Maintenance, Reliability and Condition Monitoring
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Comprehensive sensitivity analysis on static and dynamic reservoir parameters impacting near wellbore injectivity during CO2 sequestration
Get PDFCarbon capture and storage (CCS) is proved to be effective measure for reducing CO2 emissions. whilst the world still highly depends on the use of fossil fuel energy, this method is necessary for reaching the world’s 1.5 °C goal. In CCS, CO2 is hindered from entering the atmosphere by capturing it from sources of emission and storing it in geological formation. Saline aquifers among all possible underground formations are most common targeted ones for CO2 storage due to their frequent presence, and large storage capacity. However, this storage option suffers from sufficient well injectivity to inject large volumes of CO2 at acceptable rates through a minimum number of wells. The injectivity impairment / reinforcement happens through mineral dissolution, fine particle movement, salt precipitation and hydrate formation (known so far). Each of these mechanisms will be more dominant in injectivity alteration at different distance from the injection point depending on reservoir pressure and temperature, formation water salinity, rock mineralogy, and flow rate of CO2 injection as well as its dryness. Incorporating all the finding into radial flow near wellbore will help gaining insight into the resultant of injectivity changes over time and distant from injection point. In this study we have chosen Eclipse 300 together with an open-source code to investigate the impact of formation characteristics, CO2 -Brine-Rock interaction, pressure, temperature as well as injection rate on injectivity alteration. The goal for this work is to provide a workflow which can help predicting injectivity alteration using the existing tools. Simulation results show that the high homogenous horizontal permeability in combination with vertical flow baffles in the formation (among all other parameters) has positive impact on storage capacity by increasing residual trapping. However, permeability is affected severely by salt precipitation during CO2 injection. Combined static and dynamic parameter study demonstrate that the injection rate plays a crucial role in size and expansion of CO2 plume as well as growth rate of dry out zone length, amount of salt precipitation and length of equilibrium region. The higher the injection rate, the quicker activation of the capillary and gravity force which leads to drag more brine to near well-bore resulting in higher volume fraction of salt precipitation. However, low injection rate could result in smaller CO2 plume, shorter dry out zone and longer equilibrium region in term of distance from injection point
New CO2 and Hydrogen storage site marketing: How to make your storage site unique and attractive?
Get PDFToday we met the situation, when our knowledge and expertise are far away from marketing – an ability to sell our knowledge to the end-user (public, policymakers, governments, and small and big enterprises). This study aimed to attract stakeholders by proposing new techno-ecological synergy concept of geological storage of CO2 (CGS) and hydrogen (UHS) in a cost-competitive, self-supporting storage site. The “story of success” of the offshore geological structure E6 in Latvia has started from an invisible point on the European map, oil-bearing but not very promising geological structure to the unique and one of the best cost-competitive, self-supporting, conceptual techno-ecological examples of a possible synergy of storage concepts with renewables energies. Using detailed petrophysical, mineralogical and geochemical analyses of the Cambrian Series 3 Deimena Formation reservoir sandstones in this structure, the CO2 storage capacity was estimated with different levels of reliability from a conservative 158 Mt (106-252 Mt) up to an average optimistic average of 396 Mt (264-631 Mt). The theoretical CO2 storage capacity in the oil-bearing limestones of the Upper Ordovician Saldus Formation was estimated at the end of the Enhanced Oil Recovery cycle using the CO2 (CO2-EOR) as an average of 110 Mt (65-144 Mt). The E6 structure was estimated as the most prospective and the largest for CO2 geological storage in the Baltic Region with a total average CO2 storage capacity of about 500 Mt. Time-lapse numerical seismic modelling was applied to analyze the feasibility of CO2 storage monitoring in the E6. The novelty of this approach was the coupling of the chemically induced petrophysical alteration effect of CO2-hosting rocks, measured in the laboratory during the CO2 injection-like experiment, with time-lapse numerical seismic modelling. According to changes in the amplitude and two-way travel times in the presence of CO2, reflection seismic could detect CO2 injected into the deep aquifer formations even with low CO2 saturation values. Our results showed the effectiveness of the implemented time-lapse rock physics and seismic methods in the monitoring of the CO2 plume evolution and migration in the E6. The new concept of techno-ecological synergy of the CCUS project with different eco-friendly renewable energy recovery technologies, which support circular economy targets, is presented. The concept of the CCUS project includes six innovative elements of techno-ecological synergy: (1) CGS, (2) Geothermal energy recovery during CO2 geological storage (CPG), (3) CO2-EOR, (4) underground hydrogen storage (UHS), (5) solar energy and (6) wind energy recovery. This concept should maximise efficiency, minimize the carbon footprint of the full-chain CCUS process and demonstrate the “winx” situation (where “x” is a number of additional benefits of the project). We demonstrated an example of the project supporting also a win5 global situation (that is, a win-win scenario with a minimum of five potential global outcomes): greenhouse gas emissions (GHGE) reduction, (2) economic profitability, (3) increased CO2 storage capacity, (4) public acceptance and (5) retargeting of oil and gas businesses. Small wind offshore floating plant installed around the rig and solar panels covering free surfaces of the rig and a compact geothermal plant using CO2 (20 times smaller than a conventional plant) will produce renewable energy added to the project electricity net to cover the energy needs of the project. The excess energy will be used by compact hydrogen production plant established directly on the rig. The produced hydrogen could be stored underground and when needed, transported by ship to the port. For the first time, we estimated hydrogen storage capacity in the E6-B, the smaller compartment of the E6 offshore structure as 30 Kt. This scenario is a basis for the new concept of CO2 and hydrogen storage site marketing: how to retarget fossil fuel business (the depleted oil and gas fields) into the storage-targeted and renewable energy business, permitted to achieve the carbon-free energy transition using principles of circular economy and sustainable use of resources and environment
Vibration characteristics of axial compressor blade under complex loads
Get PDFIn this study, 3D models of a compressor blade for an aero engine with three different levels of surface accuracy (with 4, 6 and 10 section profiles) were obtained via reverse engineering by fitting point-cloud data. Then, finite element and flow-field models of the blade were established and validated. The vibration characteristics of the blade under typical operating conditions were analyzed by considering the interaction between the aerodynamic load by airflow and the centrifugal load by blade rotating. The results showed that, under complex centrifugal and aerodynamic loads, the three blade models differed significantly in their high-order dynamic frequencies, and the modal frequencies that were dominated by a torsional mode of vibration were sensitive to the aerodynamic load. Hence, considering both the aerodynamic excitation and the centrifugal load increased the accuracy of the numerical computation of the blade vibration characteristics. Moreover, a comparison of the computational results from the three blade models showed that models B6 and B10 differed only insignificantly, and B6 decreased the complexity of the modeling process while satisfying the required computational accuracy. Thus, model B6 is the best option for engineering analysis and computation
Design optimization and feasibility analysis of pneumatic DTH Hammer with self-rotation bit
Get PDFThis paper presents a novel pneumatic Down-The-Hole (DTH) hammer with self-rotation bit used for rock drilling, and the mechanical structure and working principle are mainly covered. A unique mechanism with ratchet and pawl incorporated in pneumatic DTH hammer is proposed for percussion-rotation drilling to break rock. The drill bit can rotate while the drill pipe stays still because of the structure design and reduces the friction between the drill pipe and borehole. Firstly, the rationality of mechanical invention is verified via the finite-element software ANSYS and the numerical simulation of impact dynamics. Moreover, the energy transfer regulation is revealed in the impact process under differential final impact velocity, which can help practical experience in mechanical design. Finally, based on the experimental study on the novel hammer, we found that its function can satisfy the requirement, as well as overall performance, was improved
Tests of selected anti-vibration gloves available on the Polish market
Get PDFThe authors of the paper conducted tests of anti-vibration gloves available on the market (17 types) in accordance with the methodology of the EN ISO 10819: 2013 standard. The main purpose of these studies was to verify the data provided by manufacturers in product specifications and user manuals. Based on the determined values of the vibration transmissibility coefficients, it was found that, despite the certificates held by all the tested gloves, as many as 6 types do not meet the minimum requirements for anti-vibration gloves, and two types achieve properties on the verge of meeting these requirements. Two types of gloves (despite the certificate) did not show any significant vibration damping in the whole tested frequency range. The obtained test results indicate the need to verify the anti-vibration properties of the available certified gloves from unverified suppliers. It also seems necessary to assess the effectiveness of protection of anti-vibration gloves in the conditions of their actual use
Seismic response analysis of tunnel with cavity behind lining
Get PDFFor the seismic safety of tunnels with cavity behind lining, based on the finite element method, the viscoelastic artificial boundaries are introduced to study the influence of the location of cavity behind lining on the seismic response of tunnel structure under vertically incident SV wave. The analysis results show that the cavity behind the lining has a significant effect on the seismic response of tunnel structure, and the appearance of cavity behind lining will significantly change the dynamic characteristics of tunnel structure; when the incidence frequency of wave is close to the natural vibration frequency of tunnel structure, the lining stress has the largest amplification when the cavity appears behind the vault; Regardless of the cavity location, the maximum of lining stresses always appears at the arched foot, and the vault stress has the largest amplification; Under the Taft wave, the maximum stress 1.642 MPa of lining without cavity appears at the arched foot, and the minimum 0.118MPa at the arched waist, the stress amplification at the vault can reach about 760 %, which is unfavorable to tunnels. In addition, the soil property also has a great influence on the tunnel; the layered site will lead to the obvious change of the seismic wave, hence the geological data should be collected in detail in the seismic design of tunnel. Meanwhile it is proposed that the PE material can be filled back into the cavities behind the tunnel lining to reduce the earthquake damage of tunnels
Analysis of mechanical properties of steel-concrete joint of large-span hybrid beam bridge
Get PDFThe mechanical properties of the steel-concrete joint determine the mechanical properties of the whole bridge. The mechanical properties of the steel-concrete joint of Jianhua railway rigid-frame bridge are analyzed by using nonlinear finite element method. The results show that the overall stiffness transition of the joint is smooth, the maximum stress of concrete section and steel box girder section are lower than the design value of the strength, which indicates that the structural stiffness and strength of the steel-concrete joint section meets the requirements. The error range of the finite element analysis results and the measured data is within 6 %, which shows that the finite element method can simulate the actual stress state of the bridge and it could save a lot of time and energy compared to the actual test
Simulative analysis on large local deformation features of single-shell and double-shell cylinders subjected to underwater explosion
Get PDFSimulative studies on a series of the cylinders subjected to underwater explosion were presented using coupled acoustic-structural analysis in ABAQUS in order to analyze the large local deformation feature and the influence of the outer water tank. The results revealed that large inward local deformation occurs on the front side of the cylinder, and the plastic hinge locates near the boundary of the spherical projection of the explosion to the cylinder with an approximate elliptic type. The inner water and the outer shell’s thickness of double-shell cylinders have great influence on the large local deformation feature of the inner shell, and with the increase of the outer shell’s thickness, large local inward deformation occurs on the back side of the cylinder, which is caused by the local jet effect of the inner water. The research can provide reference to the design and assessment of underwater anti-explosion structures
Parametric studies on SEA parameters for coupled plates made of composite laminate
Get PDFStatistical Energy Analysis (SEA) has been used to compute velocity responses and Coupling Loss Factors (CLF) for two composite laminates joined in a 'L' junction configuration. Two case studies were carried on SEA. The effect of fibre orientation on SEA parameters was studied. The effects of internal damping were also determined. The computation of SEA parameters has been done using classical wave approach and Finite Element Method using Nastran/Patran. CLF determined using classical wave approach is independent of fibre orientation and internal damping factor. This study using FEM reveals that the SEA parameters vary in comparison with classical wave approach as fibre orientation and internal damping are also considered in the analysis. Also, by classical wave approach, the CLF varied linearly with the increase in frequency while there was some scatter in CLF determined by finite element method
Multi-objective structural optimization of honeycomb cells
Get PDFThis paper develops an optimum cell structure design method considering the in-plane tensile/compression and shear properties to improve the stiffness and strength of the honeycomb core. The equivalent elastic modulus in the X or Y direction and shear modulus in the XY plane are derived using Energy Method for hexagonal, quadrilateral and concave hexagonal cells, and are compared with the results in the related literatures. The multi-objective optimization model in which the vertical wall length, wall thickness and inner angle of the cell are taken as design variables is solved by Genetic Algorithm to maximize the equivalent elastic moduli. The static and dynamic characteristics of the honeycomb cores with original and optimized cells are studied using Finite Element Method. The results show that after the cell optimization, the maximum displacement, stress and strain obviously decrease, thus improving the structural performance of the honeycomb core. The research provides significant guidance for the design of the cell structure