Types Of Interlayers Research Articles

Interfacial microstructure and mechanical properties of Si3N4/Invar joints using Ag–Cu–In–Ti with Cu foil as an interlayer

Abstract Si3N4 and Invar alloy brazed joints were achieved using two types of Ag-based interlayers: a Ag–Cu–In–Ti foil and a Ag–Cu–In–Ti/Cu/Ag–Cu multi-interlayer. The results showed that when only using a single Ag–Cu–In–Ti filler, the wave-shaped Fe2Ti + Ni3Ti intermetallic compounds are concentrated in the middle of the brazing seam. When adding Cu as the interlayer, the dissolution of the Cu interlayer formed a large number of Cu(s,s) blocks of different sizes in the brazing seam, which hindered the concentrated distribution of Fe2Ti + Ni3Ti intermetallic compounds in the brazing seam. As a result, Fe2Ti and Ni3Ti were dispersedly distributed in the brazing seam, increasing the shear strength of the brazed joint. The shear strength of brazed joints was increased by 82 % compared to joints brazed with a single Ag–Cu–In–Ti filler when the Cu interlayer was added.

Installation of geosynthetic interlayers during overlay construction: Case study of Texas State Highway 21

Geosynthetic interlayers in the form of geotextiles, geogrids, and geocomposites have been used to minimize reflective cracks and enhance overlay performance through functions such as stress relief, reinforcement and moisture barrier. However, proper geosynthetic installation and asphalt overlay construction practices are essential to the adequate performance of geosynthetic-reinforced asphalt overlays. In this study, various factors determining the successful construction of a geosynthetic-reinforced asphalt overlay are discussed in light of experiences during the construction of experimental test sections constructed in Texas State Highway 21. The project included nine different types of geosynthetic interlayers including four polymeric geogrid composites, three fiberglass geogrid composites, one fiberglass grid, and a fiberglass paving mat. The experimental test section included both sensor- and non-instrumented sections. The constructability evaluation of such experimental sections revealed that the primary factors influencing tack coat type and application rates include the pre-existing surface condition, geosynthetic type and their asphalt retention capacities. The geosynthetic installation procedures adopted in the experimental sections were proficient and comprised a specialized installation equipment that is capable of pre-tensioning the geosynthetics during the installation to minimize wrinkles and irregularities. Additionally, particularly high temperature of the pre-existing asphalt surface resulted in blistering of geotextile backing and subsequently leading into an excessive bleeding of tack coat through the geosynthetic apertures that resulted in tracking of construction equipment wheels. Recommendations on efficient geosynthetic installation and overlay construction techniques include adopting the tack coat type and application rates based on project-specific conditions, and using such tack coat to determine the asphalt retention capacity of the geosynthetic interlayer to be used in the project. Additional recommendations include minimizing the movement of construction vehicles on top of the geosynthetic interlayer, and adopting asphalt sanding technique to restore the friction between the paver and surface to minimize possible damage to the geosynthetic interlayer.

An intelligent identification method of interlayers in deep clastic rock – An example of Donghe Sandstone in Hade Oilfield, Tarim Basin

The identification of interlayer types is the key to improve the geological model to study the characteristics of oil and water distribution. The Donghe Sandstone in Hade Oilfield is used as the research object to calibrate the interlayer type and location by means of the outcrop, core, conventional logging curves and electrical imaging data. However, the logging response characteristics of different types of interlayers are similar, which is difficult to be accurately characterized by the conventional method. Therefore, a Random Forest (RF) intelligent method based on the Ensemble Empirical Mode Decomposition (EEMD) and Hilbert Huang Transform (HHT) is proposed to identify the type of intercalation layer. The model consists of two parts: firstly, EEMD-HHT is used to automatically identify the location of the interlayer, secondly, RF is used to classify the interlayer type. The results show that the EEMD-HHT-RF model corresponds to the results of core identification of interlayer, which can achieve rapid identification and accurate prediction in the block.

Heterogeneity of a Sandy Conglomerate Reservoir in Qie12 Block, Qaidam Basin, Northwest China and Its Influence on Remaining Oil Distribution

In view of the key geological factors restricting reservoir development, the reservoir heterogeneity of an alluvial fan sandy conglomerate reservoir in the Qie12 block of Qaidam Basin, Northwest China, and its influence on remaining oil distribution, were studied according to geology, wireline logging data, and dynamic production data. This study illustrates that the difference in pore structures, which are controlled by different sedimentary fabrics, is the main cause of reservoir microscopic heterogeneity. Besides, the temporal and spatial distribution of architectural units in the alluvial fan controls reservoir macroheterogeneity. Our results show that the thick sandy conglomerate develops two types of pores, two types of permeability rhythms, two types of interlayers, two types of interlayer distribution, two types of effective sand body architecture, and four types of sand body connecting schemes. The strongest plane heterogeneity is found in the composite channel unit formed by overlapping and separated stable channels of the middle fan, and the unit’s permeability variation coefficient is >0.7. However, the variation coefficient in the range of 0.3–0.5 is found in the extensively connected body unit sandwiched with intermittent channels of the inner fan. The distributions of the remaining oil vary significantly in different architectural units because of the influence of reservoir heterogeneity, including distribution patterns of flow barriers, permeability rhythm, and reservoir pore structures. The composite channel unit formed by overlapping and separated stable channels, or the lateral alternated unit with braided channel and sheet flow sediment of the middle fan, is influenced by the inhomogeneous breakthrough of injection water flowing along the dominant channel in a high-permeability layer. The microscopic surrounding flow and island-shaped remaining oils form and concentrate mainly in the upper part of a compound rhythmic layer. Meanwhile, in the extensively connected body unit sandwiched with intermittent channels of the inner fan, poor injector–producer connectivity and low reservoir permeability lead to a flake-like enrichment of the remaining oil.

Mechanical Mechanism and Shaping Effect of Tunnel Blasting Construction in Rock with Weak Interlayer

The weak interlayer, as a problematic geological body during tunnel construction, greatly influences the propagation of the blasting stress wave, the blasting excavation qualities, and the explosion efficiency. A series of numerical models were established to study the changes in the propagation process of blasting stress waves and the failure morphology of the surrounding rock mass, aiming to reveal the weak interlayer’s influence mechanism. The result indicates that the weak interlayer’s existence reduces the propagation velocity and stress peak of the stress wave at barred zones but strengthens the peak stress at reflection zones, which leads to an asymmetrical distribution of rock damage. Furthermore, the type and distribution of the weak interlayer were classified and generalized into four types. The tunnel blasting outlines under different types of weak interlayers are derived through numerical modeling for designing references. A strategy to resist tunnel overbreak and underbreak was proposed combined with previous work. The actual blasting solution is compared to the designed blasting solution with optimised blasting parameters.

Impacts of Lightweight Aggregate Interlayers for Air Convection Embankment on Pavement Thermal Profile and Pavement Performance in Alaskan Permafrost Regions

Crushed-rock air convection embankment (ACE) has been used to mitigate pavement distresses caused by climatic extremes in permafrost regions for more than three decades. This study proposes using lightweight aggregates as cost-effective alternative materials to overcome the shortage of desired crushed rocks needed for ACE in interior Alaska. This paper presents an investigation of the performance of six selected pavement structures: an asphalt pavement typical of the northern region of Alaska and five pavements reinforced with different paving interlayers (i.e., silty sand/gravel, crushed rocks, cellular concrete aggregate, foam glass aggregate, and lightweight expanded clay aggregate). Pavement thermal analyses using Temperature Estimate Model for Pavement Structures (TEMPS) program and ANSYS Fluent software were performed to predict heat transfer patterns and thermal performance for each case. Pavement performance analyses using viscoelastic-based FlexPAVE™ and the elastic-based Alaska Flexible Pavement Design (AKFPD) program were conducted to evaluate the long-term performance and structural stability of subgrade soil with different types of interlayers. The results showed that the lightweight aggregate ACEs improved cooling performance more effectively than the crushed-rock ACE. The lightweight aggregate interlayers could maintain desired thermal insulation in summer and enhance the cooling effect in winter. The modeling results identified the high potential of using lightweight aggregates as alternative ACE materials to improve pavement service life and subgrade stability.

Impurity Gettering in Polycrystalline‐Silicon Based Passivating Contacts—The Role of Oxide Stoichiometry and Pinholes

AbstractPolycrystalline‐silicon/oxide (poly‐Si/SiOx) passivating contacts for high efficiency solar cells exhibit excellent surface passivation, carrier selectivity, and impurity gettering effects. However, the ultrathin SiOx interlayer can act as a diffusion barrier for metal impurities and this potentially slows down the overall gettering rate of the poly‐Si/SiOx structures. Herein, the factors that determine the blocking effects of the SiOx interlayers are identified and investigated by examining two general types of the SiOx interlayers: 1.3 nm ultrathin tunneling SiOx with negligible pinholes and 2.5 nm SiOx with thermally created pinholes. Iron is used as tracer impurity in silicon to quantify the gettering rate. By fitting the experimental gettering kinetics by a diffusion‐limited segregation gettering model, the blocking effects of the SiOx interlayers are quantified by a transport parameter. Both the oxide stoichiometry and pinhole density affect the effective transport of iron through SiOx interlayers. The oxide stoichiometry depends strongly on the oxidation method, while the pinhole density is affected by the activation temperature, doping concentration, doping technique, and possibly the dopant type as well. To enable a fast gettering process during typical high‐temperature formation of the poly‐Si/SiOx structures, a SiOx interlayer that is less stoichiometric or with a higher pinhole density is preferred.

Numerical Analysis of Laminated Glass Panels with Articulared Bolted Point Fixings

AbstractThis paper reports on a finite element numerical investigation for pointed fixed laminated glass panels (PFLGP). The study focused on the influence of the fixing elements and interlayer material. Two mechanical point fixing solutions were studied: i) embedded and ii) countersunk bolt fixings. Two types of interlayers were considered: EVASAFE and PVB. The numerical models were developed with FE software Abaqus. Results are validated with ongoing experimental research, considering a selection of single PFLGP subjected to wind loads. The different numerical modelling techniques for each fixing type are described and detailed, allowing further developments on the characterization of these systems.

Effects of Different Types of Interlayers on the Interfacial Reaction Mechanism at the Cu Side of Al/Cu Lap Joints Obtained by Laser Welding/Brazing.

The influence of tin foil and Ni coatings on microstructures, mechanical properties, and the interfacial reaction mechanism was investigated during laser welding/brazing of Al/Cu lap joints. In the presence of a Zn-based filler, tin foil as well as Ni coating strengthened the Al/Cu joints. The tin foil only slightly influenced the joint strength. It considerably improved the spreading/wetting ability of the weld filler; however, it weakened the bonding between the seam and the Al base metal. The Ni coating considerably strengthened the Al/Cu lap joints; the highest tensile strength was 171 MPa, which was higher by 15.5% than that of a joint without any interlayer. Microstructure analysis revealed that composite layers of Ni3Zn14–(τ2 Zn–Ni–Al ternary phase)–(α-Zn solid solution)–Al3Ni formed at the fusion zone (FZ)/Cu interface. Based on the inferences about the microstructures at the interfaces, thermodynamic results were calculated to analyze the interfacial reaction mechanism. The diffusion of Cu was limited by the Ni coating and the mutual attraction between the Al and Ni atoms. The microstructure comprised Zn, Ni, and Al, and they replaced the brittle Cu–Zn intermetallic compounds, successfully strengthening the bonding of the FZ/Cu interface.

On the delamination of polyvinyl butyral laminated glass: Identification of fracture properties from numerical modelling

This work investigates the delamination behaviour of polyvinyl butyral (PVB) laminated glass under quasi-static loading based on a cohesive zone model (CZM) with an isotropic bilinear traction - separation (T – δ) law. It presents a 2D model of a through-cracked tensile (TCT) test within an implicit finite element framework of the commercial software ANSYS. Test results from literature are used to calibrate the adhesion properties of the PVB-glass interface in a numerical cohesive zone approach. The previous TCT tests were performed at a loading rate of 6 mm/min and a temperature of approx. 22 °C. Three different PVB adhesion grades, i.e., BG R10 (low), BG R15 (medium) and BG R20 (high) are considered. Given the uncertainty in the identification of adhesion parameters, including interfacial fracture energy, cohesive strength and stiffness, a parametric analysis is conducted quantifying the influences of model parameters on the simulation results. The study allows for decoupling of individual parameters in the calibration. Then, interfacial fracture energies and cohesive strengths of the PVB-laminated glass are calibrated by matching the force – displacement curves of the numerical simulations with those from the TCT experiments. One representative case was chosen for each adhesion grade. We obtain interfacial fracture energies of 425 J/m2, 650 J/m2 and 1000 J/m2 for BG R10, BG R15 and BG R20 PVBs, respectively, while the corresponding cohesive strengths are 3 MPa, 5 MPa and 10 MPa, respectively. Moreover, based on numerical simulation results, the conversion of energy during the delamination process is extracted and discussed. The mixed-mode delamination mechanism is investigated by calculating the mode I and mode II energy release rates with respect to different PVB thicknesses and adhesion. The results show that the proportion of the mode I energy release rate is around 30%∼40% of the total energy release rate at the stable delamination stage and increases with PVB thickness. The presented study contributes to the adhesion properties of various types of PVB interlayers reported in open literatures and proposes a methodology for the unique identification of adhesion properties.

Aliphatic polyketone-based thin film composite membrane with mussel-inspired polydopamine intermediate layer for high performance osmotic power generation

Polydopamine (PDA), formed from self-polymerization of dopamine, was coated on aliphatic polyketone membrane substrate prior to interfacial polymerization (IP), preparing a pressure retarded osmosis (PRO) thin film composite (TFC) membrane with a PDA interlayer. The effect of the formation of two types of PDA interlayers — smooth and particulate — on substrate morphology, polyamide formation, and PRO osmotic performance were investigated. Also, the effect of pH on the particulate PDA interlayer was studied. It was found that the introduction of both smooth and particulate PDA contributes to enhanced water flux and power density of the PRO membranes. pH was found to have significantly affected the formation of particulate PDA and the polyamide formation, as well. At higher pH, PDA self-polymerization led to the formation of more nanoparticles, the subsequent increase in surface roughness and decline in the polyketone substrate porosity. The particulate PDA interlayer formed looser polyamide, compared to the thinner and denser polyamide formed on pristine and smooth PDA-interlayer-coated TFC membranes. The membrane performance was evaluated using deionized water and 1.0 M NaCl as feed and draw solutions, respectively. The TFC membrane with nanoparticulate PDA layer formed at pH 9.0 exhibited the best initial water flux of 40.8 L m−2 h−1, and this membrane also showed the highest power density of 17.1 W m−2 at 25 bar. The results of this study indicate that nanoparticulate PDA interlayer formation is a simple and scalable TFC membrane development method for engineered osmosis.

Tribology of Electroless Nickel and Interlayer Coatings: A Review

This review emphasizes on the development of electroless nickel composite coatings by incorporating different types of material and interlayers to improve the mechanical and tribological properties of the coatings. Electroless nickel coatings are the main focus of this review as it possesses excellent mechanical and tribological properties such as, hardness, wear and corrosion resistance. Besides, electroless nickel coating may behave as lubricating as well as wear resistance coating compared to other interlayer coatings. Tribology aspect is concern on the friction and wear phenomena which involved the moving parts that measures the overall systems’ life, efficiency, and reliability. Interlayer coatings are applied to improve the adhesion between the substrate and the outer coating materials. Various materials are used as interlayers either pure or compound metallic elements.

Identification, distribution characteristics, and effects on production of interlayers in carbonate reservoirs: A case study from the Cretaceous Mishrif Formation in Halfaya Oilfield, Iraq

Carbonate reservoirs play an essential role in the oil and gas exploration, especially in the Middle East. Halfaya oilfield is a super-giant oilfield, in which Mishrif Formation is the main oil-bearing formation. Mishrif Formation has a strong heterogeneity with an alternative appearance of interlayers and reservoirs. The appearance of interlayers has an obvious effect on oil production. Therefore, it is necessary to identify and characterize interlayers in Mishrif Formation in Halfaya oilfield. The interlayers in the study area can be divided into three types with different lithology according to the core and well logging data. In this study, a zonal identification method is established to accurately identify these three types of interlayers. In this method, the reservoir and interlayer are divided based on their permeability. The identification criteria of the three types of interlayers are developed based on analyzing the well logging data. After identifying the interlayers at wells based on the newly developed identification criteria, the distribution of interlayers far away from the well is characterized by a zonal interwell comparison method. Then, the planar distributions of the interlayer thickness in each member are generated. The identification results show that barriers develop in members MA1, MB1-1, MC2-1 and MC3-1. For the intercalations, there are 8 members developing large-scale continuous intercalations, which are members MA2, MB1-2A, MB1-2B, MC1-3, MC1-4, MC2-2, MC2-3 and MC3-2. Comparing the distributions of the interlayers and those of the sedimentary microfacies, the development of interlayers is controlled by sedimentary microfacies. It can be concluded that the interlayers prefer to appear in shallow open sea and subtidal flats. To quantitively characterize the effects of intercalations on oil production, intercalation density and intercalation frequency are compared with half-year oil production decline rate. The results show that the half-year decline rate increases with the increase of intercalation density and frequency. The intercalation density can better reflect the effect of intercalations on oil production than the intercalation frequency.

Realization of Separated Imprinting Fabrication Process Driven from Interfacial Wetting Mechanism for Durable Perovskite and Organic Photovoltaic Devices

Recently, fabrication procedure has become a key factor directly related to the efficiency and cost reduction of products. Despite the importance of process improvement, due to the limitations of the application range, many fabrication processes are limited to laminating one by one. Particularly, when applied to a roll-to-roll process, since the only method is to increase the length of the rail for heat treatment and drying time, realization of the separated fabrication process can minimize waste. One of the separated imprinting processes, transfer process using by soft mold, has been considered by advanced technology to overcome limits of conventional lamination process (spin-casting, dip-coating, etc.), because a layer is previously formed on the other medium substrate, as well as the material loss and penetration of solvents are minimized in the process.In this research, we introduced polyurethane acylate (PUA) of which the surface property was modified by applying the various functional group of the monomer, because control of the surface property of the medium was required to minimize interfacial wettability with a material. As a result, we designed the proper PUAs to enable the transfer process of each organic semiconductor via adhesion control between each interface. First, we applied the transfer process to inter-layer in planer-type perovskite photovoltaics. We successfully transferred two types of inter-layer, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) [1], and 6,6-phenyl-C71 butyric acid methyl ester (PC71BM) [2]. Interestingly, when the PEDOT:PSS was transferred onto Indium tin oxide (ITO) substrate, the corrosion of ITO was extremely suppressed due to solid-state film formation, which enhanced the stability of the perovskite devices. Especially, the device with transferred PC71BM exhibited the performance improvement caused by improved coverage of inter-layer on perovskite layer, correlated with increased electron mobility and exciton dissociation. Finally, the transfer process was introduced to organic photodiode (OPD) fabrication [3]. Despite the separated imprinting system, a comparable performance was confirmed in the OPD from the transfer process. Furthermore, the OPD with transferred sensitive layer showed a superior durability (over 95%) to the device from conventional process, owing to morphology stabilization of organic semiconductor layers. This work provides a strategy for promising next-generation technologies of separated imprinting fabrication process, and at the same time can make a significant contribution to increase of process yield and reduction of unit prices.[1] M. Yi, W. Jang, J. S. Cho, and D. H. Wang, Appl. Surf. Sci., 2019, 467, 168.[2] S. Ahn, W. Jang, S. Park, and D. H. Wang, ACS Appl. Mater. Interfaces, 2017, 9, 15623.[3] W. Jang, and D. H. Wang, ACS Appl. Mater. Interfaces, 2018, 10, 38603.

Effect of interlayer addition on microstructure and mechanical properties of NiTi/stainless steel joint by electron beam welding

NiTi/Stainless Steel (SS) sheets have been welded via a vacuum electron beam welding process, with three methods (offsetting electron beam to SS side without interlayer, adding Ni interlayer and adding FeNi interlayer), to promote mechanical properties of the NiTi/SS joints. The joints with different interlayers are all fractured in the weld zone near the NiTi side, which is attributed to the enrichment of intermetallic compounds including Fe2Ti and Ni3Ti. The fracture mechanisms of different joints are strongly dependent on the types of interlayers, and the joints without interlayer, adding Ni interlayer and adding FeNi interlayer exhibit cleavage fracture, intergranular fracture and mixed fracture composed of cleavage and tearing ridge, respectively. Compared with the brittle laves phase Fe2Ti, Ni3Ti phase can exhibit certain plasticity, block the crack propagation and change the direction of crack propagation. The composite structure of Ni3Ti and Fe2Ti will be formed when the FeNi alloy is taken as the interlayer, which provides the joint excellent mechanical properties, with rupture strength of 343 MPa.

Review Article. What are the nature and formation conditions of hydroxy‐interlayered minerals (HIMs) in soil?

AbstractPrimary minerals of the parent material undergo weathering during the formation of terrestrial soils to varying extent. As a result, secondary minerals develop, which comprise, among many others, hydroxy‐interlayered minerals (HIMs). These minerals have formed by interlayering of hydroxy‐metal complexes (especially of Al3+, also Mg2+, Fe2+/3+) into micas, expansible 2:1 phyllosilicates and forming oligomers, or by weathering of primary chlorite. The degree of interlayer filling and the stability of these fillings affect several physico‐chemical soil properties, for instance the cation exchange capacity. Although many studies have been conducted on formation, occurrence, and properties of HIMs in soil during the last decades, several challenges still exist. These challenges include analytical identification and quantification of HIMs in soil, the nature of the interlayer filling and the identification of favorable conditions in soil for the formation of HIMs. In order to deepen the understanding of formation, properties, and fate of HIMs in soil, we critically reviewed the available literature. Based on the review, we recommend using a new structural model that enables quantification of hydroxy‐interlayered smectite in soil by X‐ray diffractometry, laboratory experiments on the formation and preservation of different types of interlayers and considering the temporal and spatial dimension of the formation of HIMs in soil in more detail.

Design and fabrication of HfC, SiC/HfC and HfC-SiC/HfC interlayers for improving the adhesion between diamond coatings and cemented carbides

Three types of interlayers named Hafnium carbide (HfC) single-interlayer, SiC/HfC double-interlayer, and HfC-SiC/HfC double-interlayer were designed and fabricated on cemented carbide (WC–Co) to seek out the optimal coating structure for well-adhered diamond coatings. The phase composition, microstructure, adhesion and effectiveness in diamond coating adhesion of these interlayers were investigated and compared. The results showed that the HfC single-interlayer was a HfC-dominant nanostructured layer composed of HfC, Si, and SiC. The SiC/HfC and the HfC-SiC/HfC double-interlayers had an inner layer with a structure similar to the HfC single-interlayer. However, the former had a SiC-dominant outer layer, while the latter had a gradient HfC-SiC mixed outer layer. The double-interlayers possessed better adhesion and higher hardness than those of the HfC single-interlayer. This could be attributed to the introduction of SiC in the outer layer, which endowed the substrates with significantly enhanced microhardness and decreased TEC, closer to those of diamond coatings. After the subsequent CVD process, dense nanocrystalline diamond coatings with a thickness of ∼5.0 μm were deposited onto the double-interlayered substrates. The coatings possessed good adhesion. Between them, the diamond coating on the HfC-SiC/HfC double-interlayered substrate had better adhesion (HF1∼HF2) and lower residual stress (−1.7 GPa) than those of the coating on the SiC/HfC double-interlayered substrate. These experimental results provide a feasible way for fabrication of well-adhered diamond coating on WC-Co tools.

Estimation of Service Life of Geosynthetic-Reinforced Asphalt Overlays from Beam and Large-Scale Fatigue Tests

Abstract In this study, an attempt has been made to develop a model to predict the service life of geosynthetic-reinforced hot mix asphalt (HMA) overlay placed over distressed pavements based on fatigue behavior observed in beam and large-scale tests. A two-stage detailed experimental program was designed to understand the fatigue behavior and reinforcement effects of asphalt overlays reinforced with geosynthetic interlayers. During the first stage, small-scale beam flexural fatigue tests were conducted on the HMA overlays to understand the reflection cracking and deformation behaviors with the aid of digital image correlation (DIC) techniques. During the second stage, the fatigue behavior of overlays was evaluated under repeated load tests on large-scale pavement sections built over a weak subgrade in a large test tank. Two types of geosynthetic interlayers, namely, polyester grid coated with polymer modified binder (PE) and a glass-grid composite (GGC) with different tensile strength and strain characteristics, were employed. The beam flexural fatigue test results along with DIC data indicated that the geosynthetic-interlayers have effectively minimized the crack propagation into overlays even under unconfined conditions. Whereas, for the same permanent deformation, the large-scale test sections sustained a higher number of load repetitions, reaching 100-fold, because of the presence of a base course structural support. A simple model to estimate the service life of the geosynthetic asphalt overlays has been proposed based on the beam fatigue tests viz. normalized complex modulus × cycles and a corresponding number of load repetitions for a prescribed rutting. Overall, for a vertical deformation of about 7.5 mm, it is estimated that GGC and PE interlayers would give a service life of 4.1 and 2.9 years, respectively, in real field scenarios.

Fine Characterization Method for Interlayers in Complex Meander River Sandstone Reservoir: A Case Study of Um7 Sand of C Oilfield in Bohai Bay Area

Taking the Um7 meandering river complex sandstone reservoir of Bohai Bay C oilfield as an example, the interlayer type is defined according to the interlayer lithology and sedimentary genesis, and the identification mode of different types of interlayer is established, and the interlayer comparison of the whole area is carried out by using this mode. The results show that the interlayer can be further defined as the stable distributed interlayer and the randomly distributed interlayer according to the morphology of the interlayer. The distribution characteristics of the two types of interlayers are characterized by the well-to-well comparison method and the data analysis method, and the three-dimensional characterization is carried out. The results more closely reflect the spatial distribution of the interlayer, but also are closer to the underground real situation.

Impact assessment of interlayers on geological storage of carbon dioxide in Songliao Basin

Reservoirs in the Songliao Basin are characterized by strong heterogeneity, which increases the difficulty of exact reservoir prediction. The clay interlayer developed in the reservoir is an important factor affecting the heterogeneity of the reservoir. Using the reservoir numerical simulation technology, an attempt has been made to investigate the storage efficiency during CO2 sequestration in Songliao Basin considering different types of interlayer in underground formations. Results indicate that type I interlayer, with a large thickness embedded between the two sand bodies has function of shunting and blocking to alleviate the impacts on cap rock. The type II interlayer has a small thickness and locates inside a single sand body, with poor physical properties and continuity, which has the same blocking effect on CO2 distribution and moderating influence on the cap rock. The physical properties of type III interlayer are same as the type II interlayer, but it has uneven distribution and poor continuity. In addition, three schemes of perforated zone were designed and their effects on CO2 storage efficiency and stability were studied. For a single reservoir, the scheme I is to perforate a whole reservoir, which is more conducive to maintain the reservoir’s stability. For multiple sets of “single-reservoir”, the scheme II can be preferentially selected to perforate the reservoir section below the interlayer when the injection volume is small. However, the scheme III can be used to perforate the interlayer and the reservoir below that when the injection volume is large. The study is beneficial to provide guidance and advice for selecting a suitable CO2 geological storage and reduce the risk of CO2 leakage.