bluuebunny/crossref_metadata_2025_split huggingface dataset:
Managed-Pressure-Drilling Technology in Offshore HP/HT Gas/Condensate Fields
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 171429, ’The Deployment of Managed-Pressure-Drilling Technology To Assist in the Development of Offshore HP/HT Gas/Condensate Fields in Vietnam: Planning, Engineering, and Implementation,’ by Ben Gedge, Tan Chai Yong, Jordan Rao, Harpreet Kaur Dalgit Singh, Joseph Oracion, and Bao Ta Quoc, Weatherford; Nguyen Viet Bot, PVD Well Services; Nam Hong Tran, Tri Le Tran Minh, Richard Buitenhuis, and Lich Tran Dai, Bien Dong POC; and Alan E. Wittry, Peter Malpas, Aldric Beaugeois, Nhieu Nguyen Huu, and Nguyen Van Que, Cuu Long JOC, prepared for the 2014 SPE Asia Pacific Oil and Gas Conference and Exhibition, Adelaide, Australia, 14-16 October. The paper has not been peer reviewed.
The paper discusses two gas/ condensate-development projects offshore Vietnam that deploy managed-pressure-drilling (MPD) technology. Bien Dong POC in 2010 commenced planning for the Bien Dong 1 high-pressure/high-temperature (HP/HT) gas/condensate-development project. The Bien Dong 1 development is a complex HP/HT project ranking as one of the most difficult and challenging projects of its kind in the Asia Pacific region. The second project covered by this paper is the gas-condensate development for Cuu Long JOC.
Introduction
The Bien Dong drilling team decided to deploy MPD technology in the planning phase of the development drilling and mobilized it for the first well drilled in the project. This decision was made because of the very low kick-and-loss margin and potential for ballooning and kick events, given the very high pore pressure. The frequency of well-control incidents can be higher in HP/HT wells; MPD enables easier control of kicks with the automated choke manifold.
A semisubmersible tender assist rig is being used to drill all the current development wells; it is the largest of its type in the world and incorporates a quad mast. The MPD equipment was integrated into the rig on a flexible “plug-and- play” basis.
The Cuu Long JOC wells, drilled from a cantilever jack-up over the platform, had somewhat different drivers, given that a number of wells in this field had previously encountered challenges that MPD could mitigate. These included low rates of penetration and fracture-induced losses because of the equivalent-circulating-density (ECD) effect. Managing the ECD became the main driver as experience was gained with MPD.
Unique System for Underbalanced Drilling Using Air in the Marcellus Shale
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 171024, ’Unique System for Underbalanced Drilling by Use of Air in the Marcellus Shale,’ by Chris Maranuk, SPE, Ali Rodriguez, SPE, Joe Trapasso, SPE, and Joshua Watson, SPE, Weatherford, prepared for the 2014 SPE Eastern Regional Meeting, Charleston, West Virginia, USA, 21-23 October. The paper has not been peer reviewed.
Air drilling has become popular in the Marcellus and Utica shale reservoirs because of its higher rate of penetration (ROP) and less resulting formation damage. A unique drilling system incorporating the use of downhole mud motors, electromagnetic (EM) measurement-while-drilling (MWD), and air hammers has been specifically designed and ruggedized to address downhole shock and vibration encountered in air drilling. Use of this system has resulted in significant reduction of nonproductive time (NPT).
Introduction
While seeking alternatives to increase ROP and reduce drilling costs, a few operators in the northeastern US implemented batch-drilling practices from pad locations. This provides an attractive alternative by allowing multiple wells to share the same surface location, effectively reducing footprint and environmental impact. Common well design uses streamlined well construction, where low-cost rigs can drill the tophole sections and larger, more-expensive rigs drill the curve and lateral sections. The typical well plan incorporates surface, intermediate, curve, and lateral sections that, combined, may exceed 18,000 ft. The lateral sections are the most critical and range between 2,000 and 8,000 ft, depending on formation and well geometry. The goal for close-proximity-well design is to minimize well-to-well interference and maximize reservoir exposure.
Air drilling provides a significant decrease in hydrostatic pressure over common mud types, resulting in an increased ROP. Additionally, significantly better hole cleaning can be achieved because of the high air velocities used to drill the well. Finally, mud- and cuttings-handling costs can be reduced because there are no chemicals to absorb and no cuttings-cleaning requirements on virgin formations. Early tests of this application proved it to be a viable option for the Marcellus and the Utica fields. Initially, hammer bits were used for air drilling, but significant challenges involving directional control emerged as well-plan trajectories became more advanced. The development of ruggedized mud motors and MWD tools capable of handling these challenges, and the use of specialized fluid-control systems, eventually allowed more-conventional bottomhole assemblies (BHAs) to be successful when used for air drilling.
Mars-B Development: An Evolution of Traditional Well, Rig, and Facility Design
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 25437, ’Mars-B Development: Well Challenges and Solutions - An Evolution of Traditional Well, Rig, and Facility Design,’ by Arno L.M. van den Haak, Wylie J. Cameron, Lisa S. Grant, Nor Janiah H. Japar, and Deandre R. Reagins, Shell, prepared for the 2014 Offshore Technology Conference, Houston, 5-8 May. The paper has not been peer reviewed.
The Mars-B project is the operator’s sixth Gulf of Mexico (GOM) tension-leg- platform (TLP) development. The Mars-B project is aiming to unlock resources over the next 50 years through the deployment of a new 24-slot TLP structure [the Olympus direct-vertical-access (DVA) TLP] and additional subsea infrastructure for the west Boreas and south Deimos fields. The Olympus rig is a novel platform drilling rig designed specifically to meet the execution requirements of complex well designs. A high-level overview of the design challenges and the resulting surface-equipment requirements of this project is discussed in this paper.
Introduction
The operator discovered the Mars field in the Mississippi Canyon Area Block 763 in 1989, located 130 miles southeast of New Orleans in approximately 3,000 ft of water. The Mars-B project made its final investment decision in September 2010 to expand the existing Mars operation with a new 24-slot TLP structure and additional subsea infrastructure for the west Boreas and south Deimos fields. The Olympus TLP is located approximately 1 mile southwest of the existing Mars TLP and represents the first brownfield development of a deepwater field in the GOM. It will enable production of an additional 1.1 billion BOE over the approximately 700 million BOE that has been produced today with the Mars TLP.
Improving the Interpretation of Formation-Damage Laboratory Tests
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 165110, ’Use of Micro-CT-Scanning Visualizations To Improve Interpretation of Formation-Damage Laboratory Tests Including a Case Study From the South Morecambe Field,’ by Justin Green, Ruaridh Cameron, and Ian Patey, Corex, and Vishal Nagassar and Mark Quine, Centrica, prepared for the 2013 SPE European Formation Damage Conference and Exhibition, Noordwijk, The Netherlands, 5-7 June. The paper has not been peer reviewed.
The paper presents a new approach that uses X-ray-microcomputed-tomography (micro-CT) scanning to produce high-resolution data of entire core samples. The images of core produced are superior to those produced by commonly used medical scanners and give insight into core properties as well as issues such as drilling-mud-constituent infiltration, mudcake structure and thickness, and alterations in the pore network. Through a technique that the authors refer to as “difference mapping,” data sets captured before and after laboratory testing are compared to reveal the distribution of changes within samples.
Introduction
Formation-damage laboratory studies aid in risk reduction when making important well-design decisions, so reducing uncertainty surrounding test results is an important effort.
The major areas in which laboratory testing can be influenced to provide the most meaningful (and therefore more valuable) information include the following:
Performing tests at reservoir conditions of temperature and pressure by use of reservoir overbalance and underbalance pressures and real/representative fluids and exposure periods
Ensuring that the equipment and procedures used have minimal or no effect on the results of testing
Understanding test results through interpretive analysis to put laboratory-test results into a field context
For a discussion of current techniques used to aid in core-sample interpretation, such as scanning electron microscopy (SEM), thin-section analysis, X-ray diffraction (XRD), and computed- tomography scanning, please see the complete paper.
Micro-CT Scanning
Micro-CT scanning uses a class of scanner that can rapidly capture a series of scans at high resolution; these scans can be reconstructed with software to create a 3D model of the object scanned. Resolution of significantly less than 1 Μm can be achieved on smaller subsamples, reducing as the sample size and length increases. The time taken to capture a data set also decreases as the resolution lowers, so the selection of operational settings is a balance of resolution vs. sampling times and data-set sizes. For scans of intact core samples, a maximum resolution of 10–15 Μm is achievable after taking into account sample size and sampling time.
Modeling Formation Damage and Completion Geometry in the Gyda Reservoir
Authors: Carpenter Chris 
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 165113, ’Modeling Formation Damage and Completion Geometry in an Old Well Enables Better Planning for New Wells: Gyda Development Case Study,’ by M. Byrne, SPE, and E. Rojas, SPE, Synergy, and V.B. Holst, SPE, Talisman Energy, prepared for the 2013 SPE European Formation Damage Conference and Exhibition, Noordwijk, The Netherlands, 5-7 June. The paper has not been peer reviewed.
This study concerns the mature Gyda reservoir, where some recent production wells have underperformed relative to equivalent initial wells. In particular, a sidetrack to an early successful well had very poor performance on initial startup. Subsequently, the geometry of both the original well and the sidetrack was simulated. In the original well, an attempted hydraulic fracture was assumed to have failed. This assumption was challenged in the model. The model has enabled evaluation of old wells and, more importantly, design of new wells in this mature-reservoir development.
Introduction
Gyda is a mature oil development in the Norwegian sector of the North Sea. The first production wells were drilled more than 20 years ago. Some recently drilled Gyda wells have not fulfilled production objectives. A numerical 3D model was proposed in order to investigate and understand the flow dynamics and the production potential from the Gyda A19 and A19A wells. This modeling process includes a detailed numerical 3D fluid-flow simulator based on computational fluid dynamics (CFD), which captures the reservoir, well, and completion geometry complexity.
The CFD simulations are used to determine potential explanations for the wells’ performance and lead to stimulation options and development of optimum drilling and completion for future wells. Because Well A-19 is very similar to Well A19A, some conclusions may be derived from the present study that could support the understanding of the productivity behavior of Well A19A.
To achieve the objective, one CFD model of both wells was constructed. Different completion options were provided, including the case of the hydraulically fractured well. Several sensitivity analyses were carried out in order to depict the well potential.
High‐Throughput Phenotyping of Cotton in Multiple Irrigation Environments
Authors: Sharma Bablu , Ritchie Glen L. 
Published: February 2015

ABSTRACTRapid screening of plant growth provides additional phenological information for cotton (Gossypium hirsutum L.), which may then be linked to productivity analysis in breeding and agronomy. We tested automated measurements of plant height, ground cover fraction (GCF), normalized difference vegetation index (NDVI), and canopy temperature (Tc) using a ground‐based platform mounted on a research sprayer on four cotton cultivars (DP1212, DP1219, FM2484, and PHY499) grown under 10 different irrigation levels at Lubbock, TX. Measurements consistently identified all irrigation treatments throughout the season in 2012, a dry year, and the lower irrigation treatments in 2013, a wet year, as well as differences in growth habits among cultivars in both years. The coefficient of determination (r2) of each in‐season parameter had a positive correlation with lint yield during both years. Lint yield values were compared with in‐season measurements at each sampling date. All cultivars had higher correlations between in‐season measurements and lint yield in 2012 than in 2013 because of the increased rainfall in 2013. In 2012, canopy temperature had highest correlation with lint yield, followed by plant height, GCF, and NDVI. In 2013, GCF, NDVI, and plant height all had higher correlations than Tc with lint yield. All the methods showed value in determining growth and yield, but selection of methods for screening may require adaptations based on the growth environment of the study.
Agro‐morphological Characterization of West and Central African Pearl Millet Accessions
Authors: Pucher Anna , Sy Ousmane , Angarawai Ignatius I. , Gondah Jada , Zangre Roger , Ouedraogo Mahamadi , Sanogo Moussa D. , Boureima S. , Hash C. Tom , Haussmann Bettina I.G. 
Published: February 2015

ABSTRACTPearl millet [Pennisetum glaucum (L.) R. Br.] was domesticated in Sahelian West Africa. This highly outcrossing crop is one of the most important staple cereals in the semiarid tropics, adapted to very harsh rain‐fed conditions. Agro‐morphological characterization of local germplasm is very important to better understand existing diversity, ease targeted genetic broadening of breeding populations, and potentially link this knowledge to genotypic information. The objectives of our study were to (i) characterize West and Central African (WCA) pearl millet accessions based on their agro‐morphological traits; (ii) evaluate the possibility to group accessions based on their agro‐morphological characteristics; (iii) determine geographic patterns of phenotypic differentiation; and (iv) derive conclusions for pearl millet improvement in WCA. A total of 360 early‐to‐medium maturity accessions were phenotyped for 12 agro‐morphological traits at six environments in WCA. Wide ranges of all observed traits indicated a high diversity of the tested accessions. Principal component analysis revealed very large diversity within individual countries, especially within Mali and Burkina Faso. Some limited grouping of accessions from Niger, Senegal, Cameroon, Morocco, and Mauritania was observed for individual principal component axes. Geographical differentiation and country differences were detected for several traits. The results and data presented in our study reflect WCA pearl millets’ tremendous diversity and adaptability to a wide range of environments and give a sound basis for breeders to select and utilize this germplasm to serve the manifold needs of WCA pearl millet farmers.
Molecular Mapping and Candidate Gene Analysis of a Yellow‐Green Leaf 6 (ygl6) Mutant in Rice
Authors: Shi Junqiong , Wang Yaqin , Guo Shuang , Ma Ling , Wang Zhongwei , Zhu Xiaoyan , Sang XianChun , Ling Yinghua , Wang Nan , Zhao Fangming , He Guanghua 
Published: February 2015

ABSTRACTA novel rice (Oryza sativa L.) mutant derived from the ethyl methane sulfonate‐treated restorer line Jinhui10 was identified that exhibited stable inheritance and was tentatively named yellow‐green leaf 6 (ygl6). Leaves of ygl6 were yellow‐green at the seedling stage and pale green at the jointing stage. The contents of chlorophyll a, chlorophyll b, and carotenoids were significantly lower in the mutant than those in the wild‐type (WT) at the seedling and heading stages. Leaf mesophyll cells of the ygl6 mutant and WT showed no obvious differences in ultrastructure. However, ygl6 chloroplasts developed abnormally with poorly developed thylakoids and fewer grana stacks. Genetic analysis demonstrated that the mutation was controlled by a single recessive gene. Genetic mapping of the mutant gene was conducted using 1997 recessive individuals from the F2 segregating population. YGL6 was mapped to the centromeric region of chromosome 12 between the insertion/deletion primers Ind23 and Ind37, with an interval of 143 kb. Sequence analysis of the candidate genes within the delimited region showed a single base‐pair change in Os12 g23180 that corresponded to a codon transition from leucine to a stop codon. Results of RNA interference knockdown of YGL6 suggested that Os12 g23180 is the candidate gene. Further characterization of YGL6 will provide insights into the molecular mechanisms of chloroplast development.
Carbonyl-Iron Electrodes for Rechargeable-Iron Batteries
Authors: Sundar Rajan A. , Ravikumar M. K. , Priolkar K. R. , Sampath S. , Shukla A. K. 
Published: February 2015

AbstractNickel-iron and iron-air batteries are attractive for large-scale-electrical-energy storage because iron is abundant, low-cost and non-toxic. However, these batteries suffer from poor charge acceptance due to hydrogen evolution during charging. In this study, we have demonstrated iron electrodes prepared from carbonyl iron powder (CIP) that are capable of delivering a specific discharge capacity of about 400 mAh g−1 at a current density of 100 mA g−1 with a faradaic efficiency of about 80%. The specific capacity of the electrodes increases gradually during formation cycles and reaches a maximum in the 180th cycle. The slow increase in the specific capacity is attributed to the low surface area and limited porosity of the pristine CIP. Evolution of charge potential profiles is investigated to understand the extent of charge acceptance during formation cycles. In situ XRD pattern for the electrodes subsequent to 300 charge/discharge cycles confirms the presence of Fe with Fe(OH)2 as dominant phase.
An assessment of the reliability of sea-ice motion and deformation retrieval using SAR images
Authors: Linow Stefanie , Hollands Thomas , Dierking Wolfgang 
Published: February 2015

AbstractThe local mass balance of sea ice is dependent on the advection of ice into and out of an area and on the deformation processes in that area. Sea-ice motion can be observed from space by synthetic aperture radar (SAR) and quantified by drift-detection algorithms. Due to the scarcity of field observations, it remains a challenging task to validate the resulting motion fields. We analyse the quality of sea-ice motion fields derived from SAR data, using an example dataset from the Weddell Sea region. We apply a quality indicator for sea-ice motion fields which is independent of field data and evaluate it with reference data obtained from visual analysis of the SAR images. Together with the motion field, sea-ice deformation can also be retrieved from SAR data. Similarly to ice motion, it is very difficult to obtain field data to evaluate the quality of the results. Based on a manually derived reference dataset, we introduce a method to validate the retrieved deformation rates. This procedure requires no additional field data. Our analysis shows that deformation rates derived from SAR data are consistent with results obtained from buoy analysis by previous studies.
Interannual variability of glacier basal pressure from a 20 year record
Authors: Lefeuvre Pierre-Marie , Jackson Miriam , Lappegard Gaute , Hagen Jon Ove 
Published: February 2015

AbstractBasal pressure has been recorded at the Svartisen Subglacial Laboratory, northern Norway, for 20 years, and is measured by load cells installed at the ice–rock interface under ~200m of glacier ice. Synchronous pressure variations between load cells are investigated as evidence of stress redistribution and hydrological bed connectivity. A running Pearson correlation is used to study the temporal variation in the response of several sensors. By studying the nature of this correlation as well as the correlation between sensor pairs, it is possible to investigate the evolution of the degree of synchronous response, and to some extent basal connectivity, at the glacier bed. Persistent seasonal variations associated with the melt season are observed throughout the measurement period, indicating dependence on surface hydrological forcing. Overlying this pattern, specific years with longer periods of positive and negative correlation of pressure between sensors are presented to show contrasting interannual variability in basal pressure. An anticorrelated connectivity is associated with a local increase in the rate of daily subglacial discharge, and is caused by load transfer or passive cavity opening. Stable weather appears to enhance connectivity of the sensors, which is attributed to the development of a persistent drainage system and stress redistribution.
Contrasting glacier variations of Glaciar Perito Moreno and Glaciar Ameghino, Southern Patagonia Icefield
Authors: Minowa Masahiro , Sugiyama Shin , Sakakibara Daiki , Sawagaki Takanobu 
Published: February 2015

AbstractGlaciar Perito Moreno (GPM) and Glaciar Ameghino (GA), Southern Patagonia Icefield, are in contact in the accumulation area, but have shown contrasting frontal variations in the past few decades. To investigate recent changes of the two glaciers and processes controlling the different responses to similar climate conditions, we measured surface elevation change from 2000 to 2008 and terminus positions from 1999 to 2012 using several types of satellite data. GPM shows no significant changes in terminus position and 0.4 ± 0.3 m a–1 thickening over the period, whereas GA retreated 55 ± 2 m a–1 and thinned 2.6 ± 0.3 m a–1. Mass-balance measurements over the period 1999/2000 show that accumulation at GPM was ten times greater than that at GA, but ablation was only three times greater. The mass-balance–altitude profile is similar for the two glaciers; differences in the mass-balance distribution are caused by differences in the accumulation–area ratio (AAR). Our results suggest that the AAR and the calving flux exert strong control on the evolution of glaciers in the region.