bluuebunny/crossref_metadata_2025_split huggingface dataset:
Challenges and Solutions for Qualifying Proppants for Deepwater Wells
Authors: Fuss Tihana , Shi Jingyu , Thompson Matthew J. , Wilcox Craig , Herndon Daniel C. , Stephens Walter T. 
Published: September 2014

Abstract
Gulf of Mexico Continental Shelf and Deepwater formations represent a harsh environment which causes difficulty predicting operational requirements for proppants using traditional methods. Common formation conditions are very high closure stresses approaching 20,000 psi and temperatures varying from 220°F and upwards, nearing 500°F, such as in the Lower Wilcox Formation on the continental shelf. Deepwater wells present economic investment for investors several orders of magnitude larger than onshore conventional and unconventional plays common in current land assets. Operators therefore place a great deal of focus on the design of the frac pack, completion tools, production and field development. Required qualification and understanding of proppant performance at these conditions far exceeds that needed for today's extensive shale market.
Understanding the proppant behavior that brings economic value to these applications is difficult as current API/ISO performance measurements do not apply under these extreme conditions. Measurement artifacts due to limitations in laboratory materials, highly integrated measurement environment, apparatus limitation or statistical variability in proppant performance are common. New proposed protocol individually examines loss mechanism as a function of mechanical, thermal and chemical forces at high-temperature and high-pressure conditions. Integration of these proposed protocols with conventional testing allows better understanding of root causes of proppant performance losses.
Laboratory measurements of proppants permit defining a boundary that separates stable, predictable performance from variable, unreliable performance. Closure stress, temperature, and several degradation mechanisms, such as cyclic stress and corrosion attack, influence the position of this boundary with respect to the mechanical strength of the proppant. Results show that commercially available high strength proppants exhibit a statistically proven variable performance when used under high-temperature, high-pressure conductions common to Deepwater conditions.
Employing materials operating within a predictable performance regime is both an engineering and economic design decision for any fracturing application. Through independent evaluation of the mechanical, thermal, and chemical forces acting upon materials in the application, optimized solutions are possible that permit extracting value and stable performance from the well.
Evaluation of Defoamer Chemistries for Deepwater Drilling and Cementing Applications
Authors: Bava Luciana , Wilson Robert 
Published: September 2014

Abstract
The search for high performance defoaming agents has been intensified in recent years due to, for example, the challenging deepwater conditions and new environmental regulations for offshore drilling. The major task is to find suitable additives that pose little to no risk to the environment without compromising the performance and system integrity.
The use of defoamers in drilling and cementing applications is of vital importance for controlling and preventing excessive foam that can lead to problems ranging from operational difficulties (e.g., pump cavitation) to quality control and performance interferences (e.g., miscalculation of slurry density as most field mixers determine the water/cement ratio by measuring the density of the slurry). The detrimental effect of foam in cementing and drilling operations becomes more serious in deepwater applications where not only new technical and logistic challenges are encountered (e.g., poorly consolidated formation, high potential for shallow-flow hazards, low temperatures, etc.), but also optimum drilling efficiency and reduced operational time are required to keep costs down.
In this study, traditional blender tests and a novel dynamic foam analyzer were used to benchmark defoamer performance during simulated slurry mixing operations. In-depth evaluation of the initial and persistent efficiency enables accurate dosage comparisons in the lab, resulting in effective and reliable field operations. This paper presents a comprehensive study of various defoamer chemistries. Testing on high-foaming media comprising fluid loss additives, dispersants and gas migration control agents indicates that non-silicone outperform silicone chemistries. In the case of foaming agents for drilling, studies show that only silicone defoamers were a feasible alternative.
The oilfield industry is presently facing several challenges both from increasing environmental restrictions and also from specific field application requirements. The focus on finding suitable replacement additives for cementing and drilling systems without compromising the properties of completion fluids is a priority for many oil service companies. The use of a systematic approach for material selection is instrumental in reducing or eliminating risks to ensure maximum operation efficacy and longevity of cementing and drilling jobs while accommodating the unique factors pertaining to each individual project.
Experimental Research on Structural Casing Soaking Time in Deepwater Drilling
Authors: Zhou Bo , Yang Jin , Xu Yunjin , liu Zhengli , Luo Junfeng , Ye Jihua , Liu Shu Jie , Zhou Jianliang , Wu Yi 
Published: September 2014

Abstract
Structural casing is defined as the first string of casing installed in the well construction process. It provides structure and support for all the casing strings, the subsea christmas tree, and BOP stact. In the deep water drilling process, the soaking time of structural casing has directly influence on the bearing capacity and drilling period, and that is crucial in deep water drilling design.
Jetting of structural casing has become the preferred method of installation in most deep-water drilling. In order to decrease the risk of deep water surface drilling work, and to shorten the drilling period, this paper gives a simulation experiment on soil-pile interaction to get the change rule between soaking time and bearing capacity.
Once the structural casing string has been jetted successfully to final depth, a period of soak time is employed to allow the skin friction to increase and improve the soil to casing adhesion. Based on field experiments and mechanical analyses, the paper builds up a calculate method on wellhead load in different situations.
Considering the structural casing safe driving depth and drilling efficiency, it gives a design method of soaking time window of deep-water structural casing in different formation. Soak period of two to three hours is prudent insurance against casing subsidence after running tool release in clay strata, and one to two hours in sand and mud interbed strata.
This method optimized the setting depth of structural casing, improved the drilling efficiency, and saved more than 12 h per well on average with the ensurance of deep water drilling safety. It turns out a great application results in South China Sea deep-water drilling practice.
Overcoming Losses in Tophole Sections in Deepwater Namibia
Authors: Awalt M.. , Bogaerts M.. , Bonsu-Gyimah M.. , Joneja G.. , Meyer A.. , Auman J.. , Paul J.. 
Published: September 2014

AbstractThe continual increase in exploration drilling in southern Africa has translated into a number of remote deepwater campaigns, the most recent ones being in Namibia. One particular three-well campaign was exceptionally challenging as there was no near offset-well data available. The challenges were especially acute in the riserless tophole section.The well designs called for top of cement (TOC) at seabed for the surface casing. This was of the utmost importance for adequate structural and axial support for the blowout preventers (BOP) and subsequent casing strings. The very low fracture gradient near the seabed was the main challenge as the formations would not support the hydrostatic pressure of the cement column. On the first well, total losses were encountered prior to and during the entire cementing operation. As a result, no cement returns were observed at seabed, contrary to what was expected from hydraulic simulations and volume calculations and required to meet the job objective.To achieve objectives required for the success of the subsequent two wells, all aspects of drilling and cementing operations were reviewed based on the findings of the first well. Mud weight and casing setting depth were critically challenged, with other parameters adjusted. Cement formulation and density were optimized to reduce hydrostatic and hydrodynamic pressures and to increase the chance of success. The cement slurry was changed to a bimodal lightweight system with better fluid- and set-cement properties. Lost circulation fiber technology was also incorporated in the spacer preflush and in the cement slurry to mitigate any losses during placement.Alignment of service company and operator objectives and optimization of drilling and cementing parameters were critical for the successful cementation of these challenging tophole sections. Continuous improvements resulted in the second well being effectively cemented to seabed, even though intermittent losses were observed. After further optimization, the third well was cemented to seabed with full returns. Reaching the target TOC eliminated the need for a top-up job, saving valuable rig-time.
Reducing Drilling Risk Using Look-Ahead VSP – A Success Case Study for Carbonate Exploration Well, Offshore Vietnam
Authors: Dac The Nguyen , Sanders Michael , Millot Pascal , Rehman Sadu-Ur , Al Badi Othman , Golding Christopher James , Aquilina Giovanni , Fichera Rosario 
Published: September 2014

Abstract
The accurate prediction of the depth of top carbonate while drilling carbonate reservoirs is important to avoid losses and well control problems. This can have a significant financial impact. This paper demonstrates the use of innovative look-ahead VSP technology in Vietnam to refine depth prediction of the top of carbonate ahead of the bit for accurate geo-stopping.
An offshore exploration well was being drilled in an area with drilling challenges. This was the first well in the field and lacked offset well velocity information, so there was a high degree of depth uncertainty to the top of the carbonate target from surface seismic interpretations, making drilling operations risky. An intermediate VSP was requested to look for reflections ahead of the intermediate TD using Schlumberger VSI1 tool. The VSP data was acquired in open and cased hole using an air gun cluster as the seismic source.
The drilling program required the casing to be set immediately above the top of the carbonate. By acquiring an intermediate VSP, the depth uncertainty was reduced and the target depth prediction was refined. This was achieved using the look-ahead VSP technique, from which the acoustic impedance and velocity ahead of the bit was estimated. This was combined with time-depth from the VSP data over the logged interval to help refine the predicted depth to the top of the carbonate. This was used to optimize the depth at which the casing was set. The error range for the top carbonate depth from the surface seismic interpretation was +/−50m. The final prediction depth from the VSP interpretation is 6m shallower than the actual carbonate reservoir.
Guided by the inverted acoustic impedance log and velocity ahead of the bit from look-ahead VSP, a further 100m was safely drilled before setting the casing. The casing point was set successfully without penetrating the carbonate. The intermediate VSP results helped to decide drilling ahead in a safe manner with confidence, after setting the casing before penetrating the carbonate target.
Yield Improvement and Genotype × Environment Analyses of Peanut Cultivars in Multilocation Trials in West Africa
Authors: Narh Stephen , Boote Kenneth J. , Naab Jesse B. , Abudulai Mumuni , M’Bi Bertin Zagre , Sankara Philippe , Burow Mark D. , Tillman Barry L. , Brandenburg Rick L. , Jordan David L. 
Published: September 2014

ABSTRACTYield trials are used in plant breeding programs to evaluate the yield potential and stability of selected lines. The objectives of this study were to evaluate yield potential, genotype × environment interactions, and stability of peanut genotypes for the savannah region of West Africa. Twenty peanut (Arachis hypogaea L.) genotypes were tested at two sites in Ghana and two sites in Burkina Faso in 2010 and 2011. The experimental design was a randomized complete block design with three replicates. Genotype, location, and genotype × environment interactions were highly significant, indicating genetic variability among genotypes across changing environments. Stability analyses showed that genotypes ICGV‐IS 96814, ICGV (FDRS)‐20 × F‐MIX 39, Gusie Balin (92099), ICGV‐IS 92093, and ICGV‐IS 92101 had broad adaptability, with above‐average yield across sites and a regression coefficient close to 1.0. Genotype ICGV‐IS 96814 produced the highest pod yield (1760 kg ha−1) across all environments and had a regression coefficient close to unity (b = 1.06). Therefore, genotype ICGV‐IS 96814 is less responsive to varied environmental and soil conditions. However, the released cultivar Nkatesari was considered equivalent in some respects because it had pod yield equal to ICGV‐IS 96814 but with a higher regression coefficient. High‐yielding cultivars, mostly from ICRISAT‐derived crosses, yielded nearly 80% more than the three farmer check cultivars TS 32–1, Doumbala, and Chinese, which had pod yields from 890 to 980 kg ha−1. The higher‐yielding cultivars had longer life cycle, greater leaf spot resistance, and higher partitioning than the farmer check cultivars.
Mixed Stocking by Cattle and Goats for Blackberry Control in Rhizoma Peanut–Grass Pastures
Authors: Krueger N.C. , Sollenberger L.E. , Blount A.R. , Vendramini J.M.B. , Lemos N.L.S. , Costa A.G. , Adesogan A.T. 
Published: September 2014

ABSTRACTBlackberry (Rubus fruticosas L.) can be a weed in rhizoma peanut (Arachis glabrata Benth.)–grass pastures. Goats (Capra hircus) have provided effective control of Rubus spp. in other environments, but their efficacy has not been tested in legume‐grass swards in this context. The objective was to evaluate rotational stocking by goats alone or with cattle (Bos spp.) for blackberry control. Treatments stocked at 2.6 animal units (AU) ha−1 included a cattle‐alone control, goats alone, concurrent stocking of cattle and goats, sequential stocking of cattle followed by goats, and sequential stocking of goats followed by cattle. The final treatment was concurrent stocking at a stocking rate of 3.5 AU ha−1. Goats grazed blackberry readily, but cattle avoided it. Blackberry selection was greatest when goats followed cattle sequentially. The blackberry proportion of total biomass increased 10% when cattle grazed alone but was reduced 11% with goats alone and 13% with mixed concurrent grazing at a high stocking rate. Treatments including goats resulted in reductions or smaller increases in blackberry mass than for cattle alone. Goats alone or with cattle resulted in greater removal of blackberry leaf and in reduced height and stem density than cattle alone. Goats reduced the blackberry contribution more than cattle, but it was not eliminated from initially heavily infested pastures across 2 yr of grazing. A greater goat stocking rate or a combination of grazing and mowing may be needed for complete eradication.
Function Analysis of Sugarcane A20/AN1 Zinc‐Finger Protein Gene ShSAP1 in Transgenic Tobacco
Authors: Li Xiao‐jun , Wu Yuan‐Li , Yang Ben‐peng , Wang Jun‐Gang , Zhang Shu‐Zhen , Zhang Mu‐qing 
Published: September 2014

ABSTRACTWe tried to characterize the function of ShSAP1, a member of the stress‐associated protein (SAP) gene from sugarcane (Saccharum officinarum L.). The expression of ShSAP1 was much higher in mature part of vegetative organs, and significantly lower in young leaves and roots in mature sugarcane plants. ShSAP1 can be up‐regulated by salt and drought stress in 2‐mo‐old sugarcane seedlings. At the late seedling stage, transgenic tobacco with ShSAP1 exhibited an enhanced tolerance to salt and drought stress, and seven stress‐related genes showed higher expression level in transgenic lines than wild‐type (WT) plants under drought stress. Drought resistance was also presented during the vegetative stage in transgenic plants, as shown by the examination of drought physiological indexes. These results suggest that ShSAP1 plays a positive role in osmotic stress response.
Mapping of Quantitative Trait Loci Associated with Terminal Raceme Length in Soybean
Authors: Yamaguchi Naoya , Sayama Takashi , Sasama Hiroko , Yamazaki Hiroyuki , Miyoshi Tomoaki , Tanaka Yoshinori , Ishimoto Masao 
Published: September 2014

ABSTRACTSoybean [Glycine max (L.) Merr.] develops inflorescence meristems on each node, including the shoot apex. The flower clusters of the soybean raceme have a highly branched inflorescence structure, and their racemes are classified as terminal, primary, secondary, and so on. Raceme phenotype is an important trait associated with the number of floral buds and pods, and is dependent on the genotype. The breeding line 1532–1 was characterized by remarkably long racemes at the shoot apex of the main stem. To identify quantitative trait loci (QTLs) conditioning the terminal raceme length (TRL), a recombinant inbred line (RIL) population was developed from a cross between 1532–1 and an ordinary cultivar, Toyoharuka. The RILs were divided into two groups according to their alleles for a maturity locus, E1. The early‐maturing RIL group with the e1 genotype was used for QTL analysis of TRL, while the late‐maturing RIL group with the E1 genotype could not mature normally and lodged severely. Analysis of the early‐maturing group resulted in the identification of a stable QTL, qTRL18–1, where the 1532–1 allele had a positive effect on TRL. Another QTL, qTRL11–1, was detected only in the RILs with the 1532–1 alleles at the qTRL18–1 locus, indicating an interaction between qTRL18–1 and qTRL11–1. The qTRL18–1 locus was located in the proximal region of the Dt2 locus. No stable QTLs for flowering time or maturing time were detected in the proximal region of qTRL18–1 or qTRL11–1. Our results provide a new strategy to increase pod number on the main stem by marker‐assisted selection (MAS) for qTRL18–1 and qTRL11–1.
Laser Measurement System for the Diagnostics of Mine Hoist Components/Laserowy System Pomiarowy Do Diagnostyki Elementów Górniczych Wyciągów Szybowych
Authors: Olszyna Grzegorz , Sioma Andrzej , Tytko Andrzej 
Published: September 2014

Abstract
This article discusses a completely new concept for the diagnostics of sheaves in rope hoisting equipment used in deep mining, where excavated material, consumables, and people are transported via shafts. Rope sheaves involve shafting, guide sheaves, and support rollers on which ropes reel in special grooves. Those grooves may be made directly in the material of the sheave rim or in a specially installed plastic liner. Those grooves are made in the appropriate dimensions. Any change to those dimensions is due to a number of phenomena that occur in life cycle processes and significantly affects the condition of ropes. Measurement of the geometrical parameters of rope grooves for diagnostic purposes provides information about the condition of the rope system and guidance on the appropriate corrective actions. This article presents a solution that permits continuous measurement of selected geometrical parameters of the grooves using a non-contact method of scanning sheave rims with a laser beam. The basic geometric parameters of grooves and sheave rims were defined. The system was shown to be useful in the determination of axial and radial run-out of rope sheaves.
Applied Research of U-Shape Ventilation Network in Underground Mine/Badania Stosowane Sicie Wentylacyjnej W Kształcie „U” W Kopalni Podziemnej
Authors: Zhang Haoran , Pera Lluis Sanmiquel , Carla Vintro Sanchez , Zhao Yaojiang 
Published: September 2014

Abstract
For the purpose of fully and systematically observe, research and optimize the U-sharp ventilation system in Vilafruns mine, a simulation model based on the principles of geometric, kinematic and dynamic similarity is established in the simulation laboratory. By simulating a U-shape ventilation network, t he air volume distribution and wind velocity in different sections of the model were measured and compared with practical data obtained in Vilafruns mine. Results show that the lowest wind velocity in the model is higher than 0.42 m/s, thus it is in a turbulent f low state, which satisfies the kinematical and dynamic similarity principles. T he characteristic of air volume distribution and wind velocity in Vilafruns mine are basically simulated by the experimental model through the obtained data and figures, which reflects the establishment of the model is correct and successful, and the experimental data is accurate and reliable. Moreover, this model provides useful references for the selection of mine ventilation types and for the optimization of the existing ventilation network.
Mine Pressure and Rock Displacement Temporal Variation Analysis for Jiu Valley Directional Drifts in the Context of “n” Stability Criterion/Analiza Ciśnień I Chwilowych Przemieszczeń Skał W Badaniach Kierunkowych Wyrobisk W Kopalniach W Dolinie Jiu Z Uwzględnieniem Kryterium Stabilności ‘N’
Authors: Toderaş Mihaela , Moraru Roland Iosif 
Published: September 2014

Abstract
Ensuring mine workings stability over their entire operation period largely depends on the chosen support system and on their interaction with the surrounding rock. Looking at how the main horizontal mine workings are supported in Jiu Valley coal basin, we found that they fall into the category fulfilling a reinforcement role. From the data provided by the documentation of the collieries within this basin, it was found that there were generalized different metal - type supporting systems that with respect to operating and working mode are with constant or malleable strength and increasing - strength (rigid supporting systems). Research conducted on the stability analysis of horizontal mine workings aimed at elucidate the intensiveness and characteristics of mine pressure, the deformation character and contour displacement of rocks, the interplay between geo-mechanical deformation conditions and deformation extension, as good as the influence of these parameters on the supporting system’s behavior. This paper presents a methodology for determining the main laws of mine pressure regime distribution, the results of the burden load values and displacement of support, considering the “n” stability criterion as a complex parameter which can express the laws of variation, for the specific location and operating conditions of directional galleries within the floor of coal seam 3 in Jiu Valley.