bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flexural Attenuation With SLG (Solid Liquid Gas) Mapping – A New Technology to Evaluate Light and Contaminated Cements First Case Study in Pakistan
Authors: Hussain Atif , Khan Moin Raza , Gilani Rashid Hassan , Dar Usman , Mughal Muhammad Haroon , Khalid Arsalan , Javed Qasim 
Published: February 2016

ABSTRACT
Hydraulic or zonal isolation behind pipe plays a vital role in the life of a well. It guarantees well control, production from hydrocarbon zones and preventing the production of unwanted fluids. Perforation zone’s selection and remedial jobs are based on cement integrity. Common challenges faced in cementing wells in Pakistan are presence of thief zones, water/gas invasion in cement and improper mud displacement resulting in cement channelling.
Cement evaluation is as crucial as the cementing job itself. It is done using conventional sonic tools (CBL-VDL) which provides information about cement integrity. Sonic tools provide a qualitative uni-directional measurement. Then we have ultrasonic technology which measures "Acoustic Impedance" (AI) of annulus material; gives 100% azimuthal coverage with much better vertical and radial resolution than sonic tools. However, for light cements; the above conventional cement evaluation techniques cannot be used due to its limitations like: Effect of liquid and gas micro-annuli and dual casingInability to resolve micro-debonded/contaminated class G cement due to its threshold principleLow acoustic impedance contrast between liquid and cement i.e. for liquid 1.4–2.6 MRayls and for light cement 1.5-3.6MRayls
To address the above limitations a novel measurement of "Flexural Attenuation" (FA) is combined with AI that classifies the annulus material into three distinct states Solid, Liquid and Gas (SLG). In flexure mode casing is vibrated at an angle and combined with AI (vibration in thickness mode); giving us a unique output of SLG map. AI stand alone cannot evaluate light cements and contaminated class G cements with certainty.
A case study is presented; where light cement slurry was used. FA and AI measurements technology was combined to evaluate for zonal isolation. First time in Pakistan an ICE "Integrated Cement Evaluation" processing was applied; specifically designed for light cements and confident answers were obtained successfully. The AI showed 40–50% liquid contamination whereas SLG map confirmed solidified light cement behind pipe. FA and AI together confirmed zonal isolation and in turn provided aid for successful well control and completion of the well.
A Case Study of Improved Oil Recovery through Successful Application and Effective Management of Dumpflood Water Injection Technique
Authors: Noman Muhammad , Mehmood Faisal , Majeed Waqar , Mufti Madiha 
Published: February 2016

Abstract
Dumpflooding technique is defined as intentional cross-flow of water from a high pressure layer into depleting oil producing zone for the purpose of pressure maintenance. It is a highly economical method to improve oil recoveries as it requires no capital and operational expenses. After implementation, however, it is challenging to maintain optimal injectivity in dumpflooded potential oil zone given the nature of its subsurface process without direct measurements and monitoring.
This paper describes a case study of oil field discovered in 1993 by drilling of N-1 well which successfully penetrated two Sandstone reservoirs (B & C Sands). Open-hole logging and formation testing confirmed presence of oil in both Sands. Pressure production history of N-1 and subsequently drilled three developments wells determined C Sand to be moderate-tostrong water drive reservoir, whereas, B Sand witnessed poor pressure support with faster decline in oil production. Due to remote nature of this field, a full-fledge water injection project did not attract economics. In order to improve recovery of B Sand, it was evaluated to initiate dumpflood at the third development well, N-4, where C Sand was watered out. Geological analysis of the logs/core data suggests B Sand to be a laterally extensive Sand body, supporting the use of the dumpflooding technique in the given area. Engineering analysis was carried out using nodal analysis and tank models to estimate injection rates and additional recovery. After evaluating technical feasibility, dumpflooding was recommended and implemented at N-6, most downdip well located at Northern structure. The impact of dumpflood was realized on liquid withdrawals as well as pressures of B Sand. The injection performance of N-4 was routinely monitored and maintained through remedial measures. This way, the successfully implemented and well managed dumpflood process achieved significant increase in oil recoveries of the field.
Reaming with Casing Technology Reduces Rig Time by 50% in Challenging Limestone and Shale Formation in Pakistan
Authors: Khan Sajjad Ullah , Berghofer Karl , Prinz Albert , Khan Kafayat Ullah , Iftikhar Bilal , Rashid Muhammad , Ishaq Adnan , Mir Bilal Zafar , Mushtaque Saba 
Published: February 2016

Abstract
This paper covers successful Reaming with Casing job in Maino-17 located in Sindh, Pakistan. Throughout previous jobs during drilling in Miano block, Operator observed hole packoff and continuous caving, which raised concerns about running casing to TD. Specifically, drilling 12 ¼" hole section in Sui Main Limestone and Ghazij Shale, pressure and mechanical caving were observed throughout till TD. During wiper trip prior to run in hole 9–5/8" casing the hole condition was not good as it was packing off.
Based on the challenges faced in Miano, Reaming with Casing technology was selected. The objective was to run and ream 9 5/8" casing to a total depth (TD) of 5,581 ft (1,701 m) in unstable hole conditions using Reaming with Casing. The difference in pressures between the limestone and the shale increased the possibility of hole caving during casing running. Operator’s team deployed the technology with internal catch tool to run and ream the casing through the pressurized formation. The Reaming with Casing technology provided remotely operated casing running, which eliminated the need for a stabber in the derrick, reduced the number of floor hands, integrated self-interlock system and reduced the risk of casing drop. While running in, the mud weight was 9.7ppg (1,162 kg/m3), which was kept to the minimum to avoid hydrostatic burden on loss prone formations, encountered an obstruction at 5,213 ft (1,589 m) and could not pass through. Using the Reaming with Casing, operator reamed the last ten joints of casing to casing shoe depth at 5,590 ft (1,701 m). The job was completed in approximately 12 hours without incurring any nonproductive time.
Based on results, Reaming with Casing Technology was found very efficient, reducing approximately 50% of non-productive time, risk of POOH of whole casing string and associated cost as compare to conventional 9–5/8" casing job bedsides drill string/casing stuck in unstable hole. Using the Reaming with Casing technology enabled OMV to run the casing string to TD and improve operational efficiency in a challenging shale formation and enhanced safety by eliminating or removing personnel from the rig floor.
Application of Underbalanced Drilling in Conventional Reservoirs and is Prospects
Authors: Raza Shahzada Hassan , Lashari Shan e 
Published: February 2016

Abstract
The under balanced drilling technology has been under applied to the oil and gas well since the first cable tool well drilling. By the advent of rotary system the drilling fluid modified into mud system for controlled and smooth drilling operations. The under balanced technology revived again in mid-70’s due to the fore most need of such technology that can enable monitoring of reservoir fluid influx while drilling in progress and minimize reservoir damage. Some of the major prospect of under balanced drilling includes depleted zones, sub-normal zones and naturally fractured reservoirs. Where the prevailing myth about UBD Technology is its utilization in naturally fractured reservoirs, this paper will help to unfold enhance reservoir production achieved by UBD technology in conventional reservoirs.
The purpose of this paper is to acknowledge the UBD Technology in conventional reservoirs, specifically. The prospects of application will be discussed with a major focus on mature reservoirs (reduced formation damage in depleted formations) and newly developed fields. Early Screening for the right reservoir and different screening criteria for the application of UBD technology in conventional reservoirs will help the readers to understand the limitations and applicability. The economic and technological advantages will be discussed along with value added by UBD technology in the form of increase reservoir production in normal pressure reservoirs which mostly get damaged to some extent with conventional drilling techniques.
The paper will briefly describe the scope of UBD in Lower Indus and Middle Indus Basin. Through the work that has been done in similar reservoirs in Middle East, analogies will be developed. For further understanding, feasibility criteria of projects in local context will be considered that will enable the operators to take decision accordingly. The paper will also briefly explain the application of under balanced technology in normal pressure reservoirs with its limitations depending upon the UBD equipment safe pressure ratings in relation to reservoir pressures.
Production Enhancement by Installation of Jet Pump in SSD in Pakistan - Ghauri Oil Field
Authors: Kumar Sandeep , Farouque Khurram , Ahmed Sheraz , Qureshi Saeed , Awan Mohammad Saleem , Anjum Zulfiqar 
Published: February 2016

Abstract
This paper presents the first ever successful (Sliding Sleeve Door) SSD Jet Pump application in Ghauri oil field located in Jhelum, Pakistan. Ghauri is single completed well flowed with 22 API gravity from Sakessar Formation. Being a solution gas drive reservoir, the initial production rate declined quickly. Where, the jet pump was motivated by the need to use and revive the well without work-over.
Based on initial testing Data, jet pump was selected as a preferred artificial lift method. SSD was installed as a part of initial completion. As per SSD dimensions, downhole jet pump was designed. The pump was operated to enhance/ restore the production of well. During operations, the real time monitoring was conducted to optimize the parameters of pump, such as Nozzle/Throat combination or horsepower. In addition, the life of jet pump was calculated in relation to economic limits of the production.
Based on results, Jet pump was found the most economical and cost-effective artificial lift method for Ghauri. SSD Jet Pump deployment achieved expected performance and reliability. It has allowed the operator to save the cost of work over. The cumulative production with jet lift is folded twice when compared to cumulative production on natural energy. When the well production declined, the jet pump was easily re-optimized by pulling the pump using slick line for changing the nozzle and/or throat. The rest of the pump was unchanged to keep the CAPEX at low. In addition, further production of 200,000 BBLS is expected through jet pump.
THE RESULTS OF PHOTOMETRIC RECORDING OF THE OCCULTATION OF THE STAR HIP 97157 BY ASTEROID (41) DAPHNE WITH THE TELESCOPE OF THE GLOBAL MASTER ROBOTIC NET
Authors: Trunkovsky E. M. , Gorbovskoy E. S. , Denisenko D. V. , Tsvetkov D. Yu. , Lipunov V. M. , Kornilov V. G. , Ivanov K. I. , Gress O. V. , Poleshchuk V. A. , Budnev N. M. , Yazev S. A. 
Published: February 2016

ABSTRACT
We have carried out photometric observations of the occultation of the star HIP 97157 by asteroid (41) Daphne on 2013 October 25 with the 40 cm telescope of the Global MASTER Robotic Net, located in the Tunka Valley near Irkutsk. We have obtained the photometric drift-scan of the occultation in broadband visible light. The photometric curve of the occultation of the star by asteroid Daphne was obtained. From analysis of this curve we have determined the length of the “chord” of the asteroid in the direction of its motion corresponding to the time interval during which the asteroid completely “screened” the star's light: a ≃ 146.86 ± 0.24 km. Also, assuming that the angular diameter of the star is equal to d ≃ 0.″002, we have determined the angles between the velocity vector of the asteroid and its two opposite edges (considered as straight lines) where the disappearance of the star and its reappearance occurred:

for the front edge of the asteroid and

for its opposite edge. So these edges of the asteroid are inclined toward each other at an angle of about 8°.
TOWARD PRECISION SUPERMASSIVE BLACK HOLE MASSES USING MEGAMASER DISKS
Authors: van den Bosch Remco C. E. , Greene Jenny E. , Braatz James A. , Constantin Anca , Kuo Cheng-Yu 
Published: February 2016

ABSTRACT
Megamaser disks provide the most precise and accurate extragalactic supermassive black hole (BH) masses. Here we describe a search for megamasers in nearby galaxies using the Green Bank Telescope (GBT). We focus on galaxies where we believe that we can resolve the gravitational sphere of influence of the BH and derive a stellar or gas dynamical measurement with optical or NIR observations. Since there are only a handful of super massive BHs that have direct BH mass measurements from more than one method, even a single galaxy with a megamaser disk and a stellar dynamical BH mass would provide necessary checks on the stellar dynamical methods. We targeted 87 objects from the Hobby–Eberly Telescope Massive Galaxy Survey, and detected no new maser disks. Most of the targeted objects are elliptical galaxies with typical stellar velocity dispersions of 250 km s−1 and distances within 130 Mpc. We discuss the implications of our non-detections, whether they imply a threshold X-ray luminosity required for masing, or possibly reflect the difficulty of maintaining a masing disk around much more massive (

) BHs at a low Eddington ratio. Given the power of maser disks for probing BH accretion and demographics, we suggest that future maser searches should endeavour to remove remaining sample biases, in order to sort out the importance of these covariant effects.
MAXIMUM LIKELIHOOD FOREGROUND CLEANING FOR COSMIC MICROWAVE BACKGROUND POLARIMETERS IN THE PRESENCE OF SYSTEMATIC EFFECTS
Authors: Bao C. , Baccigalupi C. , Gold B. , Hanany S. , Jaffe A. , Stompor R. 
Published: February 2016

ABSTRACT
We extend a general maximum likelihood foreground estimation for cosmic microwave background (CMB) polarization data to include estimation of instrumental systematic effects. We focus on two particular effects: frequency band measurement uncertainty and instrumentally induced frequency dependent polarization rotation. We assess the bias induced on the estimation of the B-mode polarization signal by these two systematic effects in the presence of instrumental noise and uncertainties in the polarization and spectral index of Galactic dust. Degeneracies between uncertainties in the band and polarization angle calibration measurements and in the dust spectral index and polarization increase the uncertainty in the extracted CMB B-mode power, and may give rise to a biased estimate. We provide a quantitative assessment of the potential bias and increased uncertainty in an example experimental configuration. For example, we find that with 10% polarized dust, a tensor to scalar ratio of r = 0.05, and the instrumental configuration of the E and B experiment balloon payload, the estimated CMB B-mode power spectrum is recovered without bias when the frequency band measurement has 5% uncertainty or less, and the polarization angle calibration has an uncertainty of up to 4°.
APOGEE KINEMATICS. I. OVERVIEW OF THE KINEMATICS OF THE GALACTIC BULGE AS MAPPED BY APOGEE
Authors: Ness M. , Zasowski G. , Johnson J. A. , Athanassoula E. , Majewski S. R. , Pérez A. E. García , Bird J. , Nidever D. , Schneider Donald P. , Sobeck J. , Frinchaboy P. , Pan Kaike , Bizyaev Dmitry , Oravetz Daniel , Simmons Audrey 
Published: February 2016

ABSTRACT
We present the stellar kinematics across the Galactic bulge and into the disk at positive longitudes from the SDSS-III APOGEE spectroscopic survey of the Milky Way. APOGEE includes extensive coverage of the stellar populations of the bulge along the midplane and near-plane regions. From these data, we have produced kinematic maps of 10,000 stars across longitudes of 0° < l < 65°, and primarily across latitudes of

< 5° in the bulge region. The APOGEE data reveal that the bulge is cylindrically rotating across all latitudes and is kinematically hottest at the very center of the bulge, with the smallest gradients in both kinematic and chemical space inside the innermost region

< (5°, 5°). The results from APOGEE show good agreement with data from other surveys at higher latitudes and a remarkable similarity to the rotation and dispersion maps of barred galaxies viewed edge-on. The thin bar that is reported to be present in the inner disk within a narrow latitude range of

< 2° appears to have a corresponding signature in

and

. Stars with

> −0.5 have dispersion and rotation profiles that are similar to that of N-body models of boxy/peanut bulges. There is a smooth kinematic transition from the thin bar and boxy bulge

< (15°, 12°) out to the disk for stars with

> −1.0, and the chemodynamics across (l, b) suggests that the stars in the inner Galaxy with

> −1.0 originate in the disk.
NuSTAR UNVEILS A HEAVILY OBSCURED LOW-LUMINOSITY ACTIVE GALACTIC NUCLEUS IN THE LUMINOUS INFRARED GALAXY NGC 6286
Authors: Ricci C. , Bauer F. E. , Treister E. , Romero-Cañizales C. , Arevalo P. , Iwasawa K. , Privon G. C. , Sanders D. B. , Schawinski K. , Stern D. , Imanishi M. 
Published: February 2016

ABSTRACT
We report the detection of a heavily obscured active galactic nucleus (AGN) in the luminous infrared galaxy (LIRG) NGC 6286 identified in a 17.5 ks Nuclear Spectroscopic Telescope Array observation. The source is in an early merging stage and was targeted as part of our ongoing NuSTAR campaign observing local luminous and ultra-luminous infrared galaxies in different merger stages. NGC 6286 is clearly detected above 10 keV and by including the quasi-simultaneous Swift/XRT and archival XMM-Newton and Chandra data, we find that the source is heavily obscured (N
H ≃(0.95−1.32) × 1024 cm−2) with a column density consistent with being Compton-thick (CT,

). The AGN in NGC 6286 has a low absorption-corrected luminosity (L
2−10 keV ∼ 3−20 × 1041 erg s−1) and contributes ≲1% to the energetics of the system. Because of its low luminosity, previous observations carried out in the soft X-ray band (<10 keV) and in the infrared did not notice the presence of a buried AGN. NGC 6286 has multiwavelength characteristics typical of objects with the same infrared luminosity and in the same merger stage, which might imply that there is a significant population of obscured low-luminosity AGNs in LIRGs that can only be detected by sensitive hard X-ray observations.
EVOLUTIONARY TRACKS FOR BETELGEUSE
Authors: Dolan Michelle M. , Mathews Grant J. , Lam Doan Duc , Lan Nguyen Quynh , Herczeg Gregory J. , Dearborn David S. P. 
Published: February 2016

ABSTRACT
We have constructed a series of nonrotating quasi-hydrostatic evolutionary models for the M2 Iab supergiant Betelgeuse (α Orionis). Our models are constrained by multiple observed values for the temperature, luminosity, surface composition, and mass loss for this star, along with the parallax distance and high-resolution imagery that determines its radius. We have then applied our best-fit models to analyze the observed variations in surface luminosity and the size of detected surface bright spots as the result of up-flowing convective material from regions of high temperature in the surface convective zone. We also attempt to explain the intermittently observed periodic variability in a simple radial linear adiabatic pulsation model. Based on the best fit to all observed data, we suggest a best progenitor mass estimate of

and a current age from the start of the zero-age main sequence of 8.0–8.5 Myr based on the observed ejected mass while on the giant branch.
ARE WE THERE YET? TIME TO DETECTION OF NANOHERTZ GRAVITATIONAL WAVES BASED ON PULSAR-TIMING ARRAY LIMITS
Authors: Taylor S. R. , Vallisneri M. , Ellis J. A. , Mingarelli C. M. F. , Lazio T. J. W. , Haasteren R. van 
Published: February 2016

ABSTRACT
Decade-long timing observations of arrays of millisecond pulsars have placed highly constraining upper limits on the amplitude of the nanohertz gravitational-wave stochastic signal from the mergers of supermassive black hole binaries (∼10−15 strain at f = 1 yr−1). These limits suggest that binary merger rates have been overestimated, or that environmental influences from nuclear gas or stars accelerate orbital decay, reducing the gravitational-wave signal at the lowest, most sensitive frequencies. This prompts the question whether nanohertz gravitational waves (GWs) are likely to be detected in the near future. In this Letter, we answer this question quantitatively using simple statistical estimates, deriving the range of true signal amplitudes that are compatible with current upper limits, and computing expected detection probabilities as a function of observation time. We conclude that small arrays consisting of the pulsars with the least timing noise, which yield the tightest upper limits, have discouraging prospects of making a detection in the next two decades. By contrast, we find large arrays are crucial to detection because the quadrupolar spatial correlations induced by GWs can be well sampled by many pulsar pairs. Indeed, timing programs that monitor a large and expanding set of pulsars have an ∼80% probability of detecting GWs within the next 10 years, under assumptions on merger rates and environmental influences ranging from optimistic to conservative. Even in the extreme case where 90% of binaries stall before merger and environmental coupling effects diminish low-frequency gravitational-wave power, detection is delayed by at most a few years.
ALMA OBSERVATIONS OF A GAP AND A RING IN THE PROTOPLANETARY DISK AROUND TW HYA
Authors: Nomura Hideko , Tsukagoshi Takashi , Kawabe Ryohei , Ishimoto Daiki , Okuzumi Satoshi , Muto Takayuki , Kanagawa Kazuhiro D. , Ida Shigeru , Walsh Catherine , Millar T. J. , Bai Xue-Ning 
Published: February 2016

ABSTRACT
We report the first detection of a gap and a ring in 336 GHz dust continuum emission from the protoplanetary disk around TW Hya, using the Atacama Large Millimeter/Submillimeter Array (ALMA). The gap and ring are located at around 25 and 41 au from the central star, respectively, and are associated with the CO snow line at ∼30 au. The gap has a radial width of less than 15 au and a mass deficit of more than 23%, taking into account that the observations are limited to an angular resolution of ∼15 au. In addition, the 13CO and C18O

lines show a decrement in CO line emission throughout the disk, down to ∼10 au, indicating a freeze-out of gas-phase CO onto grain surfaces and possible subsequent surface reactions to form larger molecules. The observed gap could be caused by gravitational interaction between the disk gas and a planet with a mass less than super-Neptune (2

), or could be the result of the destruction of large dust aggregates due to the sintering of CO ice.