Porosity Of Filter Cake Research Articles

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.

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.

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.

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.

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.

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.

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.

Primary Investigation of Ilmenite Dosage Effect on the Water-Based Drilling Fluid Properties

Abstract A high-density mud is required for deep drilling operations to keep formation pressure under control and avoid the kick. The high-density mud showed several challenges including sagging issues, undesirable rheology parameters, and higher possibility of inducing formation damage. Ilmenite is a weighting material that is used to increase the density of the drilling fluid. The effect of ilmenite dosage on the density of drilling fluid, rheological parameters, filtration, and filter cake qualities was explored in this study. Three different models were used to match the rheological properties including the Bingham model, the power-law model, and the Herschel–Bulkley model. The results showed that the prepared drilling mud density was correlated exactly with the amount of ilmenite added to the formulation. Similarly, the viscosity parameters were increased as ilmenite dosage increased. Even so, the results show that the rheological behavior seems to exhibit perfect matching using the three models, Herschel–Bulkley model was showing the highest accuracy compared to the other investigated models. Notably, the filtration behavior was dominated greatly by ilmenite dosage. The filtration volume and filter cake increased drastically as the ilmenite concentration increased. Correspondingly, the filter cake permeability was increased as the ilmenite concentration increased. Meanwhile, the dense packing of ilmenite particles at high concentrations produced lower filter cake porosity. Correlations were found with excellent accuracy between the ilmenite dosage and the filtration volume and filter cake properties.

Effect of surfactant and flocculant on low-rank coal slime filtration: From filter cake characteristics point of view

Filter aids are widely used in low-rank coal (LRC) slime filtration. However, their impact on filter cake characteristics is still unclear. In this paper, the effect of anionic polyacrylamide (APAM) and cetyltrimethylammonium bromide (CTAB) on the filter cake characteristics was investigated using Darcy’s filtration theory and low-field nuclear magnetic resonance (L-F NMR). The slime and filtrate property change was determined by contact angle, XPS, FBRM, Zeta potential and surface tension measurements. The results showed that the filter aid improved slime filtration rate and reduced filter cake moisture. The filter aid effect of APAM was better than that of CTAB. CTAB significantly improved the slime surface hydrophobicity with the contact angle increasing to 90.5°, and reduced the filtrate surface tension to 35.26 mN/m. However, APAM decreased the absolute value of slime Zeta potential by 7.48 mV, and increased the slime floc size by about 7–9 µm. Both CTAB and APAM can reduce the filtration resistance, but the effect of APAM was better than that of CTAB, because APAM greatly improved the filter cake permeability. L-F NMR results showed that CTAB increased the filter cake porosity only by 2.65%, while APAM significantly improved the filter cake porosity by 11.65%, especially the mesopore porosity of cake, which increased by 10.48%. It was indicated that CTAB reduced the filtration resistance by “lubricating” the pore wall of the filter cake, while APAM improved the filter cake porosity and permeability by weakening the electrostatic repulsion between slime particles and promoting floc formation through aggregation effect. This research provided a new perspective to reveal the mechanism of LRC slime filtration.

Prevention of hematite settling using perlite in water-based drilling fluid

The stability of the weighting materials in the high-density water-based drilling fluid was remarked as a serious issue to be controlled. It can cause several problems including formation fracturing, circulation loss, well control issues, etc. The usage of an anti-sagging chemical as a drilling additive is one of the sagging mitigation methods. In this study, amorphous volcanic alumina silicate (perlite) was evaluated as an anti-sag additive for hematite water-based drilling fluid. Several experiments were conducted to assess the perlite efficiency including static and dynamic sag test, mud properties measurements such as filtration behavior, filter cake properties, rheological and viscoelastic behavior. The tests were conducted at elevated temperature (250 °F). Perlite concentration was varied from 0, 1, 2, 3, and 4 lb/bbl. The obtained results showed that the loaded perlite was able to improve the mud stability and eliminate the sagging under static and dynamic issues at an optimum concentration of 4 lb/bbl. In term of filtration properties, there was an obvious improvement that could be observed through the reduction of filtration volume with 50% and filter cake thickness. In addition, the perlite contacting drilling fluid was able to form a thin and dense filter cake layer. The filter cake porosity and permeability were decreased by 24% and 68%, respectively. The rheological and viscoelastic behaviors were improved as well by the addition of perlite.

The Role of Drilled Formation in Filter Cake Properties Utilizing Different Weighting Materials.

The filter cake formed during a filtration process plays a vital role in the success of a drilling operation. There are several factors affecting the filter cake build-up such as drilled formation, drilling fluid properties, and well pressure and temperature. The collective impact of these two factors (i.e., formation and the drilling fluid) on the filter cake build-up needs to be fully investigated. In this study, two types of formations represented as limestone and sandstone were used with different weighting materials to assess and compare their impact on the filter cake properties, filtration behavior, and solid invasion. The used weighting materials are manganese tetroxide, ilmenite, barite, and hematite. The filter cake was formed under a temperature of 200 °F and differential pressure of 300 psi. Nuclear magnetic resonance spectroscopy was employed to explore the pore structure of the used core samples. The results showed that the properties (i.e., shape and dimensions) of the different weighting materials are the dominant factors compared to the formation characteristics in most of the investigated filter cake properties. Nevertheless, the formation properties, namely, the permeability and pore structure, have a somehow higher contribution when it comes to the filter cake porosity and thickness. For solid invasion, there were no clear results about the main factor contributing to this issue.

Transient response of near-wellbore supercharging during filter cake growth

Supercharging in the vicinity of a borehole is an important factor that affects formation damage and drilling safety, and the filter cake growth process has a significant impact on supercharging in the vicinity of the borehole. However, existing models that predict pore pressure distribution overlook dynamic filter cake growth. Thus, an analytical supercharging model was developed that considers time-dependent filter cake effects, and this model was verified using a two-dimensional numerical model. The influences of filter cake, formation, and filtrate properties on supercharging were investigated systematically. The results indicate that time-dependent filter cake effects have significant influence on supercharging. Supercharging increases in the early stage but decreases over time because of the dynamic growth of filter cake, and the supercharging magnitude decreases along the radial direction. Because of filter cake growth, the magnitude of supercharging falls quickly across the filter cake, and the decreased magnitude of pore pressure caused by the filter cake increases. Supercharging in low-permeability formations is more obvious and the faster rate of filter cake growth, a lower filtrate viscosity and faster reduction rate of filter cake permeability can help to weaken supercharging. The order of importance of influencing factors on supercharging is overbalance pressure > formation permeability > formation porosity ≈ filtrate viscosity > filter cake permeability attenuation coefficient > initial filter cake permeability control ratio > filter cake growth coefficient > filter cake porosity. To alleviate supercharging in the vicinity of the borehole, adopting drilling fluids that allow a filter cake to form quickly, optimizing drilling fluid with a lower filtrate viscosity, keeping a smaller overbalance pressure, and precise operation at the rig site are suggested for low-permeability formations during drilling.

Evaluating drilling fluid infiltration in porous media – Comparing NMR, gravimetric, and X-ray CT scan methods

The infiltration of drilling fluids into underground rocks during drilling can cause adverse effects such as underground fluid loss, formation damage, and borehole collapse. An effective filter cake formed by the drilling fluid on the borehole wall can minimize such adverse effects to a degree that is dependent on the characteristics of the drilling fluid. For this reason, drilling fluids are routinely screened in the laboratory based on the sealing properties of their filter cakes. However, there appear not to be a universally adopted method for characterizing filter cakes. This study utilizes a nuclear magnetic resonance (NMR) approach to characterize filter cakes and then compares the result with some existing methods. Fluid loss tests were conducted to form filter cakes over four consolidated sandstone and carbonate rock samples. NMR measurements were conducted pre and post filter cake deposition. NMR measurements of filter cake porosity and infiltrated solids were compared with those from conventional methods such as gravimetric and X-ray computer tomography (CT) measurements. The results obtained from the three methods show significantly different values. To resolve this, cross correlations plots were made between measurements obtained from the three methods and the measured cake thickness. NMR measured porosity and infiltrated solids showed an excellent correlation with the measured cake thickness compared to the other two methods. However, the porosity values from NMR is significantly lower than the values obtained from the other methods. Through sensitivity analyses, we provide reasons why values from other methods are high and not as representative as the NMR method. We also gave a detailed explanation why NMR method is more accurate and useful compared to the other methods.

Characterizing distinctive drilling mud properties using new proposed hyperbolic fluid loss model for high pressure and high temperature conditions

The currently in use fluid loss model (American Petroleum Institute (API)) was developed using the Darcy relationship and assuming that there is no changes in the permeability, solid content in the filter cake and filter cake thickness during the 30 min of fluid loss. Hence, in the current API model, the fluid loss is directly propositional to the square-root of time. In this study, a new proposed hyperbolic fluid loss model has been developed based on a time dependent variation in the filter cake properties. Also, the new proposed model has the power to quantify the short-term and long-term fluid losses (more than 30 min). Moreover, the new model has a limit on the total fluid loss compared to the current API model that shows an infinite fluid loss with time. The new model parameters are related to the applied pressure and temperature using nonlinear power models. The new model predictions are verified with the fluid loss results reported in the literature (225 °C and 300 psi) and tests performed in the laboratory at high pressure and high temperature on bentonite drilling muds during this study. The laboratory tests are both limited to 2% and 8% (by weight) bentonite drilling muds at 100 °C and 100 psi (689.5 kPa) up to 420 min (7 hrs) till the end of the fluid loss. The new model predicts the experimental results on maximum fluid loss and changes in the filter cake porosity, permeability, solid content, and thickness with time, pressure and temperature very well.

Relaxation Equations of Consolidating Cake Filtration

In this paper, on the basis of conservation laws suspensions filtration equations with forming a relaxing cake are derived. The equations are numerically solved. To solve the equation for cake growth a Stefan problem is posed and solved with using the method of catching a moving front. On the basis of numerical results influence of relaxation phenomena on filtration characteristics is established. It is shown that the relaxation slows down the increasing of local filter cake porosity and decreasing of cake permeability, as well as increase fluid relative velocity through cake for given applied pressure. Increasing of relaxation time leads to a faster growth of the cake thickness when all other conditions are constants, thus relaxation effects cause more intensive transfer of particles from suspension to the cake. It, in turn, alters all other filtration characteristics, such as fluid pressure distribution, compressive pressure, porosity and consolidation of the cake, fluid flow rate through the cake and effective hydrodynamic resistance. With increasing of relaxation phenomena dynamics of current and total outlet filtrate flow rate becomes more intensive.

Filtration of coal tailings aided by a novel physical conditioner carbon–containing fly ash

ABSTRACT Chemical conditioner is employed widely to improve the filtration rate of coal tailings in coal preparation plant. However, little attention has been paid to physical conditioner which could be economic and effective. In this study, the carbon-containing fly ash (CCFA) was used to improve the filtration rate of coal tailings. The filtration experiments of coal tailings were conducted with the addition of CCFA. It was found that the filtration rate increased with the increase of CCFA addition amount from 0 to 150 kg/t. The permeability of the filter cake, which was obtained in the framework of the Darcy’s filtration theory, was found significantly increased after CCFA conditioning. The nuclear magnetic resonance (NMR) measurements of the filter cake indicated that the addition of CCFA increased the porosity of filter cake. The properties of CCFA were analyzed by scanning electron microscopy (SEM), NMR, and inverse gas chromatography (IGC). The results indicated that the unburned carbon particles in CCFA contained rough surfaces and the porosity of CCFA was as high as 58.30%. The hydrophilicity index revealed that CCFA was much more hydrophobic than the particles in coal tailings. These results supported that CCFA provided more water transmitting passages in the filter cake due to its high porosity and hydrophobicity, so the filtration rate of coal tailings was improved.

Filtration and dewatering of the mixture of quartz and kaolinite in different proportions

Fine minerals, such as silicate and clay minerals are difficult to filtrate and dewater in mineral processing industry. In this study, quartz and kaolinite particles were mixed in different proportions to investigate the filtration and dewatering behavior difference. Combined with the calculation of DLVO theory, the particles size of quartz flocs, kaolinite flocs and the flocs of quartz and kaolinite mixture under pH of 7 and 11 were analyzed by focused beam reflectance measurement (FBRM). In addition, the structure of quartz/kaolinite flocs and the filter cake porosity were analyzed by 3D-high solution X-ray microanalyser (3D-XRM). The mixture of 80% quartz and 20% kaolinite had the maximum filtration velocity. The DLVO theoretical analyses show that the interaction between the aluminum-oxygen surface of kaolinite and silicon-oxygen surface of kaolinite/quartz particles is an attractive force at pH of 7, but repulsion force at pH of 11. The FBRM tests found that quartz and kaolinite tended to form relative larger agglomerates at pH of 7 when compared to a pH of 11. The results of 3D-XRM showed the kaolinite flocs were surrounded by amounts of quartz particles at pH of 7, which formed many quartz-kaolinite agglomerates, and therefore the porosity of the cake was increased for the water to easily pass through, which finally sped up the filtration process. However, quartz and kaolinite were evenly dispersed and had no obvious aggregates phenomenon at pH of 11, and the filtration velocity was slow because the kaolinite filled in the gap between quartz particles, which reduced the porosity of filter cake.

Synergistic effects of surfactant-flocculant mixtures on ultrafine coal dewatering and their linkage with interfacial chemistry

Flocculants are widely used in ultrafine coal dewatering to improve the particles settling rate. However, water entraps inside flocs that consequently increase generated filter cake moisture. In this paper, we report the effectiveness of a chemically enhanced approach to effectively increase particles settling rate and reducing filter cake moisture by taking advantage of the synergistic effect of dewatering chemicals. The effect of the dewatering chemicals on centrifugal dewatering performance, filter cake structure were studied. Applied anionic surfactant did not show a significant effect on dewatering rate and the filter cake structure, but it reduced solid recovery from 89% to 70% and filter cake moisture 19%–13% through strong attribution to decrease in liquid phase surface tension. However, cationic surfactant revealed a slight expansion in solid recovery to 94%, dewatering rate, and the filter cake permeability while there was a decrease in the filter cake moisture to 15% due to the increased coal particles hydrophobicity. Anionic flocculant also improved dewatering rate and filter cake permeability with an increase in solid recovery to 96%, but with the sacrifice of increased filter cake moisture to 24%. Mixed anionic surfactant/flocculant did not show a positive effect on dewatering parameters. However, cationic surfactant-flocculant mixtures led to a higher dewatering rate and solid recovery of 97% with lower moisture (22%) in comparison with single flocculant condition. X-ray Computed Tomography (XCT) results confirmed improved filter cake porosity in the cationic surfactant/flocculant mixture conditions. In agglomerate structure studies, flocculation and agglomeration of ultrafine particles with the cationic surfactant, flocculant, and mixed flocculant-cationic surfactant were observed. Nevertheless, the structure of the agglomerates in the mixed anionic surfactant/flocculant condition was loosened. The financial analysis confirmed using cationic surfactant or its mixture with the flocculant has an economic benefit in comparison with single flocculant condition.

Effect of Arenite, Calcareous, Argillaceous, and Ferruginous Sandstone Cuttings on Filter Cake and Drilling Fluid Properties in Horizontal Wells

Fine, small-size, drilled cuttings, if not properly separated using mud conditioning equipment at the surface, are circulated with the drilling fluid from the surface to the bottom hole. These drilled cuttings have a significant effect on the drilling fluid properties and filter cake structure. During drilling long lateral sandstone formations, different cuttings with varied properties will be generated due to sandstone formations being heterogeneous and having different mineralogical compositions. Thus, the impact of these cuttings on the drilling fluid and filter cake properties will be different based on their mineralogy. In this paper, the effect of different sandstone formation cuttings, including arenite (quartz rich), calcareous (calcite rich), argillaceous (clay rich), and ferruginous (iron rich) sandstones, on the filter cake and drilling fluid properties was investigated. Cuttings of the mentioned sandstone formations were mixed with the drilling fluid to address the effect of these minerals on the filter cake thickness, porosity, and permeability. In addition, the effect of different sandstone formation cuttings on drilling fluid density and rheology, apparent viscosity (AV), plastic viscosity PV), and yield point (YP) was investigated. High-pressure high-temperature (HPHT) fluid loss test was conducted to form the filter cake. The core sample’s petrophysical properties were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD) techniques and scanning electron microscopy (SEM). The results of this work indicated that all cutting types increased the rheological properties when added to the drilling fluid at the same loadings but the argillaceous sandstone (clay rich) has a dominant effect compared to the other types because the higher clay content enhanced the rheology. From the filter cake point of view, the ferruginous sandstone improved the filter cake sealing properties and reduced its thickness, while the argillaceous cuttings degraded the filter cake porosity and permeability and allowed the finer cuttings to penetrate deeply in the filter medium.

Comparison on Filtration Performance of Metallic Wire Mesh Filter at Different Temperatures

Metallic wire mesh filter is characterized by corrosion resistance, high strength and plasticity, stability under high pressure difference, favourable regeneration performance and long lifetime, which can be used to purify cryogenic liquid. In order to research its filtration performance at different temperatures and to discuss the filtration mechanism at cryogenic temperature, experiments were carried out to purify liquid nitrogen, and filtration performance was compared with two kinds of wire mesh filter in literatures. Emphasis was laid on the effect of filtration medium. The results show that filtration pressure drop is proportional to fluid speed at cryogenic temperature, which coincides with the condition at atmospheric temperature. However, at the same fluid speed, the higher the temperature, the lower the pressure drop due to thermal expansion and the permeability increase of wire mesh filter medium at high temperature. Furthermore, filtration efficiency increases with filtration speed and such trend is more obvious at later stage at cryogenic temperature, while it is not obvious at high temperature due to the larger porosity of filter cake at high temperature which has no significant effect on filtration efficiency.