bluuebunny/crossref_metadata_2025_split huggingface dataset:
Casing Stretch Simulation in Extended Reach Wells Prevents Unintentional Blockage of Flow Path While Displacing the Slurries to the Annulus in a Primary Cement Job
Authors: Corona Mauricio , Ruzhnikov Alexey , Sebbane Slimane , Jain Bipin 
Published: November 2019

Abstract
This paper describes the process followed to explain the mechanical blockage in the flow path observed while displacing the cement slurries in long casing strings set with short rat holes. In most of the cases, those blockages ended with amount of cement left in pipe and significant remedial works.
All the incidents were investigated involving casing design experts, cementing specialists and data analysts to understand the root causes. Mud logging unit, cementing and rig sensors data from several cementing jobs were analyzed in an integrated and holistic approach. Four different software’s were used to simulate and prove the theory that total elongation of the casing was enough to exceed the rat hole length bringing the casing in contact with the bottom of the well, and therefore blocking the flow path.
In all the incidents, the issue was observed at the beginning of the slurry displacement stage where the entire volume of the cement was still inside the casing. Other possible causes of blockage (cement contamination, mechanical failures, loss control material,…) were also checked and ruled out.
Hookload data was available to be analyzed whenever a conventional wellhead was installed, and the casing was held on the elevators during the cementing job. However, in some cases this information was not available as a compact wellhead was used. For those cases, it was necessary to drill out the shoe track using LWD to detect the location of casing shoe.
Recommendations were made to add new loads the current casing design. Results will define the minimum rathole length and the maximum tension at surface experienced by the casing during the cementing job in both static and dynamic conditions. Also, it is important to properly estimate the rathole the physical measurement of the casing joints in the tally can carry measurement errors.
Interbed Demultiple Workflow for Low Relief Structures Onshore Abu Dhabi
Authors: Roig Carlos , Elmansoury Alaa , Glushchenko Anna , Vargas Jose Edgardo , Utami Yeni Prasetyo , Seo Youngtak , Al Ghafri Thuraya Mohammed , Liu James , Kim Dongoh 
Published: November 2019

Abstract
Good quality seismic data are essential for seismic reseirvoir characterization, from seismic applications (wavelet estimation, low frequency model building, seismic velocity calibration and time to depth conversion) to petro-physical interpretation, rock physics modelling and hard data in deostatistical modeling. Surface seismic data need to possess the necessary level of quality to make the advanced inversion techniques successful in providing the reservoir characterization results to be input into the static models.
Interbed multiples occur in all types of seismic datasets and are challenging to address, directly and negatively affecting structural and stratigraphic mapping, as well as extracting concise petrophysical attributes from the seismic data. This is particularly a problem for deep and fractured reservoirs, where strong internal multiple contamination increases the ambiguity of the interpretation and inversion of the seismic data, leading to misleading reservoir characterization, ultimately affecting well construction and placement.
These interbed multiples can appear at a very similar timing and amplitudes to primaries due to comparable velocities which makes it difficult to differentiate from primary energy in areas with relatively flat geology. In current paper we will demonstrate the demultiple workflow for low relief structures in Abu Dhabi. To address the specific challenges, Extended Interbed Multiple Prediction or a combination of methods presented. The multiple attenuation workflow described in this work follows forward modelling and adaptive subtraction with primary protection approach, improves the preconditioning of seismic for pre-stack inversion over the target oilfield. "The output seismic data after the optimal multiple attenuation workflow provide a superior seismic inversion and a suitable input for reservoir assessment and delineation of the thin carbonates reservoirs present in UAE" (Melo, Glushchenko et al. 2017).
Decline Curve Analysis Using Artificial Intelligence
Authors: Masini Shashipal Reddy , Goswami Shubham , Kumar Aditya , Chennakrishnan Balaji 
Published: November 2019

Abstract
DCA (Decline curve analysis) is the most followed and useful approach for the short-term production forecasts. The objective of this paper is to demonstrate automated DCA using AI (Artificial Intelligence) Techniques.
Cutting-edge clustering techniques were used to identify the data points where the decline curve is applicable. As the well's pressure depends on factors such as production rates, field and surrounding well's production rates, Multi-variate regression was used to increase the pressure prediction's robustness. As the production forecasting is a time-series sequence problem, models like XGBoost (Extreme Gradient Bosting Algorithm), RNN (Recurrent Neural Networks) i(Lipton 2015) were chosen to perform this regression. After training the model on the data, the model's predictions were combined with outputs of well-modelling to assess the well's flowing ability at each timestep.
The solution removes anomalous data and perform automatic DCA in a scalable manner. The observed and calculated data have a very good agreement (very less root mean square error and a deviation less than 5%). Probable Well ceasure times were predicted with very minimal uncertainty (with an Average deviation of 3 months).
The novelty of this approach is the ability of the AI and machine learning algorithms to perform the DCA automatically and its scalability. It frees the engineers from data gathering, anomaly removing and rate break identifying process leading to quicker interpretations and effective decision making. This approach can also be combined with well modelling using AI to predict the probable well shut-in timelines.
Real Time Operation Centre Monitoring and Optimizations in Highly Deviated Deepwater Development Wells in Malaysia
Authors: Ng Mui Ted , Lum Terry , Yeap Fabian , Abdul Talib Sa'aid Hazley , Zainal Abiddin Mohamad Sukor , Hooi E-Wen 
Published: November 2019

Abstract
As the search for hydrocarbon offshore runs deeper and farther from land, it is best we gear ourselves to embrace what it takes for delivering highly deviated deepwater development wells to push the frontiers of petroleum extraction. This paper discusses the monitoring and optimizations of deepwater wells operations in Malaysia by the Shell Malaysia Exploration and Production Real Time Operation Centre (SMEP RTOC).
The scopes of monitoring and optimizations discussed in this paper include: Hydraulics management in narrow pressure margin drilling, including modelling, optimization, measurement and monitoring of equivalent circulating density (ECD).Engineering support in pre-drill study for Managed Pressure Drilling (MPD) application.Mitigation of drilling vibration in highly deviated wells, especially stick-slip vibration.Hole cleaning modelling, monitoring and optimization.Drilling roadmaps and database are archived by RTOC for future wells reference.Drilling operations performance tracking and benchmarking.24/7 Top Tension Riser, Hawser and mooring lines tension monitoring.
Deepwater drilling operation costs are typically significantly higher than shallow water and land rig operations. This is partly due to higher rig rates in deepwater operations. In this case any reduction in Invisible Lost Time (ILT) and Non-Productive Time (NPT) may result in significant cost reduction. Like a safety net that catches anomalies that slipped the first line of defense, RTOC monitoring has the facilities and trained capabilities to oversee and optimize the operations in totality both during real time and post run. An investment in RTOC services in exchange of more cost efficient and safer operations will be justified in the paper.
Real Time Operation Centre (RTOC) is becoming more indispensable over the years. Hawk-eyeing operations in areas where attention is diluted by other tasks on the rig, could probably be the insurance needed in every future oil and gas drilling. The methods, procedures and processes in well operations will definitely advance with time and further developments and innovations in this subject will be closely followed within the industry.
Performance Prediction and Optimization of Acid Fracturing Based on the Dynamic Differential Modeling Method
Authors: Zhao Xing , Wang Hehua , Lu Lize , Liu Zhibin , He Enjie 
Published: November 2019

Abstract
For prediction of the post production of acid fracturing, a numerical method has been introduced in this paper. This prediction approach is developed by the dynamic differential modeling method for forecasting single well acid fracturing performance. In this study, the average production during 30 days and fracture geometry after acid fracturing were determined as predicted indices. Fifteen parameters were considered as influencing factors consisted of geological, reservoir and treatment parameters. The field data of predicted indices and influencing parameters were collected from the data of 7 acid-fractured wells in the XB oil field. The historical data was input into the dynamic differential model to establish and discretize the relation functions. Three target well were chosen and their corresponding influencing factors were used to calculate the predicted indices. The results showed that for the target wells, the modeling predicted indices were fairly close to the real numbers. This model is practical for the engineer in the field since the input parameter acquisition is accessible from the common oil field data. It could help the engineers to optimize the acid fracturing treatment design by correlating the scale of the treatment.
A Case Study on Reducing Uncertainty by using Correct Procedure & Desaturated Reservoir Fluid on NMR Core T2 Bound Fluid Cut-Off Analysis for Gaint Abu Dhabi Onshore Carbonate to Compute Reliable Field Wide Swirr Analysis from NMR Logs
Authors: Singh Maniesh , Dey Swapan Kumar , Farooq Umer , Radwan El Sayed , Rajwade Sachin , Tombokan Xenia , Mendoza Rafael , Hannon Loay , Watson Rayvan 
Published: November 2019

Abstract
The estimation of bulk volume of irreducible water (BVI) is one of the earliest and the most widely used applications of NMR logging using either a fixed T2 cutoff value or Spectral BVI. NMR BVI assumes that bound fluid resides in small pores and producible free fluids (FFI) resides in large pores where the pore throat and pore body sizes are often related. As T2 distribution is related to a pore body size, a T2 cutoff can partition BVI & FFI.
In Carbonates there is no clear relationship of pore throat size to pore body size, thus measuring BVI T2 cutoff per rock type becames important although challenging. This paper covers the importance of following correct laboratory procedures, quality assurance of laboratory experimential data, and innovative methods to determine reliable T2 cutoff which otherwise are very low and not practical to apply in the NMR log domain.
NMR analysis was performed with a 2 MHz field instrument using a CPMG sequence and sufficient echo trains to acquire reliable T2 distribution. T2 cutoff was determined on core samples with a wide range of porosity, permeability, and rock types. Core samples were analyzed for T2 distribution at elevated temperature and pressure. First the cores were saturated with formation brine to 100% Sw, followed by desaturation using the porous plate pressure equilibrium method to Swirr. Initially, desaturation with gas provided very low T2 cutoffs; desaturation steps were repeated using a lab oil with reservoir property to investigate its positive impact on the T2 cutoffs and to use in the NMR log domain.
The T2 curve of the fully saturated plugs with brine shows a shift towards the shorter T2 time. Determination of T2 cutoff from the gas-brine system in the laboratory results in lower T2 cutoff values approximately 15 to 50 msec. This is due to the lower T2 response at the Swirr state from the combined affect of pores still partially saturated with brine and gas diffusivity affects. When desaturating with lab oil, the NMR response results in more reliable T2 cut-off of 55 to 100 msec.
NMR T2 cutoff for BVI using the oil-brine system has been determined using two methods, a conventional method where T2 cutoff is determined where the cumulative T2 value of the Sw at 100% brine equals the cumulative T2 value of the Swirr. The other method is where the T2 cutoff separates major peaks of bound and free fluid in the incremental T2 response. The conventional method posed a challenge in picking correct T2 cutoff due to various complexity as outlined in the paper. The latter method provided more reliable and better control on picking T2 cutoff to apply in the NMR log domain.
Highly Sour Gas: The Best Options to Process it
Authors: Manuel Jacques , Damien Menet , Christian Bladanet 
Published: November 2019

Abstract
TechnipFMC was appointed by one its major client to conduct a feasibility study for the development a highly sour gas-condensate field. Sour gas levels are in the range of 22-28%vol of H2S and 13-17%vol of CO2 and contains also organic sulphur components such as carbonyl sulphide, mercaptans and disulphides.
The study addresses the evaluation of onshore technologies for gas and condensate processing (gas sweetening, gas dehydration, NGL recovery, condensate stabilization and sweetening) for five different set of export product: sales gas, LPGs, hydrocarbon condensates, Sulphur or re-injection of the acid gases, with the objective of selecting the most attractive scheme based on economic and HSE criteria.
Using this case study, this paper aims to present the methodology, the different process configuration screened, the pros and cons of each technology, and the influence of basic technico-economic parameters on the plant architecture and technology selection.
An Investigation of Pressure Buildup Tests in Bounded Reservoirs
Authors: Cobb William M. , Smith James T. 
Published: November 2019

INTRODUCTION
One of the most important aspects of formation evaluation is the design, implementation, and interpretation of a pressure buildup test. Basically, this test requires that a producing well be shut in and that the associated change in bottom-hole pressure be measured as a function of shut-in time. Muskat1 introduced the first interpretation method for these pressure data to the petroleum industry in 1937, but for the most part, its significance was largely overlooked until the late 1940's. At that time, van Everdingen and Hurst2 revived new interest in transient pressure analysis with their classical paper on the behavior of unsteady-state fluid flow in a porous media.
Metagenomic next-generation sequencing for mixed pulmonary infection diagnosis
Authors: Wang Jiahui , Han Yelei , Feng Jing 
Published: November 2019

Abstract
Background: Metagenomic next-generation sequencing (mNGS) is emerging as a promising technique for pathogens detection. However, reports on the application of mNGS in mixed pulmonary infection remain scarce.Methods: From July 2018 to March 2019, 55 cases were enrolled in this retrospective analysis. Cases were classified into mixed pulmonary infection (36 [65.5%]) and non-mixed pulmonary infection (19 [34.5%]) according to primary diagnoses. The performances of mNGS and conventional test on mixed pulmonary infection diagnosis and pathogen identification were compared.Results: The sensitivity of mNGS in mixed pulmonary infection diagnose was much higher than that of conventional test (97.2％ vs 13.9％; P< 0.01) , but the specificity was the opposite (63.2％ vs 94.7％; P= 0.07) . The positive predictive value of mNGS was 83.3% (95% CI: 68.0-92.5%) , and the negative predictive value was 92.3% (95% CI: 62.1-99.6%) . A total of 5 (9.1%) cases were identified as mixed pulmonary infection by both conventional tests and mNGS, however, the pathogens identification results were consistent between these two methods in only 1(1.8%) case. In summary, the pathogens detected by mNGS in 3 (5.5%) cases were consistent with those by conventional test, and only 1(1.8%) case was mixed pulmonary infection. According to our data, mNGS had a broader spectrum for pathogen detection than conventional tests. In particular, application of mNGS improved the diagnosis of pulmonary fungal infections. Within the 55 cases, mNGS detected and identified fungi in 31 (56.4%) cases, of which only 10 (18.2%) cases were positive for the same fungi by conventional test. The most common pathogen detected was H uman cytomegalovirus in our study, which was identified in 19(34.5%) cases of mixed pulmonary infection . Human cytomegalovirus and Pneumocystis jirovecii, which were detected in 7(12.7%) cases, were the most common co-pathogens in the group of mixed pulmonary infection.Conclusions: mNGS is a promising technique to detect co-pathogens in mixed pulmonary infection, with potential benefits in speed and sensitivity.
Methicillin-resistant Staphylococcus aureus in veterinary professionals in 2017 in the Czech Republic
Authors: Neradova Katerina , Jakubu Vladislav , Pomorska Katarina , Zemlickova Helena 
Published: November 2019

Abstract
Background Cases of colonization or infection caused by Methicillin-resistant Staphylococcus aureus (MRSA) are frequently reported in people who work with animals, including veterinary personnel. The aim of this study was to determine the prevalence of MRSA colonization among veterinary professionals. A total of 134 nasal swabs from healthy attendees of a veterinary conference held in the Czech Republic were tested for presence of MRSA. The stains were further genotypically and phenotypically characterized. Results Nine isolated MRSA strains were characterized with sequence type (ST), spa type (t) and Staphylococcal Cassette Chromosome mec type. Five different genotypes were described, including ST398-t011-IV (n=5), ST398-t2330-IV (n=1), ST398-t034-V (n=1), ST225-t003-II (n=1) and ST4894-t011-IV (n=1). The carriage of the animal MRSA strain was confirmed in 8 cases, characteristics of one strain corresponded to the possible nosocomial origin. Among animal strains were described three spa types (t011, t034, t2330) belonging into one dominating clonal complex CC11. Conclusion According to our results, the prevalence of nasal carriage of MRSA in veterinary personnel is 6.72%. Although we described an increase compared to the results of previous study (year 2008), the prevalence in the Czech Republic is still remaining lower than reported from neighboring countries. Our results also indicate that healthcare - associated MRSA strains are still not spread among animals.
Ranking top-k trees in tree-based phylogenetic networks
Authors: Hayamizu Momoko , Makino Kazuhisa 
Published: November 2019

Abstract
'Tree-based' phylogenetic networks provide a mathematically-tractable model for representing reticulate evolution in biology. Such networks consist of an underlying 'support tree' together with arcs between the edges of this tree. However, a tree-based network can have several such support trees, and this leads to a variety of algorithmic problems that are relevant to the analysis of biological data. Recently, Hayamizu (arXiv:1811.05849 [math.CO]) proved a structure theorem for tree-based phylogenetic networks and obtained linear-time and linear-delay algorithms for many basic problems on support trees, such as counting, optimisation, and enumeration. In the present paper, we consider the following fundamental problem in statistical data analysis: given a tree-based phylogenetic network $N$ whose arcs are associated with probability, create the top-$k$ support tree ranking for $N$ by their likelihood values. We provide a linear-delay (and hence optimal) algorithm for the problem and thus reveal the interesting property of tree-based phylogenetic networks that ranking top-$k$ support trees is as computationally easy as picking $k$ arbitrary support trees.
Immediate implant placement in anterior teeth with grafting material of autogenous tooth bone vs xenogenic bone
Authors: Wu Dong , Zhou Lin , Lin Jichao , Chen Jiang , Huang Wenxiu , Chen Yonghui 
Published: November 2019

Abstract
Background: The aim of the study was to compare the efficacy of the autogenous tooth bone and xenogenic bone grafted in immediate implant placement with bone defect. Methods: Thirty patients whose compromised anterior teeth need immediate implant placement were enrolled. Autogenous tooth bone made from the extracted teeth by chair-side or the xenogenic bone were used to repaired bone defect. Clinical examination, radiographic assessment about the horizontal bone change in the level of 0mm, 3mm and 6mm below the implant neck and the marginal bone loss were made immediately, 6 and 12 months after implant placement. Questionnaire of feeling was made at the time of removing the sutures. Results: All implants achieved the success criteria without any complications at the follow-up period. The percent of the horizontal bone change and the marginal bone loss at 6 and 12 months were almost the same between two groups (P>.05). The horizontal bone loss at the first or the latter 6 months is almost the same (P>.05). But the horizontal bone loss at the 6 mm level is less than the 0 mm and 3 mm levels at 6 and 12 months (P<.05). Meanwhile patients seem more satisfied with the autogenous tooth bone derived from the questionnaire. Conclusion: The bone volume change in the facial part of the implant after immediate placement is almost the same between two groups. Providing clinical evidence that the autogenous tooth bone made from compromised tooth can be an acceptable bone graft material.