bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Shot in the Dark: How Your Post-Fracture Perforation Imaging can be Misleading and How to Better Understand Cluster Efficiency and Optimize Limited Entry Perforating
Authors: Horton Blake 
Published: April 2021

Abstract
With recent advances in downhole imaging technology, it has become evident that surface perforation testing does not directly translate to downhole conditions. A total of 279 pre- and 595 post- fracture treatment perforations were imaged in this analysis. Pre-treatment perforation hole size was highly variable, even with oriented equal-entry charges. Because of high pre-fracture treatment variability, it is not recommended to use an average diameter of unstimulated perforations to evaluate cluster efficiency of perforations post-fracture treatment. Ideally, perforations should be individually imaged before and after treatment for direct comparison. However, since pre-treatment imaging is costly, an alternate methodology is presented. The findings in this paper will challenge current understanding of actual pre-treatment hole sizes, their variability, and their implications on cluster efficiency.
Cluster efficiency cutoff limits have historically been subjective and promoted a false confidence in the ability of Completions Engineers to extend stage lengths and adjust perforation designs. A more stringent and calculated method of determining cluster efficiency is presented.
Utilizing both wireline pumpdown for pre-treatment measurements, and coil tubing for post-treatment measurements, downhole imaging technology was deployed to measure perforations from four separate perforation charge manufacturers for pre- and post- treatment erosional analysis.
Additionally, while understanding the strike/slip stress state of the Anadarko basin, perforations were oriented at 90° and 270° (degrees from top of wellbore), parallel to the maximum rock stress, promoting a shorter and less tortuous path to the fracture initiation point. Perforating at 90° and 270° reduced tortuosity and surface treating pressure, promoted a less variable pre-treatment perforation hole size due to its symmetry, and resulted in a significant increase in cluster efficiency verses pervious designs.
This project effectively optimized a perforation design utilizing pre- and post- fracture treatment perforation imaging and a thorough understanding of pre-treatment perforation hole size to evaluate the effectiveness of stress-targeted, oriented perforating and its effect on cluster efficiency, tortuosity, and pre-treatment hole size variability. The optimized design resulted in 84%-97% cluster efficiency and reduced surface treating pressure by 770 psi. This workflow can be applied by Completions Engineers to any unconventional basin where plug and perf design is utilized.
Practical Design Considerations for Stage Length, Perforation Clusters and Limited Entry Pressure Intensities
Authors: Huckabee Paul , Ledet Chris , Ugueto Gustavo , Tolle John , Mondal Somnath 
Published: April 2021

Abstract
This paper presents design considerations and field trial applications for determining practical dimensions and limits for interdependencies associated with stage length, perforation clusters and limited entry pressures. Recent applications by multiple authors and companies have begun to reverse the decade-long trend of reducing stage length and perforation spacing, in favor of extending stage lengths, to capture free cash flow value for unconventional resource development. Aggressive limited entry has been an enabler for successful extended stage length applications. Multiple authors have advocated "eXtreme Limited Entry" (XLE) applications. We present diagnostics data and applications that challenges the need for XLE and better constrains the necessary amount of limited entry pressures for effective stimulation distribution for resource development across multiple North American Basins.
Data is presented from integrated application of field trials, stimulation distribution diagnostics, and well performance analysis. Field trials and well performance analysis are from the Permian Delaware Basin Wolfcamp. The field trials include both: greater perforation cluster intensities for base design stage lengths; and extended stage lengths of 50% greater than the base designs. Diagnostics are from multiple North American Basins and include discrete treatment pressure diagnostics and optic fiber distributed sensing. Data is presented to quantify the magnitude and variability for components necessary for maintaining active fracture extension for multiple perforation clusters. Components include: fracture breakdown pressures; in-situ stress, net fracture extension pressure, and near wellbore complexity pressure drop.
Data and examples are presented from multiple wells, and resource development areas, to show the variability in measured treatment pressures for different length scale dimensions. This variability is used to determine the amount of limited entry pressure required to maintain fracture extension, dependent on the stage length dimension. Although Aggressive Limited Entry (ALE) is generally required to enable effective stimulation distribution and extended stage lengths in multiple cluster stages, examples are presented that demonstrate XLE is generally not required. We also discuss some of the considerations and observations that limit perforation cluster spacing intensities. Well performance data from the field trials is presented to validate the applications.
This work demonstrates the value of integrated application of field trials, stimulation distribution diagnostics, and well performance analysis to capture free cash flow value from improved completions and stimulation designs. The discussion will include an assessment of future opportunities for further extension of stage length dimensions.
Modeling Wellbore Proppant Transport and Distribution Across a Single Hydraulic Fracturing Stage Under Field Conditions Using Computational Fluid Dynamics
Authors: Kebert Brent , Almulhim Abdulraof , Miskimins Jennifer , Hunter William , Soehner Gage 
Published: April 2021

Abstract
Successfully treating each cluster within a hydraulic fracturing stage is a key objective for "plug-n-perf" well completions. Most operating companies would agree that the main underlying desire for a successful completion is related to future production capability. In unconventional reservoirs, propped and conductive hydraulic fractures are the primary completion result that drives production and reserve recovery. When designing a treatment, the spacing of clusters is critical to optimizing production and reserve recovery parameters, and therefore, even proppant distribution across a single stage delivers a well the greatest potential for optimized production performance. Diverting the fracturing fluid and proppant evenly across the clusters in a stage allows the greatest opportunity for each cluster to produce equally and drain the associated reservoir volume. Generating equal, producing fractures across a horizontal wellbore is a difficult problem that operators are still trying to solve.
This work models the fluid and proppant distribution across a field-scale, 250-ft long, horizontal hydraulic fracturing stage, replicating realistic field conditions. By utilizing computational fluid dynamics (CFD), this paper investigates the effected proppant distribution results from a fracturing stage mimicking the presence of both a leaking plug and the impacts of stress shadowing. The proppant concentration throughout the wellbore, along with internal wellbore pressure and velocity, are also reviewed to gain an understanding of the effect of the field conditions. Additionally, this paper illustrates the effect of different proppant "ramping" conditions during the fracturing stage. Proppant ramping schedules can be smooth or sharp when increasing proppant concentration, which alters the proppant concentrations throughout the wellbore and associated perforation clusters. Unanticipated alterations of the proppant concentration within the wellbore can lead to early screenouts. Gaining a better understanding of the proppant distribution and concentration inside the wellbore can lead to improved designs of hydraulic fracturing completions.
Application of DFIT-FBA Tests Performed at Multiple Points in a Horizontal Well for Advanced Treatment Stage Design and Reservoir Characterization
Authors: Zeinabady Danial , Zanganeh Behnam , Shahamat Sadeq , Clarkson Christopher R. 
Published: April 2021

Abstract
The DFIT flowback analysis (DFIT-FBA) method, recently developed by the authors, is a new approach for obtaining minimum in-situ stress, reservoir pressure, and well productivity index estimates in a fraction of the time required by conventional DFITs. The goal of this study is to demonstrate the application of DFIT-FBA to hydraulic fracturing design and reservoir characterization by performing tests at multiple points along a horizontal well completed in an unconventional reservoir. Furthermore, new corrections are introduced to the DFIT-FBA method to account for perforation friction, tortuosity, and wellbore unloading during the flowback stage of the test.
The time and cost efficiency associated with the DFIT-FBA method provides an opportunity to conduct multiple field tests without delaying the completion program. Several trials of the new method were performed for this study. These trials demonstrate application of the DFIT-FBA for testing multiple points along the lateral of a horizontal well (toe stage and additional clusters). The operational procedure for each DFIT-FBA test consists of two steps: 1) injection to initiate and propagate a mini hydraulic fracture and 2) flowback of the injected fluid on surface using a variable choke setting on the wellhead. Rate transient analysis methods are then applied to the flowback data to identify flow regimes and estimate closure and reservoir pressure. Flowing material balance analysis is used to estimate the well productivity index for studied reservoir intervals.
Minimum in-situ stress, pore pressure and well productivity index estimates were successfully obtained for all the field trials and validated by comparison against a conventional DFIT. The new corrections for friction and wellbore unloading improved the accuracy of the closure and reservoir pressures by 4%. Furthermore, the results of flowing material balance analysis show that wellbore unloading might cause significant over-estimation of the well productivity index. Considerable variation in well productivity index was observed from the toe stage to the heel stage (along the lateral) for the studied well. This variation has significant implications for hydraulic fracture design optimization, particularly treatment pressures and volumes.
Frac Charge Performance at Downhole Conditions: Assessments and Implications
Authors: Grove Brenden , McGregor Jacob , DeHart Rory , Dusterhoft Ron , Stegent Neil , Grader Avrami 
Published: April 2021

Abstract
Hydraulically fractured completions dominate industry perforating activity, particularly in North American land basins. This has led to the development of fracture-optimized perforating systems in recent years. Aside from overarching safety, reliability, and efficiency priorities, the main technical performance attribute of these systems is consistent hole size in the casing, driven by limited entry fracture design considerations. While the industry continues to seek further improvements in hole size consistency, attention is also being directed to the perforations more holistically, from a perspective of maximizing the effectiveness of subsequent hydraulic fracturing and ultimately production operations.
To this end, this paper presents two related activities addressing the development, qualification, and optimization of perf-for-frac systems. The first is a surface testing protocol used to characterize perforating system performance, in particular casing hole size and consistency. The second is a laboratory program, recently conducted to investigate perforating stressed Eagle Ford shale samples at downhole conditions. This program explored the influences of charge size, formation lamination direction, pore fluid, and dynamic underbalance on perforation characteristics. Casing hole size was also assessed.
For the first activity (surface testing), we find that using cement-backed casing can be an important feature to ensure more downhole-realistic results. For the second activity (laboratory program), perforation casing hole sizes for the charges tested were in line with expectations based on existing surface test data, exhibiting negligible pressure dependency. Corresponding penetration depths into the stressed shale samples generally ranged from 3.5-in to 5-in, which is much shallower than might be expected based on surface concrete performance. Dynamic underbalance was found to exhibit some slight effect on the tunnel fill characteristics, while pore system fluid was found to have minimal influence on the results.
An interesting feature of the perforated samples was the complex fracture network at the perforation tips, which appeared "propped" to some extent with charge liner debris. Some of these fractures were formation beds which had delaminated during the shot, a phenomenon observed for perforations both parallel and perpendicular to the laminations.
The implications of these results to the downhole environment continues to be assessed. Of particular interest is the impact these phenomena might have on fracture initiation, formation breakdown, and treatment stages which accompany subsequent hydraulic fracturing pumping operations.
Characterization and abatement of SOx, NOx and PCDD/Fs in iron ore sinter machine wind legs
Authors: Angalakuditi Veera Brahmacharyulu , Gujare Ramarao , Anbarasu Ramados , Gandikoti Thimmappa , Raydurg Srinivas Rao , Singh Lokendra Raj , Baral Saroj Sundar 
Published: April 2021

Abstract
It was observed that SOx and NOx, in large concentrations, are getting released from certain wind boxes below the sinter machine. The particulates released from specific wind legs were characterized using Quantitative Evaluation of Materials by Scanning Electron Microscopy (QEMSCAN). Particulates with spherical, cubical, needle and bar-like morphologies containing K, Na, Cl were found. Nitrogen-based solids were found in clutter-like morphology. Some particles had a mixture of the above, SOx and NOx. A method of dissolving SOx, NOx and breaking them down into harmless substances was explored in this research. The deposits in the wind legs were dissolved in demineralized water and solutions of sodium bicarbonate, urea, and di-sodium borate deca-hydrate (borax) to estimate the absorbance of K, Na, Cl, Ca, Mg, S, and N based compounds present. Demineralized water and sodium bicarbonate were found to be the most effective sorbents of SOx and NOx. The filtrates were examined under QEMSCAN and found that SOx and NOx are not present. Based on the above finding, a solution of sodium bicarbonate and water 0.01% v/v was sprayed into a wind box and found that SOx and NOx have got reduced by about 55%. To maximize the capture of SOx and NOx, the solution was optimized at 0.02% v/v. With this novel technique, capital intensive Desulphurization (De-SOx) and Denitrification (De-NOx) installation can be avoided. Additionally, an economical solution to the Polychlorinated dibenzo para-dioxins and polychlorinated dibenzofurans (PCDD/Fs) emission was explored in this research. Various physicochemical mechanisms of forming harmful substances are described in this paper.
Magnetically actuated self-clearing catheter for rapid in situ blood clot clearance for improved hemorrhagic stroke treatment
Authors: Yang Qi , Enriquez Angel , Devathasan Dillon , Thompson Craig , Nayee Dillan , Harris Ryan , Satoski Douglas , Obeng-Gyasi Barnabas , Lee Albert , Bentley R. Timothy , Lee Hyowon 
Published: April 2021

Abstract
Maintaining the patency of indwelling drainage devices is critical in preventing further complications following an intraventricular hemorrhage (IVH) and other chronic disease management. Surgeons often use drainage devices to remove blood and cerebrospinal fluid but these catheters frequently become occluded with hematoma. Using an implantable magnetic microactuator, we created a self-clearing catheter that can generate large enough forces to break down obstructive blood clots by applying time-varying magnetic fields. In a blood-circulating model, our self-clearing catheters demonstrated a 7x longer functionality than traditional catheters (211 vs. 27 min) and maintained a low pressure for longer periods (239 vs. 79 min). Using a porcine IVH model, the self-clearing catheters showed a greater survival rate than control catheters (86% vs. 0%) over the course of 6 weeks. The treated animals also had significantly smaller ventricle sizes 1 week after implantation compared to the control animals with traditional catheters. Our results suggest that these magnetic microactuator-embedded smart catheters can expedite the removal of blood from the ventricles and potentially improve the outcomes of critical patients suffering from often deadly IVH.
Soil fertility of fluvial islands increases with proximity to an Amazonian white-water river
Authors: Neto Gilson de Souza Ferreira , BACCARO FABRICIO BEGGIATO , QUESADA CARLOS ALBERTO NOBRE , FIGUEIREDO AXA SIMÕES , OLIVEIRA REGISON , GOMES ERISON , SPIRONELLO WILSON ROBERTO , BARNETT ADRIAN PAUL ASHTON 
Published: April 2021

Abstract
The nutrient content of soils is considered a productivity key factor. Sediment input from Amazonian rivers is one of the natural sources of soil fertility for fluvial islands and riverbank flooded forests. Despite the importance of soil factors for ecosystems, few edaphic studies along riverine sediment-gradients have been undertaken in tropical areas. The current study provides a step forward by describing soil nutrients in a mixed water (sediment-poor black water with input of sediment-rich whitewater) fluvial archipelago. To investigate how geographic distance from a whitewater river mouth affects island soil properties, soil chemical and physical attributes were determined at 61 sampling sites on 35 islands. The studied Central Amazon fluvial islands showed high variability in our fluvisols soil properties. In general, the fluvial island soils were acid and with low fertility. Islands from Jaú and other sites closer to the sediment source (the river Rio Branco) had higher soil fertility than islands of the Anavilhanas Archipelago, which are further away from the sediment source. Our results show that sediment inputs from Amazonian rivers can play an important role in soil properties, and this research increases our understanding on the origin and evolution of one of the largest freshwater archipelagos in the world. Given that soil fertility is often correlated with forest productivity, the main results reported here may also help improve management plans and conservation policies for fluvial island environments of Central Amazonia.
Adaptive vibration control of piezoelectric cantilever beams with uncertainties
Authors: Cui Mingyue , Liu Hongzhao , Jiang Hualong , Qu Chongnian , Liu Wei 
Published: April 2021

Abstract
Considering the stiffness characteristics of piezoelectric layer, the bending stiffness of piezoelectric cantilever beam is obtained by applying the first-order shear deformation theory. The finite element model of piezoelectric cantilever beam is established by Hamilton variation principle. At the maximum strain point, the sensors/actuators are equipped in pairs. Based on the uncertain dynamic model of piezoelectric cantilever beam, an adaptive sliding mode controller (ASMC) is designed by using backstepping technique. The correctness of the finite element model of cantilever beam established is verified by comparing the calculation results of ANSYS software. The effectiveness and superiority of the proposed the ASMC method are verified by the numerical simulations, in comparison with traditional linear quadratic regulator (LQR) control method.
Heat Preconditioning Protects Skin Pressure Injury and Reduces Incidence of Intraoperatively Acquired Pressure Ulcers in Both Humans and Animals
Authors: Xue Huiping , Chang Shuwen , Hou Ping , Xie Ping , Chen Yajie , Wang Yanwei , Miura Daiji , Fan Jianglin , Liang Jingyan , Kitayama Akio , Fang Fang , Yuan Haijuan , Wu Xiaoling , Zhang Xiaolin , Wang Jing , Ding Ning , Zhang Can , Sun Xiuyun , Takashi En 
Published: April 2021

Abstract
To examine the preventive effect of heat preconditioning (HPC) on intraoperatively acquired pressure ulcers (IAPU) in surgical patients and explore the mechanisms of HPC on pressure injury (PI) in rat skin. We generated a skin PI model using hairless rats and treated these rats with HPC. Skin injury size was measured and the expression of heat shock proteins (HSPs) in the skin were examined by real-time RT PCR, Western blotting, and immunohistochemical staining. For human studies, 118 surgical patients were randomly divided into HPC and control groups. We measured sacral skin temperature, sacral pressure and compared the PI prevalence rate. HPC treatment significantly reduced both area(p =0.007, p =0.007, p =0.012) and incidence (p=0.025, p =0.019, p =0.012) of PI in rats on the second, third and fourth days. HSP27 expression was increased in HPC group. Immunohistochemical staining showed that HSP27 was distributed in all types of dermal cells with increase in basal cells. In human studies, HPC treatment increased sacral temperature (p<0.001). The incidence of IAPUs was significantly decreased by 75% in HPC group. HPC can reduce the incidence of PI in both experimental animals and humans. Beneficial effects of HPC were possibly mediated by upregulation of HSP27.
Benefits of Betanin in Rotenone-Induced Parkinson Mice
Authors: Thong-asa Wachiryah , Jedsadavitayakol Sujira , Jutarattananon Suchawalee 
Published: April 2021

Abstract
The present study aimed to investigate betanin’s neuroprotective effect in mice with rotenone-induced Parkinson-like motor dysfunction and neurodegeneration. Forty male ICR mice were divided into 4 groups: Sham-veh, Rot-veh, Rot-Bet100 and Rot-Bet200. Rotenone (Rot) at 2.5 mg/kg/48 h was subcutaneous injected, and betanin (Bet) at 100 and 200 mg/kg/48 h were given alternately with the Rot injections in Rot-Bet groups for 6 weeks. Motor dysfunctions were evaluated weekly using hanging wire and rotarod tests. Malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), neuronal degeneration in the motor cortex (MC), striatum (Str) and substantia nigra par compacta (SNc) were evaluated. The immunohistochemical densities of tyrosine hydroxylase (TH) in Str and in SNc were also measured. We found that rotenone significantly decreased the time to fall in a hanging wire test after the 4th week and after the rotarod test at the 6th week (p<0.05). The percentage of neuronal degeneration in MC, Str and SNc (p<0.05) significantly increased, and the TH density in Str and in SNc (p<0.05) significantly decreased. Betanin at 100 and 200 mg/kg significantly prevented MC, Str and SNc neuronal degeneration (p<0.05) and prevented the decrease of TH density in Str and in SNc (p<0.05). These findings appeared concurrently with improved effects on the time to fall in hanging wire and rotarod tests (p<0.05). Treatment with betanin significantly prevented increased MDA levels and boosted GSH, CAT and SOD activities (p<0.05). Betanin exhibits neuroprotective effects against rotenone-induced Parkinson in mice regarding both motor dysfunction and neurodegeneration. Betanin’s neurohealth benefit relates to its powerful antioxidative property. Therefore, betanin use in neurodegenerative disease therapy is interesting to study.