Cement Bond Research Articles

Self-adhesive cement bond strength to differently surface treated relined posts

Self-adhesive cement bond strength to differently surface treated relined posts

In-situ-investigation of superplasticizer-particle-interaction by fluorescence microscopy

In modern construction chemistry, the interaction of organic polymers, so called superplasticizers, with all kinds of mineral substrates present in cement bond systems is a very important field. The addition of those polymers allow the development of high and ultra-high performance concretes (HPC and UHPC). To investigate the working mechanisms and influencing variables a new method is presented here: the fluorescence microscopy for in-situ measurements of the polymer-particle-interaction. To verify this approach some results concerning the influence of calcium ion concentration are compared to zeta potential measurements, because the particles surface charge effects this interaction. As model system, suspensions of tobermorite, ettringite and aluminum oxide are chosen.

Multi-frequency acoustic method and equipment for cement bond log of wells based on one-sided excitation and reception of elastic waves from the top of the well

Multi-frequency acoustic method and equipment for cement bond log of wells based on one-sided excitation and reception of elastic waves from the top of the well

Responses and data inversion of four-detector scattered-gamma-ray logging in cased holes

In cased holes, detector response of scattered-gamma-ray logging tool is subject to casing, cement sheath, and formation density, while the logging result requires four parameters—casing thickness, cement sheath density, cement sheath thickness, and formation density—for cased-hole formation evaluation and cement bond evaluation. Therefore, It is necessary to study the detector response and logging data inversion. We designed a four-detector scattered-gamma-ray logging tool for cased holes and performed Monte Carlo numerical simulations to obtain relationships between the responses of four detectors versus casing, cement sheath, and formation, respectively; on this basis, forward modeling formulas for the detector responses were established, and an optimization inversion method was applied to obtain the casing thickness, cement sheath density and formation density from the forward model. As demonstrated by the result, detector response was a function of formation density, cement sheath thickness, cement sheath density, and casing thickness; the response of detector count rate versus casing thickness was less influenced by ambient conditions, compared to the other parameters. Relatively accurate casing thickness values could be calculated when the condition of the borehole and formation is normal; accurate cement sheath density values could be obtained when the cement sheath was relatively thick; and relatively accurate formation density values could be obtained when the cement sheath has neither of low density nor of great thickness.

Durability and Reliability of Electro-Mechanical Relays for Oil and Gas

AbstractElectro-mechanical relays (EMRs) are widely used in variety of manufacturing industries including oil and gas. One of their applications in the oil and gas industry is in the design of downhole logging wireline and measurement-while-drilling/logging-while-drilling (MWD/LWD) instruments such as magnetic resonance instruments, formation testing instruments, cement bond tools, etc.EMRs are mainly electrically operated switches that multiplex high-powered circuits using a low-power signal. Typically, EMRs consist of one or two wire coils wrapped around magnetic cores, a movable armature, and a set of contact(s) that reside inside a sealed vacuum compartment.The structural durability and reliability of EMRs has been the subject of research for many years, and these characteristics are considered a prime reliability concerns in the oil and gas industry. Their poor reliability has been documented by their several inherent failure modes, e.g., limited life expectancy due to shock, vibration, temperature and moisture, thermal stresses caused by soldering, contact wear, contact bouncing, and contact arcing/welding.This paper presents results from a reliability study and an engineering assessment to determine the applicability and functionality of EMRs in electromagnetic-acoustic sensors. The discussion includes steps to improve and minimize the risk.

Strength comparison of anterior teeth restored with ceramic endocrowns vs custom-made post and cores

PurposeThe aim of the study was to compare strength of the anterior teeth restored with ceramic endocrowns versus custom-made post and core. MethodsThe investigation used the finite element analysis. Three 3-D models of maxillary central incisor were created: model A—tooth restored with metal post and core with ceramic crown; model B—tooth with leucite ceramic endocrown; model C—tooth with lithium disilicate ceramic endocrown. Each model was subjected to a 100N force applied at a distance of 5mm from the incisal edge, at the angle of 130° to the long axis of the tooth. The modified von Mises failure criterion was used to evaluate the strength of the dentin, ceramic and resin cement, and Huber–Mises–Hencky failure criterion for cast alloy. Contact stresses in the cement-tissue adhesive interface were calculated. ResultsThe lowest stresses occurred in the anterior tooth restored with custom post and core (model A). The mvM stress of 47.5MPa concentrated in leucite ceramic endocrown (model B) and its value was close to the tensile strength of this material. The maximal mvM stresses in the lithium disilicate ceramic endocrown (model C) were 4 times lower than tensile strength of this material. In all cases contact stresses in the adhesive interface under restorations did not exceed the resin cement bond strength to dentin. ConclusionsLeucite ceramic endocrowns in incisors may fracture during physiological loading. Endocrowns made of lithium disilicate ceramic are resistant to failure. Posts and prosthetic crowns are still recommended for anterior teeth restorations.

Discrete Element Modeling of Micro-scratch Tests: Investigation of Mechanisms of CO2 Alteration in Reservoir Rocks

The injection of CO2 into geological formations leads to geochemical re-equilibrium between the pore fluid and rock minerals. Mineral–brine–CO2 reactions can induce alteration of mechanical properties and affect the structural integrity of the storage formation. The location of alterable mineral phases within the rock skeleton is important to assess the potential effects of mineral dissolution on bulk geomechanical properties. Hence, although often disregarded, the understanding of particle-scale mechanisms responsible for alterations is necessary to predict the extent of geomechanical alteration as a function of dissolved mineral amounts. This study investigates the CO2-related rock chemo-mechanical alteration through numerical modeling and matching of naturally altered rocks probed with micro-scratch tests. We use a model that couples the discrete element method (DEM) and the bonded particle model (BPM) to perform simulations of micro-scratch tests on synthetic rocks that mimic Entrada sandstone. Experimental results serve to calibrate numerical scratch tests with DEM–BPM parameters. Sensitivity analyses indicate that the cement size and bond shear strength are the most sensitive microscopic parameters that govern the CO2-induced alteration in Entrada sandstone. Reductions in cement size lead to decrease in scratch toughness and an increase in ductility in the rock samples. This work demonstrates how small variations of microscopic bond properties in cemented sandstone can lead to significant changes in macroscopic large-strain mechanical properties.

The Effect of Lithium Disilicate Ceramic Thickness and Translucency on Shear Bond Strength of Light-cured Resin Cement

Introduction: To achieve acceptable clinical performance, a ceramic veneer must be bonded to enamel by well-polymerized resin cement. Among different factors, thickness and translucency of the ceramic may affect the resin cement polymerization. Thus, the current study evaluated the effect of the thickness and translucency of lithium disilicate ceramic on light-cured resin cement bond strength to enamel. Methods: In this laboratory study, 208 sound bovine incisors were equally divided into 16 groups (n = 13). The lithium disilicate ceramic cubes in four thicknesses (0.4, 0.6, 0.8 and 1 mm) with four translucencies (high and medium opaque, high and low translucent) were fabricated and bonded to prepared enamel surfaces using a light-cured translucent resin cement according to manufacturer recommendations. After 5000 cycles of thermocycling, the bonded specimens were placed in a universal testing machine and loaded to the point of fracture. To determine the mode of failure, each sample was observed under a stereomicroscope. Data were recorded and analyzed by Shapiro-Wilk test and two-way analysis of variance (ANOVA). Results: The ceramic thickness and translucency could not significantly affect shear bond strength (SBS) of resin cement to enamel (p = 0.17 and p = 0.097, respectively). The Adhesive and ceramic cohesive failures were reported as the maximum and minimum mode of failure, respectively. Conclusion: The SBS of the light-cured resin cement bonding to enamel and lithium disilicate ceramic was not affected by the translucency of ceramics having a thickness of less than 1 mm.

Well Integrity Assessment of Monitoring Wells at an Active CO2-EOR Flood

Assessment of well integrity has become more important for CCS and CO2-EOR as it has become apparent that wells represent the most likely migration pathway for CO2 to leave a CCS storage unit or a CO2-EOR reservoir. Although wells represent a migration pathway they are also the best vehicle for employing technology monitoring CO2 injection and storage. This contradiction of being a potential migration path and key monitoring technology leads to a need to understand how monitoring wells may be similar or different in comparison to other types of wells with respect to migration risk. The maturation and completion US Department of Energy sponsored research projects presents an opportunity to assess the integrity of monitoring wells that have been exposed to injected CO2. This paper discusses an integrity assessment of two monitoring wells in an operating CO2-EOR flood in Mississippi, USA. It provides an early assessment of how monitoring equipment affects well integrity and isolation capacity.Each of the monitoring wells in this study were similarly constructed using both fiberglass and conventional steel casing. Each of the wells was instrumented with multiple monitoring technologies including, electrodes, pressure gauges, and temperature sensors on the outside of the casing. Control lines and cables were run from the surface on the outside of the long-string casing in each well to communicate with the monitoring equipment.A comprehensive logging, testing, and sampling program was developed to assess integrity in both wells. Ultrasonic well mapping was used to create radial maps of the location of cement, liquid, and gas behind the casing. Cement bond logging provided information on the casing-to-cement and cement-to-formation bonds for the long-string section. The logs showed that the monitoring equipment attached to the long-string casing is visible as continuous low acoustic impedance features and may represent a leakage risk. Cased-hole sidewall cores were collected and provided some validation of the log results and provide local information on the isolation capacity of the wells.The combination of information from the log data sets and cores was used to assess isolation capacity. The results of the study show that careful design and assessment of the materials used in monitoring well construction, the types of monitoring technology, and the location of monitoring technology within a well needs to be conducted with limiting migration potential and maximizing well integrity as objectives.

Short- and Long-Term Bond Strength Between Resin Cement and Glass-Ceramic Using a Silane-Containing Universal Adhesive.

This study aimed to evaluate the effect of various silane-containing solutions on bonding between resin cement and glass ceramic after 24 hours and after six months of water storage. Glass-ceramic plaques (IPS e.max CAD) were sandblasted with aluminum oxide, etched with 10% hydrofluoric acid (HF), and divided into five "silane treatment" groups: RelyX Ceramic Primer (RCP), RelyX Ceramic Primer and Single Bond Plus (RCP+SB), Scotchbond Universal (SBU), Clearfil Ceramic Primer (CP), and no solution (HF-only control). Each group was divided into two "storage time" subgroups: 24 hours or six months in 37°C water. Eighteen resin cement cylinders (RelyX Ultimate) were bonded to each treatment group substrate (n=18) and then subjected to microshear testing. Failure mode was analyzed using scanning electron microscopy. Debond data were analyzed using a two-way analysis of variance and the Tukey post hoc test (α=0.05) as well as Weibull distributions. The factors "silane treatment," "storage time," (p<0.0001), and their interaction were statistically significant (p<0.0010). Group means (MPa±SD), RCP (24 hours: 27.2±3.1; six months: 18.0±4.9), and HF-only control (24 hours: 21.1±3.4; six months: 15.7±5.8) showed a reduced bond strength after six months of water storage, while RCP + SB (24 hours: 23.4±4.4; six months: 22.2±5.4), SBU (24 hours: 18.8±3.0; six months: 17.2±3.6), and CP (24 hours: 21.7±4.3; six months: 17.4±4.8) remained constant. Weibull analysis revealed that more reliable bond strengths were obtained after six months for SBU and RCP + SB. Evaluation by scanning electron microscopy revealed that all groups demonstrated hydrolytic degradation at six months of storage, but RCP + SB and SBU indicated less. Use of a separate application of silane and adhesive system improved short and long-term ceramic/resin cement bond strength.

Engineering geology of basaltic residual soil in Leiqiong, southern China

The physical, mechanical, chemical, mineralogical, and microstructural properties of basaltic residual soil obtained from Leiqiong area in southern China were examined. Emphasis was placed on the influences of minerals, oxides, and the soil fabric on engineering geological characteristics, particularly on strength and deformation properties. Distinctive properties, such as high strength and low compressibility relative to high void ratios, high liquid limits, and low natural densities, were explained. The soil fabric with the cement bond formed by iron oxides was considered as the main factor that caused to peculiar mechanical behavior, whereas mineralogy and climate processes also played important roles. Under the influence of repeated cycle of alternate wetting and drying, the residual soil generated a large collapsible deformation upon soaking, and its strength significantly decreased because of the derogation of cement bond, the formation of microcracks, and the weakening of microstructure failure zones.

Petrophysical Properties of Casing Cement While Curing

For geothermal as a well as hydrocarbon wells the casing is cemented to ensure a good contact between casing and the rock mass and, more importantly, for preventing the contamination of water resources. Cement shall thus have sufficient strength to prevent collapse of unstable formations and sufficient little permeability to prevent movement of undesired fluids along the well. The ultimate goal is the long-term integrity of the casing and the well. In a series of experiments, we conduct tests on various cements (with some bentonite content) for strength (uniaxial and triaxial), static elastic properties (Young's Modulus and Poisson's ratio), permeability, compressional wave velocities and dynamic elastic properties of the cement while curing. With this set of data the qualitative insight from cement bond logs may be enhanced by quantitative mechanical properties.

The effect of phosphoric and phosphonic acid primers on bone cement bond strength to total hip stem alloys

Aseptic loosening at alloy-cement interfaces constitutes a main failure mechanism of cemented total hip replacements (THR). As a potential solution we investigated the effect of metal primers containing phosphoric and phosphonic acid on shear bond strength (SBS) of bone cement to THR alloys (CoCrMo, TiAlNb) and pure tin (Sn) substrates (20×8×3 mm). Metal surfaces were modified by polishing or Al2O3 blasting and primer application. Substrates without primer treatment served as references. Cylindrical cement pins (Ø 5mm) were polymerised onto substrate surfaces and aging (1, 5, 14 and 150 days) was simulated in aqueous NaCl solution (0.9%) before SBS determination and failure mode evaluation.Regardless of surface roughness and aging time, SBS for THR alloys and Sn was always significantly higher with primer treatment. Compared to untreated reference specimens (≤0.2MPa) SBS values increased even up to 350 fold (TiAlNb, 14 days) or 400 fold (CoCrMo, 5 days). In general, the phosphoric acid containing primer revealed significant higher SBS values on THR alloys compared to the phosphonic acid containing one. Al2O3 blasted specimens showed generally higher SBS values than polished ones with the exception of Sn which showed high SBS values in general. With primer treatment on polished Sn a significant reduction of SBS could not be detected even up to 150 days, whereas THR alloys showed only an SBS improvement in the short term (≤14 days). A NaCl-pitting corrosion probably led to an increasing and durable SBS on polished Sn surfaces over time.Compared to modern THR in clinical practice that shows survival rates of 10, 15, 20 or more years, the receivable bond strength enhancements described in this study appeared to be very short. The improved SBS on THR alloys lasted only a few days before it was lost again. In contrast, the phosphoric acid primer treatment of polished Sn appeared to be very promising and may play a key role in further investigations dealing with the prevention of the stem-cement debonding in THR.

Numerical Analysis of Effect of Cyclic Thermal Load on Concrete to Concrete Bonding

This paper presents a numerical simulation and preliminary experimental investigation of bonding of concrete structures using cement and polymer cement as adhesive materials. The numerical model of concrete plates bonded with the polymer cement is created and subjected to cyclic thermal loading. As a result, the critical stresses are obtained. Also all the necessary materials for carrying out high-quality, fast and inexpensive experimental investigation of the strength of cement and polymer cement bond are prepared. The experimental setup and the first results obtained are also described. The bonding quality of the polymer cement shows satisfactory results under this kind of loading, thus the use of the polymer cement for bonding of concrete structures of different properties is reasonable in the specific fields considered in this study.

Performance of a modified particle swarm optimization in determining the thickness of the liquid layer outside a well casing pipe

The liquid layer outside a well casing develops from flaws along the cement–casing interface, which have been identified as leakage pathways in wellbores. The thickness of the liquid layer is one of the important parameters for determining cement bond quality. However, it is difficult to accurately determine the thickness of the liquid layer outside a well casing pipe with the traditional ultrasonic pulse echo method. To address this problem, we propose a novel inversion method for determining the thickness of the liquid layer between the casing and the cement sheath. According to test specimens, multi-layered structures are modeled to determine the overall reflected wave at the mud–casing interface. An improved particle swarm optimization algorithm is used to simultaneously inverse the thicknesses of the liquid layer, the casing, and the annular space between the casing and formation. Using synthetic data, this algorithm is more robust and stable when compared with standard particle swarm optimization inversion procedures. In addition, the influences of noise in the reflected wave and deviations of medium parameters on the inversion results of the liquid layer thickness are discussed. Finally, the method was used to determine the thicknesses of the liquid layer in test specimens. Numerical and experimental results demonstrate that the improved particle swarm optimization algorithm provides an effective approach to accurately determine the thickness of the liquid layer outside a well casing pipe.

Effect of dentin desensitizers on resin cement bond strengths

Introduction: The crown preparation promotes the exposure of dentin tubules. Thus, to avoid post-operative sensitivity, the first approach involves the use of dentin adhesives, and the second one the use of dentin desensitizers. Objective: This study evaluated the effect of dentin desensitizers on microtensile bond strengths (µTBSs) of a resin cement to dentin. Material and methods: Twenty bovine teeth were prepared until obtaining flat dentin surfaces. A standardized smear layer was created (#600-grit SiC paper). The samples were randomly divided into the following four groups (n = 5): no treatment (Control), treatment with Gluma Desensitizer (Heraeus Kulzer), Super Seal (Phoenix Dental) and Teethmate Desensitizer (Kuraray Noritake Dental). The dentin surfaces were then treated with ED Primer II (Kuraray Noritake Dental). Twenty composite blocks, 4 mm thick (Estenia CB Gluma Desensitizer and Super Seal decreased the µTBSs, however, Teethmate Desensitizer improved it.

Effect of Enamel and Dentin Surface Treatment on the Self-Adhesive Resin Cement Bond Strength.

The aim of this study was to evaluate the effect of enamel and dentin surface treatment on the micro-shear bond strength of self-adhesive cement. Seventy-two extracted third molars had their crowns embedded in acrylic resin and worn to obtain a flat enamel or dentin surface. The enamel and dentin specimens were randomly assigned to 8 groups (n=12) that were based on surface treatment (11.5% polyacrylic acid solution or no treatment), substrate condition (wet or dry) and storage period (1 day or 90 days), and treated accordingly. Cylinders (1 × 1 mm) were fabricated using self-adhesive resin cement (RelyX U200) following the manufacturer's instructions. The specimens were stored in distilled water at 37 °C for either 1 day or 90 days and subjected to micro-shear bond strength test (EMIC DL 2000 at 0.5 mm/min). After this, the failure type of the specimens was determined. Data were subjected to statistical analysis (a=0.05). According to the results, the 11.5% polyacrylic acid application decreased the bond strength in both enamel and dentin samples. The moist groups showed higher bond strength than the dry ones, regardless of the substrate and surface treatment. Storage period did not influence bond strength. In conclusion, surface treatment with 11.5% polyacrylic acid and absence of moisture decreased the bond strength of the resin-cement (RelyU200), regardless of the storage period.

Comparative wellbore integrity evaluation across a complex of oil and gas fields within the Michigan Basin and implications for CO2storage

AbstractWellbore integrity is a fundamental aspect of site characterization and selection for storage in areas with existing or abandoned oil and gas wells. The condition of well cement, installed casing strings, and plugs determine if a well can sustain optimal hydrostatic pressures and prevent fluid migration. This is a necessary but underappreciated aspect of assessing potential storage sites when optimal and sustainable pressure conditions are critical for success. To apply the systematic wellbore integrity evaluation to realistic CO2storage conditions, seven fields in the Michigan Basin were selected which were actively being used for CO2injection for enhanced oil recovery. Data on wellbore construction were collected for wells on and surrounding the reefs and were evaluated to determine the overall condition of boreholes in the study area using EPA guidelines and industry standards. Available cement bond logs were also reviewed to assess the quantity and quality of cement in the wells. The majority of the wells in the study area were shallow and did not penetrate the confining layers, thus, posing little to no risk. Most of the deep wells demonstrated sufficient plugs and cement quality that meet the desired standards. Some wells have missing or incomplete records and inadequate cement and/or plugs making them candidates for further evaluation, should large‐scale CO2storage be considered in the area. The results of the study show that readily available well records and cement bond logs can be used to efficiently evaluate and characterize CO2storage study sites for overall wellbore integrity. © 2016 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Ceramic Inlays: Effect of Mechanical Cycling and Ceramic Type on Restoration-dentin Bond Strength

This study aimed to evaluate the bond strength between dentin and five different ceramic inlays in permanent maxillary premolars, with and without mechanical cycling. One hundred permanent maxillary premolars were prepared and divided into 10 groups (n=10) according to the ceramic system (IPS e.Max Press; IPS e.Max CAD; Vita PM9; Vita Mark II; and Vita VM7) and the mechanical cycling factor (with and without [100 N, 2 Hz, 1.2×10(6) cycles]). The inlays were adhesively cemented, and all of the specimens were cut into microbars (1×1 mm, nontrimming method), which were tested under microtensile loading. The failure mode was classified and contact angle, roughness, and microtopographic analyses were performed on each ceramic surface. The mechanical cycling had a significant effect (p=0.0087) on the bond strength between dentin and IPS e.max Press. The Vita Mark II group had the highest bond strength values under both conditions, with mechanical cycling (9.7±1.8 MPa) and without (8.2±1.9 MPa), while IPS e.Max CAD had the lowest values (2.6±1.6 and 2.2±1.4, respectively). The adhesive failure mode at the ceramic/cement interface was the most frequent. Vita Mark II showed the highest value of average roughness. IPS e.max Press and Vita Mark II ceramics presented the lowest contact angles. In conclusion, the composition and manufacturing process of ceramics seem to have an influence on the ceramic surface and resin cement bond strength. Mechanical cycling did not cause significant degradation on the dentin and ceramic bond strength under the configuration used.

Decomposing full-waveform borehole acoustic data with application to data from a North Sea well

The objective of this study is to establish whether sonic data acquired in a cased hole can be used to estimate the material behind a second casing when the annulus between the two sets of casings is fluid filled. We have analyzed full-waveform data acquired using the Schlumberger tool Sonic Scanner for a double casing with a fluid between them, and where the outer annulus, outside the outer casing, might be cement filled or fluid filled. The sonic tool uses a cylindrical array of 104 omnidirectional receivers. The cylindrical array — approximately 4 in. in diameter and 1.8 m (6 ft) long — allows a formal decomposition of the acquired data into quasi-plane waves. Analyzing these plane waves, we have identified subtle but distinct changes in the waveforms. These changes appear to be dependent on the material filling the outer annulus, allowing for the determination of the fill material. The most significant changes relate to the propagating Stoneley waves. The identifications made are confirmed by cement bond log (CBL) analysis done on the exposed outer pipe after pulling the inner pipe. In one instance, for single-casing logging and a clean top-of-cement, like with conventional CBL analysis, we were able to confidently and accurately identify the cement/fluid boundary. In another instance, we were able to identify it as a nondistinct/smooth transition zone. For double-casing logging, we could confidently and accurately identify the cement/fluid boundary behind the second casing. For one case, we have substantiated that this zone has a longer interval of smooth transition from cement to consolidated/unconsolidated barite to a fluid-filled annulus.