bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stimulation of a High-Temperature Granitic Reservoir at the Utah FORGE Site
Authors: McLennan John , England Kevin , Rose Peter , Moore Joseph , Barker Ben 
Published: January 2023

Abstract
Utah FORGE (Frontier Observatory for Research in Geothermal Energy) is a field laboratory for developing, testing, and prototyping technologies that could be adopted for commercializing Enhanced Geothermal Systems (EGS). The principle of developing an EGS is to use multiple hydraulic fracturing stages to interconnect an injection well and a production well – forming the surface area within a large heat exchange system. At the Utah FORGE site, near Milford, Utah, an injection well (65° to the vertical) has been drilled and a three-stage fracturing treatment was carried out at the toe of this well. A production well will be drilled into the stimulated domain determined from microseismic measurements. The objectives of the treatments were to establish if the created fracture networks will form independent flow networks between the injector and the producer, and ultimately to test long-term connectivity between the two wells. In addition, the mechanics of isolating stages and developing fracturing fluid viscosity in a naturally fractured granitic reservoir at 435°F [224°C] were evaluated.
Three stages were pumped. Geophones in three offset wells and shallow distributed acoustic sensors (DAS) and surface monitoring devices tracked the fracture evolution. The first stage was slickwater in a barefoot section, pumped at rates up to 50 bpm [7.95 m3/min]. Bridge plugs were used in 7-inch [177.8 mm] casing to isolate the next two stages, which each used a single long perforation cluster (20 ft [6.096 m] long, with six shots per ft at 60° phasing for each of the latter two stages). The second stage was slickwater pumped at rates up to 35 bpm [5.56 m3/min]. The final stage was crosslinked carboxymethyl hydroxypropyl guar (CMHPG) polymer fluid pumped at rates up to 35 bpm [5.56 m3/min] with low concentrations of microproppant. The well was flowed back between each stage to mitigate the potential for stage interference, facilitate running bridge plugs, and reduce the possibility of undesirable microseismicity.
Isolation technology had been a significant concern before the treatment. However, bridge plugs successfully functioned at these high temperatures – isolating stages 1 and 2 and stages 2 and 3. Treatment records show a significant morphological difference between pumping in the openhole section (stage 1), and in the two cased and perforated zones (stages 2 and 3). Microseismic data suggest nominally planar growth orthogonal to the wellbore for the two cased and perforated zones – favoring intersection with the soon-to-be-drilled production well.
These treatments superficially seem mundane. However, they successfully demonstrated the viability of hydraulic fracture creation in a cased well in hot, low permeability granitic rocks, a prerequisite for EGS development, revealed conditions for limited natural fracture interaction, and this was one of the few high-temperature granitic stimulation treatment programs since Fenton Hill in the 1980s.
Geomechanical Pumped Storage in Hydraulic Fractures
Authors: Schmidt Howard , Wright Scott , Mauroner Cliff , Lau Henry , Hill Bunker , Zhou Joe , Bunger Andrew 
Published: January 2023

Abstract
The capacity and importance of solar and wind power have been growing dramatically over the last few decades and now account for a material fraction of energy on our electric grids. These resources are intermittent, and large-scale, long-term storage methods are required. Here we describe Geomechanical Pumped Storage (GPS), and first results from feasibility studies performed in the field. GPS is a new approach for storing electric energy at scale that is conceptually similar to pumped hydro storage (PHS), which currently accounts for 94% of global energy storage. Like PHS, water is transferred from a surface pond to a high-pressure reservoir, and high efficiency pumps/turbines are employed to transfer the working fluid, effectively storing and extracting electric power by hydraulic means. Unlike PHS, which needs elevated terrain and gravity potential to realize a high- pressure reservoir, GPS injects water into a storage lens in the subsurface; the lens volume is pressurized by a combination of elastic deformation of the rock strata and overburden lift. GPS is under evaluation in four separate basins across North America. In each site, optimized completion and stimulation methods have been deployed and shown to consistently generate horizontal storage lenses with excellent connectivity to vertical wellbores. Novel methods have been developed and demonstrated for effectively increasing the fracture toughness of the rock matrix; this results in net pressures and lens widths about an order of magnitude greater than those used in stimulating unconventional reservoirs. These water-propped lenses have so far allowed injection and production rates at powers up to 100 kW with hydraulic efficiencies up to 90 percent. The completion and stimulation methods are being further developed towards commercially viable installations with powers above 1 MW for 10 hours or more.
Where's the Fluid? Using DAS Based Strain Measurement in Near Real Time
Authors: Davis Eric 
Published: January 2023

Abstract
Among the many data sets provided by fiber optic deployments in offset wells, low frequency DAS measurements provide detailed information on the wellbore axial strain during nearby hydraulic fracture treatments. Analysis of strain during a treatment typically consists of magnitude-based detection of fracture hits for location and event time. More detailed post-treatment analysis can tease out at least a few key components of far-field fracture solutions that match the pattern and evolution of measured strain, but the highly non-linear nature of the problem impedes real time solutions. This paper introduces a method that linearizes the problem, then applies a Kalman filter based inversion to determine the proximity of fluid to the offset well as it approaches the fiber during the treatment. The computationally efficient approach enables quick response during a treatment to unexpected fracture growth. The use of a Kalman filter also allows for the incorporation of other data types, such as microseismic locations, into an integrated inversion. Theoretical and field examples demonstrate the technique in action.
A Hybrid Data-Driven/Physics-Based Approach for Near-Wellbore Hydraulic Fracture Modeling
Authors: Michael Andreas 
Published: January 2023

Abstract
Variables affecting the near-wellbore region of a fractured well have a big impact on its post-stimulation well performance. Optimal hydraulic fracture (HF) initiation and early-phase propagation results in minimal near-wellbore tortuosity, decreasing the likelihood of screenouts and maximizing the resultant well productivity. While most predictive models for the HF geometry produced in a stimulation treatment consider the far-field region, the near-wellbore vicinity should be an integral part of a properly-engineered reservoir exploitation strategy, impacting the treatment's design and execution. In this work, a hybrid data-driven/physics-based approach is elaborated for modeling HF initiation and early-phase propagation from perforated horizontal wells.
An optimization scheme via oriented perforating is presented using the developed hybrid model, considering the orientation of the induced HF initiation (longitudinal or transverse with respect to a well drilled along the minimum horizontal in-situ principal stress) and the resultant formation breakdown pressure (FBP); the highest the wellbore pressure reached during the treatment. Transverse HF initiation (and early-phase propagation) is ideal for wells drilled in low-permeability "tight" formations, while FBP minimization decreases the overall on-site horsepower requirements for the stimulation treatment. The demonstrated optimization scheme is applied separately to the in-situ stress states of seven prolific shale plays from the U.S. and Argentina, suggesting oriented-perforating strategies targeting the promotion of transverse HF initiation in two of these (Barnett and Marcellus), while targeting FBP minimization in the remaining five (Bakken, Fayetteville, Haynesville, Niobrara, and Vaca Muerta). The effectiveness of such oriented-perforating strategies can potentially be compromised by fracturing fluid leakage around the borehole's circumference, which is shown to hinder transverse HF initiation.
The hybrid model is also used to estimate fracture initiation pressure (FIP) values for the seven shale plays studied, indicating significant discrepancies with analytical expressions used to approximate these FIPs in modern-day HF computational simulations. Finally, the framework is set for expanding this modeling approach over a range of in-situ stress states, incorporating data-driven (numerically-derived) aggregate correction factors to compensate for inaccuracies in the analytical approximations, which comprise the physics-based core of the proposed hybrid model. The impact of perforation geometry was not addressed in this study.
Reductions in Emissions and Fuel Cost with Start/Stop System Technology for Diesel Frac Fleets
Authors: Fulks Robert , Shelton Robert , Bishop Mark 
Published: January 2023

Abstract
Idling during hydraulic fracturing generates considerable emissions of NOX, CO, and particulate matter (PM). Field studies conducted during 2021-22 documented an average of 5 - 10 hours per day of diesel-powered idling during fracturing operations across multiple U.S. unconventional basins.
Prior to 2021 boardroom level corporate environment, social, and governance (ESG) initiatives by oil & gas producers focused on limiting gas leaks, Scope 1 (direct corporate) emissions, and overall carbon footprints. Controlling emissions during the idling of hydraulic fracturing equipment, until recently, had not been a high priority on executive ESG lists. "The name of the game in unconventional shale development has quickly shifted from production at all costs to maximizing cash flow and reducing emissions to improve ESG performance. Operators have placed a priority on their ESG efforts as financial institutions have prioritized responsible investing." (Walzel, B. et.al., 2021).
By late 2021 concerns associated with idling during fracturing operations drew more attention from operators. The issues of idle waste control (unnecessary emissions, fuel, and excessive maintenance cost), identified as easy to resolve, garnered limited attention. Yet by early 2022, the challenges associated with frac diesel idling remained prevalent and became more acute with the dramatic rise in diesel costs.
In early 2022 ESG surveys began to include mention of frac idle waste. Contributing to this is the fact U.S. frac fleets continued utilizing diesel and/or dual fuel (diesel combined with natural gas) engines for 91% of fracturing operations. One of the lesser-known characteristics of Tier 2 and Tier 4 diesel frac pump engines is the fact they burn 100% diesel during idling – including dual fuel engines.
Stop/Start technology, first adopted in the auto industry and later by long haul diesel-powered trucking companies, began gaining traction within the oil & gas industry in 2017. The reduction in idle times attributed to Start/Stop systems proved lower fuel consumption and emissions generation rates were possible. This study focuses on the contributions made by diesel Start/Stop technologies. Positive results from 2019 forward substantiate the efficacy of idle reduction methods used in conjunction with hydraulic fracturing. Limiting frac idle times proved effective in reducing frac emissions, lowering fuel consumption, as well as cutting maintenance costs for hydraulic fracturing fleets.
This report highlights a new Start/Stop technology with field results from 2021 – 2022. This recent technology delivered a simpler, innovative hydraulic start centralized plug & play method of powering an entire frac fleet rather than using multiple Start/Stop systems installed to electrically start each individual frac pump. The results of a 2022 Permian basin technology field application are presented here.
Validation of Continuous Wavelet Transform Closure Detection Technique Using Strain Measurements
Authors: Adel Gabry Mohamed , Eltaleb Ibrahim , Soliman M. Y. , Farouq-Ali S. M. , Cook Paul. J. , Soom Florian. A. , Guglielmi Yves 
Published: January 2023

Abstract
Although closure detection has a crucial role in hydraulic fracturing operations, significant debate surrounds the various methodologies to determine its value. Several competing methodologies have been presented in the literature that sometimesyield significantly different estimates of closure pressure and time. The conventional techniques rely on assumptions that may be competing or even contradictory.
The continuous wavelets transform technique is a data transform technique that convolves the pressure and/or temperature data using a short wavy signal called "wavelet". The wavelet transform provides a representation of the pressure signal by letting the translation and scale parameters of the wavelets vary continuously. That enables the analyst to find the details of the pressure data by observing the wavelet energy spectrum for the monitored signal (pressure and/or temperature) signal. In this case the event of contact between two fracture faces and complete fracture closure is clearly identified.
As a part of The EGS Collab project, a series of fracture injection tests have been conducted to estimate the minimum principal stress with direct observation of well bore deformation using the SIMFIP tool (Step-Rate Injection Method for Fracture In-Situ Properties). The tool monitors the deformation using strain gauges as a fracture opens and closes during multiple tests. The publicly available data provide a great opportunity to experimentally calibrate the new technique for detecting the closure event using continuous wavelet transform. The effect of fracture closure events and fracture faces contact events detected using continuous wavelet transform were compared to the experimental measured deformation.
The continuous wavelet transform technique for closure detection showed an agreement with the deformation measurement. The effect of the presence of natural fractures and complex fracture closure events were recognized using the continuous wavelet transform technique. The Contineous Wavelet Transform (CWT) is a global technique that can be applied to the pressure decline data without requiring further information about the reservoir geomechanical parameters or pumping data. The technique can be easily embedded in machine learning algorithms for hydraulic fracturing diagnostics.
Pressure Transient Analyses and Poroelastic Modeling of Hydraulic Fracture Dilation for Multiple Injections at the Devine Fracture Pilot Site
Authors: Haddad Mahdi , Ahmadian Mohsen 
Published: January 2023

Abstract
Our team has conducted electromagnetic (EM) surveys for the past six years to monitor hydraulic-fracture behavior at the Devine Fracture Pilot Site (DFPS). The sub-horizontal orientation of a shallow hydraulic fracture at the DFPS provides uniform access to the fracture area for interrogation and data collection. Ahmadian et al. (2023) suggested a possible correlation between spatiotemporal changes in the flow rate, bottomhole pressure (BHP), and the observed surface recorded electric field at the DFPS. In this paper, we present the development of poroelastic forward models and pressure transient analyses (PTAs) to support the development of a multiphysics inverse model for these EM surveys.
First, we conducted PTAs of the shut-in periods after six injections out of 10 to determine the fracture closure pressure (FCP) or the overburden pressure used in a poroelastic fracture reopening model. Second, we developed a finite-element poroelastic model throughout five injection cycles to include the effect of the cumulative injected volumes due to the previous injections on current fracture dilation in the presence of highly permeable unpropped and propped zones adjacent to the cohesive layer that models fracture reopening. Fracture reopening in this poroelastic model is based on a calibrated traction-separation response using the bottomhole pressure collected in two injection campaigns in 2020 and 2022. We used the outcomes of a previous simulation study of the primary hydraulic-fracturing stimulation to define the dimension of an unpropped fracture zone ahead of the propped fracture area.
The PTAs led to FCPs consistent with those obtained using the injection data collected at the DFPS in 2020. Further, these analyses showed that at later injections, the fracture closure occurred at a later time with respect to the shut-in time, inferring the effect of cumulative injected volumes in previous injections. The simulation results show that considering the propped and unpropped fracture zones improves our poroelastic model in predicting the injection-well BHP. The numerical simulation results demonstrate a significant excess pore pressure near the fracture because of the preceding formation loadings by the previous injections.
The obtained fracture dilation area and fluid pressure distribution provide a basis to improve the development of a multiphysics inverse model. Furthermore, in an iteratively coupled scheme, this pressure distribution can be introduced into EM models to render a holistic view of the causative mechanisms for the surface signal anomalies.
Sealed Wellbore Pressure Monitoring (SWPM) and Calibrated Fracture Modeling: The Next Step in Unconventional Completions Optimization
Authors: Olson Karen , Merritt Joshua , Barraez Rair , Fowler Garrett , Haffener Jackson , Haustveit Kyle 
Published: January 2023

Abstract
Sealed Wellbore Pressure Monitoring (SWPM) has been utilized across North and South America Basins with over 16,000 stages monitored as of June 2022. Since May 2020, the analysis procedure has been automated using a cloud-based software platform designed to ingest, process, and analyze high-frequency hydraulic fracturing data (Iriarte et al., 2021). A real time option of SWPM was also developed to aid in real time fracturing decisions (Ramirez et al., 2022).
The latest development is the added capability of a fracture model that can automatically history match the volume to first responses (VFRs) determined from SWPM. This next level allows for the matching of the VFRs and the visualization of the resulting fracture geometries from a fully-coupled fracture propagation, reservoir, and geomechanics simulator. The simulator is capable of accounting for complex processes such as poroelastic stress changes from depletion, allowing for evaluation of complex interactions of fracture propagation and depletion. Insights gained from this process allows the operator to optimize their completion design faster and with fewer field trials.
This paper’s focus is a case study of the DOE Eagle Ford refracturing project where a range of completion designs were trialed while monitoring offset SWPM and fiber optic strain. The resulting VFRs of the SWPM project were compared to the fiber data and then used to calibrate the fracture model. Fracture model calibration was first performed assuming that restimulation fractures propagated independently of the previously created fractures. The VFR of each stage design was calculated and summarized. The model is constructed with three stage designs primarily identified by cluster count: 7-clusters, 12-clusters, and 22-clusters. The VFR for the 7-cluster stage design was then used as an objective in an automated history matching algorithm employing the fracture model. The resulting best fit model was then evaluated on VFRs for the 12 and 22-cluster stage designs.
The results demonstrate the model calibrated to the VFR of the 7-cluster stage design was able to predict VFRs in the far field for 12 and 22-cluster stage designs. Further, it is shown that including the original fractures in the model and allowing crossflow between the original and newly created fractures can match the rapid VFRs observed on a minority of stages. These same results were confirmed by the fiber data (not shared with modelers prior to calibration).
Conclusions of the DOE project will show the optimum cluster spacing, cluster count and stage spacing as confirmed by the SWPM analysis and the fracture modeling.
Hydraulic Fracturing Value Boosting Through Operational Innovation and Data Analytics, MDC and Inchi Fields Case Study
Authors: Salazar Franck , Vasconez Nestor Danilo , Artola Pedro , Jaramillo Dorian , Cueva Diego , Cuenca Dario , Coronel Bernardo , Unapanta Mauricio 
Published: January 2023

Abstract
A fracturing campaign in mature fields in Ecuador demonstrated the advantages of hydraulic fracturing to optimize production and maximize the extraction of the remaining reserves. Good design practices were key to the success of the fracturing campaign in MDC and Inchi fields.
Initially, a comprehensive process of characterization was carried out to select the candidates for hydraulic fracturing in the Napo U and T formations to perform an initial fracturing campaign, studying among other characteristics, reservoir permeability, skin, pore pressure, remaining oil saturation, porosity, geomechanical properties, and completion integrity. A small group of wells was selected for hydraulic fracturing using the channel fracturing technique. The second phase consisted of optimizing the fracture design by improving the fracture geometry and conductivity, as well as the application proppant flowback control. Improved fracture geometry and proppant flowback prevention were identified as key elements for the success of the fracturing campaign in these mature fields.
Fracturing channel technique was implemented to generate higher fracture conductivity in a low reservoir pressure environment by creating a highly conductive fracture that reduce the drawdown pressure during production. Because of successful implementation, the channel fracturing technique became the preferred completion method in the field for wells requiring stimulation. Twenty five hydraulic fracturing treatments were performed from 2018 to 2022, all demonstrating outstanding production results. The implementation of hydraulic fracturing increased the volume of recoverable reserves by 20%. Operationally, the application of channel fracturing allowed performing more aggressive pump schedules without the risk of screenout, achieving fracture conductivities in the order of 90,000 md-ft and skin values of –2 and –3.5.
The learning curve and the results obtained in these fields are important sources of information for implementing hydraulic fracturing in mature fields to increase production and reduce risk.
A Novel Semi-Supervised Clustering Method for Carbonate Pore Size Distribution in Middle East Using Earth Mover Distance
Authors: Ma Ruicheng , Hu Dandan , Zhao Zeqi , Li Yong , Zhao Yixuan , Gu Fei , Wang Yuning 
Published: January 2023

Abstract
Pore space texture and its pore size distribution are critical parameters for displacement efficiency for waterflood, which have been applied in Middle East. For sandstone, pore size is a log-normal distribution usually. However, when it comes to carbonate reservoir, complex sedimentary and diagenesis yield complex pore size distributions including unimodal, bimodal and multimodal distribution. Therefore, it is not reasonable to classify different pore size distribution through statistic parameters such as mean, standard deviation, skewness and kurtosis. It is essential to propose a novel method to classify numerous pore size distribution results accurately and automatically by curve shape. This paper proposes the application of earth mover's distance (EMD) to pore size distribution, which is not mentioned before. The automatic clustering method is efficient and accurate to process massive data. Therefore, this method can prompt to systematic analysis and research of a giant scenario of reservoir injection characteristics in Middle East.