bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel End-To-End Solution for Developing Geomechanical Models Along Horizontal Wells Without Well Logs
Authors: Soroush Hamed , Gentry Emilie , Madyarov Andrew , Harmouche Jinane 
Published: September 2023

ABSTRACT
Knowledge of rock properties and in-situ state of stress along the horizontal laterals is essential to optimize frac and stage designs for maximum recovery and avoid casing deformation during fracturing. Also, the integrity of the borehole is directly dependent on the stress profiles along the well trajectory and appropriate design of the drilling and stimulation operations. However, lack of wireline logs such as dipole sonic, porosity, image, and density, which are required for estimation of geomechanical properties, prevents operators from having this valuable information and, thus, optimizing their operations. Our solution to this data challenge is Drilling Dynamic Geomechanics (DDG) technology that utilizes downhole drilling dynamics data to calculate continuous 1-D profiles of the rock mechanical properties, pore pressure, and principal stresses along the entire well length. Using a combination of Bit Vibration Signals (measured down-hole) and Electronic Drilling Recorder, EDR, data (routinely measured at surface) provides a low-cost high-value solution to this major problem. It uses readily available data, imposing no additional time for data acquisition. Drilling dynamics data are high resolution high scanning-rate and are available along the entire well length providing higher resolution estimates of geomechanical properties with significantly larger coverage in comparison to well logs. This paper describes our methodologies and results of field testing the technology in different basins.

INTRODUCTION
To ensure safe and cost-effective subsurface operations, knowledge of the state of stress is essential. Characterizing rock properties and the in-situ stress state in the complex reservoirs and cap rocks is critical for optimizing well designs and completions. Also, the integrity of the borehole is directly dependent on the 3D stress profile along the well trajectory and appropriate design of the drilling and stimulation operations. In-situ stresses are notoriously difficult to determine.
The currently available methodologies for stress estimation are heavily dependent on well logs such as density, sonic, porosity, etc. These inferences are based on simplified models or correlations which generally result in stress profiles with a large range of uncertainties and requirement to be calibrated against expensive field tests such as Extended Leak-off Test (XLOT), minifrac, and Diagnostic Fracture Injection Test (DFIT). The required logs are rarely available in horizontal wells, where understanding the lateral changes in the state of stress is very important. Also, seismic data that cover a larger volume of subsurface formations are not of sufficient spatial resolution for the required subsurface characterization, especially for carbon storage purposes.
Development of a Weak But Brittle Analog Sediment Rock for Experimental Study
Authors: Wibisono Doandy Y. , Gutierrez Marte , Majumder Dipaloke , Gautam Pradeep K. 
Published: September 2023

ABSTRACT
Laboratory-tested results in rock mechanics have played a crucial role in understanding rock behavior and failure mechanisms. This paper outlines the development of an analog rock, similar to sandstone, for an experimental study that yields a low unconfined compressive strength yet exhibits brittle failure characteristics. The F-75 Ottawa sand, Type I/II commercial grade Portland cement, air entrainment admixture, and water constitute the raw mixtures of the developed analog rock. The result is a reproducible homogeneous and isotropic rock. The effect of the air entrainment admixture and freezing-thawing cycle on the analog rock are investigated. This study amplifies the notable macroscopic fracturing after a limited post-yield strain. The unconfined compressive strength has been bounded at around 1.5 MPa, and the material continues to exhibit brittle behavior at a range of confinement. A set of Brazilian indirect tensile tests was used to assess the tensile strength, including the brittle failure analysis governed by the ratio between the unconfined compressive strength and tensile strength. In addition, the material physical properties were obtained, along with the thin-section-based porosity analysis. The synthetic sandstone is developed for a scale-model experimental study of brittle failure in tunnels using a true-triaxial apparatus that include spalling, dog-earing, and rockburst.

INTRODUCTION
Brittle failure in the underground excavation can be sudden and catastrophic, resulting in large cracks and fractures such as spalling and rockburst. This stress-induced failure is typically encountered in sparsely fractured or massive rocks at deep underground excavations (Martin et al., 1997). Therefore, understanding the nature of undesirable rock mass brittle failure is essential to provide mitigation plans for the associated risks.
One approach to enhance the understanding of behavior and failure mechanisms of rocks is through laboratory testing. However, it is challenging to collect natural, homogeneous, and undisturbed rock specimens of varying sizes from the field. Additionally, the natural specimen may introduce alterations to the variables that could differentiate the investigation plan in terms of reproducibility (Johnston & Choi, 1986). Hence, developing a repeatable analog rock mix can be considered with a flexibility range of controlled properties. In this case, the prepared analog rock specimens must have the characteristics of the investigated phenomenon (i.e., brittle behavior).
Investigating Grain Size Influence on the Stress-Dependent Permeability of Porous Rocks Using Particulate Discrete Element Method
Authors: Pothana Prasad , Ifrene Ghoulem , Ling Kegang , Garcia Fernando E. 
Published: September 2023

ABSTRACT
Reservoir in-situ stresses continuously evolve during the reservoir life cycle because of the production of hydrocarbons, injection of water and CO2 for enhanced oil recovery, storage of CO2, and nuclear waste disposal. The induced changes to the stress state deform the reservoir rock, including the pores and fractures in the rock, and hence change the permeability of the rock. Studies demonstrate that grain size significantly affects the mechanical properties and strength of rock, yet little research exists on the effect of grain size on stress-sensitive seepage behavior.
In this study, we investigated the effect of grain size on the stress-dependent flow behavior of a porous rock using the three-dimensional discrete element method. We modeled the porous rock geometry using randomly generated rigid spherical grains of given size distribution enclosed in a cuboid. Particle-particle interactions and wall-particle interactions are governed by the Flat-Joint contact model. Rigid boundary walls are used, and a constant strain rate is applied to the boundaries to reach a pre-defined confining stress state. Subsequently, we used the pore scale finite volume method to model the steady-state fluid flow of single-phase fluid at each confining stress state of the model.
The permeability-stress relationship data is best described by the exponential model, and the exponent of the exponential model (stress-sensitive coefficient) indicates how rapidly the permeability changes with stress. Our results show that the stress-sensitive coefficient varied very little with the grain size and shows a general decreasing trend with an increase in the mean grain size of the spherical pack. We argue that the effect of other parameters such as pore morphology, micro-cracks, and cementation has a greater influence on the stress-sensitive permeability than the grain size alone.

INTRODUCTION
The subsurface in-situ stresses exhibit dynamism, which is attributed to the influence of several anthropogenic factors such as reservoir depletion during hydrocarbon extraction, CO2 sequestration, geothermal activities, nuclear waste disposal, and natural causes arising from tectonic movements. Such stress variations significantly impact the physical properties of rocks, particularly their porosity, permeability, and dynamic elastic properties. Given the practical applications associated with these effects, the geoscience community has shown significant interest in this aspect.
The Role of Shear Deformation on Shale Fracture Reactivation and Conductivity Evolution
Authors: Yu Jiayi , Wang Jiehao , Li Yan , El-Fayoumi Amr , Wu Ruiting , Liu Xiaolong , Rijken Peggy , Rathbun Andrew P. , Elsworth Derek 
Published: September 2023

ABSTRACT
In this study, we conduct laboratory experiments reproducing fracture slip on both propped and unpropped fractures in Marcellus shale to explore the role of shear deformation as a primary control on permeability evolution and its correlation with initial stress state, shear stress magnitude and loading rate, and proppant loading concentration. For tests on unpropped fractures, we incorporate the complexity in both form and response of natural fracture topography by using pristine natural fractures directly split along bedding planes. Under low shear stress, unpropped fracture is prohibited from slipping by strongly mated interlocking asperities. As we increase shear stress exceeding the frictional strength of the contact, it exhibits great conductivity enhancement upon fracture reactivation followed by immediate and continuous decay. If shear stress is loaded incrementally instead of instantaneously – broadly representing different fracking fluid injection rate – fracture conductivity response to shear deformation is considerably muted. Unpropped fracture behaviors are also found to be strongly related to fracture roughness and fidelity of the interlocking asperities, while less sensitive to background stress state. For propped fractures, we use manually ground fractures to specifically focus on the proppant impacts. In contrast to unpropped fractures, conductivity enhancement upon shear reactivation only presents where proppant is placed as non-uniformly distributed monolayer, which can be attributed to the generation of interparticle highly permeable flow paths. Otherwise, conductivity decreases as a result of proppant embedment, crushing, and compaction, however the reduction is muted with thicker proppant pack.

INTRODUCTION
The shale gas revolution dramatically changed the mix of energy supply in the United States over the past decade. The deployment of horizontal drilling and massive hydraulic fracturing to generate highly permeable flow paths has unlocked the massive store of hydrocarbons held in deep, ultralow-permeability shale reservoirs (Warpinski and Teufei, 1987; Maxwell et al., 2002; Taleghani and Olson, 2011; Taleghani et al., 2016).
Quantifying the Potential for Induced Seismicity and the Associated Hazard and Risk for EGS Projects in Nevada and Oregon
Authors: Wong Ivan , Bubeck Alodie , Gray Brian , Lewandowski Nora , McGregor Ian , Smith Sarah , Wu Qimin , Chowdhury Ishika , Yenihayat Nesrin , Akerley John , Garrison Geoffrey , Cladouhos Trenton 
Published: September 2023

ABSTRACT
As part of the development of Induced Seismicity Mitigation Plans (ISMPs) for four proposed enhanced geothermal system sites in Nevada and Oregon, we are evaluating the potential for induced and triggered seismicity and the associated seismic hazard and risk at each site in line with the seven steps described in the U.S. Department of Energy's (DOE) Protocol for Addressing Induced Seismicity Associated with Enhanced Geothermal Systems. In Step 1, preliminary screening-level risk analyses are being performed to assess the potential impacts on the local communities and stakeholders during routine operations, including a possible worst-case scenario. In Step 3, criteria for ground vibration and noise are being reviewed and selected to assess the existing ground vibration and noise environments to establish a baseline, and evaluate the anticipated impacts. In Step 5, the seismic hazard at each project site is being estimated due to both natural and induced seismicity. The former provides a baseline from which to evaluate the additional hazard that may be imposed by induced earthquakes. In Step 6, a robust estimate of the seismic risk is being developed prior to the project and associated with the stimulation. The risk analysis helps evaluate alternative operational procedures, including those that could mitigate negative effects and minimize the risk from induced seismicity.

INTRODUCTION
As part of the development of Induced Seismicity Mitigation Plans (ISMPs) for four proposed enhanced geothermal system (EGS) sites in Nevada and Oregon, we are (1) evaluating the potential for induced and triggered seismicity, (2) performing probabilistic seismic hazard analyses (PSHAs) that address the hazard from both natural tectonic seismicity and potential induced seismicity, and (3) evaluating the associated seismic risk at each site. The ISMPs are being developed consistent with the seven steps described in DOE's Protocol for Addressing Induced Seismicity Associated with Enhanced Geothermal Systems (Majer et al., 2012).
The overarching purpose of the Protocol is to promote the safety of EGS projects and to help gain acceptance of geothermal development from the general public. The Protocol represents best practices regarding geothermal-induced seismicity and provides guidelines that should be followed to mitigate potential adverse effects from induced earthquakes.
Research on Targeted Hydraulic Fracturing Control Method Based on Theoretical Model
Authors: Wang W. Z. , Yang G. , Wang H. G. , Zhou Z. , Wang L. 
Published: September 2023

ABSTRACT
Targeted Hydraulic Fracturing (THF) is an effective method to increase oil or gas well production. This method involves injecting fluid into the reservoir to create fractures and stimulate the flow of hydrocarbons. Vuggy carbonate reservoirs provide a unique structure, allowing THF to optimize production. The key to successful fracturing is accurate targeting of the reservoir and the creation of artificial fractures connecting with the reservoir through construction methods. Therefore, in vuggy carbonate reservoirs, the turning radius of fractures is critical. The turning radius is affected by various factors, including the pre-existing fracture angle and construction parameters. A fracture expansion model that considers the influence of fluids was established to simulate the trend of fluid energy dissipation and the effect of internal fluid pressure on the expansion of fractures. Moreover, an accurate quantitative evaluation was conducted on the factors affecting the fracture turning range.

INTRODUCTION
Carbonate reservoirs, widely distributed throughout the world, contain a significant portion of conventional hydrocarbon reserves. Regions such as Tarim Basin in China, Arum River Basin in Turkmenistan, and Arab-D reservoir in Saudi Arabia are notable examples [1,2]. Exploiting these reserves, however, presents difficulties due to characteristics such as high temperature and pressure, depth of burial, low matrix permeability, poor porosity, and complex reservoir structure. Understanding the five primary carbonate formation types: pore, fractured, fracture-pore, fracture-cavern, and pore-fracture-cavern, is essential for reasonable and efficient development of these reservoirs. Due to the fact that the storage space for oil and gas in these reservoirs is primarily natural cavities and fractures, creating seepage channels through hydraulic fracturing is necessary. Acid fracturing has been shown to be the most effective technique for stimulating these reservoirs and making hydrocarbon production viable, with the primary mechanics of acid fracturing being acid dissolving and high-speed impact[9]. Specifically, establishing a targeted fracture propagation and steering model using pre-treatment fracture technology, which forms pre-treatment fractures with controllable direction and length around the well, is critical for achieving the goal of targeted fracturing of carbonate reservoirs.
Spatial Data Analysis of Water Production from Unconventional Reservoirs, Case Study from the Williston Basin, North Dakota
Authors: Bakelli Omar , Kegang Ling , Nesheim Timothy , Mahmood Taufique , Khetib Youcef 
Published: September 2023

ABSTRACT
With the instability of oil prices and the high investment cost associated with developing unconventional reservoirs, oilfield operators, contractors, and service companies are exploring new ways to optimize produced water (PW) management and reduce transportation, treatment, and disposal costs. In addition to this global trend, the Williston Basin faces more challenges due to pressurizing of underground disposal formation and the inadequacy and cost of existing purification technologies. Besides efforts toward the investigation of novel treatment methods that might offer new frontiers for PW reuse, reducing the co-produced water from upstream is still among the top solutions. Recent research showed the potential of spatial data analytics to disclose important information that serves future wells development and minimizes water production. The present study subscribes to these energies to demonstrate the role of spatial data analytics in a better understanding of the PW trend and to identify the high-volume root causes. Production data including multiple fields and producing formations were treated, normalized then visualized for this purpose. The first step, two production sections have been segregated from the data, flow back water and PW section. In the second step, an open-source GIS software was used to generate surface maps. Results analysis showed high values of water oil ratio (WOR) in West, Northeast, and Southwest fields of the Williston Basin with values reaching 94%, and low WOR recorded in central fields with values as low as 10%. The study confirmed the substantial correlation between WOR and the basin's geology configuration. The findings can be used to select a storage facility location and screen out field candidates for water control intervention. The research suggested merging production data with geology, well geometry, and completion data for in-depth insights and analysis.

INTRODUCTION
The petroleum industry is placing increasing focus on optimizing produced water (PW) management and reducing associated costs and environmental impacts. PW from oil and gas production encompasses various sources, including formation water, injected water for enhanced oil recovery EOR, associated chemicals and solids, and flowback water from hydraulic fracturing (Chard & Saunders, 2019).
Integrated Reservoir Simulation and Discrete Fracture Network Modeling for Produced Water Source Identification in Tight Reservoirs, Case Study from the Bakken Formation, Williston Basin
Authors: Bakelli Omar , Chellal Hichem Aimen Ketib , Aoun Ala Eddine , Khetib Youcef , Mellal Ilyas , Kegang Ling 
Published: September 2023

ABSTRACT
The Bakken reservoir in the Williston Basin recorded an increase in produced water volume, previous research suggested two possible reasons: Bakken formation pressure depletion allowing for more water migration and fractures propagation FP enabling fluid flow from the upper Lodgepole and/or from the lower Three Forks formations. The aim of this study is to investigate the two theories and to identify the best match with the real production data. An integrated reservoir model and a discrete fracture network DFN have been used for this purpose, wells and literature data from a Bakken reservoir field were associated to build the reservoir model and then compiled with natural fractures network generated using a DFN modeling tool. The assessment included four production cases: from the Bakken formation only, from the Bakken and Three Forks formations with downside FP, from the Bakken and Lodgepole formations with upside FP, and simultaneously from the three layers. The simulated models were evaluated using monthly production rates and cumulative volumes. Producing from the Bakken and Lodgepole formations case resulted in a good match, whereas the other three scenarios requested an unreasonable range of parameters for history matching. The third model's tight match establishes fracture propagation through the Bakken and Lodgepole formations as the most likely source of produced water. Natural pressure depletion of the Bakken formation and downside fracture propagation are implausible due to the unrealistic values required to match the models. This study might be expanded to include more fields to gain a more comprehensive knowledge of the Bakken produced water sources, and the outcomes serve as a guide for future wells implementation and development.

INTRODUCTION
In 2021, the United States oil and gas industry generated 25.86 Bbbls of produced water (GWPC, 2022). Effective management of produced water is crucial for the industry's sustainability and cost efficiency.
A Novel MCMC-Based Hydraulic Fracture Diagnostics Approach Using Water Hammer Data
Authors: Liu Lijun , Liu Yongzan , Wang Xiaoguang 
Published: September 2023

ABSTRACT
The water hammer signatures, which can be observed after pump shutdown at the end of a hydraulic fracture treatment, have proven to contain useful information about the geometry of generated hydraulic fractures. This paper presents a novel hydraulic fracture diagnostics approach using the water hammer data. A water hammer model that describes the pressure transient in hydraulically fractured horizontal well is established. In the model, a new multi-cluster hydraulic fracture boundary condition is derived by considering the perforation friction and leak-off in fractures. The method of characteristics is applied to efficiently solve the water hammer model. The water hammer signals can be effectively reproduced under different fracture characteristics. The MCMC method is applied to construct the posterior statistics of fracture parameters (e.g., width, length, height). The proposed approach is first verified by a series of synthetic models, and then applied to a real field case of a multi-stage hydraulic-fractured horizontal well in a shale gas reservoir to demonstrate its applicability and efficiency.

INTRODUCTION
Hydraulic fracturing has been the commonly used stimulation technique for the economic development of shale/tight gas and oil reservoirs. Although rapid progress has been made in fracturing technology, accurate characterization of hydraulic fracture is a great challenge which hinders the evaluation of fracturing efficiency and prediction of well productivity.
Various techniques have been developed to characterize hydraulic fractures, which can be divided into two categories, i.e., direct monitoring methods and indirect interpretation methods. Direct monitoring methods mainly include micro-seismic monitoring (Le Calvez et al. 2007; Zhu et al. 2017), fiber-optic sensing (Liu et al. 2020; Liu et al. 2023), coring observation (Maity et al. 2018), and downhole imaging (Roberts et al. 2018a; Roberts, et al. 2018b). These methods are usually characterized by their high accuracy, but limited by the high cost and limited observation range. Instead, indirect interpretation methods, including flowback analysis (Chen et al. 2018; Liu et al. 2019), pressure transient analysis (He et al. 2017; Wang et al. 2021), and water hammer analysis (Carey et al. 2015; Hu et al. 2022), are commonly used low-cost fracture diagnosis techniques. However, flowback analysis and pressure transient analysis usually require the production data after the well completion, which can hardly provide the real-time fracture information during hydraulic fracturing. The water hammer analysis has the advantages of short testing time, low-cost and real time.