bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intelligent Lost Circulation Early Warning Method Based on HALSTM Network
Authors: Wang H. T. , Wen X. , Zhang R. , Song X. Z. , Zhu Z. P. , Yao X. Z. , Han L. 
Published: September 2023

ABSTRACT
To further reduce the risk of lost circulation and improve the accuracy and real-time lost circulation warning, this paper proposes a lost circulation warning model based on hybrid attention long short-term memory (HALSTM) network. Firstly, combined with the mechanism of lost circulation occurrence, the characteristic parameters of lost circulation risk and their variation rules were analyzed. Then, the characteristics of the model were screened, and the time of lost circulation occurrence was accurately located by using the drilling activity identification model and the variation rules of the characteristics. Based on the standard LSTM model, the feature and temporal hybrid attention mechanism is proposed to dynamically capture the potential correlation between the risk of lost circulation and the input features. By obtaining the rank importance from both features and temporal, which realizes the interpretability of the model to a certain extent. The results demonstrate that the HALSTM model outperforms the random forest (RF), support vector classification (SVC), artificial neural network (ANN), and LSTM models, exhibiting greater accuracy and enhanced robustness. With a precision of 98%, the HALSTM proves to be a highly practical and effective tool for early warning and decision-making during drilling operations.

INTRODUCTION
Lost circulation is a common downhole risk in the drilling operations (Xu & Li, 2018), which can occur suddenly and is complex to deal with. Typically, lost circulation risks are highly concealed, evolve dynamically, and fluctuate non-linearly, which can lead to other downhole risks such as wellbore instability, pipe sticking, and blow out (Li et al., 2018). Therefore, efficient and accurate diagnosis of lost circulation is of great importance for the safety and economy of drilling operations.
Traditional prediction methods for lost circulation use only one or a few factors, which can cause accident delay, misclassification, and omission. Meanwhile, the comprehensive mudlogging (CML) technique is the most widely used lost circulation diagnosis method, which diagnoses by real-time monitoring whether the logging parameters exceed the threshold value. However, the threshold setting depends on the field experience and is not time-sensitive, resulting in limited accuracy of lost circulation diagnosis.
Rockbursts Characterization in the Merensky Reef: A Case Study in Siphumelele Platinum Mine, South Africa
Authors: Masethe R. T. , Durapraj S. 
Published: September 2023

ABSTRACT
Rockbursts have remained one of the most serious and least understood problems facing deep mining operations, claiming the lives of thousands of mine workers. Despite many technical advances, rockburst continues to pose a significant risk in deep platinum mines of South Africa as they damage excavations, mining equipment and infrastructures, delay production and cause injuries or even deaths of mining personnel. We analyzed the source mechanisms of large mining-related seismic events (ML1.0 − 2.5) that caused damage to stopes in Siphumelele Platinum Mine. This study attempts to mitigate the risk of rockburst by integrating rock mass complexities (high stress, complex structural geology, mining elements, etc.) with the source mechanisms of mining-induced earthquakes to understand better the main drivers of seismicity within the Merensky Reef. The energy ratio (Es/Ep) was used as a discriminator to define two classes of seismic events. Shear (Es/Ep &gt;10, 22 events), located between 1226 and 1470 m depths and non-shear (Es/Ep &lt;10, 51 events), concentrated from 907 to 1460 m below and above the Merensky Reef. About 76% of these seismic events were related to elements of the mining geometry (pillars, abutments, and back-areas); while 24% were located near known geological structures (faults, dykes).

INTRODUCTION
As the depth of underground mining increases, the stresses in the rock mass increase, and as a result, the level of induced seismicity usually increases. Mine seismicity is a risk to mine personnel and infrastructure. It has become a major operational issue and a problematic planning factor for most underground mines worldwide, particularly at depths greater than 1000 m. As a result, the characterization of rockbursts in the Merensky Reef is critical to understanding the true nature of seismicity and developing mitigation strategies. Given the mine's increased seismicity and risks to production, infrastructure, and mine personnel safety, it is critical to comprehend the rock masses’ behaviour.
Seepage and Stress Analysis of High-Pressure Bifurcated Pipes in a Pumped Storage Power Station
Authors: Fan Bowen , Wang Tao , Wu Hegao , Yang Kai , Wang Suifeng , Liu Songcheng 
Published: September 2023

ABSTRACT
The filling and drainage process of high-pressure bifurcated reinforced concrete pipes in pumped storage power stations (PSPS) can significantly affect the propagation of cracks in the reinforced concrete lining, which in turn impacts the structural safety and long-term stress state of the reinforced concrete lining. Specifically, we study the reinforced concrete bifurcated pipes of a PSPS in China. We use the finite difference method to simulate the fluid-structure interaction and analyze the critical penetration pressure and propagation of cracks in the lining during the water filling and drainage process. Additionally, we calculate the seepage field of the lining and the long-term stress state after the formation of stable seepage, and analyze the structural stability of the lining under the condition of graded drainage. We investigate the influence of structural elements such as rebars and bolts on the propagation of lining cracks, and propose an optimization scheme for the restricted crack design.

INTRODUCTION
PSPS are essential to ensure the safe and stable operation of power systems (Huang et al., 2018). They are considered to be the most environmentally friendly, efficient, and economical means of developing large-scale energy storage facilities. Therefore, the construction of such power stations is highly valued by countries worldwide (Dennehy et al., 2015; Sun, 2018; Yang, 2014). Bifurcated pipes, as the connection area between the main pipe and the branch pipe, are a crucial component of the hydraulic building diversion system, and their design is evolving to accommodate longer lines, larger diameters, and deeper burial depths. Consequently, the surrounding rock and bifurcation areas must withstand high-pressure heads (Hu et al., 2011).
With the increasing development of water resources and hydropower engineering, a considerable number of high-pressure and large-diameter bifurcated pipes are now used in PSPS projects. For instance, the Yangjiang PSPS's high-pressure bifurcated pipe can withstand a static head of 799 m and a maximum dynamic head of 1108 m (Liu et al., 2021). Similarly, the Tianhuangping PSPS's high-pressure bifurcated pipe can withstand a static head of 680 m and a maximum dynamic head of 800 m (Zhang, 2001), while the Guangzhou PSPS's high-pressure bifurcated pipe can withstand a static head of over 600 m (Ye, 2001).
A New Post-Drilling Evaluation Method for Formation Pore Pressure
Authors: Yang H. W. , Li J. , Huang H. L. , Zhang G. , An J. T. , Li J. M. , Li W. T. , Zhang X. J. 
Published: September 2023

ABSTRACT
Eaton and Bowers model are two commonly used methods for formation pore pressure evaluation methods. However, both of them belong to univariate model, which takes few factors into consideration, is subject to many conditions, and has large error. Therefore, combining the results of previous laboratory experiments and field logging data, the correlation between shale content, density, porosity, effective stress and p-wave velocity was analyzed. The function form of each factor term was optimized, and a new p-wave velocity model was established by using multivariate nonlinear regression. Based on the effective stress theorem, a new post-drilling evaluation method for formation pore pressure was proposed. The results show that the density, porosity and effective stress are highly correlated with the p-wave velocity, while the shale content is relatively low. The optimal function forms of their correlation with p-wave velocity are linear, "linear + exponential" combination form, power function form, and linear form, respectively. The accuracy of the developed model is more than 99%, which is much higher than the Eaton and Bowers model. The research results have important reference significance for improving the evaluation accuracy of formation pore pressure, and provide a basis for rational casing design, determination of mud density and adjustment of production technology.

INRTUDUCTION
Formation pore pressure refers to the fluid pressure in the pores of formation. The establishment of a reasonable pore pressure profile is the basis for the reasonable casing design, the mud density determination and the production technology adjustment (Fan, 2006). The logging information can reflect the compaction law of formation and the lithology and physical property of underground rock, and the data amount is very large, which is the most ideal data for evaluating pore pressure. Therefore, using logging data to evaluate pore pressure after drilling is the one of most effective methods (Wang and Guo, 2015). At present, almost all formation pore pressure evaluation methods are indirect estimation based on p-wave velocity, resistivity, density, porosity and other logging parameters as well as effective stress. The evaluation methods mainly fall into two categories: one is based on the normal compaction trend line (Foster, 1966; Ham, 1966; Eaton, 1972, 1975); the other is based on the effective stress theorem (Bellotti, 1978; Bowers, 1995, 2001; Bryant 1989; Alixant, 1991). The above models are univariate models with few factors, more constraints and large errors.
Pre-Drilling Prediction of 3D Geomechanical Parameters Based on Seismic Data: A Case Study of Tarim Oilfield
Authors: Zhou Bo , Zhang Xin , Zhao Li , Zhou Bao , Chen Long , Lu Yunhu 
Published: September 2023

ABSTRACT
A pre-drill prediction method of 3D geomechanical parameters based on seismic data is proposed. Firstly, the wave impedance parameters are predicted in the target area by the logging-constrained method, which mainly uses post-stack seismic data and logged data from drilled wells. The density and velocity data are obtained by separating the wave impedance data. Then, the density and velocity data are used as input to calculate 3D geomechanical parameters in the region, including elasticity parameters, strength parameters, and stress parameters. In particular, experimental data are used to correct the accuracy of the model. The results accurately reflect the geological complexity and non-homogeneity of the region by evaluating the elastic properties, mechanical properties, and stress magnitude of each point. This method can greatly improve the longitudinal resolution of the inversion results by fully exploiting a priori information from the logs and involving them in the seismic inversion process. Pre-drill parameters prediction of a complex field in the Tyuritag of the Tarim Basin is carried out.

INTRODUCTION
A growing number of oil and gas field development projects are facing the challenge of safe, rapid, and efficient development, such as offshore projects like Hibernia and the Gulf of Mexico in Canada, and onshore projects in tectonically active areas like the Cusiana field in Colombia and the Tarim Basin in China. However, as drilling depths continue to deepen, the geological environment encountered in oil and gas development is becoming increasingly complex. The difficulty of engineering problems related to geomechanics is also increasing. On the one hand, there are more and more complex accidents in various wells, such as well wall instability, well leakage, and sand production. Underground accidents seriously increase the time and cost of construction operations. It is estimated that at least 10% of the average well budget is used for unplanned operations due to wellbore instability (Sheng, 2006; Wei, 2012). On the other hand, the inaccuracy of geomechanical modeling makes geomechanics-related engineering measures unable to achieve the expected goals. In shale oil and gas development, about 30-50% of fracturing clusters do not contribute to product improvement. The root cause is poorly designed hydraulic fracturing strategies due to the lack of accurate geomechanical data (Zhang, 2018; Parshall, 2015).
Field-Scale Modeling of Fracturing with Slickwater, N2, CO2 and Foams – A Fundamental Investigation
Authors: Gala Deepen , AlTammar Murtadha J. , Sharma Mukul M. 
Published: September 2023

ABSTRACT
Hydraulic fracturing is typically done with water-based, incompressible fracturing fluids. However, other fluids such as pure gases or foams are also used as driven by logistics or well productivity optimization. There are differences in fracture growth behavior amongst various fracturing fluids due to variability in properties such as viscosity, density, compressibility, leakoff, etc. Several laboratory experiments have recently been performed which indicated differences in breakdown pressure, fracture growth rate, complexity of the created fractures and amount of fracturing fluid leaked off into the formation. However, the laboratory results cannot be directly applied to the field without proper upscaling. In this work, we perform a field scale modeling of different fracturing fluids to provide more insights on how to design a fracturing job using non-water based fluids. We systematically study the role of wellbore volume, viscosity, compressibility, reservoir permeability, poroelasticity and magnitude of minimum horizontal stress on the fracture propagation behavior. It was found that poroelasticity effects are quite important for low viscosity fluids in micro-Darcy reservoirs. Also, when wellbore storage effects are considered, breakdown time is higher and breakdown pressure is lower for higher compressibility fluids. In low permeability reservoirs, an increase in fluid viscosity reduces the fracture length and increases width. In higher permeability reservoirs, an increase in viscosity reduces leakoff and thus increases both length and width. Low stress environments behave differently than high stress environments due to differences in fluid compressibility and stress/tensile strength ratio. A multi-cluster study of a single stage in a horizontal well is also performed for slickwater, gases (CO2 and N2) and foams (with different quality). The injection period and shut-in are both modeled and compared among the different fluid injection cases.

INTRODUCTION
Hydraulic fracturing treatments of oil and gas formations are mostly performed using slickwater, gelled water and hybrid fluids (Dejam et al. 2018). Many field applications, however, require minimizing the amount of water used in fracturing treatments due to water scarcity, environmental issues, and/or local regulations. In addition, using less water in fracturing can improve well productivity by reducing gel damage, relative hydrocarbon permeability damage, clay swelling and fines migration, and proppant embedment (AlTammar 2014). Alternatives to water-based fluids such as nitrogen, CO2, and foams are promising candidates for use as fracturing fluids.
Induced Stress in Reservoirs Under Dual Boundary Conditions of Deformation and Seepage
Authors: Pei Xuehao , Liu Yuetian , Xue Liang 
Published: September 2023

ABSTRACT
Stress sensitivity is a vital factor affecting the seepage mechanism in oil and gas reservoirs. The accurate simulation of reservoir development must comprehensively consider the mechanical properties of fluid and rock. However, the description of boundary conditions in fluid–solid coupling calculations of oil and gas reservoirs mainly adopts a constant overburden stress and uniaxial deformation assumption or involves artificial boundary conditions of stress and displacement; these methods produce results that do not accurately represent the actual situation of the reservoir. In this study, under the condition that the specified compressive stress is positive, the reservoir stress and strain are completely defined, the reservoir induced stress model is constructed, the deformation-seepage dual boundary is proposed, and the semi-analytical solution method of the model under dual boundary conditions is examined. The study shows that the mechanical law followed by the skeleton stress change in the process of oil and gas reservoir development is equivalent to the continuum stress change under the action of certain body and boundary forces. The seepage boundary acts as a boundary force in the deformation model. The induced stress model can be solved by convolution according to the superposition principle using the help of basic solution of the semi-infinite body under the action of concentrated force. The case study of radial flow in infinite formations shows that the radial and vertical strains are in the same order of magnitude near the wellbore, and there is a large error in the assumption of uniaxial deformation and constant overburden stress. The radial deformation of the reservoir has a triple structure, consisting of the compression, micro-tension, and undeformed zones. Vertically, all the reservoirs are compressive and deformed; however, the vertical skeleton stress has a triple structure consisting of falling, rising, and unchanged zones. The proposed solution method lays the foundation for studying the stress sensitivity of oil and gas reservoirs and the numerical simulation of fluid–solid coupling.
Numerical Simulation of Landslide Acoustic Emission Characteristics Using Waveguide Techniques
Authors: Chen Y. , Pan R. , Yuan H. Y. , Chen J. G. , Sun Z. H. , Zhang M. Z. , Huang L. D. , Deng L. Z. 
Published: September 2023

ABSTRACT
Numerous landslide accidents lead to thousands of casualties each year and pose great threats to residents nearby in China. Landslide monitoring and early warning are of great significance. As a deep deformation monitoring method, acoustic emission (AE) monitoring technology is expected to realize the goals of early warning and cost saving. To uncover the mechanisms of AE waveguide, this paper chooses a representative element and establishes a series of models by the discrete element method (DEM) to simulate the reaction between the waveguide and landslide. The AE and mechanical parameters are recorded simultaneously. For the landslide geological characteristics, the mass mechanical properties and the surface structure parameters are considered. The roughness of the sliding surface is simulated by changing the angle and quantity of the convex. Moreover, the impacts of backfill particles are investigated through the particle stiffness, strength, dimension or distribution mode. To improve the performance of AE monitoring, the applicable monitoring parameters in different simulated conditions are determined. For the backfill particles, it can promote the ability of AE monitoring by reducing the strength or dimension, enhancing the stiffness, and utilizing better gradation.

INTRODUCTION
Landslide is a kind of slope rock mass deformation failure process and phenomenon under the action of gravity and external factors (such as rainfall, earthquake, human activities, etc.). As a geologic disaster, landslide is characterized by its high frequency, wide distribution and severe loss, seriously threatening the safety of human life and property and major facilities (Petley, 2012). China is one of the heaviest exposed countries to landslide in Asia and even in the world. Especially since the reform and opening up, land use is progressively expanding to areas at high risk of landslide disasters, leading to an annual increment in landslide disasters (Persichillo et al., 2017). To achieve landslide prevention and mitigation, in addition to landslide treatment, landslide monitoring and early warning are particularly important.
Towards Ultra-Deep Exploration in the Moon: Modeling and Implementation of a Mole-Type Burrowing System
Authors: Yuan Zihao , Zhao Haifeng 
Published: September 2023

ABSTRACT
Effective scientific exploration of extraterrestrial locations requires reaching subsurface destinations and obtaining geology samples of high scientific value. One of the most widely used techniques for geological sampling is drilling, but there is still a need for investigation to achieve greater depth and efficiency. This paper proposes a mole-type autonomous burrowing robotic system for drilling, steering, and accessing scientific samples from the deep subsurface of the Moon. The paper describes the robotic locomotion and operational loads of the self-burrowing robot. The self-burrowing robot with dual-screw configuration is designed and a mathematical model is developed to simulate its excavating capacities. Finally, the paper discusses the robot's performance and compares it with conventional drilling methods using the specific energy method.

INTRODUCTION
The core of near-earth exploration missions, such as those to the Moon, Mars, or asteroids, is extraterrestrial subsurface drilling and sampling (Gorevan et al., 2003). The primary tools for gaining insights into the evolutionary history of the solar system are subsurface exploration equipment, such as coring machines or robots. To achieve scientific objectives, it is necessary to reach the subsurface destination and obtain geological samples of high scientific value (Glass et al., 2020). Typically, the lunar subsurface within about 10 meters in depth consists of igneous regolith and disturbed materials from fine granular particles to chunky rocks along the depth direction (Slyuta, 2014). Drilling is one of most widely used techniques in geological sampling for sand or soil. These have been implemented in extraterrestrial exploration, in missions such as Luna, Apollo and Chang’e (Prissel & Prissel, 2021).
Towards the deep exploration and samples collection in subsurface, there are proposed the conceptual designs or prototypes. This recent research focused on the new technical system to achieve deeper and more efficient soil movement (Lopez-Arreguin & Montenegro, 2020), which imitates locomotion mechanisms of animals and insects such as crawling, swimming, and burrowing in granular mediums. Among these developed bio-inspired robot, typical prototypes, the inchworm robots, such as IDDS (Gorevan et al., 2000) and IBR (Zhang et al., 2018), operate sequentially combining the actions of anchoring and drilling. The wood wasp robots (Cerkvenik et al., 2019) mimic a reciprocating motion of two halves saw-toothed bits to shear and stick into the soil.