Ideal Packing Research Articles

Research and Application of Intelligent Well Completion Technology in Offshore Oilfield

Abstract The reservoirs in Bohai oilfield were mainly composed of unconsolidated sandstone. A single multi-layer gravel packing operation could greatly reduce the packing operation time and improve the operation efficiency. However, the conventional tools were limited by the double-layer central tube structure, which resulted in large packing friction and high pressure consumption due to its small annular area, which limited the limit operation length and displacement. In order to solve this problem, we independently developed a double-layer screen tube one-time multi-layer fracturing packing tool, innovatively set up production interlayer in the screen pipe, formed a bypass diversion screen pipe system, so as to reduce the downward entry of one layer of central pipe during filling, simplify the structure of the filling string, and greatly reduce the friction of the string. The results showed that the limit packing length and displacement were 1200m and 45bpm respectively, which were 300% and 50% higher than the traditional packing tools, and the operation range of the tools was improved. The safety and efficiency of double screen fracturing and filling operation were ensured by innovating the quick connection method of double screen pipe, fast pressure test tool and expanding switch tool of oil pipe. The application in well LX has realized the purpose of sand control by five layers filling in one time. The packing length was more than 400 m. Combined with the problems in field operation, it had been applied in 5 areas The improvement suggestions of the tool are put forward. The double screen pipe one-time multi-layer fracturing packing tool and its supporting technology realized the ideal packing parameter requirements of low pump pressure and high return velocity. It could be widely used in sand control operation of multi-layer gravel packing fracturing in large-span perforation section in the future, which greatly improved the operation efficiency and has good economic benefits and promotion value.

Sustainable Heat Generation in Flow from a Molecular Solar Thermal Energy Storage System

As the global deployment of renewable technologies accelerate, finding efficient ways to store energy will aid in responding to shifting energy demands. A prospective option not only in harvesting solar energy but also in emission‐free heating is MOlecular Solar Thermal (MOST) energy storage. A central part of MOST applications is to develop methods to release the stored energy. Herein, the Quadricyclane (QC)‐to‐Norbornadiene catalyzed back reaction is explored in a specially designed packed‐bed reactor. Four distinctly sized and purposely synthesized platinum on activated carbon catalysts are studied to trigger the heat release from the energy‐dense QC isomer. The catalysts are fully characterized using a variety of structural, surface, and spectroscopic techniques. Parameters to optimize catalytic conversion and heat release in flow conditions are explored including particle size and packing behavior, flow rates, and molecular residence times. Moreover, using CO pulse chemisorption technique, site time yield values and a turnover number are reported. Complementary to the flow reactions, computational fluid dynamic simulations applying lattice Boltzmann methods to two catalytic packed beds of different size ranges are done to evaluate fluid‐dynamic behavior within the reactor bed to ascertain the ideal particle size and packing density for catalysis in MOST applications.

Linking Electronic and Structural Disorder Parameters to Carrier Transport in a Modern Conjugated Polymer.

Understanding charge transport in conjugated polymers is crucial for the development of next-generation organic electronic applications. It is presumed that structural disorder in conjugated polymers originating from their semicrystallinity, processing, or polymorphism leads to a complex energetic landscape that influences charge carrier transport properties. However, the link between polymer order parameters and energetic landscape is not well established experimentally. In this work, we successfully link statistical surveys of the local polymer electronic structure with paracrystalline structural disorder, a measure of statistical fluctuations away from the ideal polymer packing structure. We use scanning tunneling microscopy/spectroscopy to measure spatial variability in electronic band edges in PM6 films, a high-performance conjugated polymer, and find that films with higher paracrystallinity exhibit greater electronic disorder, as expected. In addition, we show that macroscopic charge carrier mobility in field effect transistors and and trap influence in hole-only diode devices is positively correlated with these microscopic structural and electronic parameters.

Fabrication of high-performance recrystallized silicon carbide ceramic membrane based on particle packing optimization

Overcoming the challenges associated with achieving high uniformity and connectivity of pore channels in ceramic membranes, we designed silicon carbide ceramic membrane derived from the recrystallization process based on the Dinger-Funk equation of the closest-packing model with various grain grading. Furthermore, the effects of particle size distribution on the resulting microstructure and pore architecture of the ceramic membrane was also explored. The findings corroborated the critical importance of raw material particle size distribution in controlling pore size distribution and morphology. After sintering at 1900°C, the silicon carbide ceramic membrane, benefiting from ideal particle packing, exhibited a remarkably uniform pore structure. Notably, the most probable pore size constituted over 70 %, while achieving an open porosity of 51.3 % even without the addition of pore-forming agents. The silicon carbide ceramic membrane also demonstrated exceptional hydrophilicity (water contact angle:∼0°), impressive water permeation (1210 L m−2 h−1·bar−1), coupled with efficient turbidity removal (∼100 %) in carbon black wastewater treatment applications. Additionally, membrane regeneration proved effective using a dilute NaOH solution backwash, achieving a flux recovery efficiency of 98 %. This strategy had directive significance for designing high-performing silicon carbide ceramic membranes.

Hyperuniformity of maximally random jammed packings of hyperspheres across spatial dimensions.

The maximally random jammed (MRJ) state is the most random (i.e., disordered) configuration of strictly jammed (mechanically rigid) nonoverlapping objects. MRJ packings are hyperuniform, meaning their long-wavelength density fluctuations are anomalously suppressed compared to typical disordered systems, i.e., their structure factors S(k) tend to zero as the wave number |k| tends to zero. Here we show that generating high-quality strictly jammed states for Euclidean space dimensions d=3,4, and 5 is of paramount importance in ensuring hyperuniformity and extracting precise values of the hyperuniformity exponent α>0 for MRJ states, defined by the power-law behavior of S(k)∼|k|^{α} in the limit |k|→0. Moreover, we show that for fixed d it is more difficult to ensure jamming as the particle number N increases, which results in packings that are nonhyperuniform. Free-volume theory arguments suggest that the ideal MRJ state does not contain rattlers, which act as defects in numerically generated packings. As d increases, we find that the fraction of rattlers decreases substantially. Our analysis of the largest truly jammed packings suggests that the ideal MRJ packings for all dimensions d≥3 are hyperuniform with α=d-2, implying the packings become more hyperuniform as d increases. The differences in α between MRJ packings and the recently proposed Manna-class random close packed (RCP) states, which were reported to have α=0.25 in d=3 and be nonhyperuniform (α=0) for d=4 and d=5, demonstrate the vivid distinctions between the large-scale structure of RCP and MRJ states in these dimensions. Our paper clarifies the importance of the link between true jamming and hyperuniformity and motivates the development of an algorithm to produce rattler-free three-dimensional MRJ packings.

Bridging Structure, Magnetism, and Disorder in Iron-Intercalated Niobium Diselenide, FexNbSe2, below x = 0.25.

Transition-metal dichalcogenides (TMDs) intercalated with magnetic ions serve as a promising materials platform for developing next-generation, spin-based electronic technologies. In these materials, one can access a rich magnetic phase space depending on the choice of intercalant, host lattice, and relative stoichiometry. The distribution of these intercalant ions across given crystals, however, is less well defined-particularly away from ideal packing stoichiometries-and a convenient probe to assess potential longer-range ordering of intercalants is lacking. Here, we demonstrate that confocal Raman spectroscopy is a powerful tool for mapping the onset of intercalant superlattice formation in Fe-intercalated NbSe2 (FexNbSe2) for 0.14 ≤ x < 0.25. We use single-crystal X-ray diffraction to confirm the presence of longer-range intercalant superstructure and employ polarization-, temperature-, and magnetic field-dependent Raman measurements to examine both the symmetry of emergent phonon modes in the intercalated material and potential magnetoelastic coupling. Magnetometry measurements further indicate a correlation between the onset of magnetic ordering and the relative degree of intercalant superlattice formation. These results show Raman spectroscopy to be an expedient, local probe for mapping intercalant ordering in this class of magnetic materials.

Novel method to select chemical particulates for near-wellbore fluid diversion during hydraulic fracturing treatment

The application of chemical particulates as diverter is an evolving technology and has become popular among E&P operators. The primary objective of Near-Wellbore Diversion (NWD) is uniform distribution of treatment slurry within the target zone. The mixture of bead, powder and flakes composed of Polylactic Acid (PLA) are commonly employed for NWD application to plug temporarily already stimulated perforations and pre-existing fractures. The successful NWD application largely depends on the selection of diverter chemical, particle size distribution, proportions of each particle sizes, and total diverter quantity. The advantages of chemical diverters are simple injection without any pumping system modification and negligible increase in treatment time. Their chemical composition can be tailored according to the reservoir properties.The diverter works on jamming and sealing mechanisms. The popular Abrams rule for drilling fluid selection and Ideal Packing Theory for obtaining minimum pack permeability are customized here to be used for diverting particles selection. The diverter selection parameters are investigated in laboratory by performing plug-stability experiments on simulated perforations. It was learned that the size of coarse particles should be greater than 0.4 times the size of perforation diameter. The medium and fine particle diameters should be greater than 0.15 times the size of coarse and medium particles respectively. It is also recommended to use a minimum of 0.5 ppa diverter concentration, and Ideal Packing Theory modified for diverter application to determine the proportions of available particle sizes. The behaviour of pressure build-up and fluid leakoff during experiments were compared to evaluate the performance of various diverter blends.The present novel method will help to select the proper diverter for a successful NWD application that will aid to uniformly distribute treatment fluid during hydraulic fracturing treatment. The guidelines for its successful application are provided to help engineers to increase the effectiveness of NWD.

A New Method for Designing the Bridging Particle Size Distribution for Fractured Carbonate Reservoirs

Summary Possessing a strong heterogeneity of fracture space; fractures, in carbonate reservoirs are well developed. Because of the frequent occurrence of lost circulation during the drilling procedure, the matching of the particle-size distribution (PSD), which is the plugging material with the fracture space, becomes the key to forming bridges and improving plugging capacity. To improve the matching between the PSD and the crack width, the surface response optimization method is adopted to determine the optimal PSD (OPSD) of lost circulation materials (LCMs) and plot the effective plugging data points in the ternary diagram. To simulate the multiscale fracture distribution in a wellbore, a multislit plate plugging apparatus (PPA) is used to evaluate the leakage of plugging materials with different PSDs. The PSD test results show that the OPSD has a multipeak structure, which is conducive to plugging cracks of different sizes. Compared with the ideal packing theory, this method, conducive to the later removal of the plugging material and recovery of carbonate reservoir productivity, is more applicable to fractured carbonate reservoirs and testing the involving oil, also to estimate the acid dissolution of the plugging layer, which shows that the dissolution percentage of the plugging layer is 95.9%. Hence, it is able to achieve the reservoir protection effect. The field application indicates that the new method possesses the capability to effectively prevent the leakage of small- and medium-sized fractures in carbonate reservoirs, which ensures safe and effective drilling.

How to perform intra-aneurysmal coil embolization after Pipeline deployment: a study from a hemodynamic viewpoint

BackgroundPipeline embolization device (PED) deployment combined with coil therapy for large complex intracranial aneurysms is effective and considered superior to PED deployment alone. However, the optimal strategy for use of...

Tessellation based quantitative framework for the spatial analysis of subcellular structures

A cell exhibits microtubule-motor-dependent spatiotemporal organization of its subcellular structures. Previously, we observed self-organized asters in the ooplasm enclosed within hexagon dominant polygonal domains similar to the cell packing in epithelial tissues. However, an active, non-crystalline and crowded cell often deviates from an ideal packing behaviour. Here, we discuss the image analysis pipeline and the geometric method to characterize the features of the spatial organization. The algorithm automatically (or user-defined) detects the aster centers that serve as seed points for Voronoi tessellations.

An organic cocrystal based on phthalocyanine with ideal packing mode towards high-performance ambipolar property

The identical macrocyclic pair promotes desired packing mode with tight and large-overlapped π–π stacking in phthalocyanine-based cocrystal, which ensures high-performance ambipolar property.

Mixed monolayer of a nucleolipid and a phospholipid has improved properties for spectroelectrochemical sensing of complementary nucleobases

A mixed monolayer of 1,2-dipalmitoyl-sn-glycero-3-(cytidine diphosphate) nucleolipid (DG-CDP) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was transferred from the air–water interface onto an gold (1 1 1) electrode surface using the Langmuir-Schaeffer (horizontal touch) technique. Compression isotherms were recorded for the monolayer spread at the air–water interface. These measurements demonstrated that the mixture composition 7:3 of DG-CDP:DPPC displayed reduced repulsive interactions between polar heads and ideal packing of acyl chains. Chronocoulometric experiments were performed to demonstrate stability of this film at the gold–solution interface. Photon polarization modulation infrared reflection absorption spectroscopy showed that the tilt angle of the acyl chains is slightly higher, and the chains are less twisted in the mixed than in the pure nucleolipid monolayer. In the mixed film, the tilt of the cytosine moiety (the sensing element of the monolayer) assumes a large angle with respect to the surface normal, even when the monolayer becomes detached from the gold surface. The mixed monolayer has improved properties for future applications for detection of guanine, its complementary base.

Preparation and characterization of a novel packing material for the gas-phase fluidized-bed bioreactor

Gas-phase fluidized-beds reactor (FBR) can overcome the shortages of bed clogging and performance decline in packed-bed reactors on VOCs treatment. Ideal FBR packing materials with minimum fluidized velocity and surface characteristics are required. In this study, an expanded polystyrene (EPS) with particle size 1.0–2.0 mm was selected as the skeleton among six types of EPS and two types of expanded polypropylene (EPP). They were then physically coated with a combination of potato dextrose medium, fine wheat bran particles, and inorganic glue. Different glue concentrations and amounts of medium were tested and the optimal values of 2 % and 0.22 g∙cm−2 were achieved. The wheat-coated EPS obtained hydrophilic functional groups on the surface, and its contact angle decreased from 93° to 37° after coating. By scanning electronic microscopy, more microorganisms were observed on the surface of the coated EPS than that of the uncoated EPS. A lab-scale fluidized bioreactor was built to treat gaseous ethanol. The minimum fluidized velocity of coated packing materials was 0.2 m∙s−1 under a relative humidity of 50 ± 10 %, reaching an average elimination capacity of 681 g m-3 h−1 during the 28-days operation, while the bioreactor packed with uncoated EPS reached only 18 g m−3 h−1.

Development of Hybrid Drilling Fluid and Enzyme-Acid Precursor-Based Clean-Up Fluid for Wells Drilled with Calcium Carbonate-Based Drilling Fluids.

Significant formation damage can occur during drilling operations because of the invasion of drilling fluid fines and filtrates that lead to pore blocking and saturation alteration mechanisms. This study demonstrates the ways to minimize drilling fluid-related damage and the removal of the deposited filter cake in the carbonate reservoir through judicious selection of bridging particles using “ideal packing theory” and formulation of an enzyme-based clean-up fluid with an acid precursor. The polymer-based drill-in-fluid with a mixed grade of CaCO3 bridging particles resulted in a compact filter cake with reduced filtration loss preventing internal pore damage significantly. Several ester hydrolysis reaction kinetics were studied, and finally, one combination was chosen as the suitable acid precursor because of its ability to generate a required concentration of acid within the downhole condition. The return permeability of mud-damaged carbonate core plugs was higher than 95% after exposure to the clean-up solution. The corrosion rates were found to be significantly below the industry limits, and the use of acid corrosion inhibitors is eliminated.

Radiation Controllable Synthesis of Robust Covalent Organic Framework Conjugates for Efficient Dynamic Column Extraction of 99TcO4−

Summary Anion-scavenging materials tailored for 99TcO4− trapping are urgently needed for both nuclear-related environmental remediation and management of spent nuclear fuel. For the first time, we report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy, for efficient capture of 99TcO4−. The charged imidazolium moieties are controllably anchored into the channel of the COF by simply adjusting the γ-ray dose, thereby leading to tunable ReO4− uptake up to 952 mg g−1 with high selectivity and fast kinetics. More importantly, the high porosity and ultra-robust nanofiber structure of the COFs make them ideal packing materials for dynamic column experiments. >99.98% ReO4−/TcO4− can be efficiently separated and re-collected, even after four adsorption-desorption cycles, ranking a new record of the elimination rate for ReO4− adsorption. The performance of these materials suggests attractive opportunities in practical applications for TcO4− removal from the environment and nuclear waste.

Structure of two-dimensional electron clusters with various shapes, at low temperatures

The molecular dynamics method is used to study the structure of two-dimensional clusters that can be created in electronic systems above the surface of superfluid helium, using triangular, square, hexagonal and round holding electrode geometries. Clusters with a fixed surface density of 108 cm−2, but different numbers of particles (from 3 to 406) are considered. The spatial configurations of particles in clusters are calculated corresponding to a temperature of 10−2 K. The shape of the cluster significantly affects the arrangement of the electrons inside. If the symmetry of the cluster is consistent with the triangular symmetry of the electronic crystal, then for some numbers of particles, clusters with ideal defect-free packing are possible; otherwise, the clusters contain defects. An additional external field applied to the cluster significantly changes the configuration of its particles.

On the implicit immersed boundary method in coupled discrete element and lattice Boltzmann method

SummaryThe coupled discrete element method and lattice Boltzmann method (DEMLBM) has increasingly drawn attention of researchers in geomechanics due to its mesoscopic nature since 2000. Immersed boundary method (IBM) and immersed moving boundary (IMB) are two popular schemes for coupling fluid particle in DEMLBM. This work aims at coupling DEM and LBM using the latest IBM algorithm and investigating its accuracy, computational efficiency, and applicability. Two benchmark tests, interstitial fluid flow in an ideal packing and single particle sedimentation in viscous fluid, are carried out to demonstrate the accuracy of IBM through semi‐empirical Ergun equation, finite element method (FEM), and IMB. Then, simulations of particle migration with relatively large velocity in Poiseuille flow are utilized to address limitations of IBM in DEMLBM modeling. In addition, advantages and deficiencies of IBM are discussed and compared with IMB. It is found that the accuracy of IBM can be only guaranteed when sufficient boundary points are used and it is not suitable for geomechanical problems involving large fluid or particle velocity.

Bulks of Al-B-C obtained by reactively spark plasma sintering and impact properties by Split Hopkinson Pressure Bar

Mixtures of B4C, α-AlB12 and B powders were reactively spark plasma sintered at 1800 °C. Crystalline and amorphous boron powders were used. Samples were tested for their impact behavior by the Split Hopkinson Pressure Bar method. When the ratio R = B4C/α-AlB12 ≥ 1.3 for a constant B-amount, the major phase in the samples was the orthorhombic AlB24C4, and when R < 1 the amount of AlB24C4 significantly decreased. Predictions that AlB24C4 has the best mechanical impact properties since it is the most compact and close to the ideal cubic packing among the Al-B-C phases containing B12-type icosahedra were partially confirmed. Namely, the highest values of the Vickers hardness (32.4 GPa), dynamic strength (1323 MPa), strain and toughness were determined for the samples with R = 1.3, i.e., for the samples with a high amount of AlB24C4. However, the existence of a maximum, detectable especially in the dynamic strength vs. R, indicated the additional influence of the phases and the composite’s microstructure in the samples. The type of boron does not influence the dependencies of the indicated mechanical parameters with R, but the curves are shifted to slightly higher values for the samples in which amorphous boron was used.

Total-scattering pair-distribution function analysis of zinc from high-energy synchrotron data

The crystal structure of zinc metal deviates from the ideal hexagonal close packing structure by a significantly increased axial ratio (c/a). The local atomic structure of zinc metal is investigated using the total scattering atomic pair distribution function (PDF) analysis based on X-ray powder diffraction data collected at ambient conditions. The X-ray total scattering PDF analysis confirms that the crystal structure of zinc can be described in terms of wurtzite structure, but with an anomalously atomic displacement parameters [Formula: see text], indicating a significant displacement disorder along the [Formula: see text]-axis. For the long [Formula: see text]-range PDF refinements, the thermal motion of zinc shows a notable anisotropy as expressed by the ratio [Formula: see text]/[Formula: see text] of 2.5 at ambient conditions. This average distortion level along the [Formula: see text]-axis, was not reflected locally for the features below 5.0 Å as it fits the high [Formula: see text] region. Based on PDF refinements over different [Formula: see text]-ranges, we measure an interesting increase of the [Formula: see text] value with decreasing the [Formula: see text]-range of the refinement. This suggests that the local structure features in zinc metal differ from the average structure ones.

Stochastic point process applied in aggregates composition for concrete

The objective of this work is to apply a stochastic point process technique in the evaluation of aggregate composition parameters for concrete. Several experimental, numeric and computational methods have been used for determining an ideal packing of aggregates for concrete, based on the principle of the lowest content of voids. Experimental method is quite hard-working. On the other hand, the mathematical and computational models need potent computer and be tested experimentally. Equipment and computational methods have been developed, to provide images of the particle distribution, approaching the actual distribution of aggregates and allowing to obtain ideal aggregates compositions. This work uses a stochastic point process, based on the point processes method, which a simple sequential inhibition (SSI) process on the arbitrary closed region places the particles. The SSI generates image of spherical particles distributions for viewing and checking compliance of parameters of aggregates compositions. The characteristics of aggregates (porosity, granulometry, proportion of each aggregate composition, and specific mass) and the problem’s domain are input data. The SSI’s output data of interest are virtual image of particles distribution, particles composition, porosity of each composition, diameter and number of particles. From SSI’s output data, it can be determined the packing factor and a histogram of particles diameters. This information is evaluated and compared with the input composition. As a result, the stochastic SSI demonstrates to be efficient in comparing the output and experimental data, complying with the purpose of the study.