bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancing Intelligent Drilling Rate of Penetration PredictionModeling Through Anomalous Drilling Data Handling Methodology
Authors: Ye Shanlin , Zhu Lin , Lv Zehao , Song Xianzhi , Liu Zihao , Zhu Zhaopeng , Pan Tao 
Published: August 2024

ABSTRACT:
Intelligent drilling represents a future trend in petroleum drilling. Intelligent prediction and optimization of drilling rate of penetration (ROP) constitute pivotal research areas within intelligent drilling, promising enhanced drilling efficiency and cost reduction. The establishment of intelligent prediction models for ROP relies heavily on a vast amount of drilling data. However, data collection devices in oil fields exhibit instability, accompanied by significant environmental noise. Consequently, drilling data often contain numerous outliers and noise, which disrupt the training of ROP models and degrade their accuracy. In this paper, a methodology for handling anomalous data is proposed based on oilfield drilling data. Firstly, isolated forest (IF) detection is employed to identify and remove outliers, followed by the application of K-nearest neighbor (KNN) interpolation algorithm to address missing values. Finally, locally weighted scatterplot smoothing (LOWESS) is utilized to smooth the data and eliminate noise. Results indicate that the drilling speed prediction model built upon the processed data exhibits higher predictive accuracy. The proposed anomalous data handling methodology contributes to the enhancement of intelligent ROP prediction models, demonstrating practical utility.

1. INTRODUCTION
With the advancement of technology in the petroleum industry, intelligent drilling, as an efficient and intelligent drilling technique, has gradually garnered widespread attention (Lig, et al. 2022). Within this trend, intelligent prediction and optimization of drilling rate of penetration (ROP) have emerged as significant research areas in the field of intelligent drilling. Accurate prediction and optimization of mechanical drilling speed can significantly enhance drilling efficiency and reduce drilling costs, thereby injecting new vitality into the development of the petroleum industry (Barbosa, et al. 2019).
However, in reality, we face numerous challenges. The complex and dynamic nature of oilfield environments, coupled with the instability of data collection devices and the influence of environmental noise, pose significant challenges to the quality of drilling data (Geekiyanage, et al. 2021). In such circumstances, drilling data often contain various outliers and noise, which not only have the potential to misguide decisions made by drilling engineers but also interfere with the training of intelligent prediction models for mechanical drilling speed, thereby reducing the accuracy of the models.
Salt is Not a Steady-State Creep Material
Authors: Chieslar J. D. 
Published: August 2024

ABSTRACT:
Steady-state creep is increasingly used to model structures hosted in salt and potash. This is presumably due to the absence of representative constitutive models available in commercial geomechanics software. We consider a standard suite of tests performed on salt. These include creep, dilation and tension. These tests are fit to a simple material model and evaluated. Simulations of a solution mine are performed with varying degrees of completeness with respect to the constitutive model. Volumetric closures are calculated. This exercise quantifies the ramifications on closure (deformations) according to the various material assumptions. It is observed that both the creep transient and dilation contribute to closure. Furthermore, if a failure criterion is considered, dilation is the most appropriate candidate. It is insufficient merely to post-process a creep calculation to evaluate the potential for dilation. By it's nature, dilation is a strain-softening response. It localizes and concentrates and therefore must be included in the constitutive calculation.

1. INTRODUCTION
Numerous material models have been considered for describing salt and potash. Among these are MatMod (Miller, 1976), the WIPP creep law (Senseny, 1985) and more recently, the much researched and enhanced Munson-Dawson model (Reedlum, 2018). The principal shortcoming of these models is that each geological site is typically unique and has to be characterized anew, that is, there is not a universal constitutive model for salt nor for potash, as is typical for various metal alloys. The large suite of tests required to calibrate these models is impractical. These models typically have several tens of parameters. Tests must be diverse enough to span the basis represented by all of these parameters/freedoms and furthermore be consistent. For industrial operations, this becomes infeasible due to the expense of the expanded test regime and also the limited amount of core available, layered media, for example. Characteristic of the aforementioned models is the lack of attention to dilation. Salt and potash are complex materials, exhibiting a crystalline creep response much like metals, and also a dilational response (expansion as grains shear against one another) characteristic of granular materials, i.e., rock. Only the Munson-Dawson model addresses dilation but the corresponding state variable is a scalar. Anisotropy requires, at a minimum, a second-order tensor state variable.
Enhancing Cluster Efficiency by Modeling Swelling Diverter Particles in PKN-Type Fractures
Authors: Luo Bo , Wong George K. 
Published: August 2024

ABSTRACT:
Uneven fracture propagation stemming from reservoir heterogeneity, nonoptimal design, and stress interference significantly affects cluster efficiency in unconventional reservoirs. While the use of diverter agents in field to mitigate overgrown or less stimulated fractures holds promise, a thorough comprehension of the underlying mechanisms remains crucial. This work presents a coupled simulator that integrates a PKN-type fracturing model with a particle transport model to address the challenges of uneven fracture propagation in unconventional reservoirs. By combining nonlocal elasticity for stress interaction, a global tip asymptotic solution for multiscale tip behavior, and Eulerian-Eulerian method for particle transport and bridging, the simulator provides a robust framework for modeling field-scale particle diversion. The model includes particle swelling and dissolution characteristics to enhance fluid diversion effectiveness. The simulator replicates field treatment procedures, incorporating sequential additions of a fluid pad, diverter particle slug, and proppant-laden slurry. Numerical examples demonstrate its capability to achieve uniform non-propped lengths in viscosity-dominated propagation regimes and equal propped lengths in transition propagation regions. This tool optimizes pumping schedules and applies particle diversion technology to improve cluster efficiency during stage fracturing, enabling the design of optimal procedures for enhanced field performance.

1. INTRODUCTION
The heterogeneous nature of formations, coupled with nonoptimal well completions and stress interference, often results in unequal stimulation among clusters during stage fracturing (Rafieepour et al., 2020; Soliman et al., 2008; K. Wu & Olson, 2015; Zheng et al., 2019). This disparity in fracture growth leads to production variability substantiated by production logs (Cipolla et al., 2011; Miller et al., 2011). To counter this, fluid diversion techniques have emerged as a mitigation strategy by modifying or redirecting fluids toward less stimulated fractures. Field-tested applications have demonstrated the effectiveness of this approach (Evans et al., 2016; Fragachán et al., 2016; Gomaa et al., 2016; McCartney & Kennedy, 2016; Ugueto et al., 2020). Diverter agents, strategically placed at various locations such as perforation inlets, perforation tunnels, fracture entrances, and fracture tips, serve this purpose (Daneshy, 2019).
Modification of the Rock Mechanical Design of Salt Caverns on the Basis of Recent Research
Authors: Zapf Dirk , Körner Feline , Leuger Bastian , Baumgärtel Lukas 
Published: August 2024

ABSTRACT:
For some years now, the world has been facing the challenge of achieving an energy turnaround in the coming years. In this context, renewable energies are increasingly coming into focus, also with regard to the construction and operation of storage caverns in rock salt. In order to be ready for these challenges from an engineering point of view, a lot of research work has been carried out in recent years in the sector of dimensioning salt caverns for the storage of renewable energies. At the Institute of Geotechnical Engineering at Leibniz University in Hanover, Germany, a test apparatus was created that allows fracturing processes to be induced in rock salt test specimens. Various rock salt locations were investigated in the process. Research work on this aspect will be completed in the near future. The results of the research project will be presented and their consequences for the future storage of renewable energies in salt caverns will be discussed from an engineering point of view. In addition to the maximum and minimum operating pressures of a storage cavern, the thermodynamic stress during operation and the resulting stress and fracture conditions on a cavern wall will be discussed. The results of the research project are used to explain the modified dimensioning approaches.

1. INTRODUCTION
Energy in the form of gas, oil or petrol has been stored in salt caverns around the world for decades (Bays 1963, Thoms 2000). Some cavern structures already exist for storing renewable energies such as compressed air and hydrogen. The storage capacities of these media will be greatly expanded in the future and thus contribute to the global energy transition.
In Germany, the dimensioning of salt caverns is the responsibility of civil engineers specializing in geotechnical engineering. There is a strict mining law, and the approval authorities have high demands on the tightness and stability of the caverns. For this reason, dimensioning concepts have been developed by companies and universities in recent years, which differ in detail but all pursue the same goal: Safe storage of energy sources in salt caverns.
Experimental Study of the Effect of Porosity on EICP Biomineralization in Dolostone and Shales Under Uniaxial Compressive Stress Condition
Authors: Ngoma M. C. , Kolawole O. , Olorode O. , Kwon T.-H. 
Published: August 2024

ABSTRACT:
Biogeochemical-induced rock alteration is an evolving process that focuses on harnessing biologically induced chemical activities to change the mechanical properties and behavior of rocks. It often relies on enzyme-induced carbonate precipitation (EICP) which utilizes biomineralization by promoting the formation of calcium carbonate (CaCO3) in the rock pores and fractures. However, there is still a lack of knowledge on the effect of porosity on biomineralization in rocks from a mechanistic view. This study uses an experimental method to investigate the core-scale thermo-biogeomechanical alterations in low-permeability clay-rich rock (shale) and in high permeability dolomitic rock using the EICP treatment method. We first conducted EICP treatment of shale and dolostone samples using jack bean urease enzyme over a 3-day period at a distinct temperature. Subsequently, the mechanical properties were measured using uniaxial compression test. Finally, we analyzed the pre- and post-treatment changes in the dolomite-rich and shale rock samples to better understand the effect of enzyme-induced calcite precipitates on mechanical response of the rock samples. The results suggest that in dolostones with higher porosity, carbonate precipitation will have a greater impact on the mechanical properties than in shales with ultra-low porosity, when treated with EICP.

1 INTRODUCTION
Biogeochemical processes can enhance mechanical and flow (porosity and permeability) properties of rocks (Phillips et al., 2015; Kirkland et al., 2020; Kolawole et al., 2021). Prior research has provided insights into the impact of such complex processes for various geotechnical and energy engineering applications (Kolawole et al., 2021, 2022; Whiffin et al., 2007; Gao et al., 2019; Kolawole et al., 2023; Kolawole, 2023). For instance, Kolawole et al. (2022) evaluated the effect of bio-induced precipitation on tight carbonates for long-term storage integrity. To investigate this, biological media was injected into low-porosity carbonate samples for 30 days and the mechanical strength of the treated samples was measured using the uniaxial compression test. The results of the study showed an increase (&gt;100%) in Uniaxial Compressive Strength (UCS) of the carbonate samples. This increase in rock strength suggests that biogeomechanical alterations can enhance the strength of rocks and facilitate security of low-porosity carbonate caprocks.
An Efficient Coupled Hydro-Geomechanical Model for Determination of Open Hole Extended Limit of Drilling Horizontal Wells in the Permian Basin by Using Developed Environmentally Friendly High Performance Water-Based Mud
Authors: Metwally Mohamed , Gyimah Emmanuel , Koray Abdul-Muaizz 
Published: August 2024

ABSTRACT:
Drilling horizontal and extended reach wells (ERW) has played critical role in enhancing well productivity, efficient reservoir drainage, and minimizing environmental impact. Despite the benefits, technical challenges like high torque, shale instability, and managing equivalent circulation density pose limitations to extending lateral sections. To address these issues, the paper proposes a high performance environmentally friendly water-based mud (WBM) with a friction reducer (FR) for ERW drilling in the shaly Wolfcamp and Spraberry formations within the Permian Basin. Objectives include developing a thermally stable WBM, inhibiting shale instability problems, mitigating barite sagging, being environmentally friendly and determining the maximum open hole extension limit for ERW using the hydraulic Herschel-Bulkley rheological model coupled with geomechanics. The laboratory analysis showcases the WBM's thermal stability, improved capability to inhibit shale, effectiveness in preventing bit balling, reduction in barite sagging, and mitigated adverse effects on the ecosystem. The hydraulic model utilizing the Herschel-Bulkley rheological model exhibits high accuracy in determining equivalent circulation density and annular pressure losses. The study introduces an innovative environmentally friendly WBM that not only minimizes pressure loss but also effectively addresses shale-related challenges, serving as a viable substitute for oil-based mud. It provides a reliable hydro-geomechanically model for predicting the increase in open hole extension limit within a safe mud weight window, thereby enhancing wellbore stability in the Permian Basin.

1. INTRODUCTION
In the context of oil and gas exploration, the stability of wellbores plays a pivotal role in determining the success and safety of drilling operations. The subsurface environment introduces formidable challenges, with diverse geological conditions that can significantly impact the structural integrity of a wellbore (Amanullah et al., 2018). Geomechanics analysis emerges as a crucial tool in this scenario, providing a systematic framework for comprehending and addressing the intricate interactions between the wellbore and the surrounding rock formations (Gyimah et al., 2023). This analysis integrates geological, geophysical, and engineering data to construct predictive models, offering insights into potential instabilities and guiding drilling operations. Key parameters such as in-situ stress conditions, rock strength, pore pressure, and the effects of drilling fluid circulation are carefully considered in geomechanics analysis for wellbore stability (Bagheri et al., 2021).
The Role of Thick Competent Strata in Face Bursting in Underground Longwall Mines
Authors: Chambers D. , Boltz M. S. , Khademian Z. , Walton G. , Shragge J. 
Published: August 2024

ABSTRACT:
Coal bursts are violent dynamic failures that occur in underground coal mines and can injure workers and disrupt mining operations. The coal bursting phenomenon is complex and many factors contribute to a mine's propensity to experience bursting. Among these is the presence of thick competent strata (TCS) in the immediate roof or floor, but how the TCS contribute to bursting is not fully understood. In this work, we created a suite of simple 2D models of a longwall cross section whose stratigraphy is dominated by sandstone. We used these models to explore which TCS parameters influence burst severity and to define a likely failure mechanism. We found that the undermined length of un-caved TCS and properties of the coal-sandstone interface have the greatest effects on a model's burst severity. Interface slip initiated by coal yielding and driven by stored strain energy is the primary failure mechanism. Although real coal bursts are certainly more complex, this work provides insight into a plausible burst mechanism and contributing TCS factors that can guide future research.

1 INTRODUCTION
Coal bursts are violent dynamic failures that occur in underground coal mines. Much like earthquakes, coal bursts are notoriously difficult to predict and can be highly destructive. For example, in the past 40 years, coal bursts have resulted in more than 240 injuries and 20 fatalities in the United States (Iannacchione and Tadolini, 2016). In China, over 300 coal burst related fatalities have occurred since 2006 (Zhang et al., 2017). Many other countries have also experienced coal bursts including Japan, Australia, India, South Africa, Czech Republic, Canada, Germany, and Russia.
Coal bursts are driven mainly by stored strain energy in the coal or nearby strata, or triggered by a pressure wave from a remote source (Gale, 2018). Coal bursts continue to injure workers and disrupt mining operations and, despite research dating back nearly a century (e.g., Rice, 1935), many questions remain about the associated mechanisms and causative factors. For longwall mines, the most productive underground coal mining method, Mark (2016) identified significant seam depth (&gt; 600 m), mining proximity to faults or intrusions, dipping coal beds, multiple seam interaction, and the presence of thick competent strata (TCS) in the immediate (&lt; 15 m) roof or floor as risk factors. Face bursts (coal bursts occurring on the longwall face) have been particularly problematic for many deep mines in the Western United States. For example, between 1983 and 2017 the majority of the 149 bursts reported to the Mine Safety and Health Administration (MSHA) from mines in the state of Utah occurred on the longwall face (Mark, 2018). Severe face bursting has resulted in fatal injuries and even mine closures (Mark, 2016).
A Review of the Anelastic Strain Recovery (ASR) Technique for In-Situ Stress Measurements: A Suggested Test Protocol and Further Challenges
Authors: Lin W. , Sakai Y. , Kamiya N. , Cao Y. , Ishitsuka K. , Sun D. , Zhang C. , Nagano Y. 
Published: August 2024

ABSTRACT:
Determination of in situ stress states is one of the most important issues for rock mechanics, rock engineering, and geomechanics, but difficult challenges in its measurement technique remain. In the past two decades, we have conducted more than ten case studies related in-situ stress measurements by a core-based method called anelastic strain recovery (ASR) technique in both oceanic and continental deep drilling projects. The case studies covered a wide range in terms of rock types, retrieved depths of core samples, and research backgrounds. Through learning by trial and error of the applications of the ASR technique, we have established a practical test protocol and data processing procedure for determining three-dimensional in-situ stresses from the ASR measurement data. In this paper, we review previous case studies of stress measurements using the ASR technique and summarize the detailed test procedures, and suggest a standard test protocol for both oceanic and continental deep drilling project. In addition, we will also address challenges for the future.

1. INTRODUCTION
Stress state is a key parameter to understand plate tectonics, structural geological setting of subduction zones and to ensure safe and efficient developments of underground energy resources in great depths. Therefore, determination of in-situ stress states is one of the most important issues for rock mechanics, rock engineering, and geomechanics, but difficult challenges in its measurement technique remain. Stress measurements are carried out both in tunnels with large overburdens in civil and mining engineering and in deep boreholes for natural underground resources developments and for scientific investigations. Here, we focus on the in-situ stress measurements in both deep ocean drilling and continental (onshore) drilling in this paper.
In deep boreholes, methods of stress determination can be divided as downhole measurements such as hydraulic fracturing / extended leak off test, stress analysis using borehole breakouts and drilling induced tensile fractures, and core-based techniques. As the core-based techniques, Anelastic Strain Recovery (ASR), Diametrical Core Deformation Analysis (DCDA), Acoustic Emission (AE), Differential Strain Curve Analysis (DSCA), Deformation Rate Analysis (DRA) have been proposed (Amadei and Stephansson, 1997; Zoback et al., 2003; Zoback, 2007; Zang and Stephansson, 2010; Ito et al., 2013). In the past two decades, we have successfully conducted more than ten case studies of in-situ stress measurements by the core-based method called anelastic strain recovery (ASR) technique in both oceanic and continental deep drilling projects in geoscience and/or geoengineering areas. In this paper, we review previous case studies of stress measurements using the ASR technique, summarize the detailed test procedure, and suggest a standard test protocol mainly for deep boreholes.