Assessment of zonal isolation risk to changes in design parameters

The Well Containment Screening Tool (WCST) focuses on well integrity evaluation after well control incident. The WCST favors a greater wall thickness and, hence, a narrower cementing annulus, potentially increasing the risk of cement loss. We develop a structured and systematic physical model to simulate and track formation damage. A simulation process is conducted to assess the sensitivity of zonal isolation risk as design parameters are changed. In this paper, a physical model involving wellbore, casing and cement fluid is developed to understand the interaction between cement fluid and the formation. Two failure metrics are defined that provide a comprehensive understanding of the zonal isolation risk. Quantitative risk assessment is implemented with Monte Carlo simulation to assess the risk of zonal isolation problems when design parameters are changed. Models of production casing and intermediate casing are studied to verify the generality of this analysis. Taking both failure metrics into consideration, sensitivity analysis for models of production casing and intermediate casing present common observations regarding changes of design parameters. Our analysis suggests that minor increases (within 0.05”) in casing thickness, due to increased outer diameter, has little influence on the risk of cement loss, as does slight decreases in mean open hole diameter (within 0.05”). To verify the generality of this approach, in addition to casing and wellbore parameters, the sensitivity to cement fluid flow rate is analyzed. We find that risk is not significantly affected by small increase of flowrate (e.g. from 40 to 100 gpm). This paper applies a novel quantitative risk analysis to assess the influence of different design parameters on zonal isolation problems. This approach, if well implemented, can help to assess the impact of changes in design parameters (e.g., casing length and depth, mud density and cement fluid density, etc.) on drilling safety. It can also help to inform drilling decisions by providing forecasts of zonal isolation risk for particular geological condition.Mechanical Engineerin

Miocene deep water agglutinated foraminifera from Viosca Knoll, offshore Louisiana (Gulf of Mexico)

An exploration well from the Gulf of Mexico, Amoco Viosca Knoll-915, has been studied in order to document the Neogene foraminiferal assemblages. Ditch cuttings samples from the Amoco V.K. 915 well yielded diverse assemblages of agglutinated and calcareous benthic foraminifera over a stratigraphic interval of 2940 m. Three species associations can be identified in the studied interval; the stratigraphical location of these associations is evident when total agglutinated species abundance for each sampling interval is plotted. In this study we use a combination of morphotype habitat preference and test functional morphology to interpret depositional environments. The associations indicate a change from a well-ventilated water column, to the development of a strong oxygen minimum zone characterised by alveolar foraminifera. The species composition of the lowermost association indicates a depositional environment dominated by fine-grained overbank fines and channel levee deposits, in agreement with sedimentological data. Colour plates of key agglutinates species are presented, created using digital image manipulation techniques (Palaeovision Technique, NHM)

Time-aware metric embedding with asymmetric projection for successive POI recommendation

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Successive Point-of-Interest (POI) recommendation aims to recommend next POIs for a given user based on this user’s current location. Indeed, with the rapid growth of Location-based Social Networks (LBSNs), successive POI recommendation has become an important and challenging task, since it can help to meet users’ dynamic interests based on their recent check-in behaviors. While some efforts have been made for this task, most of them do not capture the following properties: 1) The transition between consecutive POIs in user check-in sequences presents asymmetric property, however existing approaches usually assume the forward and backward transition probabilities between a POI pair are symmetric. 2) Users usually prefer different successive POIs at different time, but most existing studies do not consider this dynamic factor. To this end, in this paper, we propose a time-aware metric embedding approach with asymmetric projection (referred to as MEAP-T) for successive POI recommendation, which takes the above two properties into consideration. In addition, we exploit three latent Euclidean spaces to project the POI-POI, POI-user, and POI-time relationships. Finally, the experimental results on two real-world datasets show MEAP-T outperforms the state-of-the-art methods in terms of both precision and recall

Superhydrophobic Paper from Nanostructured Fluorinated Cellulose Esters

The development of economically and ecologically viable strategies for sup erhydrophobization offers a vast variety of interesting applications in self-cleaning surfaces. Examples include packaging materials, textiles, outdoor clothing, and microfluidic devices. In this work, we produced superhydrophobic paper by spin-coating a dispersion of nanostructured fluorinated cellulose esters. Modification of cellulose nanocrystals was accomplished using 2H,2H,3H,3H-perfluorononanoyl chloride and 2H,2H,3H,3H-perfluoroundecanoyl chloride, which are well-known for their ability to reduce surface energy. A stable dispersion of nanospherical fluorinated cellulose ester was obtained by using the nanoprecipitation technique. The hydrophobized fluorinated cellulose esters were characterized by both solid- and liquid-state nuclear magnetic resonance, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle measurements. Further, we investigated the size, shape, and structure morphology of nanostructured fluorinated cellulose esters by dynamic light scattering, scanning electron microscopy, and X-ray diffraction measurements.Peer reviewe

A tetraquark or not a tetraquark: A holography inspired stringy hadron (HISH) perspective

We suggest to use the state $Y(4630)$, which decays predominantly to $\Lambda_c\bar\Lambda_c$, as a window to the landscape of tetraquarks. We propose a simple criterion to decide whether a state is a genuine stringy exotic hadron - a tetraquark - or a "molecule". If it is the former it should be on a (modified) Regge trajectory. We present the predictions of the mass and width of the higher excited states on the $Y(4630)$ trajectory. We argue that there should exist an analogous "$Y_b$" state that decays to $\Lambda_b\bar\Lambda_b$ and describe its trajectory. We conjecture also a similar trajectory for tetraquarks containing strange quarks, and the modified Regge trajectories can in fact be predicted for any resonances found decaying to a baryon-antibaryon pair. En route to the results regarding tetraquarks, we also make some additional predictions on higher excited charmonium states. We briefly discuss the zoo of exotic stringy hadrons and in particular we sketch all the possibilities of tetraquark states.Comment: v1: 28 pages, v2: typos fixed, references added, 29 pages, v3: revised, published version, 30 page

Open Research Data and Innovative Scholarly Writing: OPERAS highlights

Pre-print of the article to be puslihed in OA on http://www.ressi.ch/ We present here highlights from an enquiry on the innovations in scholarly writing in the Humanities and Social Sciences in the H2020 project OPERAS-P. This article explores the theme of Open Research Data and its role in the emergence of new models of scholarly writing. We examine more closely the obstacles and fostering conditions to the publication of research data, both from a social and a technical perspective