The shale oil horizontal wells in the Songliao Basin are affected by a lack of mature theories, technologies and experiences in the direction of wellbore stability. Wellbore collapse may occur, and in severe cases, the wellbore may be scrapped, resulting in huge economic losses. Therefore, aiming at addressing the above problems, rock mechanics experiments were carried out. Based on the theories of elasticity and rock mechanics, this paper considers not only the influence of the bedding plane, but also the influence of hydration on the strength weakening of the shale body and the bedding plane. The analysis shows that no matter under which in situ stress mechanism, the wellbore in the vertical well section is the most stable, and when the inclination angle is approximately 45°, the wellbore is most likely to be unstable. Changes in water content do not affect the most stable or unstable regions. Under the same conditions, the equivalent density of collapse pressure increases with the i... [more]

To solve the problems of complex structure, poor reliability, and low intelligence of existing fan clutches for large hybrid vehicles, this paper proposes a new adaptive shape memory alloy intelligent fan clutch for large hybrid vehicle motor cooling. Based on the pure shear shape memory alloy thermodynamic effects, the relationship between shape memory alloy spring recovery force and temperature has been established; based on the shape memory alloy spring thermal drive characteristics and clutch construction dimensions, clutch torque transmission equations have been established. The shape memory alloy fan clutch transmission characteristics were quantitatively analyzed in terms of temperature, torque, rotational speed, and slip rate. The results show that the shape memory alloy fan clutch model based on the finite element method (FEM) and the established transmission model can accurately describe the mechanical characteristics of the shape memory alloy phase change process and the clu... [more]

In seismic exploration, obtaining accurate bandwidth of the reflected signal is essential for determining seismic resolution. A portion of the stored energy is attenuated during signal propagation, narrowing the received seismic signal bandwidth. Therefore, compensating the energy attenuation is important for improving the seismic resolution. The current method of compensating absorption and attenuation based on a single channel can only compensate the post-stack data (self-exciting and self-receiving), whereas in practice, seismic waves do not propagate along the self-exciting and self-receiving seismic wave path; the propagation path is complex. The absorption and attenuation depend on the propagation path. The primary methods used for Q-compensation along the propagation paths are one-way wave extrapolation in the Cartesian coordinate system and Gaussian beam Q-compensation migration in the ray-centered coordinate system. However, the large angle limits the one-way wave method, and... [more]

The geomechanical behavior of methane hydrate bearing sediments (MHBS) is influenced by many factors, including temperature, fluid pressure, hydrate saturation, stress level, and strain rate. The paper presents a visco-elastoplastic constitutive model for MHBS based on an elastoplastic model that incorporates the effect of hydrate saturation, stress history, and hydrate morphology on hydrate sediment response. The upgraded model is able to account for additional critical features of MHBS behavior, such as, high-dilatancy, temperature, and rate effects. The main components and the mathematical formulation of the new constitutive model are described in detail. The upgraded model is validated using published triaxial tests involving MHBS. The model agrees overly well with the experimental observations and is able to capture the main features associated with the behavior of MHBS.

With the successful development of unconventional hydrocarbons, the production of unconventional hydrocarbons has increased rapidly. However, a single conventional or unconventional model is not suitable for the mechanism of hydrocarbon accumulation in a given basin or sag. Based on data from drilling, logging, and geophysical analysis, the hydrocarbon accumulation mechanism in the Hari sag in the Yingen-Ejinaqi basin, China, was analyzed. There are three sets of source rocks in the Hari sag: the K1y source rocks were evaluated as having excellent source rock potential with low thermal maturity and kerogen Type I-II1; the K1b2 source rocks were evaluated as having good source rock potential with mature to highly mature stages and kerogen Type II1-II2; and the K1b1 source rocks were evaluated as having moderate source rock potential with mature to highly mature stages and kerogen Type II1-II2. Reservoir types were found to be conventional sand reservoirs, unconventional carbonate-shale... [more]

The discovery of the BZ19-6 large-scale condensate gas field illustrates the great potential of the sandy conglomerate reservoirs in the Bohai Bay Basin. However, the stratigraphic correlation of the sandy conglomerate sequence in northern Huanghekou Sag remains a challenge due to the lack of syn-depositional volcanic layers and biostratigraphic constraints. The challenge limits understanding the regional strata distribution and further exploration deployment. In this study, we conducted in situ U-Pb dating of vein calcite and detrital zircons of the sandy conglomerate samples from borehole BZ26-A. The vein calcite age and the youngest age of detrital zircons provide the upper and lower bounds of the depositional age, respectively. We also correlated the samples with those from well-understood strata through a comparison of XRD mineral components. The absolute age of 47.0 Ma of the vein calcite and the youngest detrital zircon age of 103.5 Ma suggest the sedimentary sequence is suppose... [more]

The intrusive rock buried-hill reservoir is one of the main targets for oil and gas exploration in the offshore sedimentary basins of China. In order to discover the reservoir as early as possible for decision-making to save costs, reservoir interpretation with mud-logging data needs to be studied. Previous studies have showed that the homogeneity rocks reservoir can be well interpreted with mud-logging data u the Kb (mechanical specific energy ratio) method and the WL (tangential power)-WH (vertical power) intersection method. However, reservoir interpretation with mud-logging data for intrusive rock buried-hill has not been reported. The key steps or parameters of these two kinds of methods used for reservoir interpretation need to be modified for the vertical variation of intrusive rock buried-hill. Furthermore, confirming the interpretation of these two kinds of methods has not been reported. Taking the Y area in the Qiongdongnan Basin of the South China Sea as an example, the intr... [more]

The 2010 Maule earthquake was a megathrust event that occurred along the Peru−Chile Trench. The earthquake source can be modelled as a fault with two asperities with different areas and strengths. By employing a discrete fault model, where asperities are the basic elements, the event can be described as a sequence of three dynamic modes involving simultaneous asperity slip. Interaction between asperities by mutual stress transfer plays a crucial role during fault slip. With a careful choice of values for the model parameters, the mode durations, the slip distribution, the seismic moment rate and the final moment calculated from the model are found to be consistent with the observed values. An important amount of frictional heat is produced by an event of this size and is calculated by summing up the contributions of each asperity. The seismic event produces a heat pulse propagating through the Earth’s crust and contributing to the average heat flow in the region. The calculated heat pr... [more]

The establishment of a rock constitutive model considering microcrack propagation characteristics is an important channel to reflect the progressive damage and failure of rocks. The prepeak crack strain evolution curve of rock is divided into three stages based on the triaxial compression test results of granite and the definition of crack strain. According to the nonlinear variation characteristics of crack strain in the stage of rock crack stable propagation, rock deformation is expressed as the sum of matrix strain and crack strain. Then, the exponential constitutive relationship of rock crack stable propagation is deduced. The axial crack strains of the rock sample and its longitudinal section are equal. Thus, the longitudinal symmetry plane of the rock sample is abstracted as a model containing sliding crack structure in an elastic body, and the evolution equation of crack geometric parameters in the process of stable crack propagation is obtained. Compared with the experimental d... [more]

The COVID-19 pandemic is accelerating the rapid development of the digital economy. Previous studies have indicated that shipping fees are essential in delivery strategies and significantly impact order generation rates. According to market research, 68% of consumers would increase their orders to reach the minimum threshold for free delivery. However, previous studies have focused on the problem of setting free shipping thresholds, so the existing model of the e-commerce platform only allows consumers to choose whether to pay the total shipping fees or conditional free delivery with a free shipping threshold. A lack of literature concerns the partial pay for shipping fees before reaching the free shipping threshold. Therefore, this study proposes a new pricing model for shipping strategy that allows consumers to pay partial shipping fees. This model can increase the flexibility of consumer choice, thus increasing consumers’ willingness to purchase, which in turn increases the revenue... [more]

Precise data processing from the Global Navigation Satellite Systems (GNSS) reference station network is mainly based on a combination of double-differenced carrier phase and code observations. This approach allows most of the measurement errors to be removed or reduced and is characterized as the most accurate method. However, creating observation differences between two receivers and two satellites increases the measurement noise of the observations by a factor of 2. As a result, it increases the impact of the incorrect definition of the noise characteristic on the results of the estimation of the unknowns in the positioning model. This is especially important in Multi-GNSS solutions, which integrate measurements from different systems, for which the stochastic parameters of observation may differ significantly. In this paper, the authors prepared a complex analysis of the noise type in double-differenced GNSS (GPS, GLONASS and Galileo) observations, both carrier phase and code ones,... [more]

The accuracy of the monitoring information is particularly important for exploring fractured rock mass deformation and failure mechanisms and precursor characteristics. Appropriate monitoring methods can not only timely and effectively reflect the failure laws of fractured rock masses but also play an early warning role. To explore more reasonable monitoring methods, uniaxial compression experiments and real-time non-destructive monitoring on prefabricated fractured rock specimens through DIC, AE, and IRT were conducted; the strain field, temperature field, ringing frequency, standard deviation, etc. were analyzed; and correlation between the three methods in the information of audience was explored. The results show the following. (1) The failure evolution process of fractured rock mass can be divided into four stages. DIC can detect the initiation and propagation of cracks near the fractures of the specimen at the earliest stages. (2) The order of occurrence of precursor phenomena in... [more]

The authors wish to make the following corrections to their paper [...]

Today science faces the task of ensuring the innovative development of the mineral extractive sector of the economy in resource-rich countries, in the context of unfolding two opposite trends [...]

The accessibility of pores to methane has been investigated in Devonian New Albany Shale Formation early-mature (Ro = 0.50%) to post-mature (Ro = 1.40%) samples. A Marcellus Shale Formation sample was included to expand the maturation range to Ro 2.50%. These are organic matter-rich rocks with total organic carbon (TOC) values of 3.4 to 14.4% and porosity values of 2.19 to 6.88%. Contrast matching small-angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) techniques were used to generate porosity-related data before and after pressure cycling under hydrostatic (in a vacuum and at 500 bar of deuterated methane) and uniaxial stress (0 to ca. 350 bar) conditions. Our results showed that the accessible porosity was small for the samples studied, ranging from zero to 2.9%. No correlation between the accessible porosity and TOC or mineralogical composition was revealed, and the most likely explanation for porosity variation was related to the thermal transformatio... [more]

Using Meizhou City as an example, the aim of this study was to verify whether e-bike sharing systems can improve the convenience of engaging in leisure and tourism activities in cities, and thus increase residents’ well-being. First, quantitative research was carried out to collect data on users’ opinions. Then, qualitative research was carried out to obtain the opinions of experts. Finally, the investigation was conducted using multivariate review analysis. The results of the research showed that e-bikes should be classified based on electric quantity, the rental fee should be charged based on mileage, and the relevant corporate information should be integrated. It is also necessary to develop a software interface with functions for users to rent e-bikes and search for information related to consumption, leisure, and travel activities, and make promotion plans. Finally, people need to be encouraged to cycle to obtain the benefits of leisure and exercise. In this manner, the convenienc... [more]

Finding a fair system of rewarding employees in energy companies and its influence on their motivation to perform their duties is a problem faced by many economic entities. Therefore, the aim of the article is to initially direct further research, taking into account the basic characteristics of employees such as age, gender and level of education, in order to verify whether and to what extent it is necessary to dedicate the communication of the remuneration system to the needs of selected groups. Multiple correspondence analysis was used to analyse the data obtained from the questionnaires, examining the subjective evaluation of professional remuneration with regard to age, gender and level of education of the respondents in energy companies. The results obtained indicate that all enumerated features have an impact on the perception of work remuneration systems. It is also possible to adjust the applied remuneration solutions and the methods and content of messages to particular group... [more]

In order to explore the rules between gravity anomalies and oil-gas distribution characteristics in central and western Sichuan Basin, we divided the tectonic unit in central and western Sichuan basin on the base of the analysis of gravity anomaly characteristics, and studied the correlation between the oil−gas distribution and the local gravity anomaly in the study area. The results show that the variation in the range of the Bouguer gravity field in the interior of the basin is relatively small, and the southern part shows a clear gravity high zone, with gradual gravity gradient zones all around the basin periphery. The abnormal value of the residual gravity field in the basin is an obvious high−value gravity belt in the north and west, and the interior is arranged alternately with local high gravity and low gravity in the north−east direction. The tectonic units of the central and western Sichuan Basin can be divided into five regions, based on the characteristics of the Bouguer gra... [more]

During drilling, almost 70% of wellbore instability issues result from the encountering of shale formations. Various additives such as salts, silicates, and polymers are used in water-based mud to enhance its shale-inhibition capability; however, such additives have certain limitations. Lately, ionic liquids and deep eutectic solvents (DES) have been used by various research groups as shale inhibitors in drilling fluid due to their biodegradability and efficacy. However, their popularity faded when a natural derivative of DES, i.e., Natural Deep Eutectic solvent (NADES), came into the picture. This research utilizes the in-house-prepared Ascorbic acid and Glycerine (AA:Gly)-based NADES as a drilling fluid additive for shale inhibition and compares its efficacy with counterpart inhibitors such as KCl, imidazolium-based ionic liquid, and Choline Chloride-based DES. The results show that 3% NADES improved the overall Yield point to Plastic viscosity ratio, with a 39.69% decline in mud cak... [more]

In the past few years, internet celebrities have become a new and important way to get people to buy energy-saving products. Their psychological mechanisms for promoting fans’ intention to purchase have become the focus of academic attention, but a unified conclusion has yet to be reached. This study uses online communities as a scenario, with the characteristics of influencers’ expertise, social attraction, and task attraction as antecedent variables and social cognitive theory and parasocial interaction theory as the theoretical basis to explore their influence on fans’ intention to purchase household energy-saving products. The study investigates the mediating role of parasocial relationships and the moderating role of fans’ green self-efficacy in influencing internet celebrities’ expertise and attraction of fans’ parasocial relationships. The results showed that the parasocial relationships formed between fans and influencers mediated the relationship between the expertise and attr... [more]

In order to create a sustainable future for the urban environment in s=Smart cities, it is necessary to develop a concept of urban transport, partially reduce the use of traditional transport, primarily cars, as well as the environmental pressure on society, which is essential to move to a sustainable urban future. In the latest discussions on the future of the urban transport system, the quality of the environment, and the possibility of its improvement are discussed, this issue became especially relevant with the onset of the pandemic, when the lockdowns were introduced. The problem of sustainable transport in urban areas has been recognized in academic studies, searching for appropriate models and solutions. The article presents the latest literature review and illustrates the newest trends with several examples. VOS Viewer software has been used to classify the different keywords, according to their co-citation, following clustering techniques. By analyzing the research conducted b... [more]

Low insulation strength at the oil−gas surface due to oil leakage and partial discharge of oil-immersed power equipment is a major threat to the safe and reliable operation of power systems. This paper investigates the initiation and development of the oil−gas surface discharge. The oil−gas surface discharge test platform was established, and discharge tests were carried out at different gap distances (1−2.5 mm). By coupling the electric field and flow field, the multi-layer dielectric discharge streamer model was built, and the characteristics of charge and electric field distribution at different gap distances were studied. The test results show that the liquid surface between the electrodes rises during the discharge process. Furthermore, the surface discharge voltage exceeds the air gap discharge voltage. With the simulation analysis, the oil−gas surface discharge is a typical streamer development process. Under 50 kV applied voltage and 2.5 mm gap distance, the average development... [more]

Oil-based drilling fluid is currently widely utilized when drilling shale, in which the oleophilic nano-plugging agent is the major component for wellbore strengthening. However, there have been few effective and straightforward evaluation methods for the nano-plugging agent. In this study, an artificial filter cake was created to simulate the microfissure of shale formation, and the performance of the nano-plugging agent was assessed using the fluid-loss reduction rate as the index. The filter cake was made from compound crystal weights and a high molecular weight polymer, and a nano-plugging agent matching the formation pore structures was selected. The performance of three plugging agents with varying particle sizes (ultrafine CaCO3, emulsified modified rubber MORLF, ULIA nano-plugging agent) was compared. Moreover, the validity of the evaluation process was confirmed, and the underlying plugging mechanism was investigated. The proposed technique can produce an artificial filter cak... [more]

Autonomous vehicles in highway driving scenarios are expected to become a reality in the next few years. Decision-making and motion planning algorithms, which allow autonomous vehicles to predict and tackle unpredictable road traffic situations, play a crucial role. Indeed, finding the optimal driving decision in all the different driving scenarios is a challenging task due to the large and complex variability of highway traffic scenarios. In this context, the aim of this work is to design an effective hybrid two-layer path planning architecture that, by exploiting the powerful tools offered by the emerging Deep Reinforcement Learning (DRL) in combination with model-based approaches, lets the autonomous vehicles properly behave in different highway traffic conditions and, accordingly, to determine the lateral and longitudinal control commands. Specifically, the DRL-based high-level planner is responsible for training the vehicle to choose tactical behaviors according to the surrounding... [more]

A wireless charging system that supports a large sensor network not only needs to provide real-time charging services but also needs to consider the cost of construction in order to meet the actual applications and considerations. The energy transfer between mobile devices is extremely difficult, especially at large distances, while at close distances a wireless, fast-charging, automatic, and high-precision landing system would be required. However, previous studies that used wireless charging cars, wireless charging unmanned aerial vehicles (UAVs) alone, or wireless charging pads to build a large-scale wireless charging system could not meet the above two conditions at the same time. If we can make good use of the existing high-speed backbone transport, such as the vehicular ad hoc network (VANET), it can not only consider the cost of construction and the speed of movement but also support the real-time charging service required by large-scale sensor networks. In this work, we propose... [more]