Slickline Descaling Technology Delivers Cost Savings Over Coiled Tubing

Al-Khafji Joint Operations (KJO), a joint operation representing both Saudi and Kuwaiti energy interests in the divided zone, recently encountered obstructions in their offshore field. Routine pressure and temperature surveys revealed that an increasing number of wells were developing scale. The operation required an efficient mechanical tool to clean out extensive accumulated scale bridging within a vertical production string and restore full wellbore accessibility. The well had been previously shut down from operations for five years. The operator considered using a coiled tubing (CT) unit or workover rig to clear the scale but sought a more cost-effective solution. The operator chose a slickline wellbore cleanup and debris breaking tool, which is an impact-driven tool designed to break up scale deposits in a cost-effective, efficient manner. It is jarred down mechanically in the well, each jar applying a short-duration torque via the unique, helically split torque sub. The well's accessible tubing inner diameter was reduced from 2.9-in, nominal to 2-in, at the wireline reentry guide depth. To combat this issue, the slickline technology was deployed with subs increasing in outer diameter (OD) from 1.9-in. to 2.5-in. OD tools. The special features of the wellbore cleanup and debris breaking tool made it better adapted to the well environment and greatly increased the descaling efficiency. Thirty runs enabled the team to clear the scale accumulations down to 3,652 ft (1113 m). The operator confirmed integrity of the tubing at the end of the slickline operation, allowing the slickline team to access the wellbore and run a memory pressure temperature survey to check the well deliverability. The implementation of the wellbore cleanup and debris breaking tool enabled the operator to reduce inventory and overall descaling time. Microscopic and Fourier transform infrared analyses of the scale determined it was calcite (CaCO3) with some small hydrocarbon impurities from either oil or diesel. The descaling rate and cost savings achieved using the wellbore cleanup and debris breaking tool has since resulted in the operator adopting this technology and looking into the feasibility of starting a campaign for scale removal in more than 20 wells. The presence of calcite as a scaling agent is potentially due to the carbonate-saturated formation water and the loss of carbon dioxide from this water to the hydrocarbon phase as pressure decreases. Creating a detailed reservoir characterization that defines fracture orientation, relative aperture produced fluid analysis, and rock properties can help minimize the effect of scale at an early stage. Continuous well monitoring can lead to early identification of scale and determine the need for chemical treatment or further mechanical interventions. This case study demonstrates the benefits of using this wellbore cleanup and debris breaking tool as the first method of mechanical descaling.

Lifting Kit for Flooded Furnitures: Mechanical Design and Strength Analysis

<p>Almost every year, floods disaster becomes the scourge of many countries in the world, including Indonesia. When the flood comes and submerges the houses, every item and household furniture in it will also be submerged in flood water. Furniture that is heavy and difficult to move, especially electronic equipment such as refrigerators, may be left by the owner when a flood occurs. To prevent the furniture from submerging, a lifting kit is needed. For this reason, the purpose of this work is to design a mechanical tool/kit that can lift or elevate the electronic furniture such as refrigerator to a higher position and avoid the damage caused by flood. The kit is expected to be able to cover a 100 x 80 cm base of the refrigerator with maximum load of 200 kg. The elevation of the lifting kit is set to be higher than 50 cm. Calculation for the stress and fatigue analysis is also performed to determine the strength of the structure. As a result, the obtained safety factors for the critical components under static and fatigue loading conditions show values of more than one, indicating the product is safe for real operation. In addition, the required torque to produce the elevation is also calculated and discussed.</p>

Beyond Beauty. Byzantine steatite icon from Chełm. Archaeology, Petrography and Traceology

A fragmentarily preserved Byzantine icon made of steatite was discovered in 2015 during regular excavations in Chełm, eastern Poland. Identified as the left wing of a diptych illustrating the Twelve Great Feasts and created at the close of the 12th century, the find is one of the most important and beautiful Byzantine artefacts to have been found in Poland. The icon was uncovered within the confines of the palace complex which was created by Daniel (Danylo) Romanovych († 1264) in Chełm in the second quarter of 13th century. The icon, even though it was found within the borders of what is now Poland, is material evidence of contact between Byzantium and the social elite of the Galicia-Volhynia lands, rather than with the Polish Piasts. In this paper we concentrated on the presentation of the archaeological context of the find, which made it possible to establish that the icon arrived Chełm before the middle of the 13th century (terminus ante quem 1253), and especially on petrographic and traceological analyses of the icon. Assuming that greenish plaques were indeed the most characteristic steatite icon type, a decision was made to examine, apart from the Chełm artefact made from white rock, a greenish icon from the National Museum in Krakow as well. Petrographic analyses were based on optical microscopy, scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and X-ray powder diffraction (XRPD). Both icons were carved in steatite i. e. talc rich rock but their chemical compositions indicate the presence of other components. Artifact from Chełm is white. Porous, enriched in potassium (K) and locally blistering outer rim of the icon from Chełm was formed probably during the fire event. Presence of forsterite and subordinate amount of leucite also indicate high temperature influence. Local enrichment in calcium (Ca) is related to exchange reactions with ground compounds. Accumulation of different components on the surface of the icon’s surface was noted. The icon from the National Museum in Krakow is greenish probably because of the presence of chlorite. The results of the traceological analysis (icon from National Museum in Krakow was not analysed) indicate that the icon found in Chełm was created most likely by a skilled and experienced carver with access to the high-quality magnifying glass and specialist tools required for rendering minuscule objects and their details. The production of the icon also involved the use of a “mechanical” tool, probably a kind of a miller with a rotating polishing head, which also seems to point to a specialist workshop. The use-wear traces observed on artefact are limited to polish resulting from prolonged contact with human hands or storing the icon in a leather case. Most of the extant Byzantine icons are unprovenanced objects held in museum collections or church treasuries. Therefore, as the icon presented in this paper was discovered during archaeological excavations, it ranks among the few Byzantine artefacts to have been found outside of this realm. The petrographic and traceological analyses conducted are the first published natural science contributions to the study of Byzantine steatite icons and we hope they will provide the impetus for undertaking such research on other Byzantine finds, helping to develop Byzantine archaeology further.

Recovery of Conduction Following High-Power Short-Duration Ablation in Patients With Atrial Fibrillation: A Single-Center Experience

Background: Optimal duration of energy delivery in high-power short-duration (HPSD) ablation to create a durable lesion in atrial fibrillation (AF) is not clear yet. We evaluated the association of electrical reconnection with lesion duration in HPSD-ablation. Methods: HPSD ablation was defined as maximum temperature at 42°C and power delivery at 45 W for 10 to 15 seconds (5 seconds in coronary sinus [CS] and left atrial posterior wall [LAPW] near the esophagus). In some patients, a mechanical tool was used to deflect the esophagus away from the ablation site. Results: Consecutive 1749 patients with AF (left atrial appendage and CS isolation: 1451) receiving redo ablation after a prior HPSD procedure were included. At the HPSD ablation, mean duration of lesion was significantly shorter in the LAPW facing esophagus compared with elsewhere (5.2±1.5 versus 12.5±1.7 seconds, P <0.001). Application duration was reduced to <10 seconds in 1221 (84%) patients receiving left atrial appendage and CS isolation. At the redo, recovery of conduction was noted in the CS (592, 40.8%), left atrial appendage (493, 34%), and PV and LAPW (249, 14.2%). Of the 249 patients with LAPW reconnection, 91% (n=227) had the conduction recovered in the area facing the esophagus. In 73 patients, esophageal displacement device was used during the HPSD ablation. Average duration of lesions in LAPW among those 73 patients was 9.2±2 seconds. PV-LAPW reconnection was observed in 3/73 (4.1%) patients. Conclusions: HPSD ablation with lesion duration of <10 seconds was associated with conduction recovery in the left atrial appendage, CS, and the LAPW area facing esophagus.

Fundamentals of Density Functional Theory: Recent Developments, Challenges and Future Horizons

Density Functional Theory (DFT) is a powerful and commonly employed quantum mechanical tool for investigating various aspects of matter. The research in this field ranges from the development of novel analytical approaches focused on the design of precise exchange-correlation functionals to the use of this technique to predict the molecular and electronic configuration of atoms, molecules, complexes, and solids in both gas and solution phases. The history to DFT’s success is the quest for the exchange-correlation functional, which utilizes density to represent advanced many-body phenomena inside one element formalism. If a precise exchange-correlation functional is applied, it may correctly describe the quantum nature of matter. The estimated character of the exchange-correlation functional is the basis for DFT implementation success or failure. Hohenberg-Kohn established that every characteristic of a system in ground state is a unique functional of its density, laying the foundation for DFT, which is being utilized to explore the novelty of materials. This chapter is aimed to present an overview of DFT by explaining the theoretical background, commonly used approximations as well as their recent developments and challenges faced along-with new horizons.

Nut Unfastening by Robotic Surface Exploration

In this paper, we present a novel concept and primary investigations regarding automated unfastening of hexagonal nuts by means of surface exploration with a compliant robot. In contrast to the conventional industrial approaches that rely on custom-designed motorised tools and mechanical tool changers, we propose to use robot fingers to position, grasp and unfasten unknown random-sized hexagonal nuts, which are arbitrarily positioned in the robot’s task space. Inspired by how visually impaired people handle unknown objects, in this work, we use information observed from surface exploration to devise the unfastening strategy. It combines torque monitoring with active compliance for the robot fingers to smoothly explore the object’s surface. We implement a shape estimation technique combining scaled iterative closest point and hypotrochoid approximation to estimate the location as well as contour profile of the hexagonal nut so as to accurately position the gripper fingers. We demonstrate this work in the context of dismantling an electrically driven vehicle battery pack. The experiments are conducted using a seven degrees of freedom (DoF)–compliant robot fitted with a two-finger gripper to unfasten four different sized randomly positioned hexagonal nuts. The obtained results suggest an overall exploration and unfastening success rate of 95% over an average of ten trials for each nut.

Water Injection Pipeline Repair Offshore Angola Enhances Production

An international operating company detected a leak during an annual ROV inspection of a water injection (WI) pipeline offshore Angola in the Gulf of Guinea. The pipeline owner made the decision to repair the damaged line using clamps, but there were multiple challenges involved in executing the repair. First was the depth of the pipeline, which was on the seabed across an area that ranged from 1,170 m to 1,410 m (3,839 ft – 4,626 ft). Additional challenges included potential complications for clamp installation because of the location of the pipe welds and the physical condition of the pipe, which had experienced considerable wall thinning in multiple areas. Bringing the pipeline back into safe service required repairs to the aging pipe within a scope of work that included site preparation, the installation of two 12-in clamp connectors, and inspection services following clamp placement to verify proper installation. Because there were welds in the WI pipeline, there was a risk that the clamp installation site would correspond with an area of the pipe that was welded, which would impact the ability of the clamps to fit snugly over the damaged area. Survey data were cross-referenced with the client's data to determine that the weld locations would not interfere with the installation. Coating removal was critical, so a purpose-built mechanical tool was designed to prepare the pipeline for clamp installation. The project also required finite element analysis (FEA) to confirm that the pipeline could withstand the seal load applied by the repair clamps. The project was carried out in three steps. The objective of the first step was to prepare and stabilize the seabed to ensure it could bear the weight of the clamp installation frame and the impact of the ROV working nearby. The second phase focused on preparing the repair locations for installation of the clamps, a process that included coating removal and surface cleaning to return the WI pipeline to bare metal finish in the clamp areas. The third phase was the preparation and installation of the 12-in repair clamps. This included the inspection and spot cleaning of pipeline surfaces, clamp installation, and clamp seal verification. The two clamps were successfully installed and passed pressure testing in February 2020, enabling the operator to bring the WI line back online and functioning safely at reduced pressure. This repair employed the highest-pressure clamp of this type installed to date (138 bar / 2,000 psi).

The Development of Controlled Orientation of Fibres in SFRC

The article is focused on finding the possibility of the controlled orientation of fibres in fibre reinforced concrete constructions. This is because the controlled orientation of the fibres can contribute to the improvement of some properties of fibre reinforced concrete. The research is based on the experimental investigation of orientation control–rotation of fibres in a transparent matrix representing concrete replacement. From the conceptual model, the article continues with experimentation, data analysis and comparison of conclusions. During the experiment, a mechanical tool was developed and monitored to guide the fibres. The main monitored parameters of the levelling tool were the tips dimensions and the distance between them. The experiment results show the possibility of achieving a higher orientation of the fibres around one axis and suitable parameters of a mechanical tool.

Aperio: managing 3D scene occlusion using a mechanical tool analogy for visualizing multi-partmesh data.

This thesis presents a novel interaction model for browsing complex 3D scenes containing numerous layers of occluding and intertwining structures that often hide regions of interest. The interaction model is realized through the development of a custom visualization application, Aperio. Aperio provides a set of virtual mechanical "metal" tools, such as rods, rings, "cookie" cutters and a knife, that support real-time, interactive exploration. Cutter tools are designed to create easily-understood cutaway views (or context-preserving ribbon slices) and rings and rods provide simple path constraints that support rigid transformations of models via "sliding", providing interactive exploded-view capabilities. All tools are based on a single underlying superquadric formulation and can ―"iteratively" be picked up and replanted to generate various views. A multi-pass, GPU-based capping algorithm provides real-time "solid cuts" rendering of surface meshes. We also present a user study to provide supporting evidence of Aperio‘s interaction simplicity and effectiveness for occlusion management.