equilibrium process. The crucial factor for the process is related to the irreversible energy dissipation, while the internal phase volume fraction is the threshold determining the laminarization. The feasible explanation speculated that the transition corresponds to the dissipative structure, i.e., compressive droplets, arising from the spatiotemporal self-organization, to dissipate the turbulent kinetic energy. We found a new paradigm of dissipative structure, comprehending such structure in the HIPEs emulsification process, which is expected to pave the way for its industrial-scale production with the virtue of low-cost proteins.

A Finite Difference Method for Solving Unsteady Fractional Oldroyd-B Viscoelastic Flow Based on Caputo Derivative

In this paper, the effect of a fractional constitutive model on the rheological properties of fluids and its application in numerical simulation are investigated, which is important to characterize the rheological properties of fluids and physical characteristics of materials more accurately. Based on this consideration, numerical simulation and analytical study of unsteady fractional Oldroyd-B viscoelastic flow are carried out. In order to improve the degree of accuracy, the mixed partial derivative including the fractional derivative in the differential equation is converted effectively by integrating by parts instead of by direct discretization. Then, the stability, convergence, and unique solvability of the difference scheme are verified. The validity of the finite difference method is tested by making comparisons with analytical solutions for two kinds of fractional Oldroyd-B viscoelastic flow. Numerical results obtained using the finite difference method are in good agreement with analytical solutions obtained via the variable separation method. Viscoelastic characteristics of the unsteady Poiseuille flow are similar to the second-order fluid or integer-order Oldroyd-B fluid when the parameter is close to 0 or to 1. Oscillation characteristics of fractional viscoelastic oscillatory flow are similar to those of the classical viscoelastic fluid under the same condition. Compared with the previous research, the present work studies the rheological properties of fluids with the finite difference method, and the application of fractional constitutive models in describing the rheological properties of fluids is developed. Meanwhile, more cases reflecting the fractional-order characteristics are given. The present method can accurately capture the flow characteristics of unsteady fractional Oldroyd-B viscoelastic fluid and is applicable for the generalized fractional fluid.

PROSPECTIVE PHYSICO-CHEMICAL METHODS OF INCREASING THE RECOVERY (EOR) FOR OIL FIELDS WITH THE CATEGORY OF HARD-TO-EXTRACT OILS

It is known that many technologies to improve the oil recovery factor in fields at a late stage of development are being used. However, there are no universal technologies that ensure the effective displacement of residual oil in the reservoir by changing the filtration and volumetric parameters of rocks and the rheological properties of fluids depending on the geological characteristics of the reservoirs. In the article, based on the analysis of well-known works carried out on the selection of the appropriate oil for displacement oil in the reservoir, taking into account changes in some reservoir parameters, research work was conductedwith the purpose to prepare a new composition. The question of searching for a composition capable of maintaining oil-displacing properties at different temperatures in reservoir conditions, not changing its viscosity at large temperature differences, and also capable of retaining the properties of removing oil particles absorbed there from the surface in contact with the reservoir is relevant. the surface of the rock was examined by laboratory studies. The viscosities of the found composition at various temperatures were determined using a viscometer, and the optimal composition with a stable viscosity was determined by replacing the components with numerous laboratory experiments. Under laboratory conditions, the process of displacement of oil under various compositions with a slug of the composition at different temperatures was carried out. The results obtained are satisfactory, and the effective behavior of the composition at bed temperatures of 30-80 0C has been experimentally confirmed. If we take into account that the compositions injected into the reservoir undergo certain changes under the influence of reservoir temperature and pressure, then certain changes in its properties will inevitably occur when the composition comes into contact with reservoir fluids. Therefore, the ability of the prepared composition to form a precipitate or gel upon contact with various formation waters was also studied. The results of laboratory studies of physical and chemical technologies for enhanced oil recovery in fields treated by water injection and thermochemical treatment are presented. These technologies can be used in reservoirs with hard-to-recover reserves of high-viscosity oil. Keywords: viscosity, residual reserve, bed, surfactant, gel, oil displacer.

PIPE STICKING PROBLEMS AND THEIR SOLVING WAYS IN WELLBORE

In this article, we discuss the most common pipe sticking problems that occur in general drilling, explore their causes, and practices for solving and preventing them. Although there are various causes of drilling problems, they are mainly related to the drilling fluid, whose characteristics and optimization can help prevent/reduce a number of problems encountered during drilling and save a lot of money. Drilling fluids have undergone major changes since they were first used in the drilling process, leading to more optimal drilling. Its transformation from a simple mixture of water and clay to a more complex combination of various types of organic and inorganic additives has increased the fluid's rheological properties and filtration capabilities. Keywords: pipe sticking, free pipe, differential pressure stuck, drilling fluid, mud cake.

Entrapment and mobilization dynamics during the flow of viscoelastic fluids in natural porous media: A micro-scale experimental investigation

Capillary desaturation process was investigated as a function of wetting phase rheological signatures during the injection of Newtonian and non-Newtonian fluids. Two sets of two-phase imbibition flow experiments were conducted on a water-wet sandstone core sample using brine and viscoelastic polymer solutions. During the experiments, a high-resolution micro-computed tomography scanner was employed to directly map pore-level fluid occupancies within the pore space. The results of the experiments revealed that at a given capillary number, the viscoelastic polymer was more efficient than the brine in recovering the non-wetting oil phase. At low capillary numbers, this is attributed to the improved accessibility of the viscoelastic polymer solution to the entrance of pore elements, which suppressed snap-off events and allowed more piston-like and cooperative pore-body filling events to contribute to oil displacement. For intermediate capillary numbers, the onset of elastic turbulence caused substantial desaturation, while at high capillary numbers, the superimposed effects of higher viscous and elastic forces further improved the mobilization of the trapped oil ganglia by the viscoelastic polymer. In the waterflood, however, the mobilization of oil globules was the governing recovery mechanism, and the desaturation process commenced only when the capillary number reached a threshold value. These observations were corroborated with the pore-level fluid occupancy maps produced for the brine and viscoelastic polymer solutions during the experiments. Furthermore, at the intermediate and high capillary numbers, the force balance and pore-fluid occupancies suggested different flow regimes for the non-Newtonian viscoelastic polymer. These regions are categorized in this study as elastic-capillary- and viscoelastic-dominated flow regimes, different from viscous-capillary flow conditions that are dominant during the flow of Newtonian fluids. Moreover, we have identified novel previously unreported pore-scale displacement events that take place during the flow of viscoelastic fluids in a natural heterogeneous porous medium. These events, including coalescence, fragmentation, and re-entrapment of oil ganglia, occurred before the threshold of oil mobilization was reached under the elastic-capillary-dominated flow regime. In addition, we present evidence for lubrication effects at the pore level due to the elastic properties of the polymer solution. Furthermore, a comparison of capillary desaturation curves generated for the Newtonian brine and non-Newtonian viscoelastic polymer revealed that the desaturation process was more significant for the viscoelastic polymer than for the brine. Finally, the analysis of trapped oil clusters showed that the ganglion size distribution depends on both the capillary number and the rheological properties of fluids.

Rheological and filtration properties of water-based drilling fluids as influenced by cellulose nanomaterials: different aspect ratios and modified groups

Rheological and filtration properties of water-based drilling fluids as influenced by cellulose nanomaterials: different aspect ratios and modified groups

The effect of microparticles/nanoparticles surface modification on the magnetorheological fluid properties: A review

Magnetorheological fluids are considered smart materials since their properties change significantly when exposed to a magnetic field, making them interesting for a variety of industries. These fluids are composed of three main components: dispersed particles, carrier fluid, and additives. The latter of which has been the subject of various studies. Therefore, this paper reviews the characteristics and parameters of the particles dispersed in additives and their impact on fluid rheological properties and stability. Also, the surface modification of magnetic and non-magnetic micro and nanoparticles have been investigated. A detailed review of previous studies has been carried out to examine the effects of various parameters such as types of coatings, coating layers, coating thickness, density change, and change in magnetic saturation, on the stability and rheological properties of MR fluids.

Double-diffusive Hamel–Jeffrey flow of nanofluid in a convergent/divergent permeable medium under zero mass flux

In the recent era, the nanofluid's transportation due to the Jeffrey–Hemal flow phenomenon (i.e., carrying fluid through a converging/diverging channel) has significant applications in numerous engineering and science technologies. Therefore, multi-disciplinary evolution and research motivated us to present current attempt. The aim of this attempt is to present Jeffrey–Hamel mechanism of the nanofluid through non-parallel channel under thermally balance non-Darcy permeable medium impacts. The nanomaterial is represented using the Buongiorno nanofluid model. The investigation also includes zero mass flux impacts as well as variable rheological fluid properties. The influences of temperature jump are also encountered in the current analysis. The governing flow expressions under the Jeffrey–Hemal analysis are made dimensionless utilizing the similarity variables. The dimensionless equations are then solved using the analytical scheme (homotopy method) and the obtained series solutions are convergent. The influences of the involved parameters on concerned profiles are investigated through graphs. Force of drag, Nusselt and Sherwood numbers are elaborated graphically. In this analysis, intensification in Prandtl number enhances the heat transfer rate whereas decrement is seen in heat transfer rate for larger thermal slip parameter. Further, mass diffusivity parameter adversely affects the mass transfer rate. The current analysis incorporates numerous industrial and technological processes including transportation, material synthesis, microfluidics, high-power Xrays, biomedical, solid-state lighting, microelectronics, scientific measurement, medicine, molten polymers extrusion via converging dies, cold drawing operation related to polymer industry etc.

An experimental study of the merging flow of polymer solutions in a T-shaped microchannel.

The merging flow through a T-junction is relevant to sample mixing and particle manipulation in microfluidic devices. It has been extensively studied for Newtonian fluids, particularly in the high inertial regime where flow bifurcation takes place for enhanced mixing. However, the effects of fluid rheological properties on the merging flow have remained largely unexplored. We investigate here the flow of five types of polymer solutions along with water in a planar T-shaped microchannel over a wide range of flow rates for a systematic understanding of the effects of fluid shear thinning and elasticity. It is found that the merging flow near the stagnation point of the T-junction can either be vortex dominated or have unsteady streamlines, depending on the strength of elasticity and shear thinning present in the fluid. Moreover, the shear thinning effect is found to induce a symmetric unsteady flow in comparison to the asymmetric unsteady flow in the viscoelastic fluids, the latter of which exhibits greater interfacial fluctuations.

In vitro oral simulation based on soft contact: The importance of viscoelastic response of the upper jaw substitutes.

Real oral processing is the squeezing and shearing between two soft surfaces. The importance of soft palate surface cannot be ignored while focusing on tongue substitutes. Thus the effects of viscoelasticity, roughness of upper jaw substitutes, and fluid rheological properties on lubrication properties were explored by in vitro oral tribology experiments. Different palate substitutes significantly changed the friction curves of pure water, milk, and yogurt. The boundary friction coefficients of pure water and milk are higher under softer or smooth palate substitutes due to stronger viscoelastic responses of friction pairs. Their boundary friction coefficients are lowest at rigid upper jaw substitutes owing to smaller contact angles and deformation. However, the boundary friction coefficient of yogurt is lower owing to its high viscosity, low loss factor, and large particle size under soft friction pairs. In addition, it is highest at rigid palate friction pair because a smaller contact area reduces the entrainment of yogurt, resulting in poor lubricating performance.

Application of machine learning to determine the shear stress and filtration loss properties of nano-based drilling fluid

A detailed understanding of the drilling fluid rheology and filtration properties is essential to assuring reduced fluid loss during the transport process. As per literature review, silica nanoparticle is an exceptional additive to enhance drilling fluid rheology and filtration properties enhancement. However, a correlation based on nano-SiO2-water-based drilling fluid that can quantify the rheology and filtration properties of nanofluids is not available. Thus, two data-driven machine learning approaches are proposed for prediction, i.e. artificial-neural-network and least-square-support-vector-machine (LSSVM). Parameters involved for the prediction of shear stress are SiO2 concentration, temperature, and shear rate, whereas SiO2 nanoparticle concentration, temperature, and time are the inputs to simulate filtration volume. A feed-forward multilayer perceptron is constructed and optimised using the Levenberg–Marquardt learning algorithm. The parameters for the LSSVM are optimised using Couple Simulated Annealing. The performance of each model is evaluated based on several statistical parameters. The predicted results achieved R2 (coefficient of determination) value higher than 0.99 and MAE (mean absolute error) and MAPE (mean absolute percentage error) value below 7% for both the models. The developed models are further validated with experimental data that reveals an excellent agreement between predicted and experimental data.

Kinetics of isotropic to string-like phase switching in electrorheological fluids of nanocubes.

Applying an electric field to polarizable colloidal particles, whose permittivity differs from that of the dispersing medium, generates induced dipoles that promote the formation of string-like clusters and ultimately alter the fluid mechanical and rheological properties. Complex systems of this kind, whose electric-field-induced rheology can be manipulated between that of viscous and elastic materials, are referred to as electrorheological fluids. By using dynamic Monte Carlo simulations, we investigate the dynamics of self-assembly of dielectric nanocubes upon application of an electric field. Switching the field on induces in-particle dipoles and, at sufficiently large field intensity, leads to string-like clusters of variable length across a spectrum of volume fractions. The kinetics of switching from the isotropic to the string-like state suggests the existence of two mechanisms, the first related to the nucleation of chains and the second to the competition between further merging and separation. We characterize the transient unsteady state by following the chain length distribution and analyzing the probability of the transition of nanocubes from one chain to another over time. Additionally, we employ passive microrheology to gain insight into the effect of the electric field on the viscoelastic response of our model fluid. Not only do we observe that it becomes more viscoelastic in the presence of the field but also that its viscoelasticity assumes an anisotropic signature, with both viscous and elastic moduli in planes perpendicular to the external field being larger than those along it.

Study on particle cluster dynamics behavior in settling and the influence by fiber barrier

The dispersion of particle clusters is relevant to a high concentration carrying fluid such as fracturing and drilling fluid, and the fiber-containing fluid could improve the carrying performance of particles. In the present study, the settling dynamics behavior of clusters is investigated using the CFD-DEM method. The numerical simulation method employed was able to accurately predict the deformation and velocity change rules, which express the cluster settling dynamics behavior. The velocity variation of particles is affected by hindrance and contact inside the cluster, and the velocity contrast leads to particle leakage and cluster deformation. The cluster will have regular shape changes and break up in the settlement process under gravity and fluid drag force. According to the sensitivity parameter analysis, the deformation of clusters is mainly affected by the fluid rheological properties. Different from glycerol, the settling cluster in viscoelastic HPG has a more complex dynamic behavior and a better fiber barrier effect. The fiber barrier between particles in the cluster can be regarded as a weakly constrained fiber grid structure. Due to the contact force, fiber grid structure formed in the cluster could effectively restrain the shape change and break up trend in the settlement process. The design also considers the influence of fiber and HPG concentration, and we analyze the settling velocity of the mixed-fiber cluster. Overall, the research on the cluster settling dynamics behavior is helpful in analyzing the effect of fiber-containing fluid in the carrying performance of particles.

Technology Focus: Drilling and Completion Fluids (November 2022)

As the oil and gas drilling industry moves into more technically challenging environments [e.g., drilling ultradeep onshore/offshore wells under extremely high temperature (above 300°F) and pressure (mud specific gravity above 2.0)], companies increasingly come under pressure to stretch technology and improve drilling performance while continuously striving to reduce costs and meet the requirements of stricter environmental regulations. Significant reserves additions may be realized if the risks associated with drilling in such harsh conditions (e.g., pressure control, wellbore instability, lost-circulation, sour gas) can be managed effectively. Design and development of a new generation of drilling fluids able to fulfill all of the attributed functions (e.g., stabilize the wellbore, control formation pressure, transport the drilled cuttings, minimize the fluid loss, and not reduce formation productivity) under such extreme pressure and temperature conditions is one of the key requirements for unlocking these resources. Drilling fluids used under ultrahigh pressures and temperatures need to be thermally stable and able to retain their rheological properties. Traditionally, nonaqueous drilling fluids (NADFs) have been used under these extreme conditions. NADFs, however, have significantly high operational costs with an associated health, safety, and environmental risk. As a result, there has been an increasing demand from operators to use aqueous drilling fluids [water-based muds (WBMs)], which are known to be environmentally benign and relatively less expensive. The use of WBMs under extreme temperatures and pressures, however, faces several challenges, including the breakdown of polymers and other additives used as fluid-loss preventers and rheological stabilizers. Therefore, recent research has focused on design and development of WBM systems meeting the following specifications: - Use of sodium chloride (for barite-laden formulation) and sodium bromide (for barite-free formulation) as base brines to reduce the total solids content for optimal fluid properties and to maximize the quality of wireline logs - Ensure inhibition of reactive shale formations to maintain wellbore stability while drilling intermediate sections - Provide optimal and stable rheological properties for excellent hole cleaning and drilling performance The newly developed ultrahigh-temperature water-based systems used custom-made branched synthetic polymers that exhibit superior rheological properties and fluid-loss control as well as long-term stability above 400°F. These branched synthetic polymers are compatible with most oilfield brines and maintain excellent low-end rheology. Other formulations proposed the use of β-cyclodextrin polymer microspheres (β-CPMs) as an environmentally friendly ultrahigh-temperature filtration reducer. When the temperature rose above 160°C, a hydrothermal reaction occurred for β-CPMs, and, as a result, numerous micro- and nanosized carbon spheres formed, which bridged across micro- and nanopores within the filter cake and reduced the filter cake permeability effectively. Bentonite-hydrothermal carbon nanocomposites also are proposed as nonpolymer additives to solve the ultrahigh-temperature/-pressure challenge in water-based drilling fluid. The nanocomposites are synthesized by a simple hydrothermal reaction in which biomass starch and sodium bentonite are used as the precursor and template, respectively. Such formulations have shown favorable rheology and filtration properties after hot rolling at temperatures as high as 460°F. This section presents selected papers showing examples of design, development, and field applications of the new generation of WBM fluid technologies. Recommended additional reading at OnePetro: www.onepetro.org SPE 206444 - Successful Application of a New Generation of Clay-Inhibitor Polymers While Drilling a Deep Exploration Well in the Astrakhan Region by Petr Leonidovich Ryabtsev, Akros, et al. SPE 205539 - Improvement of Rheological and Filtration Properties of Water-Based Drilling Fluids Using Bentonite-Hydrothermal Carbon Nanocomposites Under Ultrahigh-Temperature and High-Pressure Conditions by Hanyi Zhong, China University of Petroleum East China, et al. SPE 209805 - The Utilization of Self-Crosslinkable Nanoparticles as a High-Temperature Plugging Agent in Water-Based Drilling Fluid by Ming Lei, University of Alberta, et al.

Influence of calcium chloride in coal on guar-based foam fracturing fluid rheological property: An experimental study

To investigate the influence of calcium chloride (CaCl2) in coal seams on the rheological property of a foam fracturing fluid, the guar powder was used as a foam stabilizer, and the anionic and cationic surfactants were used as foaming agents. The impact of CaCl2 concentrations on the foaming volume, half-life, viscosity, and surface tension of foam was investigated. The results show that CaCl2 has a more significant effect on the foaming amount and foam stability of the anionic surfactant-prepared foam. When the concentration of CaCl2 exceeds 0.25%, the viscosity of the base fluid shows a downward trend and gradually tends to a stable level below 10 mPa s. The foam half-life increases as the shape parameter an in the gamma function increases and decreases as the scale parameter b increases. The effect of CaCl2 on the bubble size of the anionic surfactant foam fracturing fluid is significantly greater than that of the cationic surfactant foam fracturing fluid. For coal reservoir foam fracturing, a foaming agent with better CaCl2 compatibility should be employed to reduce the influence of CaCl2 in the formation water on fracturing performance.