Manometric Research Articles

Correlates and Comparability of Two Devices for Measuring Bite Force in Dentate Health Volunteers.

This study aimed to correlate the bite/occlusal force measurements obtained through two methods: a hydraulic pressure gauge with a biting transducer (GM-10), and a computer-assisted device that records occlusal force on a pressure-sensitive film (Prescale II). Healthy, dentate volunteers were recruited. Participants' demographic data included age, sex, number of teeth present, presence of oral pain, history of prior orthodontic treatment and presence of parafunction. Bite/occlusal force measurements were recorded for each participant using the GM-10 and the Prescale II devices. Linear Mixed-effect model regression was performed with the significance set at p < 0.05. Forty-six volunteers (women = 25, men = 21; mean-age = 30.9 ± 9.3 years) participated. 54.3% and 34.8% presented with 28 and 29-32 teeth, respectively. 60.9% and 26.1% of the participants reported previous orthodontic treatment and oral parafunction. The overall mean GM-10 measurements recorded were 333.0 ± 192, 276 ± 167, 208 ± 134, 142 ± 103 Newtons, for the 2nd and 1st molars, 2nd and 1st premolars, respectively. GM-10 measurements were associated with the tooth position (p < 0.001) and the number of teeth (p < 0.001). The mean Prescale II measurements obtained with and without filter were 826 ± 594 and 1049 ± 595 Newtons, respectively, which were positively correlated with the occlusal contact area (r = 0.765; p < 0.001) and GM-10 (r = 0.245; p = 0.019). The regression analysis for dependent repeated data confirmed the significant effect of the GM-10 measurements (bite force) and the occlusal contact area on the Prescale II measurements. Within the limitations of this study, it can be concluded that the correlation between bite force measurements carried out by GM-10 and Dental Prescale II was low and may not be considered interchangeable methods. The maximum bite force measured in isolated point contacts was a predictive factor of the occlusal force distributed over the entire arch. Further studies are warranted to explore this influence in the clinical implications of these findings.

Harnessing electromagnetic data for tsunami source estimation: a comprehensive review.

Ocean-bottom pressure gauges are widely used for tsunami observations due to their established accuracy and stability. Recent advancements reveal that the magnetic field fluctuates when a large tsunami passes over the ocean, suggesting potential alternatives to pressure gauges in the form of ocean-bottom electromagnetometers (OBEMs). This article offers a comprehensive synthesis of recent findings concerning tsunami magnetic fields and their utility in tsunami source estimation. In addition, we scrutinize the effectiveness of tsunami observations employing OBEMs. Despite the promise of electromagnetometers, it is worth noting that the background noise inherent in electromagnetic observations tends to be approximately 10 times greater than that of pressure observations within the critical tsunami frequency bands. The Earth's magnetic field sporadically disrupts tsunami magnetic fields, presenting a potential limitation to the utility of electromagnetometers in tsunami detection when compared with pressure gauges. Nevertheless, our investigation underscores the potential of electromagnetic observations in detecting tsunamis propagating over the ocean at magnitudes of a few centimetres. An invaluable advantage of electromagnetometers over pressure monitoring lies in their capability to observe tsunami velocity fields, suggesting a promising avenue for further research and development in tsunami observation technology.This article is part of the theme issue 'Magnetometric remote sensing of Earth and planetary oceans'.

Prediction of an enigmatic tsunami in October 2023 at Kii Peninsula, Japan

On October 8, 2023, a tsunami was observed along the Pacific coast of Japan, but its cause was complicated. We applied tsunami data assimilation, a forecast method that does not consider the source, to predict coastal tsunami waveforms in the Kii Peninsula. We assimilated offshore observations recorded by pressure gauges (DONET) and reconstructed the wavefield before the tsunami arrived at the coast. The waveforms at Kumano, Kushimoto, and Shirahama were accurately forecasted at least 20 min before the tsunami arrival, indicating that data assimilation is applicable for tsunami early warning. Quantitative analysis showed that the score and accuracy index generally increased since 21:00 (UTC). Meanwhile, we investigated the tsunami decay process for tsunami warning cancellation by analysing the moving root mean squared (MRMS) amplitude. As data assimilation progressed, the prediction of tsunami later phase became increasingly accurate, and the errors between observed and predicted MRMS amplitudes decreased. Overall, the tsunami later phase was satisfactorily predicted at approximately 22:00 at coastal tide gauges. Hence, data assimilation approach contributes to a comprehensive tsunami early warning process, from the issuance to cancellation.

Numerical investigation of pressure measurement by pitot tubes in microscale Taylor–Couette flow with hyper-rotate speed and its correction

As the most classic method in fluid mechanics, pitot tubes have been widely employed to capture gauge pressure. Their effective operation is based on the premise that the measured fluid is ideal, irrotational, and incompressible, and the pitot tubes do not interfere with the measured flow field. However, in microscale Taylor–Couette flow with hyperrotation speed originating from power-to-weight ratio rotating machinery, its correction has never been investigated systematically for the case, in which the scale of the pitot tubes is much larger than the clearance. In this study, the feasibility of using pitot tubes in the measurement of pressure in a microscale Taylor–Couette flow with hyperrotation speed and its correction was considered. First, physical insight into the influence of pitot tubes on shear flow under the scale effect was obtained. The presence of the pitot tubes had less impact on the mean flow field of the shearing flow. In contrast, the sudden expansion induced by the pitot tubes caused additional instability in the shearing flow through the recirculation zone near the connection area. The influence of pitot tubes on the turbulence of the shearing flow is not confined to a local area but extends across the entire clearance between the stator and rotator. Second, the pressure in the clearance cannot fully permeate the cavity where the monitor is located. Therefore, the gauge pressure captured by the pitot tubes is underpredicted in high-pressure while overpredicted in low-pressure regions. The maximum deviation appears near the minimum clearance height. The deviation in the pressure captured by the pitot tubes increases with an increase in the depth and diameter of the pitot tubes, and the influence of the recirculation zone becomes notable. As the clearance height increases, the ratio of the scale in the pitot tubes to the clearance height decreases, degrading the deviation of the pressure captured by the pitot tubes. Within the parametric range studied, the deviation maximum in pressure captured by the pitot tubes is up to 18.5%. Moreover, the pressure captured by the pitot tubes was corrected. The coefficient α, related to the rotational Reynolds number, clearance height, and depth and diameter of the pitot tubes, was deduced. The correction in this study had improved the distribution of pressure, which shows a better agreement.

Combined Raman spectroscopy and electrical transport measurements in ultra-high vacuum down to 3.7 K

An instrument for the simultaneous characterization of thin films by Raman spectroscopy and electronic transport down to 3.7 K has been designed and built. This setup allows for the in situ preparation of air-sensitive samples, their spectroscopic characterization by Raman spectroscopy with different laser lines and five-probe electronic transport measurements using sample plates with prefabricated contacts. The lowest temperatures that can be achieved on the sample are directly proven by measuring the superconducting transition of a niobium film. The temperature-dependent Raman shift and narrowing of the silicon F2g Raman line are shown. This experimental system is specially designed for in situ functionalization and optical spectroscopic and electron transport investigation of thin films. It allows for easy on-the-fly change of samples without the need to warm up the cryomanipulator.

Accuracy assessment of recent global ocean tide models in coastal waters of the European North West Shelf

The accuracy of global ocean tide models is assessed in coastal waters of the European North West Shelf to ascertain where higher resolution local (forecast) models are most needed for geophysical and navigational applications, and which global models are most suitable for providing boundary conditions for regional and local tide models. Five recent global ocean tide models (FES2014b, EOT20, TPXO9-atlas-v5, GOT4.10c, and DTU16) are considered, with the models first compared by interpolating them onto common grids and computing the mean absolute deviation at each grid point. Coastline tide gauge and offshore bottom pressure sensor data were collated from several sources to give a total of 279 observation sites for evaluating model accuracy, including observational values from 137 locations that have not previously been released and have therefore not been assimilated into any of the global models tested. The residual errors between each model’s predicted phasor and the corresponding observed phasor were calculated at each observation location, and quantified using the root mean square (RMS) and median absolute residual (MAR) for the eight tidal constituents M2, S2, N2, O1, K1, K2, P1, and Q1. To avoid RMS values being biased by observation point density, a Voronoi-weighted RMS based on the water area of the Voronoi polygon about each observation location was also developed and used. Four zones were defined based on ocean depth to gauge model performance, and model inaccuracy is again demonstrated in near-shore regions. Seven further zones were defined based on geographical areas, which reveals inhomogeneity among the global models. The smallest overall root sum square (RSS) RMS error across all eight constituents arises with FES2014b, although TPXO9-atlas-v5 has the best performance when using the MAR and Voronoi-weighted RMS metrics. Using only the 137 observation sites that have not been assimilated by any model and therefore provide an independent accuracy assessment, FES2014b exhibits the smallest errors at the coastline, with an RSS RMS of 24.46 cm. All models exhibit larger errors with the 137 independent observation sites than with all 279 observation sites, with an average overall increase in RSS RMS error of 12%, and an increase of 30% for coastline tide gauges, highlighting the need for local model development in these areas.

Gulf of Mexico Case Study Highlights Smart-Completion Application

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 218794, “Multifaceted Smart Completion Application: A Gulf of Mexico Case Study,” by Jeffrey P. Manning, Ben J. Carter, SPE, and Leila Bannister, Occidental Petroleum, et al. The paper has not been peer reviewed. _ Reservoir heterogeneity, stacked pay systems, reservoir compartmentalization, and high temperature and pressure are common challenges seen in Gulf of Mexico (GOM) fields. The use of conventional completion design in vertical wells with commingled production from multiple zones has led to multiple operational challenges. In the complete paper, the authors explore the use of intelligent completions in deepwater GOM as a solution. Benefits of Intelligent Completions Intelligent completions allow collection, transmission, and validation of real-time, high-frequency data. This enables analysis of completion, production, and reservoir data while selected reservoir zones are controlled and monitored remotely in real time. Intelligent completions such as multiphase flowmeters, bottomhole pressure gauges, and cased-hole logging tools enable real-time data gathering and monitoring. Additionally, downhole flow-control systems, pinpoint stimulation, intelligent injection, and multizonal isolation technology are examples of intelligent completions that enable production optimization. This study concentrates on the application of downhole intelligent choke systems in wells that use radio frequency identification technology. Combining this technology with smart sensors or Global Positioning System technology enables sensor data to be transmitted wirelessly. Operations such as opening and closing of valves, indexing and release mechanisms, and a variety of other functions can be implemented using this technology. Multiple tools can be run at the same time without compromising the tool’s internal diameter. Each tool has a unique address; therefore, tags can be coded with data that identifies an individual tool to be actuated. Intelligent completions can be broadly categorized into the following: - Downhole flow-control systems: These are passive or active control systems to control flow from each zone. They are remotely controlled by hydraulic lines from the surface facility. - Permanent downhole sensors: These are discrete or distributed systems that monitor downhole parameters. - Permanent downhole chemical injection: These systems allow for treatment at different points in the wellbore and flowlines to prevent issues caused by corrosion, hydrates, asphaltenes, paraffin, and scaling. Case Study: Practical Use of Intelligent Completions in the GOM The operated field in the northern GOM has successfully used intelligent completions in multiple vertical producing wells to help significantly reduce operating costs associated with topsides water processing, mitigate the risk of sand production, and allow for better subsurface understanding using individual zone-flow tests (this synopsis concentrates on the first two of these three aspects). Intelligent completions enabled these operations without the use of an intervention vessel.

An innovative patternable microelectrode bonding technology for high-performance and cost-effective sealing in microfluidic chips

Microfluidic chips pose as an interdisciplinary frontier as they integrate various fields, while typically serving as a novel technological platform for precise manipulation of minute liquid volumes and biological analysis. However, the chase for enhanced bonding quality in order to fabricate these chips correctly, has led to the use of increasingly complex technology, limiting the marketability of microfluidic products. In this work, a novel microelectrode bonding technology is proposed, which addresses the demands for reliable, low-cost, and high-throughput bonding. The proposed process utilizes the Joule heating effect of microelectrodes at low voltages, in order to rapidly generate sufficient heat and allow for the successful bonding of the chip. The material used for the microelectrodes is nickel, and the method chosen for their fabrication is small-batch electrodeposition. The microelectrodes and microchannels morphology are characterized by Extended Depth of Field Microscopy, while the quality of heating produced is assessed by a high-speed infrared camera. The finalized bonding strength is characterized by measuring the microchannel burst pressure, using an apparatus comprising of a syringe pump, a precision pressure gauge, and a connecting tubing. The results prove that this is a rapid polymer bonding method, which uses less than 3 Volts. Additionally, the results underscore the process’s effectiveness, yielding chips with burst strengths over 2.9 MPa, while microchannel deformations are kept under 10 %. Finally, the advantages of the technology are discussed and its limitations are eliminated by further conceptualization. The proposed method uses no chemicals or contaminants, nor complex equipment, rendering it simple, green, and sustainable. This paves the way for the development of new efficient and greener paradigms, aiming towards leading engineering and manufacturing to a sustainable future.

Development of new gas analytical technique for infrared spectroscopy combined with differential pressure measurements.

A new gas analytical technique for infrared laser spectroscopy combined with differential pressure measurement (IR-DP) is developed. The basic idea of this technique is that the absorption process of molecules by laser irradiation is monitored as the pressure enhancement in a gas cell by use of a differential pressure gauge. The system is composed of a tunable IR laser system, sample cell, differential pressure gauge, and data accumulation system. Using this system, the measurements of the IR absorption spectra for cyclohexane (50 ppm) and ammonia (100 ppm) are demonstrated. By comparison of the current IR-DP spectra with conventional Fourier-transform infrared spectra, the spectral resolution is found to be about 3cm-1, reflecting the laser resolution. Furthermore, the estimated pressure enhancement based on a simple model is consistent with the experimental results. These results suggest that the newly developed IR-DP technique is one of a powerful tool for trace gas detection.

Numerical and Experimental Validation of a New Methodology for the Design of Michel-Banki Turbine

Michell-Banki cross-flow turbines (MBT) are low-cost turbines that are easy to manufacture and maintain, which makes them ideal for implementation in small-scale hydroelectric projects. Although the MBT has lower efficiencies than turbines such as the Pelton and Francis, it maintains its efficiency stable in the face of fluctuations in flow conditions. The objective of this study is to validate, both numerically and experimentally, a new design methodology that allows the construction of an MBT based on site conditions. For this purpose, the design of the different components of an MBT was implemented according to the site conditions. The experimentation was carried out in a hydraulic test bench, which consists of a water tank, a centrifugal pump, a piping system, a PMAG SGM LEKTRA magnetic flow meter, a TRS605 FUTEK torque sensor, a pressure gauge, and a model of MBT designed and manufactured from scratch. It was concluded that the proposed methodology allows for obtaining experimental and numerical efficiencies of and, respectively. Thus, a numerical-experimental validation of the MBT design and manufacturing methodology could be carried out.

Performance of ITER pressure gauges during deuterium operation in the large helical device

Abstract During deuterium campaigns on the heliotron large helical device (LHD), ITER pressure gauges with different cathode materials were used to measure the neutral pressure in the sub-divertor region. Throughout these campaigns, it was observed that the performance of the LaB6 cathodes was unsatisfactory, credited to the generation of neutrons impacting the gauges. Conversely, measurements taken with pressure gauges with a ZrC cathode performed well throughout the deuterium pulses. The ITER pressure gauge with the ZrC cathode could be operated with a very high electron current of 800 µA, thus improving the lower detection limit of the neutral pressure in LHD. With this design it was also possible to avoid jumps in the ion current within strong magnetic fields, improving the accuracy of the measurement from 15% uncertainty to 5%. These features allowed very precise neutral pressure measurements to be made in a fusion device with magnetic confinement. The total running time in the magnetic field was around 60 hours, less than the cathode life time of 350 hours.

Formation and development of the stopping vortex ring in starting jets

The formation mechanism for the stopping vortex ring (SVR) and its effects on the development of starting jets have been systematically investigated. The radial inward flow near the nozzle exit, arising from the pressure difference caused by the deceleration of starting jets, is considered to be the main contributing factor to the formation of the SVR. The formation process can generally be divided into (i) the rapid accumulation stage ( $t_d^*\leq 1$ ) and (ii) the development stage ( $t_d^*&gt;1$ ), where $t_d^*$ is the formation time defined by the duration of the deceleration stage. For starting jets with different $(L/D)_d$ , the final circulation value and circulation growth rate of the SVR can be scaled by $[(L/D)_d]^{-0.5}$ and $[(L/D)_d]^{-1.5}$ , respectively. Here $(L/D)_d$ represents the stroke ratio during the deceleration stage. Analysing the temporal evolution of fluid parcels in the vicinity of the nozzle exit reveals that SVR entrains fluid from both inside and outside of the nozzle. Additionally, the influence of the SVR on the leading vortex ring and the trailing jet has been examined, with particular attention to its effects on the propulsive performance of the starting jet. The SVR affects the profiles of axial velocity and gauge pressure at the nozzle exit, thereby enhancing the generation of total thrust during the deceleration stage. Analysis has shown that depending on the deceleration rate, SVR can enhance the average velocity thrust by at least $10\,\%$ and compensate for up to a $60\,\%$ reduction in pressure thrust due to deceleration.

Localization of hidden leaks in water supply networks by hydraulic methods

AbstractThe hydraulic gradient method is an effective approach for localizing hidden leaks in water supply networks. Relative errors in leakage location depend significantly on head measurement errors, necessitating the use of high-precision pressure gauges with an accuracy class of 0.25 or better. An optimization function, defined as the ratio of the localization relative error to the probability of detection, was used to determine the optimal location for the control section. Dependencies of localization relative error on the pressure gauge accuracy class, section length, and piezometric head are obtained. Presented multi-leakage estimation model enables the assessment of the multi-leakage probability, enhancing decision-making efficiency for emergency repairs in water supply networks.

Calibration experiments for dual-comb IPDA XCO2 measurements using a variable pressure absorption cell

Measuring XCO2, the column-averaged dry-air mixing ratio of CO2 in the atmosphere, is essential for monitoring climate change and guiding mitigation efforts. Integrated Path Differential Absorption (IPDA) is a highly effective XCO2 measurement solution for space-borne lidar. However, the limited number of wavelengths limits its capabilities. IPDA, enhanced with Electro-Optical Frequency Comb (EOFC) technology, offers a robust solution. This study validates IPDA measurements using both asymmetric and symmetric Electro-Optic Dual-Comb Spectroscopy (EO-DCS) systems at 1572 nm. This indoor experimental system does not operate in a true lidar mode, but focuses on IPDA measurements of XCO2 through a transmission-style cell. We achieved atmospheric spectral transmittance by a variable pressure CO2 absorption cell, correlating pressures from 425 to 470 mb to XCO2 of 386.81–447.08 ppm. The XCO2 measurements of asymmetric/symmetric systems both exhibit excellent linearity. Their linear fittings yielded the Root Mean Square Error (RMSE) as low as 0.198/0.064 ppm, and the Mean Absolute Percentage Errors (MAPE) was as low as 0.0386%/0.0140%. This level of measurement performance has never been demonstrated in other works. Accuracy was assessed by comparing IPDA results with a pressure gauge, and precision was confirmed through repetitive measurements (1000 times over 10 min) and Allan variance analysis. Notably, our system operates effectively without frequency stabilization, showing tolerance to laser frequency drift—a significant advantage for IPDA applications. The entire experiment was conducted in a comparison between asymmetric and symmetric systems, especially in the analysis of absorption line residuals. We discuss the error transfer from phase to spectral transmittance and its implications and explained why the residuals in the asymmetric system were larger. These results underscore the superior performance of EO-DCS IPDA in measuring XCO2 and its promising potential for applications. To our knowledge, this is the only DCS IPDA calibration demonstration to date.

A Passive-Source Ocean-Bottom Seismic Experiment in the South China Sea: Evaluations of Data Quality and Instrument Performance

Abstract This study presents a passive-source ocean-bottom seismograph (OBS) experiment conducted in the southwest subbasin of the South China Sea (SCS) aimed at exploring the geodynamic processes shaping this short-lived oceanic basin. The successful deployment and recovery of 24 passive-source OBS units, including 14 I-7C types and 10 Pankun OBS units, resulted in the acquisition of one of the most extensive passive-source seismic data sets ever recorded in the SCS. We provide comprehensive details of the experiment, with a focus on evaluating the data quality and performance of the Pankun OBS units. This evaluation includes assessments of horizontal orientation determination, leveling system effectiveness, timing accuracy, and ambient noise spectrum. In addition, we compared the waveforms recorded by the Pankun OBS units with those from land stations and I-7C units, as well as the noise spectra between Pankun and global OBSs using the same seismometer. Although these comparisons suggest that the Pankun OBS achieves satisfactory performance, we identified a few inadequacies with this new instrument, such as issues with the differential pressure gauge, clock shifts, and sensor package calibration.

Magnetic force microscopy: High quality-factor two-pass mode.

Magnetic force microscopy (MFM) is a well-established technique in scanning probe microscopy that allows for the imaging of magnetic samples with a spatial resolution of tens of nm and stray fields down to the mT range. The spatial resolution and field sensitivity can be significantly improved by measuring in vacuum conditions. This improvement originates from the higher quality-factor (Q-factor) of the cantilever's oscillation in vacuum compared to ambient conditions. However, while high Q-factors are desirable as they directly enhance the magnetic measurement signal, they pose a challenge when performing standard MFM two-pass (lift) mode measurements. At high Q-factors, amplitude-based topography measurements become impossible, and the MFM phase response behaves non-linearly. Here, we present a modified two-pass mode implementation in a vacuum atomic force microscope that addresses these issues. By controlling the Q-factor in the first pass and using a phase-locked loop technique in the second pass, high Q-factor measurements in vacuum are enabled. Measuring the cantilever's frequency shift instead of the phase shift eliminates the issue of emerging nonlinearities. The improvements in MFM signal-to-noise ratio are demonstrated using a nano-patterned magnetic sample. The elimination of non-linear responses is highlighted through measurements performed on a well-characterized multilayer reference sample. Finally, we discuss a technique that avoids topography-induced artifacts by following the average sample slope. The newly developed, sensitive, and distortion-free high quality-factor two-pass mode has the potential to be widely implemented in commercial setups, facilitating high-resolution MFM measurements and advancing studies of modern magnetic materials.

Inflation of a toroidal membrane within a fluid-filled elastic spherical enclosure

The present research investigates the growth based inflation model of an inflated toroidal membrane within a fluid-filled environment enclosed by an elastic spherical cavity. This problem statement resembles the growth of toroidal vesicle membranes within biological cells. The toroidal membrane is described by hyperelastic Mooney–Rivlin model with meridional anisotropy. The rise in internal gauge pressure of the torus causes the surrounding incompressible fluid to exert a distributed radial force on the surface of the elastic sphere, resulting in its deformation. With a subsequent gradual increase in gauge pressure, a contact is initiated as the torus indents onto the inner surface of the elastic sphere. The contact condition is assumed to be frictionless, and a variational formulation is adopted for solving the contact problem. The maximum indentation as well as the generated contact stress are found to be higher with a lesser stiffness of the elastic spherical enclosure. As the contact patch grows, the phenomenon of membrane thinning is predominantly observed at the inner equator of the torus. The growth of the contact boundary varies linearly with increasing torus gauge pressure, but non-linearly with the fluid pressure within the spherical enclosure.

A Data Assimilation-Based Method for Real-Time Monitoring and Estimation of Gas Influx Size and Distribution During Gas Migration in a Marine Drilling Riser

Effective well control is essential in marine drilling operations to prevent catastrophic blowouts that endanger human lives and cause severe environmental damage, including long-lasting impacts on marine ecosystems. Accurate real-time monitoring and management of well conditions after taking gas influxes are critical for maintaining safety and environmental protection during offshore drilling operations.When a gas influx becomes trapped in a closed marine drilling riser, its upward migration can result in excessively high surface pressure, presenting significant risks to offshore drilling and well control. Therefore, the accurate estimation of downhole gas influx size and distribution during gas migration events is crucial for effectively managing these situations. The complexities of wellbore two-phase flow and gas migration make direct measurements challenging, leading to potential inaccuracies in traditional modeling approaches. This study introduces a Data Assimilation (DA) technique, employing the Ensemble Kalman Filter (EnKF), to improve the real-time estimation of gas influx rates and distribution, thereby enhancing the accuracy of two-phase flow models in marine drilling.This research utilizes full-scale gas influx migration experiments conducted at Louisiana State University, where gas was injected from the bottom of an experimental well to simulate a riser gas event in a Water-based Mud (WBM) system. Key real-time measurements, including downhole pressure gauges at multiple depths and Distributed Acoustic Sensing (DAS) data, were employed to validate the estimated gas influx size and distribution within the riser using the EnKF. The overall gas influx distribution was captured through the real-time estimation of a dimensionless distribution index (DI), offering additional insights into the spatial characteristics of the migrating gas. Additionally, a Drift Flux Model (DFM) calibrated online through DA was used to predict flow parameters such as gas void fraction profiles within the riser during migration. The validation of these predictions demonstrated a strong correlation between the estimated and measured values.The outcomes of this study underscore the effectiveness of the proposed method in estimating parameters that are otherwise difficult to measure directly, thereby improving the predictive accuracy of gas influx behavior in marine drilling risers. This method offers significant practical value by enhancing real-time decision-making and risk management in marine drilling operations that involve gas migration, contributing to the broader goals of offshore drilling safety and marine environment protection.

Application of perforation pressure gauge in offshore ARP+TCP combined well testing

Abstract The Annulus Pressure Responsive (Hereinafter called ARP) + Tubing Conveyed Perforating (Hereinafter called TCP) combined test technology is widely used in the offshore exploration well. However, the perforation will produce a huge impact load instantaneously and pose a certain threat to the safety of the test column. Researchers usually use numerical simulation method to analyze the dynamic response and stress intensity of the column to achieve the purpose of optimizing it, but the numerical method usually requires a large number of parameters and is inconvenient to apply in the field operation. In this paper, combined with the real data measured by the perforation pressure gauge, a simple and useful prediction formula for the peak perforation pressure was established. The relative error between predicted and measured value was 2.83% and 13.92% respectively for verification by two example Wells. The rapid prediction of peak pressure provides theoretical guidance for optimizing and adjusting test string and perforation parameters and improving operation safety.

Experimental Study for Wave Overtopping Volume Estimation of Rubble-Mound Structure Using Pressure-Current Speed Relationship

In this study, a new method for wave overtopping measurement was proposed. The proposed method utilize the pressure-current speed relationship and the wave overtopping height. The relationship between pressure and current speed was studied using a flow channel, and the validity of the method for measuring wave overtopping was examined using a two-dimensional wave flume. After installing a pressure gauge in the current channel, the change in pressure according to the increase in current speed was measured, and the relationship between pressure and current speed was derived. The proposed method showed high accuracy when the incident angle was normal condition, and it was confirmed that the accuracy decreased somewhat as the incident angle increased. The reason that the accuracy is somewhat lower under oblique incidence conditions is because the sensitivity to pressure and current speed is high. In addition, when the amount of wave overtopping was large, the relative error increased, but the correlation coefficient between the measured and the estimated overtopping volume was relatively high. It was confirmed that the proposed method was possible as a method for wave overtopping measurement in the field.