Cake Porosity Research Articles

Synergistic enhancement of dewatering of montmorillonite-containing coal slime by novel combined filter aid: an experimental and simulation study

ABSTRACT The efficient dewatering of montmorillonite (Mt)-containing coal slime is still an urgent problem to be solved in coal preparation plant. In this study, the dewatering effect of poly(o-phenylenediamine)/Poly dimethyl diallyl ammonium chloride (POPD/PDADMAC) combined filter aid on Mt-containing coal slime was studied. The dewatering performance of combined filter aid was investigated by vacuum filtration test. The action mechanism of combined filter aid was revealed by contact angle, zeta potential, cake pore and atomic force microscope (AFM). The co-adsorption principle of the combined filter aid was elucidated based on density functional theory (DFT) and molecular dynamics simulation (MD). Compared to PDADMAC, the combined filter aid has better performance for dewatering of Mt-containing coal slime, and has the advantage of low reagent dosage. The combined filter aid can greatly reduce the Mt potential, increase the Mt contact angle, and increase the porosity of the filter cake. There was a co-adsorption effect between the combined filter aid. Specifically, there were ion–dipole interaction, cation–π interaction and Cl ions bridged electrostatic interaction between POPD and PDADMAC. This study has developed a novel combined filter aid, which provides theoretical and technical support for the high-efficiency pressure filtration dewatering of Mt-containing coal slime in coal preparation plants.

Influence of perlite on the stability of filter cake in low-density drilling fluids system

Enhancing drilling fluid performance in the oil and gas industry involves addressing various criteria across technical, environmental, and economic aspects. Consequently, this study encompassed several factors such as rheology, filtration, formation damage, and additives to design appropriate and cost-effective drilling fluid. The potential of perlite as an additive for low-density drilling was assessed in this work. A comprehensive laboratory experimental approach was applied to gain an in-depth understating of perlite's performance. The investigation included evaluating the rheological properties, filter cake quality, and characterizing filtration medium pore distribution. Additionally, sensitivity tests were also conducted to judge the effectiveness of perlite as a primary viscosifier and filtration agent. Through these tests, a holistic assessment of perlite's capabilities was achieved. The findings indicated that while perlite was not suitable for use as the primary viscosifier or as the main filtration agent, its use as a secondary agent exhibited a positive impact, particularly in reducing solid invasion by approximately 93%. The optimum perlite concentration was 3 lb./bbl., with good enhancements in filtration volume, filter cake thickness and porosity by 50%, 40%, and 14%, respectively. Additionally, employing a combined particle distribution approach for the calcite, rather than a singular grade, resulted in substantial improvements in the examined properties. The most notable improvement was observed in filter cake permeability, which decreased by nearly 93%. The other parameters were improved by 80% for filtration volume, 74% for filter cake thickness, and 24% for solid invasion. This work highlighted the usability of perlite in low-density mud and how it can improve the drilling fluid properties.

High efficiency filtration and optimization of pelletizing performance of fine hematite concentrate using sulfuric acid filter aid: Behavior and mechanism

Following the application of anionic reverse flotation to fine low-grade hematite ore, a significant challenge emerges with elevated slurry viscosity and heightened moisture content in the resulting filter cakes. To address the challenge of dewatering during the filtration process of fine hematite concentrate, the impact of sulfuric acid filter aid dosage and filtration temperature on the filtration performance of hematite concentrate was systematically investigated in this study. In addition, the effect of sulfuric acid filter aid on the preparation of hematite pellets was also studied. The results revealed a significant decrease from 1.10 × 1010 1/m2 to 5.7 × 109 1/m2 in the specific resistance of the hematite filter cake when the sulfuric acid dosage was 1.2 g/kg and the filtration temperature was 20 °C. The mechanism underlying the enhancement of filtration performance of fine hematite concentrate by sulfuric acid was summarized. Sulfuric acid compressed the double electric layer on the surface of hematite concentrate particles, reducing the surface zeta potential and causing the aggregation of fine particles into larger ones. This led to an increase in filter cake porosity and compression of the hydration film thickness on particle surfaces, facilitating easier removal of filtrate from the filter cake. The appropriate dosage of bentonite for pelletizing was not significantly affected by sulfuric acid filter aid. Sulfuric acid improved the porosity, drying rate, and burst temperature of hematite green pellets. While the compressive strength of preheated pellets from sulfuric acid-assisted filtration of hematite concentrate showed a slight decrease, the compressive strength of roasted pellets was significantly increased.

Experimental Study on Infiltration of Seawater Bentonite Slurry

A bentonite slurry mixed with seawater is prone to sedimentation, which will reduce the quality of the filter cake and lower the stability of the excavation surface in undersea tunnels. It is necessary to study the performance and influencing factors of the bentonite slurry mixed with seawater. This article simulates the process of undersea slurry shield tunnel construction, where the pressurized slurry penetrates into the sand layer and forms a filter cake when the shield stops pressurizing. We investigated the effects of bentonite, additives (CMC), fine sand, pressure, and formation permeability on the performance of the seawater slurry and filter cake. The sedimentation of mud caused by seawater interfered with the experiment, which manifested as the increase in bentonite, and delayed the formation of the filter cake. Fine sand with a particle size close to the average value of the formation can improve the speed and quality of filter cake formation. By conducting a sensitivity analysis on experimental data, the degree of influence of various factors on the formation rate, thickness, and porosity of the filter cake was determined. Fine sand and bentonite are the factors that have the greatest impact on the formation rate, thickness, and porosity of the filter cake.

Study on the Structural Characteristics of Mesh Filter Cake in Drip Irrigation: Based on the Growth Stage of Filter Cake

Mesh filters are frequently employed in water-saving irrigation fields. Studies addressing the method of cake formation and the characteristics of the cake during the mesh filter’s growing phase are still missing. One-way and orthogonal experiments were carried out using mesh filters with 220 μm and 320 μm aperture sizes as the research objects, taking particle concentrations, inlet flow, and growth phases as experimental factors. According to the variation rule of seed pressure drop in the formation process of filter cake, the growth process of filter cake is divided into four stages, which are as follows: slow blockage first and second stages (M1, M2), fast blockage stage (M3), and filter cake filtration stage (M4). Moreover, the size distribution, porosity (ε), pore-to-particle ratio (KP), and median size (d50) of the filter cake were used to represent the structural characteristics. The results show that the growth of filter cake was a process that started with the filling of mesh pores by intercepted particles and progressed to the filling of large-particle skeleton pores by subsequently filtered particles. During this process, the proportion of intercepted particles gradually decreased, while the proportion of filtered particles increased incrementally, and the median size (d50) and porosity (ε) decreased. Meanwhile, the smaller the aperture size of the screen, the smaller the filter cake’s median size (d50) was, but the larger the pore-to-particle ratio (KP) was. As the flow rate increased, the porosity (ε) was augmented in the M1 and M2 stages; however, it decreased in the M3 and M4 stages. The concentration had a minor influence on the filter cake’s porosity. Lastly, the regression model for filter cake porosity under two aperture size conditions was established, based on factors such as flow rate, concentration, and growth stage. The coefficients of determination, R2, for the model were 90.33% and 80.73%, indicating a good fit.

Influence of Particle Surface Energy and Sphericity on Filtration Performance Based on FLUENT-EDEM Coupling Simulation

The adhesion of dust particles on the surface of the dust collector tends to cause great resistance to the dust collector and affects the operating efficiency. In order to visualize particles in the filtration process and to grasp the mechanism of particle viscosity and sphericity on filtration performance, a numerical simulation study was conducted to investigate the deposition behavior of particles during filtration, employing FLUENT-EDEM coupling technology. By examining the deposition process, the role of particle characteristics on dust behavior within the entire filtration system was elucidated. The effects of varying particle surface energy and particle sphericity on filtration pressure drop and cake porosity were analyzed. The findings reveal that under the force of the air, particles on the surface of the filter membrane experience compaction, leading to a reduction in the porosity of the formed cake layer. The diminution of porosity serves to impede the air, consequently augmenting the pressure drop across the filtration system and hindering the operational efficacy of the dust collector. As the surface energy of the particles increases, the adhesive forces between particles are intensified, leading to an elevation in the porosity of the cake layer and a subsequent decrease in the pressure drop. When the surface energy of the particles is increased from 0.01 J/m2 to 0.04 J/m2, the porosity experiences a modest increase of only 9.1%, yet the pressure drop is significantly reduced by half, amounting to a decrease of 1594 Pa. Under high particle surface energy, as filtration air velocity increases, particles are compressed, resulting in a decrease in cake porosity and an increase in pressure drop. Concurrently, our findings indicate that as the sphericity of particles increases, their surfaces become increasingly smooth which in turn results in a decreased porosity of the cake layer and, consequently, an elevation in the filtration pressure drop.

Effect of ultrasonic pretreatment on the flocs characteristics in the flocculation filtration process of coal slurry water

The enhancement of ultrasonic pretreatment on the flocculation filtration of coal slurry water has been reported. The structural characteristics of flocs are critical parameters in the flocculation and filtration process. In this paper, the effect of ultrasonic pretreatment on the flocs' characteristics during flocculation and filtration was investigated. The flocs size, number, strength, and fractal dimension in the microstate were characterized through a polarized light microscope, PVM, and FBRM. The changes in flocs characteristics on the filter cake's pore structure and moisture distribution were analyzed using L-F NMR. The results showed that the optimal condition was an ultrasonic frequency of 30 KHz, ultrasonic time of 3 min, and the dosage of cationic polyacrylamide (CPAM) with ionicity of 60 at 50 g/t, under which the filtration rate was 597.42 mL·(m2s)−1 and the moisture content of the filter cake was 27.03 %. Ultrasonic pretreatment increased the flocs' size, with a decrease in the proportion of small flocs and an increase in the proportion of medium and large flocs, mainly medium flocs. The increase in the fractal dimension and strength of the flocs structure made the filter cake deformed less under pressure, formed a porous skeleton structure, and increased the total porosity of the filter cake, with the most significant variation in mesopores. Moreover, ultrasonic pretreatment could decrease the proportion of adsorbed and bound water while increasing the proportion of free water and effectively reducing the filter cake's moisture content. This study revealed the essential relationship between floc characteristics and flocculation filtration efficiency, filter cake pore structure, and moisture distribution and provided a new perspective for exploring the application mechanism of ultrasonic technology in enhancing flocculation filtration performance.

Reduced fat and sugar cakes developed by protein/polysaccharide/licorice extract ternary gel-like foams

Reduced sugar and fat products are increasingly in demand due to the link between excessive consumption of these substances and chronic noncommunicable diseases. Therefore, this study aimed to produce a low-calorie cake by replacing sugar and fat with whey protein isolate/sodium alginate/licorice extract ternary foam at three substitution levels of 0 %, 25 %, and 50 %. As the amount of foam used as a replacement increased, there were marked decreases in batter viscosity (5.29–2.64 Pa s) and density (1.13–0.88 g cm−3), as well as in the cake's fat (8.91–4.73 g/100 g), carbohydrate (67.92–47.09 g/100 g), specific volume (3.13–1.76 mL g−1), calories (371.37–252.57 kcal/100 g), and porosity (10.25–5.05 %). On the other hand, moisture and water activity increased significantly (p < 0.05) with the increase of foam replacement. In terms of crust color, a* decreased while L* and b* increased remarkably. The cake samples with 0 % and 50 % substitution levels had the lowest and highest values for hardness (0.76 vs. 2.38 N), cohesiveness, and chewiness, respectively. The sensory evaluation results showed that the sample with a 25 % substitution level was more similar to the control sample. This suggests that foam can be used as a substitute for sugar and fat to produce a healthier product.

A SiC membrane resistance recovery methodology based on dynamically dust cake layer analysis

Filter cake-induced resistance is a significant contributor to energy consumption in dust filtration processes. This can be optimized by adjusting inlet gas composition, membrane characteristics, and back-flushing parameters. In this study, calcium carbonate (CaCO3) dust with varying hygroscopicity was utilized to investigate the evolution mechanism of the filter cake on SiC membranes under different humidity conditions. The interacting force between particles and between the cake and membrane were analyzed to elucidate the fragmentation mechanism of the cake. It was observed that particles at higher relative humidity (increased RH from 40 % to 85 %) tend to form a more loosely packed cake (hydrophilic filter cake porosity and hydrophobic filter cake porosity increased from 70.8 % to 80.5 % and from 61.4 % to 69 %, respectively) with greater fragility (reduced cohesive force). This characteristic is advantageous for efficient backflushing operations. The strong adhesion between the filter cake and membrane hindered the recovery of the initial filtration resistance. For SiC membrane, the optimized back-flushing parameter is reservoir pressures of 0.2 and 0.15 MPa and pluse-jet intervals of 40 min to hydrophilic and hydrophobic dusts, respectively.

Digital Cake Analysis: A Novel Coal Filter Cake Examination Technique Using Microcomputed Tomography

Filtration is crucial for separating solids and liquids in various industries. Understanding slurry properties and filter cake structures is essential for optimising filtration performance. Conventional methods focus on interpreting filtration data to improve the understanding of filtration mechanisms. However, examining fragile filter cakes is challenging, and current techniques often alter their structure. Conventional methods only provide an average representation of cake porosity, neglecting variations in porosity and pore distribution across the cake thickness. This study introduces the Digital cake analysis, a non-destructive technique for evaluating filter cake structure. Filtration experiments using a custom-built unit were conducted on coal slurries to obtain filter cake samples. X-ray-microcomputed tomography (µCT) imaging was utilized for cake analysis. Image enhancement techniques were employed to improve the quality of the µCT images. The enhanced images were segmented into three phases (resolved pore, subresolution pore, and solid phases) for quantitative analysis. This segmentation technique allocated partial pore volume to voxels in the subresolution phase based on their intermediate grey-scale intensity, enabling more accurate porosity calculations. Unlike conventional methods, this approach computed porosity values for resolved (100% void) and subresolution (partially void) pores. This image segmentation technique facilitated accurate computations of porosity, pore size distribution, and pore properties, significantly advancing the understanding of cake structures. Digital cake analysis produced porosity measurements similar to the experimental results.

Insight into filter cake characteristics of fine coal tailings assisted by CPAM and α-HH during pressure filtration

To improve the filter cake structure and efficiently dewater coal slime, CPAM and α-HH were designed for combined use in filtration experiments. The conditioned coal slime dewatering effect was measured using a newly designed pressurized dewatering device; the auxiliary mechanisms were analyzed from various perspectives, including hydrophobicity, electrostatic repulsion, coal slime composition and filter cake structure. A CCD experiment indicated that the optimal concentrations of the two additives in combination were 205.90 g/t CPAM and 56.25 mg/g α-HH. Under these conditions, the coal slime water CST decreased to 31.6 s, the filtration rate increased to 177.01 mL/(s·m2), the filter cake moisture content decreased to 16.46%. CPAM still acted as a polymer flocculant, causing the coal slime particles to form large flocs, while the addition of α-HH reduced the absolute zeta potential of the filtrate to 1.36 mV, thus decreasing the static repulsive forces between coal slime particles, promoting floc formation and increasing the floc chord length to 83–185 μm. These effects enhanced the CPAM flocculation effect. In the CPAM system, these phenomena accelerated the hydration reaction of α-HH and produced many CaSO4·2H2O crystals. These crystals formed an interwoven skeleton in the coal slime flocs, increasing the CDI increased to 1650.04, and increasing the filter cake porosity from 13.26% to 16.45% and effectively improving the filter cake pore connectivity and permeability, which improved the filtration effect. This study could provide a new method and perspective for the efficient pressurized dewatering of coal slime.

Model-based optimization of multistage ultrafiltration/diafiltration for recovery of canola protein

The ultrafiltration/diafiltration (UF/DF) process is a crucial step in the canola protein isolation process from rapeseed meal. The process involves using a multi-stage membrane system to separate components of the mixture. As diafiltration dilutes the feed stream in the ultrafiltration system, a large amount of diafiltration water is required. Reducing the diafiltrate for sustainability reasons can be done by carefully selecting process variables or using recycle streams. However, finding the optimum process variables can be a meticulous process if performed experimentally or via trial and error. In this study, we performed an optimization using a mechanistic model integrated with a genetic algorithm to aid in finding an optimum combination of process variables. The mechanistic ultrafiltration model was derived by taking into account transport phenomena within the filtration system. Parameters were characterized experimentally in term of viscosity coefficient, membrane resistance, cake porosity, aggregate diameter equivalent, and material compressibility factors. Using the mechanistic model-based optimization in combination with actual experimental values, the performance of a four-stage UF/DF system could already be improved despite fixing the configuration, albeit at the cost of a reduction in purity. Further improvement could be achieved by using recycle streams. The optimized system achieved a diafiltrate reduction of up to 79%, an increase of purity of up to 31%, and an increase of dry matter content of up to 18%, while maintaining the product purity of the reference set-up.

Flow resistance characteristics of the enhanced electrostatic fabric integrated precipitator

Flow resistance is one of the most important operating characteristics of a dust collector. In this study, the Kozeny-Carman equation was used to establish a mathematical model for calculating the flow resistance of a coupling-enhanced electric bag composite dust collector called the enhanced electrostatic fabric integrated precipitator (EEFIP) based on parameters such as the dust properties and filtration velocity. A pilot test platform was built for the EEFIP, and the flow resistance characteristics under no-load and load conditions were explored. Experiments were performed to verify the accuracy of the mathematical model. The results showed that the mathematical model accurately described the flow resistance of the EEFIP, which increased with the filtration velocity according to a quadratic curve as well as with increases in the dust concentration and operating time. At an inlet dust concentration of 10–50 g/m3 and filtration velocity of 1.0 m/min, the porosity of the filter cake outside the filter bag in the EEFIP was 0.937. When the filtration velocity was increased to 1.2 m/min, the porosity of the filter cake remained stable at about 0.953. While the dust concentration at the inlet is 30 g/m3 and the filtration velocity is 0.6 m/min∼2.4 m/min, the porosity is 0.862–0.957. Considering the flow resistance characteristics and dust emission concentration, the filtration velocity of the EEFIP should be < 2.0 m/min with a recommended value of 1.6 m/min.

Influence of Oil Content on Particle Loading Characteristics of a Two-Stage Filtration System

Filter media may encounter aerosols mixed with solid and oil ingredients from various sources, such as industries, transportation, and households, in the air purification process, while the influence such oil content has on the loading performance of single-stage and two-stage filtration systems is under-reported. Thus, this study aims to evaluate oil fraction effects on the loading performance of single-stage and two-stage filtration systems. First, to reveal the oil–solid mixed particle deposition mechanisms, the filter media parameters, i.e., specific cake resistance ε and cake porosity K2, were tested, indicating that a slight amount of oil can increase the dust holding capacity (DHC) of filters by forming a more porous cake, while an excess of oil results in reduced DHC by forming impermeable liquid films on the solid skeleton. Further two-stage experimental results indicate that the effectiveness of a pre-stage filter can be significantly affected by the properties of incoming aerosol and main-stage filters. The utilization of a pre-stage filter unintentionally deteriorated the service lifetime of the main-stage filter when challenged with contaminants with certain oil particles. This counter-intuitive negative phenomenon is due to the special loading behaviors of oil–solid mixed particles. The existing pre-stage filters allow a higher fine oil particle fraction to reach the main-stage downstream, while the induced cake filtration scenario leading to a film clogging scenario adversely reduced the lifetime of the main-stage filter. The findings suggest that the feasibility of a pre-stage in the filtration system requires compressive evaluations according to the specific oil-coated contaminants.

Ultrasonication-assisted fouling control during ceramic membrane filtration of primary wastewater under gravity-driven and constant flux conditions

This study investigated the feasibility of using ultrasonication as a ceramic microfiltration membrane fouling control strategy during gravity-driven membrane (GDM) filtration and constant flux filtration of primary municipal wastewater. The fouling model fitting curves revealed that initial intermediate pore blocking was dominant in the GDM system, followed by cake filtration; while cake filtration was dominant during constant flux filtration with a continuously increasing pattern. In the GDM system, periodic ultrasonication cleaning achieved higher cake resistance reduction (∼60 % vs ∼ 26 %) and led to lower specific cake resistances (0.2–2.0 × 107vs 29.6–59.3 × 107 m/mg) compared to periodic backwash. Ultrasonication-facilitated fouling mitigation effectiveness was related to cake properties (such as cake foulant density and porosity) and improved with extending ultrasonication duration. The foulant examination indicated that ultrasonication may result in porous cake nature by cake expansion and facilitate detaching particulate foulants and soluble organics (such as biopolymers) from the membrane. Cost analysis revealed that with commercial ceramic membranes, ultrasonication-facilitated GDM systems are economically feasible for treating wastewater at a household scale (∼1.1 EUR/m3 water), while ultrasonication-facilitated constant flux filtration systems are favorable at a small-community scale (∼0.5 EUR/m3 water). Furthermore, it was predicted that the use of low-cost recycled ceramic membranes would allow GDM systems as economical decentralized wastewater treatment processes due to their lower water production cost (∼0.16 EUR/m3 water) with easy operation and maintenance.

Primary Investigation of Barite-Weighted Water-Based Drilling Fluid Properties.

Drilling fluid is a critical component in drilling operation due to its various functions. It consists of many elements, and one of the main components is the weighting material which controls the mud density. The weighting material type and concentration have a significant impact on the drilling fluid properties. A common weighting material used in the oil and gas industry is barite. In this work, the impact of barite concentration on water-based drilling fluid was evaluated. The investigated drilling fluid properties are density, pH value, filtration behavior, and rheological parameters. An intense investigation was carried out to evaluate the impact of barite concentration on the filtration and filter cake sealing properties. The density and pH values were measured at room temperature, filtration test was performed at room temperature, and differential pressure was equal to 100 psi. The rheological parameters were determined after hot rolling for 16 h at a temperature of 250 °F. The results showed that both the density and pH value increased linearly with barite dosage. The filtration volume, filter cake thickness, and permeability increased with the incremental increase in barite dosage, and the exponential relationship was the best in describing the relation with barite concentration. However, the filter cake porosity had an inverse proportional relation with barite dosage. In the case of rheological properties, all the investigated properties including the plastic viscosity, yield point, ratio of yield point to plastic viscosity, and gel strength at two different times (i.e., 10 s and 10 min) increased in general as the barite concentration increased.

Recycling waste sand from slurry shield tunneling: A sustainable filter aid for waste slurry dehydration

The slurry shield tunneling construction process produces waste slurry (WSL), which is often dehydrated using lime as a filter aid. However, a high pH limits the reusability of the mud cake produced, leading to environmental problems. Slurry shield tunneling also produces waste sand (WSA), which the present study evaluates as a substitute for lime via belt filter press testing. The ability of WSA to reduce the mud cake water content and porosity is found to be the same as that of lime, although double the amount is required. Specifically, the optimal amounts of lime and WSA addition are 2% and 4%, respectively, which produce similar total drainage rates and mud cake moisture contents and porosities. Both lime and WSA reduce mud cake macropores, increase small pores and improve compactness. The addition of >2% lime increases the bound water and moisture contents of the mud cake, while WSA reduces the bound water without affecting dehydration. Finally, the use of WSA instead of lime as a filter aid reduces the pH of the mud cake from strongly alkaline (about 12) to near-neutral (about 8). The results show that WSL can replace lime as a filter aid, providing a novel approach to WSL dehydration treatment and WSA reuse that has both environmental and economic benefits.

Effect of Ultrasonic Pretreatment on Flocculation Filtration of Low-Rank Coal Slurry.

The efficient filtration of low-rank coal (LRC) slurry was significantly beneficial to the production process of wet coal beneficiation. However, relatively few studies have been reported on novel pretreatment methods for the efficient filtration of LRC slurry. In this paper, the mechanism of ultrasonic pretreatment to promote flocculation and filtration of slurry was studied. The hydrophobic variation of the slurry surface was measured by contact angle and XPS. The flocculation properties of slurry were characterized using zeta potential and FBRM. The effects of filter cake porosity and ultrasonic pretreatment on slurry filtration resistance were calculated by L-F NMR and Darcy’s theory. The results showed that the ultrasonic pretreatment promoted the flocculation and filtration performance of LRC slurry, increased the filtration rate, and decreased the cake moisture content. Meanwhile, the contact angle of LRC increased significantly from 50.1° to 67.8° after ultrasonic pretreatment, and the surface tension of the filtrate decreased from 69.5 to 53.31 mN/m. Ultrasonic pretreatment reduced the absolute value of the zeta potential of coal slurry from 24.8 to 21.0 mV, and the average chord length of flocs increased from 5–10 μm to 25–30 μm, thus weakening the electrostatic repulsion between coals to promote floc formation. In addition, the pore tests and filtration theory calculations showed that the ultrasonic pretreatment significantly improved the permeability of the filter cake to water and reduced the resistance to slurry during filtration. In particular, the mesopore porosity increased by 9.18%, and the permeability increased by 2.937 × 108 m2. Therefore, this contributed to the reduction of slurry filtration resistance. This research provides an efficient method for promoting the efficient filtration of slurry.

Improving filter cake sealing properties for high-density ilmenite drilling fluid

Drilling fluids must be cautiously designed to form an impermeable filter cake layer that diminishes the intensity of solid and mud invasion during drilling of a well. Inability to abate solid and mud invasion can cause adverse effects on the productivity of the drilled well. As a result, a variety of additives have been proposed for improving filter cake's sealing properties, which are also utilized to control fluid filtration. This work investigates the role an amorphous volcanic glass (perlite), a novel filtration agent, to amend the quality of filter cake layer that formed using ilmenite (FeTiO3) drilling fluid. The characteristics of the filter cake were evaluated in terms of the filtration behavior, filter cake thickness, permeability and porosity. In order to accomplish this aim, several concentrations of perlite particles were loaded to the Ilmenite weighted drilling fluid. The tests were conducted under high-pressure high-temperature environment according to API standards. The results of the drilling fluid (containing perlite) were compared with a reference drilling fluid (zero concentration of perlite). It is observed that the perlite containing formulation has improved filtration properties. The flake-shaped perlite particles blocked the filter cake pores and accordingly produced an impermeable filter cake. There was a drastic drop in the filter cake overall permeability after adding perlite concentration of 3 lb/bbl, from 6.09 × 10−3 Darcy to 1.46 × 10−3 Darcy and a significant drop (55%) in the associated filtration volume from 18.5 cm3 to 8.5 cm3. Moreover, perlite-based filter cake lowered the pore size of the filter cake and decreased the filter cake thickness by 45%.

Effect of Hematite Dosage on Water-Based Drilling Fluid and Filter Cake Properties

Abstract Drilling deep wells became common in the oil and gas sector as a result of the high demand for energy in the world. This type of wells is not trivial to drill as a result several challenges that they encounter, such as harsh conditions represented by high-pressure and high-temperature (HPHT), and the high hydrostatic column required to prevent the kick. Therefore, advanced materials are desired and accordingly higher concentration of weighting material is required to drill such resources. In this work, a systematic investigation of the hematite concentration effect on the water-based drilling fluid properties is performed. Three doses were overloaded to a constant drill fluid recipe. Then, the drilling fluid properties including density, viscosities, filtration, and filter cake properties were evaluated. The viscosities were assessed at the temperature of 120 °F, before and after aging in a hot rolling oven for 16 h at 250 °F and 500 psi. The American Petroleum Institute filtration test was performed at ambient temperature and 100 psi. The results showed that the hematite concentration has proportional relation to the apparent viscosity, plastic viscosity, and yield point before and after the hot rolling. The YP/PV ratio was decreased as the hematite dose increased in the drilling fluid. Similarly, the gel strengths at 10 s and 10 min were increased as the concentration of hematite increased. The filter cake thinness, filtration volume, and filter cake permeability were also amplified as the hematite concentration increased, where the filter cake porosity was almost kept constant. In addition, several correlations were drawn as a function of the hematite dosage for the examined drilling properties.