Geologically, the systematic study of the Baku archipelago began in the 1950s of the last century. At the end of 1957, seismic exploration work and drilling of exploration wells in the structure and separate structures began here. The objective of the proposed method is the trouble-free production of a sealed and mechanically load-bearing cement bridge. The task is achieved by the fact that in the method of installing cement bridges in wells, which includes pumping cement mortar through drill pipes or tubing pipes between two cement plugs under control through a device of the UKZTS type, a flat-rubber plug is fixed to the lower end of the cement bridge, and above, cement slurry is pumped, transported through pipes centered in the installation interval of the cement bridge using all-rubber cementing plugs with an internal hydrodynamic hole. Centering drill pipes or tubing in the interval of the cement bridge provides a more complete displacement of the drilling fluid by cement and, thus, improves the tightness and the ability to withstand the mechanical loads of the cement bridge. At present, absorption zones are usually isolated using cement slurries –cement, cement-bentonite and other solutions, metakaolin and qipan-cement pastes, etc. However, these solutions have insufficiently high efficiency, especially in the elimination of catastrophic absorptions, which are determined by the low initial viscosity of the mixtures, due to the pumping conditions. In the presence of absorbing channels of small opening, cement-bentonite solutions should be used with a ratio of cement and bentonite 2:1 or 3:1 and, if necessary, with the introduction of setting accelerators and a polymer. The density of cements and clay powders must be determined in the laboratory for each batch separately. Depending on the grade of clay powder, in the fourth phase and while being at the upper mark of the installed cement bridge, the pipe suspension is flushed with drilling fluid. Attaching a rubber plug to the lower end of the cement bridge provides a sealed and mechanically load-bearing cement bridge. The application of the method gives an economic effect, because it eliminates the re-installation of cement bridges due to the receipt of a poor-quality (leaky and unable to withstand mechanical stress) cement bridge, as well as due to the prevention of possible accidents and complications when using cementing plugs with a metal rod.

Cement bridging is a fundamental technique in wellbore integrity management, widely used in the pet¬ro¬leum industry for well abandonment, zonal isolation, and pressure control. This method involves pla¬cing a cement slurry at a specific depth within the wellbore, where it hardens to form a solid barrier that prevents fluid migration, stabilizes formations, and ensures well integrity. Leading oil and gas operators, implement this technique in both offshore and onshore operations to enhance safety, efficiency, and compliance with industry regulations. Different cementing methods, including the Balanced Plug Method, Stage Cementing, Reverse Circulation Cementing, and High-Pressure Cementing, are employed based on well conditions and operational requirements. These methods help maintain pressure control, prevent cross-contamination between hydrocarbon and water-bearing zones, and provide a foundation for future well modifications. Verification techniques such as pressure testing and tagging ensure the structural integrity of the cement bridge after placement. Advancements in cement formulations and placement technologies continue to improve the effectiveness and reliability of cement bridges, making them a crucial element in modern petroleum engineering. Their strategic application minimizes envi¬ron¬mental risks, ensures regulatory compliance, and optimizes well performance, particularly in challenging deepwater and high-pressure reservoirs. Understanding and applying cement bridging techniques effec¬tively remains essential for maintaining safe and sustainable oil and gas operations. Keywords: cement bridging, wellbore integrity, well abandonment, zonal isolation, pressure control, cement slurry, solid barrier, fluid migration, formation stability.

Investigation of the field aging behavior and gradient characteristics of asphalt pavement of cement bridge deck

Abstract The Qiandao Lake water diversion project can greatly improve the water use problem of Hangzhou citizens. The site selection of the underground passage has been investigated by MT sounding method in this project. In this paper, the type of suspected anomaly filling (air, mineral water, sediment) found under cement bridge is studied by using the adaptive finite element algorithm with continuous change of conductivity. The results show that this method can identify the type of filling material in underground caves well, and can roughly understand the volume proportion of water in caves.

Quantitative assessment of cement bridges and voids in cement-stabilized permeable base materials using a mask R-CNN-based CT image segmentation strategy

Insights into Mechanical Behavior and Damage Characteristics of Permeable Cement-Stabilized Aggregate Base Materials Via a Novel Constitutive Model of Cement Bridges

While drilling from a vertical shaft the orientation of the diverter is carried out with the help of a magnetometer, leaving an interval of 18 m from the casing. The length of the milled interval could be reduced if a gyroscopic compass is used to orient the BHA. The open borehole section is covered with a strong cement sheath. To avoid magnetic interference, the bridge is drilled down to a depth of 6 m above the bottom of the open interval. A disadvantage of the full casing section milling method is an increased requirement on the strength of the cement bridge for drilling, and the difficulty in finding the head of the lower casing section if it needs to be drilled through after the sidetrack. In many cases, the mechanical drilling rate is limited by the conditions for removing cuttings, and for a horizontal section, the problem of removing cuttings becomes even more complicated. The design of modern milling tools is meant to produce small swarf that does not form clusters and is easily removed from the hole. During milling, it is preferable to flush the well with polymer drilling muds rather than clay muds. Hydrocarbon-based muds are not recommended for milling at all. An alternative to milling the entire casing cross-section is to make windows in the casing. This requires the installation of an oriented whipstock and the milling of the window in several stages. After a whipstock is positioned in the required direction, the stud connecting it with a milling machine of the first stage is cut off. On this basis, the paper proposes a method of sidetracking.

A two-surface contact model for DEM and its application to model fatigue crack growth in cemented materials

The hydration mechanism between the leaching agent and ore surface during the leaching process of ionic rare earth ore is complicated, and the inter-particle bridge cementation is prone to fracture due to the existence of multiple forces and dispersion during ion adsorption and exchange, resulting in migration and rearrangement of microfine particles, and precipitation at the pore throat, producing blockage phenomenon and affecting the leaching efficiency of ionic rare earths. In order to reveal the migration law of microfine particles during in situ leaching of ionic rare earth ores and to find suitable regulation methods, this paper investigates the effects of leaching agent mass concentration, viscosity, flow rate, hydraulic gradient, ore body height, and ore body water content on the migration of microfine particles. We compared ionic rare earth ores as raw ores and rare earth ores with particle sizes ranging from 0.075 to 0.09 mm using the laboratory column leaching method. The results showed that the migration of microfine particles during ionic rare earth ore leaching was an important factor affecting leaching efficiency. Under the action of external forces, the microfine particles tended to migrate with the leaching agent during the leaching process.

Introduction. Forecasting the intrusion of formation waters into the reservoir determines the time of watering wells and, therefore, is necessary for planning and implementing measures to limit water inflows. The study of the geological structure of gas and gas condensate deposits during the development of oil and gas condensate fields makes it possible to identify the main causes of the occurrence and development of water cut in well production. The forecast is based on the study of the ways of breakthrough of bottom and contour water from the aquifer. Also, in the process of hydrochemical control, it was determined that water breakthrough occurs due to the rise of the GWC and the violation of the tightness of the annulus [1, 2]. Materials and research methods. On the basis of field studies, it was shown that the depression funnel in the current period of development in the Aptian-Cenomanian aquifer complex was formed as a result of the exploitation of gas deposits in the Urengoyskaya and Yen-Yakhinskaya areas [3, 4]. According to the methodology of I.P. Cholovsky, the entropy of reservoirs was determined by dissection as a measure of heterogeneity in the interval of opening a productive reservoir. As a result of the analysis, the mechanism of well watering in the area of distribution of the factors of net-to-grossness and heterogeneity was revealed [5–7]. It has been determined that the intensity of water intrusion largely depends on the porosity and permeability properties (PRP) of the rocks of the deposit and the watershed. Therefore, the rate of GWC rise and the change in saturation are associated with the features of the lithological and tectonic structure of the section within individual sections of the deposit of operating production wells [8, 9]. Research results and their discussion. Most of the wells in operation at the Urengoyskoye field have a minimum porosity factor of 24%, and the net-to-gross ratio of the reservoirs in the formation interval is at least 85%. The analysis of the geological structure during the development of gas deposits in the Urengoyskaya and Yen-Yakhinskaya areas made it possible to determine the causes of the occurrence and development of water cut in well production. It is based on the study of the ways in which formation waters enter the well from the aquifer. Irregularity in thickness and area, as well as significant sandiness of clay layers causes a close hydrodynamic relationship of the layers. Therefore, the weighted average values of the analyzed parameters can be taken as the boundary conditions for predicting watering and putting the well into operation after carrying out measures to limit water flow. To predict the success of waterproofing work, an analysis of the geological factors of sand content and heterogeneity along the section was also carried out. As a measure of heterogeneity in the perforation interval, the entropy of reservoirs was determined by stratification. According to the chemical analysis of samples taken from the wells, geophysical studies of the current position of the GWC and the results of measures to limit the inflow of water (WRI), the boundaries of the sectors were determined. Conclusions. Forecasting well watering at this stage of development of gas deposits in the Far North fields is very relevant, as it necessitates the formulation and solution of the problem of production and treatment of natural gas with a high content of formation water in well production. Based on the results of the analysis of the reasons for the downtime of the well stock, taking into account the geological structure, the location of clay interlayers and the permeability of productive horizons, it is recommended to carry out geological and technical measures (GTO) on the wells. Thus, for wells with sufficiently thick shale interlayers up to 5.0 meters, it is necessary to carry out (MOW) by installing cement bridges in the zone of shale interlayers. It is also recommended to re-perforate and then re-inject the water-proofing composition with additional cement in wells with clay interlayers of a small thickness of more than one meter with alternating productive interlayers of small thickness.

A long way of development of cementing technology providing the advancement of backfill materials, the methods of preparation, chemical treatment and transportation of plugging material into the borehole annulus of the well did not solve all the problems of the quality isolation of formations. There are neither justified physical criteria nor accurate methods of estimation of supporting quality, as it is quite troublesome to set well conditions while conducting experimental works towards specifying the large number of the factors simultaneously affecting the longevity of well support. In this regard, there is no generally accepted method of testing backfill materials and the issue of necessary sustainability of stone from various bakfill materials designed for cementing of columns and setting cement bridges is not solved as well. Leading drilling service companies (Schlumberger, Halliburton etc.) of the world do not use special cement types and instead, prepare their own mixture for each cementing process on the basis of cement of selected for these oil-gas fields. As a result of mixing various types of weighting agents and other additives with base cement, a backfill system necessary for specified well is obtained. These systems are produced on specially equipped facilities in the world. The researches carried out justify that it is possible to obtain high quality simplified and weighted cement slurries on the basis of domestic raw materials with state-of-the-art technologies and equipment.

The long road of development of cementing technology, which ensured the development of cement compositions, methods of preparation, chemical treatment and transportation of binder material into the annular space of the well, did not solve all the problems of high-quality isolation of the layers. A reasonable physical criterion and exact methods for assessing the quality of fastening have not been found either as it is very difficult to reproduce downhole conditions during experimental work in order to establish a large number of simultaneously acting factors on the durability of the borehole lining. In this regard, there is no generally accepted method for testing cementing materials in the world and the issue of the necessary strength of stone from various cementing materials intended for cementing columns and installing cement bridges has not been resolved. The world's leading drilling service companies (Schlumberger, Halliburton, etc.) do not use special cements such as UCG, OCG, etc., but prepare their mixture specifically for each cementing process, based on one base cement selected for these oil and gas fields. Various types of weighting agents, lighteners and other mixing additives with the base cement provide the well-specific grouting system. All over the world, these systems are being prepared at specially equipped bases. The conducted studies give grounds to assert that high-quality normal, lightweight and weighted cement mortars can be obtained on the basis of local raw materials, provided that modern technology and equipment are available.

"Cement Bridge Over Troubled Incus" Technique in Patients With Oval Window Atresia and Anomalous Incus: A Preliminary Report.

Cement is made by milling clinker with a mix of grinded gypsum. The clinker is produced using a rotary kiln which burns a mixture of limestone, clay, magnesium, silica, and iron with desired atomic percentages. The quarry is the primary source of raw material for the rotary kiln in cement production. The consistency of material feed chemistry, in which the quarry plays a key role, is crucial for optimizing the performance of a rotary kiln. The quarry implemented a six-step methodology that comprised a modified 3D mining software modeling tool, a database computer loop prediction tools, and other tools to improve mining sequencing, optimize raw material usage, and provide consistent chemistry mix material for the kiln. By using overburden as a raw material in the mix, the quarry nearly universally reduces the environmental impact of squandering unwanted material in the quarry. This has a significant environmental impact since it requires less space to manage the overburden waste generated during mining. In addition, raw material usage was optimized for clinker production causing a reduction of 4% in sand usage as raw material, reduction in raw material purchase cost, reducing the variability of kiln feed chemistry, and producing high-quality clinker. The standard deviation of kiln feed LSF was improved by 45 percent, and the variability in kiln feed was reduced by 65 percent.

Analysis of alkali leaching mechanism on as-built cement concrete bridge deck pavement

Introduction: The available knowledge about Covid-19 mandate applying set of strict preventive measures for medical and dental professions. Dental health personnel are considered among high risk occupation group during the pandemic. Objective: This study aimed to assess the level of adherence to the preventive measures against the coronavirus disease and infection control among prosthodontists and general dentists in Tripoli, Libya. Methods: A questionnaire consisting of 8 questions was distributed among dentists who are working in private clinics or public health centers during Covid-19 pandemic, in Tripoli. Dentists were selected randomly to participate in this survey. Results: This study included a total of 70 dentists forming a response rate of about 87,5% (70 dentists participated out of 80 dentists), a total of 19 were prosthodontists and 51 were general dentists. The results showed that only 32% had attended lectures regarding COVID-19. The percentage of dentists who wear PPE during fixing post insertion complete denture complains and during fixing high spots before final cown/ bridge cementation were (60%, and 61.4%) respectively. During dental treatment, all dentists reported they do keep frequent hand hygiene by using ABHR or water and soap, (72.8%) ask their patients for pre procedural mouth rinse before starting the treatment, (62.8%) stated that they use rubber dam during aerosol generating procedures.. Conclusions: Libyan dentists in this study showed practicing of moderate infection control procedures to minimize transmission of Covid-19, limited comprehension of what constitutes as emergency dental procedures was recognized. Dentists are required for attending awareness days and workshops in this respect. Keywords: COVID-19, Dentists, Preventive measures, Infection control.

Geological conditions (presence of highly porous, fractured and cavernous rocks in the section) and technological parameters have a significant impact on the occurrence of various complications during well construction. The most frequent complications, which are recorded in almost all oil and gas provinces, include absorption of flushing fluid (circulating drilling fluid). In the process of uncovering the rocks composing the section, their equilibrium is disturbed. As you know, the stability of rocks depends on their strength characteristics, change over time under the influence of various factors: tectonic movements, secondary processes (leaching, dolomitization, calcification), opening of mine workings. Geoecological risks arise in the presence of fractured, cavernous and highly porous formations in the geological section, zones of tectonic fracturing, faults and traps (Eastern Siberia). These risks are expressed in absorption of flushing fluid used during construction of wells; rock falls, water and oil and gas occurrences, open fountains. Scientific novelty. In order to prevent these complications it is necessary to correctly select recipe of used flushing fluids, their treatment with different chemical reagents. Among technological factors causing geological risks one may mention high density of circulating and cementing solutions, speed of their pumping, rheological properties, lowering-raising operations, violation of technological mode and others. Conclusions . Absorption elimination is carried out by colmatation of complication intervals with solid particles (colmatants), special inert fillers, plugging mixtures, reduction of solution density, installation of cement bridges, which do not always give positive results.

Allergic Reaction to Zirconia Ceramic Bridge Cementation Using a Dental Adhesive Resin Cement: a Case Report

Beachrocks are sedimentary structures where gravelly or sandy beaches have been transformed into rock outcrops formed through precipitation of connective cements amid their interstices. They are well-noted coastal features along the coastal belt of Sri Lanka due to the prevalent tropical climate. This study was aimed at gathering data on surface nature and cementation characteristics of beachrock occurrences along a part of Sri Lankan shoreline through field observations and a series of analyses including X-ray diffraction, X-ray fluorescence, scanning electron microscopy (SEM) techniques and petrographic thin-section analysis. The combined research findings from different techniques are also employed as a preliminary step to determine the formation mechanism of the studied beachrocks. The seaward-inclined low-angle beds running parallel to present shoreline are composed mostly of sandstone with occasional conglomerate. Almost all the beachrocks are made of quartz grains amalgamated by cement. One remarkable feature of Sri Lankan beachrocks is the presence of heavy minerals generally in thin lamina form. The cementing agents are predominantly composed of metastable carbonate phases, high magnesium calcite (HMC) and aragonite (Ar) with varying microfabrics and textures. From SEM examinations and thin-section images, main morphologies identified are acicular Ar, scalenohedral magnesium calcites along with bridge cements and micritic coatings which are typical of a marine-phreatic precipitation with the exception of occasional meniscus cements. Further, the presence of evidences of living organisms may be an indication of influence from the biological aspects which can be confirmed by more detailed analyses.

This paper describes a minimally invasive technique of percutaneous intervertebral bridging cementoplasty (PIBC) to augment the fractured vertebrae and immobilize the intervertebral space with endplate-disc complex injury simultaneously. Thirty-two patients with adjacent multilevel osteoporotic thoracolumbar fractures (AMOTLFs) and vertebral endplate-disc complex injury (EDCI) treated by PIBC were retrospectively reviewed. The PIBC technique was a combination of puncture, balloon expansion and bridging cementoplasty. The clinical and radiological assessments were reviewed. The operation time was 82.8 ± 32.5 min, and blood loss was 76.9 ± 31.7 mL. A cement bridge was connected between the two fractured vertebrae across the injured intervertebral space. VAS at three time points including pre-operation, post-operation 1 day and final follow-up was 6.9 ± 0.9, 2.9 ± 0.8 and 1.7 ± 0.8, respectively; ODI at three time points was (71.1 ± 7.8)%, (18.4 ± 5.7)%, and (10.3 ± 5.7)%, respectively; Cobb angle at three time points was 46.0° ± 10.4°, 25.9° ± 8.5°, and 27.5° ± 7.1°, respectively. Compared with pre-operation, VAS, ODI and Cobb angle were significantly improved at post-operation 1 day and final follow-up (P < 0.05). Clinical asymptomatic cement leakage was observed in thirteen patients. No vessel or neurological injury was observed. PIBC may be an alternative way of treatment for AMOTLFs with EDCI. The technique is a minimally invasive surgery to augment the fractured vertebrae and immobilize the injured intervertebral space simultaneously.