Leakage Events Research Articles

Numerical Investigation of Wellbore Methane Leakage From a Dual‐Porosity Reservoir and Subsequent Transport in Groundwater

AbstractThree‐dimensional, multiphase simulations are used to analyze migration of methane leakage from a hydrocarbon wellbore. The objective is to evaluate the relevance and importance of coupling fast, advective transport of methane through fractures with slower, diffusive transport in the shale matrix below a freshwater aquifer on water quality assuming dual‐domain mass transfer (DDMT) in the reservoir by using the multiple interacting continua (MINC) as implemented in TOUGH2. The conceptual model includes a methane gas‐phase leak from a wellbore 20–30 m below an aquifer; multiphase, buoyant transport through shale partially saturated with brine; and, after methane leakage reaches groundwater, multiphase transport under varying lateral groundwater flow gradients. Results suggest that DDMT affects the rate of methane reaching groundwater by (i) providing long‐time secondary storage in less‐mobile pore space and (ii) creating larger methane‐plume diameters than those predicted by a single‐domain advection‐diffusion equation. Compared to models without DDMT, these factors combine to increase methane flow rates by an order of magnitude across the base of the aquifer 100 years after leakage begins. In the simulated aquifer, dissolution of gas‐phase plumes leads to bimodal aqueous‐phase methane breakthrough curves in a simulated water well 100 m downstream from leakage, with peak concentrations appearing decades after a 1‐year pulse of leakage. The major implication is that DDMT in the reservoir can explain newly discovered methane concentrations in water wells attributable to older leakage events. Therefore, remediation of abandoned or legacy wells with wellbore integrity loss may be necessary to prevent future incidents of groundwater contamination.

Corporate Data Sharing, Leakage, and Supervision Mechanism Research

Data sharing helps to make full use of each other’s data and enable the digital economy. With the gradual rise of corporate data sharing, the frequent occurrence of data leakage events highlights the dilemma of data sharing, leakage and supervision, which infringes on the data assets of the leaked party. Our paper aims to design an effective data supervision mechanism and achieve the stability of data sharing alliance. Therefore, this paper considers the data technology capabilities of both parties of the data sharing alliance and the benefits and loss of data leakage, establishes the game model and supervision mechanism of data sharing, leakage and supervision under the condition of complete information, and analyzes the game equilibrium and the influence of different supervision levels on the company’s data sharing and leakage behavior. The results show that the company sharing and leaking behavior is affected by both the level of data supervision fines and the relative technical level. Our model can make up for the weakness of the low-tech company, control the company’s choice of leaking behaviors, and ensure the stability of data sharing alliance by designing reasonable data supervision mechanism, especially the severe data supervision strategy.

IoT-based LPG Gas Leakage Detection and Prevention System

LPG (Liquefied petroleum gas) is a form of natural gas which has been liquefied under extreme pressure and then contained in a metal cylinder. It is very sensitive to fire and can cause a great disaster if it's exposed to any fire source without precaution. LPG is more available than any other natural gas so most people choose LPG for their needs like cooking and other needs. So the event of gas leakage or blast occurring by leaked gas is frequently seen and heard. In this paper, a device has been introduced to prevent any possible accident from happening. It is called Smart Gas and Fire detector. The device can detect any spillage of gas and fire very quickly and send a response via gsm tool directly to the user very fast and a buzzer is set up to alert. The device also has another feature with an exhaust fan which will be activated in case of gas leakage and fire detected, to reduce the density of gas by pushing the air outside. The device is designed to detect gas and fire as quickly as possible. Its performance is the same in case of closed and open both types of room.

Influence of Duration of CO <sub>2</sub> Leakage on the Increment of CO <sub>2</sub> Concentration in the Sea

Some studies showed that CO2 continues to leak out to the sea for a long time in the event of CO2 leakage at offshore CO2 storage sites. These results make us wonder whether CO2 concentration in the sea continues to increase until CO2 leakage stops. To elucidate this, a numerical simulation was conducted for the area off Tomakomai, Japan. In the simulation, 4 passive tracers regarded as leaked CO2 in the dissolved form began to be released every 3 months, at 1st May, 1st August, 1st November and 1st February, respectively, at a constant rate. The concentration of the second, third, and fourth tracers became almost the same as that of the first one within at most 10 days at the release grid point. It is implied that tracer concentration is influenced by the season (or stratification/destratification) rather than the duration of the release. The concentration was high in summer and low in winter. Conversion of the concentration to increment of partial pressure of CO2 revealed that anomalous pCO2, which may imply CO2 leakage, is much harder to detect in winter than in summer. The model results showed that all CO2 leakage at 50,000 tonnes/year could not be detected in winter while CO2 leakage at 10,000 tonnes/year could be surely detected in summer in an area within about 400 m from the leakage point.

Experimental investigation of fiber Bragg grating hoop strain sensor–based method for sudden leakage monitoring of gas pipeline

Pipeline, serving as one of the most important gas transportation methods, can cause serious consequences in the event of leakage, so leakage monitoring is particularly important. In our previous study, a fiber Bragg grating hoop strain sensor was developed to detect pipeline leakage by measuring circumferential strain, and this sensor was utilized in a liquid pipeline leakage test to verify its performance. In this article, we established a full-scale gas pipeline model and investigated the performance of this fiber Bragg grating hoop strain sensor in leakage monitoring. On the basis of circumferential strain variation characteristic before and after negative pressure wave arrival at a fiber Bragg grating hoop strain sensor, a linear fitting algorithm combined with threshold detection was proposed to capture the knee point of circumferential strain. Test results illustrated that the proposed approach has good performance in knee point detection, and fiber Bragg grating hoop strain sensor is suitable for gas pipeline leakage monitoring.

Membrane-Disrupting Molecules as Therapeutic Agents: A Cautionary Note.

Mechanistic studies have shown that aggregates of a common membrane disrupting molecule, Triton X-100, destroy the integrity of cholesterol-rich phospholipid bilayers via a catastrophic rupture process. In sharp contrast, attack on such membranes by monomers of Triton X-100 destroys their integrity through mild leakage events. This discovery of duplicity in the destruction of membrane integrity by a membrane-disrupting molecule has led to the design of derivatives of Amphotericin B that exhibit a lower tendency to aggregate and antifungal and hemolytic activities that are well-separated. An animal study with one such derivative has shown that its efficacy is similar to that of Amphotericin B but with substantially reduced toxicity. A related in vitro study of a series of derivatives of l-phenylalanine has revealed that monomers possess significant antibacterial activity, while aggregates of these same molecules exhibit hemolytic as well as antibacterial activity. Taken together, these experimental findings point to the need for paying special attention to differences in the selectivity between monomeric and aggregated forms of membrane-disrupting molecules as therapeutic agents, where monomers are expected to be the more selective species. Whether improving the selectivity of antimicrobial peptides and other antimicrobial agents is also possible by reducing their tendency to aggregate, and whether membrane-disrupting molecules can be created that exploit differences in the lipid composition between coronaviruses and mammalian cells, are two important questions that remain to be answered.

Microcontroller Based Monitoring and Controlling of LPG Leaks Using Internet of Things

This paper aims to monitor LPG gas leakage continuously at home or in industry. In the event of gas leakage, this information will be updated via IoT communication to the web browser. The user can continuously monitor the data using IoT. The gas sensor that can detect LPG gas is called the MQ06 sensor. IoT, the LPG leak detection system in Arduino senses LPG gas using a LPG gas sensor. This project implements LPG gas sensor interfacing with Arduino. The signal is sent to the Arduino microcontroller from this sensor. A LED, buzzer and IOT module (ESP8266) are connecting the microcontroller. The design for the IoT LPG leak detector implemented using the ESP8266 chip. This Wi-Fi module is designed to connect microcontrollers to a Wi-Fi network and to connect to TCP / IP and send data. Emotion data is then sent to the IoT. The IoT module sends data to the web. The detector is switched on when a gas leak is detected and a “leak” message is displayed on the site. LPG leak detection system based on IoT and Arduino can be installed in homes, hotels and storage areas of LPG cylinder. The main benefits of this project are that it is possible to determine the leakage and to send the data to a website to monitor it and to take corrective measures. When adequate action is taken quickly after reporting on the IoT, it can help save lives and property losses.

Research on Underground Pipeline Fault Monitoring Method Based on Big Data

Distributed optical fiber sensors can sensitively sense local temperature changes caused by leakage at any position of the pipeline, but massive monitoring data has significant spatio-temporal non-stationary characteristics, and it is difficult to directly diagnose leakage based on the monitoring data. Under the framework of statistical pattern recognition, a spatio-temporal big data analysis method based on sliding window outlier analysis is proposed. Only the internal characteristics of distributed temperature monitoring data can be used to realize the intelligent identification of pipeline leakage, and the sliding is determined. The value method of window length and abnormal state diagnosis window length, and the physical simulation of prototype insulation steel pipe leakage monitoring was carried out. The results show that when the pipeline is intact, this method will not cause false alarms. Once the pipeline leaks, the method can quickly identify the pipeline leakage event and accurately locate the leak location.

LoRa Sensor Network Development for Air Quality Monitoring or Detecting Gas Leakage Events.

During the few last years, indoor and outdoor Air Quality Monitoring (AQM) has gained a lot of interest among the scientific community due to its direct relation with human health. The Internet of Things (IoT) and, especially, Wireless Sensor Networks (WSN) have given rise to the development of wireless AQM portable systems. This paper presents the development of a LoRa (short for long-range) based sensor network for AQM and gas leakage events detection. The combination of both a commercial gas sensor and a resistance measurement channel for graphene chemoresistive sensors allows both the calculation of an Air Quality Index based on the concentration of reducing species such as volatile organic compounds (VOCs) and CO, and it also makes possible the detection of NO2, which is an important air pollutant. The graphene sensor tested with the LoRa nodes developed allows the detection of NO2 pollution in just 5 min as well as enables monitoring sudden changes in the background level of this pollutant in the atmosphere. The capability of the system of detecting both reducing and oxidizing pollutant agents, alongside its low-cost, low-power, and real-time monitoring features, makes this a solution suitable to be used in wireless AQM and early warning systems.

Aitac: an identity-based traceable anonymous communication model

In the big data background, data privacy becomes more and more important when data leakage and other security events occur more frequently. As one of the key means of privacy protection, anonymous communication attracts large attention. Aiming at the problems such as low efficiency of message forwarding, high communication delay and abusing of anonymity, this paper presents an identity-based traceable anonymous communication model by adding a preprocessing phase, modifying the ciphertext structure and increasing the controllability of anonymity. Firstly, a new identity-based signature algorithm is proposed, and its security is proved via existential unforgeability against chosen-message attacks (EU-CMA). The signature algorithm is further applied to the anonymous communication model to implement the controllability of revocable anonymity. Secondly, by adding a preprocessing Setup phase, the operations of identifications distribution and user authentication are launched before the anonymous communication phase starts, and this practice significantly improves the efficiency of the anonymous communication model. Finally, by adding the hash value of the message and the user identification as the message authentication code, we design a new ciphertext structure, which can efficiently guarantee the integrity of the ciphertext. Performance analysis and simulation results show that the proposed anonymous communication model has high message forwarding efficiency and better security and controllability of anonymity.

Chemical pleurodesis with Viscum album L. extract for secondary spontaneous pneumothorax in elderly patients.

BackgroundSecondary spontaneous pneumothorax is generally managed by surgery, if pneumothorax was not improved following chest tube insertion or in the event of persistent air leakage lasting more than 5 days. However, if surgery is not an option, chemical pleurodesis with sclerosants can be performed. Several sclerosants have been used in the chemical pleurodesis of secondary spontaneous pneumothorax, However, there is still controversy for what is the ideal sclerosant for Secondary spontaneous pneumothorax. The use of Viscum album L. for chemical pleurodesis in patients with secondary spontaneous pneumothorax aged >65 years has not been described to date, despite its extensive use. The authors tried to find out the effect of Viscum album L. for sclerosant for Secondary spontaneous pneumothorax in elder.MethodsThis retrospective analysis examined 25 patients (aged >65 years) with secondary spontaneous pneumothorax with persistent air leakage who underwent chemical pleurodesis with Abnova Viscum-F® (V. album L.).ResultsThe duration of chest tube drainage was 5.08 days after chemical pleurodesis. Adverse effects related to chemical pleurodesis with Abnova Viscum-F® were fever (7/25), pain (4/25), leukocytosis (10/25), and dyspnea with desaturation (7/25); however all the patients recovered without sequela and were subsequently discharged.ConclusionsThe present study demonstrated the successful use of chemical pleurodesis with V. album L. in the management of elderly patients with secondary spontaneous pneumothorax. Because of the high probability of dyspnea with desaturation in the elderly, caution must be exercised.

Four Way Safety Valve Tester Design for Heavy Vehicle Brake Systems

In our country, tractors are required to undergo a periodic physical ex-amination every three years after the first three years, cars and motorcy-cles every two years after the first three years, and heavy and light com-mercial vehicles every year after the first one. In the physical examina-tions of vehicles, vehicle description, lighting system, brake system, steering system, superstructure, etc. many systems and parts are checked. Although the vehicles use braking systems of various types and different technologies, the main purpose is to provide safe, slow driving and stop-ping of vehicles in traffic. Air braking systems are used in vehicles with heavy loads carrying cargo and passengers. In the event of any leakage that may occur in the brake system during the cruise, the part called Four-way Safety Valve is used in order to eliminate the possibility of the air tanks emptying and the vehicle to be left without brakes. Its task is to prevent the parking brake, front axle and rear axle brakes from being stored in separate air tanks and preventing the leak line from affecting solid lines in the event of an air leak. Air brake system Four-way safety valve test is carried out during the physical examination of vehicles. In this study, it is aimed to automate the manual safety valve test using a microcontroller card, solenoid valve, pressure transmitter and PC soft-ware. Thanks to the test device and software to be developed, it will be ensured to eliminate non-ergonomic movements performed by the tech-nician during the test, increase the reliability of the test and eliminate the environmental polluting elements during the test.

An X-ray ray tracing simulation code for mono- and polycapillaries: Description, advances and application

Polycapillary optics, consisting of bundles of narrow hollow glass channels, are regularly used in the field of (micro-)X-ray fluorescence (XRF) spectroscopy to focus X-rays down to a microscopic spot while increasing the flux density of the beam on the sample. Polycapillaries guide X-ray photons through multiple total reflection events, similar to how light is guided within optic fibers. Although the use of polycapillaries in XRF spectroscopy allows for fairly straightforward qualitative elemental analysis, fundamental parameter (FP) based quantification remains difficult due to the energy dependent photon transmission efficiency, focal size, acceptance, etc. of these optics.In order to predict the polycapillary and input beam parameter dependent beam forming properties, a multithreaded Monte Carlo based polycapillary X-ray ray tracing code is presented. Apart from supporting photon ray tracing in ‘ideal’ straight, conical and ellipsoidal shaped polycapillary optics, it also allows for the simulation of photon propagation through arbitrarily shaped optics to account for small deviations from the ideal shape, as is often the case in real world examples. The current code allows for the simulation of so-called ‘leak events’, where the probability of a photon traveling through a capillary wall is taken into account, and also includes support for photon beam polarization effects.The simulated results show good agreement with experimental results obtained at the BM26A beamline of the European Synchrotron Radiation Facility (ESRF, Grenoble, France). The (poly)capillary X-ray ray tracing simulation code, called ‘polycap’, developed in the C language and with bindings for Python, is released under the GPLv3 license. The code is expected to assist in the quantification of (poly)capillary based X-ray fluorescence spectroscopy and may yield additional insight into the manufacturing and development of polycapillary optics.

Research and practice of software protection based on virtual shell technology

Through software decompilation technology, decompiling software can obtain pseudocode of the program source code, causing more and more events of core technology leakage or threats to software intellectual property rights, especially, the proliferation of pirated software. Aiming at the problem of how to effectively protect the software, this article implements a virtual shell packer with the virtual shell technology based on the QT5 framework as the front-end page frame and the assembly language to write the interpreter. Based on this packer, the code of protected software would be decompiled into logically chaotic code in order to increase the difficulty of cracking. Experiments show that this technology can effectively prevent the original pseudo-code from being restored through decompilation. So the software products are effectively protected.

Detection of gas chimney and its linkage with deep-seated reservoir in poseidon, NW shelf, Australia from 3D seismic data using multi-attribute analysis and artificial neural network approach

Accurate delineation of hydrocarbon seepage has significant implications in accentuating hydrocarbon migration pathways and assessing seal integrity thereby alleviating drilling hazards. Knowledge of migration pathways and understanding about the source/reservoir plays a vital role in successful evaluation of hydrocarbon seepage. Many researchers have reported events of gas leakage in Poseidon area; however, it has never been investigated in detail to confirm the origin of the gas leakage and their migration pathways. In this study, an attempt has been made to decipher the relationship between shallow gas migration expressions such as pockmarks, mud-volcanos, direct hydrocarbon indicators (DHIs), push-downs, amplitude blanking, with the reservoir present in the study area. Adopted approach includes development of a chimney probability cube (CPC), in which extracted seismic attributes are optimally combined using a non-linear multi-layer perceptron (MLP) network. During the training and testing phase of the 3-layer MLP network, 0.3–0.25 normalized RMS error and <5% of misclassification is achieved. The processed cube is further validated using spectral decomposition approach, and a cross-plot of Lambda-Rho (petrophysical parameters) versus obtained chimney probability values. The CPC facilitates an enhanced 3D visualization of gas flow channels and deciphers its association with an existing deep-seated reservoir in Plover Formation. The results of this study will provide significant input for hydrocarbon prospect evaluation as well as for making informed drilling decisions in the study area.

Seismic Vulnerability Analysis of a Coupled Tank-Piping System by Means of Hybrid Simulation and Acoustic Emission

In order to shed light on the seismic response of complex industrial plants, advanced finite element models should take into account both multicomponents and relevant coupling effects. These models are usually computationally expensive and rely on significant computational resources. Moreover, the relationships between seismic action, system response and relevant damage levels are often characterized by a high level of nonlinearity, which requires a solid background of experimental data. Vulnerability and reliability analyses both depend on the adoption of a significant number of seismic waveforms that are generally not available when seismic risk evaluation is strictly site-specific. In addition, detection of most vulnerable components, i.e., pipe bends and welding points, is an important step to prevent leakage events. In order to handle these issues, a methodology based on a stochastic seismic ground motion model, hybrid simulation and acoustic emission is presented in this paper. The seismic model is able to generate synthetic ground motions coherent with site-specific analysis. In greater detail, the system is composed of a steel slender tank, i.e., the numerical substructure, and a piping network connected through a bolted flange joint, i.e., the physical substructure. Moreover, to monitor the seismic performance of the pipeline and harness the use of sensor technology, acoustic emission sensors are placed through the pipeline. Thus, real-time acoustic emission signals of the system under study are acquired using acoustic emission sensors. Moreover, in addition to seismic events, also a severe monotonic loading is exerted on the physical substructure. As a result, deformation levels of each critical component were investigated; and the processing of acoustic emission signals provided a more in-depth view of the damage of the analysed components.

Paraffin wax as self-sealing insulation material of seasonal sensible heat storage systems-A laboratory study.

Seasonal heat storage is considered as one of the key elements on the path to a low-emission economy. Embedded in local district heating networks, they raise the share of renewable energies and balance out highly fluctuating supplies of e.g. solar systems or windmills. The technology of seasonal heat storage can be described as almost technically mature, with well-established concepts and some systems being in operation for a considerable time. Nevertheless, the operating experience gained to date also revealed two critical problems. On the one hand, even smallest leakages in sealing foils led to irreparable breakdowns. On the other hand, heat loss in the marginal areas was revealed as a key deficiency, preventing the technology from advancing towards global marketability. This study presents an experimental approach to address these two key issues in the field of seasonal energy storage. Two small-scale laboratory tests were carried out to test paraffin wax as a completely novel component in the marginal area of seasonal storages. This is based on two material properties: As hydrophobic and mobile medium, the warmed and molten paraffin should actively seal the fissures and holes in the event of leakage. Additionally, the latent heat storage properties of the paraffin wax should increase the systems’ total storage capacity and reduce lateral heat losses via its low thermal conductivity. With retardation periods from 2.5 to 4 hours, the results show an effective phase change effect of the paraffin wax, which reduces energy losses and allows to buffer short-term, intensive loading and unloading processes. By storing up to 138 kJ/kg energy in the paraffin wax, increased capacities of application-scale pit storages by up to 40.70 MWh are to be expected. Additionally, the self-healing features could be successfully demonstrated: With only small losses of between 1.5 and 17%, the paraffin wax effectively sealed artificially incised leaks. Thereby, the mechanism was most effective for local defects. Following these positive demonstrations of feasibility, technical design questions still remain, which concern prevention of deformation of the paraffin wax. Once solved, this new component can then provide a path for further optimization of seasonal heat storage technologies.

Potential impact of dynamic automated CT aortic annular measurements on outcomes for transcatheter aortic valve replacement sizing.

To determine the potential impact of automated computed tomography (CT) software used for aortic annular sizing for transcatheter aortic valve replacement (TAVR) on paravalvular leak (PVL) and major adverse cardiovascular events (MACE) as compared to standard CT manual measurement. In 60 TAVR patients (84 ± 7years, 60% male), we evaluated the preprocedural CT scans. For the standard manual measurement, we measured the perimeter and area from a single cardiac phase deemed to be of maximum systolic opening. Valve type and size were determined by a multidisciplinary TAVR team per clinical routine. From the dynamic automated software, we determined the aortic annular perimeter and area as the maximum value from an entire cardiac cycle. Valve size was readjudicated by a blinded interventional cardiologist who was provided with valve type and automated values. Clinical endpoints were adjudicated for presence of at least mild PVL and MACE at 30days. There were 16 (28%) patients with PVL and 4 (7%) with 30-day MACE. When reclassifying valve size using dynamic automated values, 12 (20%) patients were undersized and 3 (5%) patients were oversized. Undersized patients were more likely to have mild-to-moderate PVL at 30days (27% vs 4%, p = 0.04) than those not undersized. Of the 5 (45%) undersized patients with at least mild PVL, all were balloon-expandable valves. Automated dynamic CT annular measurements have the potential to reclassify patients with PVL with larger TAVR valve size, particularly balloon-expandable valves.

Impacts of gold mine effluent on water quality in a pristine sub-Arctic river

Impacts of mining on water quality are a great concern in the Arctic region. This study evaluated the impact of pre-treated mine effluent on river water quality. The study was conducted along the Seurujoki River in sub-Arctic Finland, which is impacted by Kittilä gold mine. The study analyzed water quality and hydrological data upstream and downstream of the mining area over an eight-year period, including a tailing dam leakage event in 2015. The analysis focused on water quality determinants such as electrical conductivity (EC), sulfate, antimony, manganese, and total nitrogen (Ntotal). Descriptive statistics on river water at four stations along the river corridor showed negative impacts of mining activities on the recipient water body. In order to find an indicator for water quality, correlation analysis between the water quality determinants was carried out. It identified EC as a good indicator for continuous water quality monitoring, especially to detect mining accidents such as partial failure of a tailings dam. The results showed increasing contaminant concentrations due to mining as more mine effluent was generated over time. A linear mixed model was developed to predict the coefficient of different elements affecting EC at river water monitoring stations impacted by mining effluents. The results provide new information on how to assess mining water impacts and plan future water quality monitoring.

The correlation between pO2 and pCO2 as a chemical marker for detection of offshore CO2 leakage

A controlled CO2 release experiment was carried out in order to mimic unintended leakage of geologically stored CO2, and to study methods for detecting these leak events. The experiment was carried out at 60 m depth in the Oslo Fjord over the course of one month. During the simulated leak events, the water chemistry was monitored by sensors mounted on stationary templates located 10 and 22 m horizontally from the source, as well as sensors mounted on an Autonomous Underwater Vehicle (AUV). During baseline conditions (no CO2 release), we observe a strong biogenic correlation between O2 and CO2. This correlation is lacking during CO2 releases, indicating that the CO2-O2 correlation can be used as a marker for CO2 leakage. The same deviations were not initially detected by the CO2 sensor mounted on the AUV due to the longer response time of membrane-based CO2 sensors. However, by applying response time correction in the post-processing of the AUV CO2 data, the generated CO2 plume was detected. Moreover, the plume was clearly detected by the AUV using the faster responding pH sensors, where the correlation with O2 again could be used to confirm the anomaly.