Characteristic of Tuwayil Formation and New Insight into its Contribution in Middle Cretaceous Petroleum System, Western UAE

In Western UAE, the Middle Cretaceous petroleum system is composed of Shilaif source, Mishrif/Tuwayil reservoir and Tuwayil/Ruwaydha seal. Oil is discovered in Tuwayil sandstone in DH and NN fields. Well correlation of Tuwayil siliciclastic interval shows high heterogeneity and rapid lithology varies. Currently, a few general studies about Tuwayil sandstone was published. However, detailed sedimentary facies, reservoir characteristics and accumulation mechanism about Tuwayil are ambiguous. Limitation on these aspects prohibits enlarging exploration activity of Tuwayil and makes barriers to deepen understanding of the whole K2 PS. To enhance understanding on Tuwayil formation, well data in DH, NN fields and adjacent area was integrated. Dedicated single well analysis, well correlation and petrophysics study were carried out. Cores were observed and laboratory outcomes including TS, SEM, RCA, MICP, XRD were adopted into this study. Furthermore, we have also utilized 2D&3D seismic to illustrate the spatial distribution of Tuwayil siliciclastic setting and interior sediment pattern. Basically, the Tuwayil sand-shale interval represents the infilling of Mishrif/Shilaif intrashelf basin and mainly deposits in the tidal flat-delta facies. The epi-continental clast is sourced from the Arabian shield and transferred from west to east. In Western UAE, the Tuwayil depocenter located in DH field, where 4-5 sand layers deposit with net pay of 30-40ft. In NN field, only one sand layer develops with net pay about 4-6ft. Through deposition cycles identification and seismic reflection observation, two sand groups could be recognized in this interval. The lower group is constrained in the depocenter and influenced by the paleo-geomorphology background. The upper group overpassed the former set and pinched out around north of NN. The Mishrif/Shilaif slope area is another potential belt to enlarge Tuwayil discovery, where stratigraphic onlap could be observed and it probably represents the sand pinch-out in lower sand group. For the K2 PS, previous study believed the shale between Tuwayil sand and Mishrif separate these two reservoirs and works as cap rock for Mishrif grainstone. This study suggests that this shale is too thin and not continuous enough to hold the hydrocarbon in Mishrif. On that note, Tuwayil sand and Mishrif belong to the same petroleum system in NN and may have the same OWC. In the NN field, it is quite crucial to consider the extension of Tuwayil sand during evaluating the stratigraphic prospect of Mishrif because the hydrocarbon is mostly likely charged Tuwayil sand first and then gets into underlain Mishrif. This study provides updates and understandings on sedimentary facies, depositional pattern, hydrocarbon accumulation mechanism, reservoir extension and potential identification of Tuwayil formation, which has inspiring implications for the whole K2 PS and could also de-risk the further exploration activity in Western UAE.

Docosahexaenoic Acid Is Naturally Concentrated at the sn-2 Position in Triacylglycerols of the Australian Thraustochytrid Aurantiochytrium sp. Strain TC 20

The Labyrinthulomycetes or Labyrinthulea are a class of protists that produce a network of filaments that enable the cells to glide along and absorb nutrients. One of the main two Labyrinthulea groups is the thraustochytrids, which are becoming an increasingly recognised and commercially used alternate source of long-chain (LC, ≥C20) omega-3 containing oils. This study demonstrates, to our knowledge for the first time, the regiospecificity of the triacylglycerol (TAG) fraction derived from Australian thraustochytrid Aurantiochytrium sp. strain TC 20 obtained using 13C nuclear magnetic resonance spectroscopy (13C NMR) analysis. The DHA present in the TC 20 TAG fraction was determined to be concentrated in the sn-2 position, with TAG (16:0/22:6/16:0) identified as the main species present. The sn-2 preference is similar to that found in salmon and tuna oil, and differs to seal oil containing largely sn-1,3 LC-PUFA. A higher concentration of sn-2 DHA occurred in the thraustochytrid TC 20 oil compared to that of tuna oil.

Analisis Partial Discharge dan Prediksi Usia Layak Isolasi Belitan Stator Generator 143,4 MVA

ABSTRACT The arise of partial discharge in isolation of the winding stator generator is thing that general because existence ageing and excessive stress. Partial discharge in isolation of the winding stator occur in the core slot area or endwinding area. The problem that occur in isolation of the winding stator generator is the presence of corona and high partial discharge in the endwinding area caused by ineffective monitoring of partial discharge. This research discusses about that occurrence corona and partial discharge, and the effectiveness of repairing insulation of the stator winding that performed during overhaul. The analysis methods used is comparative, characteristics and trending, and linear regression to predict the age of operation worthiness in isolation of the winding stator. The results of the analysis showed that, the cause of corona and high partial discharge due to damage to the isolation surface consequence contamination from bearing seal oil which have seepage and load & thermal cycling, with the age of operation worthiness shortest isolation of the winding stator during ± 2 years 1 month 21 days or only increased 14 days after overhaul. Keywords : partial discharge, corona, linear regression, age of worthiness isolation of the winding ABSTRAK Timbulnya partial discharge pada isolasi belitan stator generator merupakan hal yang umum terjadi karena adanya penuaan dan tekanan yang berlebih. Partial discharge pada isolasi belitan stator terjadi di area slot inti atau area endwinding. Permasalahan yang terjadi pada isolasi belitan stator generator adalah adanya korona dan partial discharge tinggi pada area endwinding yang disebabkan karena kurang efektifnya monitoring terhadap partial discharge. Penelitian ini membahas tentang terjadinya korona dan partial discharge, serta efektifitas perbaikan isolasi belitan stator generator yang dilakukan saat overhaul. Metode analisa yang digunakan adalah komparasi, karateristik dan trending, serta regresi linear untuk memprediksi usia kelayakan operasi isolasi belitan stator. Hasil analisa menunjukkan bahwa, penyebab terjadinya korona dan partial discharge tinggi karena adanya kerusakan pada permukaan isolasi akibat kontaminasi minyak dari seal oil bearing 5 yang mengalami rembesan dan load & thermal cycling, dengan usia kelayakan operasi tersingkat isolasi belitan stator selama ± 2 tahun 1 bulan 21 hari atau hanya mengalami kenaikan 14 hari setelah overhaul. Kata kunci : partial discharge, korona, regresi linear, usia layak isolasi belitan

Alaska Native Traditional Food and Harvesting Activity Patterns over 10 Years of Follow-Up

ABSTRACT Background Alaska Native (AN) traditional foods and associated harvesting activities are beneficial to human health. Objective This study assessed longitudinal self-reported traditional food use and harvesting activities among Alaska Native and American Indian (AN/AI) participants in the Alaska Education and Research Towards Health (EARTH) study. Methods In 2004–2006, southcentral Alaska EARTH study participants (n = 1320) completed diet and activity questionnaires which were repeated in 2015–2017; results were compared between participants who completed both questionnaires (n = 388). Results In the follow-up questionnaire, >93% of participants reported eating ≥1 traditional food in the past year. The top 3 traditional foods were fish (75%), moose (42%), and shellfish (41%). Women were more likely than men to consume traditional foods, especially fish, gathered berries, shellfish, and seal oil (P < 0.05). Participants aged ≥60 y in the original cohort were significantly more likely to consume fish and shellfish at follow-up, whereas those aged 40–59 y were the most likely of the 3 age groups to consume seal oil (P < 0.05). Between the original cohort and follow-up, there was a significant decline in the mean number of traditional foods eaten from 6.3 to 5.5, as well as reduced consumption of multiple traditional foods (P < 0.001). Over 59% of participants reported ≥1 traditional harvesting activity in the past year; this proportion did not significantly change between baseline and follow-up. Picking berries/greens (44%), cutting/smoking fish or meat (33%), and fishing (30%) were the most common activities. Participation in traditional harvesting activities was greater among women than men (P < 0.05), but did not differ by age. Conclusions Longitudinal follow-up demonstrated that AN/AI people maintained participation in traditional harvesting activities, but the variety of traditional foods declined significantly among both men and women. Promotion of traditional foods and harvesting activities that serve as protective factors against chronic diseases may benefit this population.