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Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 43
Author(s):  
Wardana Saputra ◽  
Wissem Kirati ◽  
Tadeusz Patzek

We adopt a physics-guided, data-driven method to predict the most likely future production from the largest tight oil and gas deposits in North America, the Permian Basin. We first divide the existing 53,708 horizontal hydrofractured wells into 36 spatiotemporal well cohorts based on different reservoir qualities and completion date intervals. For each cohort, we fit the Generalized Extreme Value (GEV) statistics to the annual production and calculate the means to construct historical well prototypes. Using the physical scaling method, we extrapolate these well prototypes for several more decades. Our hybrid, physico-statistical prototypes are robust enough to history-match the entire production of the Permian mudstone formations. Next, we calculate the infill potential of each sub-region of the Permian and schedule the likely future drilling programs. To evaluate the profitability of each infill scenario, we conduct a robust economic analysis. We estimate that the Permian tight reservoirs contain 54–62 billion bbl of oil and 246–285 trillion scf of natural gas. With time, Permian is poised to be not only the most important tight oil producer in the U.S., but also the most important tight gas producer, surpassing the giant Marcellus shale play.


2021 ◽  
Vol 4 (4) ◽  
pp. 887
Author(s):  
Wilsen Hartanto Lim ◽  
Arianti Sutandi

ABSTRACTThe planed duration of  construction Project X was 730 days with the upper structure targeted to be finished in July 2020. There was delay in the beginning of project implementation and the expected duration became 745 days,  the upper structure completion date pushed back to October 2020. In order to keep in line with target, one of the alternatives was to change the formwork material from conventional to aluminium. By applying this change, there was a need to study the effects to the project duration, the upper structure finish date, and the additional cost. To calculate the project duration, and the labour coefficient of productivity using the motion and time study method, the completion time of aluminium formwork work is required. From the calculation, it can be concluded that it was more effective to apply an 8-zone of formwork division in every storey,  which will result in 711 days of project duration and the upper structure finish date will be in August 2020. The costs for the aluminium formwork which consisted of materials and labour fees amounted to Rp 7,991,548,555 or higher by Rp 1,000,000,000 compared to conventional formwork. ABSTRAKTarget durasi pekerjaan konstruksi proyek X adalah 730 hari dengan target waktu selesai pekerjaan struktur atas pada bulan Juli 2020. Pada awal pelaksanaan proyek terjadi keterlambatan sehingga diperkirakan menghasilkan durasi proyek 745 hari dan waktu selesai pekerjaan struktur atas menjadi Oktober 2020. Untuk mengejar target proyek, salah satu alternatif yang dapat dilakukan adalah dengan mengganti jenis material bekisting dari konvensional menjadi aluminium. Sehingga dengan penggantian tersebut perlu dilakukan studi pengaruh penggantian jenis bekisting terhadap durasi proyek, waktu selesai pekerjaan struktur atas, dan biaya pekerjaan bekisting. Untuk menghitung durasi proyek, dan koefisien tenaga kerja yang dilakukan dengan metode motion and time study diperlukan waktu pekerjaan bekisting aluminium. Dari perhitungan durasi proyek diperoleh waktu yang lebih efektif adalah dengan pembagian 8 zona yang menghasilkan durasi proyek 711 hari dan waktu selesai pekerjaan struktur atas adalah Agustus 2020. Untuk biaya pekerjaan bekisting aluminium yang terdiri dari biaya material dan biaya upah tenaga kerja didapatkan total biaya adalah Rp 7,991,548,555 atau lebih besar sekitar Rp 1,000,000,000 dibandingkan dengan bekisting konvensional. 


2021 ◽  
Vol 23 (09) ◽  
pp. 1073-1077
Author(s):  
Shankar C ◽  
◽  
Saranya K ◽  
Col Jacob G Podipara ◽  
V S Srinithee ◽  
...  

Delay can be delay can be defined as the extra time required or incurred either beyond the stipulated completion date or beyond the date that the project stakeholders agreed upon for the completion of the project. The various effects of delay include time overrun, cost overrun, dispute, Total abandonment, Litigation, Arbitration. The objective this study is to review various journals on causes of delay for construction projects. Hence in this paper a number journals are summarized and suggestion for reducing delay in construction is given.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5795
Author(s):  
Janusz Kulejewski ◽  
Nabi Ibadov ◽  
Jerzy Rosłon ◽  
Jacek Zawistowski

This study concerns the use of the critical chain method to schedule the construction of renewable energy facilities. The critical chain method is recognized as a useful project management tool, transforming a stochastic problem of uncertainty in activity durations into a deterministic one. However, this method has some shortcomings. There are no clear principles of grouping non-critical activities into feeding chains. Another ambiguity is sizing the feeding buffers with regard to the topology of the network model and the resulting dependencies between activities, located in different chains. As a result, it is often necessary to arbitrarily adjust the calculated sizes of feeding buffers before inserting them into the schedule. The authors present the new approach to sizing the time buffers in the schedule, enabling a quick assessment of the quality of a given solution variant and finding a solution that best meets the established criteria, conditions, and constraints. The essence of the presented approach is the two-step sizing of time buffers with the use of deterministic optimization and stochastic optimization techniques. Taking into account construction management needs, the optimization criteria are based on the construction project cash flow analysis. The effectiveness of the presented approach is illustrated by an example of developing a wind power plant construction schedule. According to the results, the presented approach ensures the protection of the scheduled completion date of the construction and the stability of the schedule.


2021 ◽  
Author(s):  
Nico Riedel ◽  
Susanne Wieschowski ◽  
Till Bruckner ◽  
Martin R. Holst ◽  
Hannes Kahrass ◽  
...  

Objective: Timely publication of clinical trial results is central for evidence-based medicine. The performance of university medical centers (UMCs) regarding timely results publication informs the local and national decision makers, patients, and the public about the need to improve trial results dissemination. Study Design and Setting: Following the same search and tracking methods used in our previous study for the years 2009 - 2013, we identified trials lead by German UMCs completed between 2014 and 2017 and tracked results dissemination for the identified trials. Results: We identified 1,658 trials in the 2014-2017 cohort. Of these trials, 43% published results as either journal publication or summary results within 24 months after completion date, which is an improvement of 3.8% percentage points compared to the previous study. At the UMC level, the 24-month publication rates varied from 14% to 71%. Five years after completion, still 30% of the trials remained unpublished. Conclusion: Despite minor improvements compared to the previously investigated cohort, the rate of timely reporting of trials lead by German UMCs remains low. German UMCs should take further steps to improve timely reporting rates.


2021 ◽  
Vol 11 (3) ◽  
pp. 1155-1183
Author(s):  
Benyamin Yadali Jamaloei

AbstractThe Montney tight siltstone reservoir is a multi-stacked play, which covers a total area of 130,000 km2 along the Alberta–British Columbia border in Western Canada. Since the late 1990s, different fracturing methods and fluids have been tested in 4000-plus Montney wells to find the optimal fracturing method and fluid. The previous studies reviewing the performance of fracturing methods in Montney do not represent a holistic evaluation of these methods, owing to some limitations, including: (1) using a small sample size, (2) having a limited scope by focusing on a specific aspect of fracturing (method/fluid), (3) relying on data analytics approaches that offer limited subsurface insight, and (4) generating misleading results (e.g., on optimum fracturing method/fluid) through using disparate data that are unstructured and untrustworthy as a result of significant regional variations in true vertical depth (TVD), geological properties, fluid windows, completed lateral length, fracturing method/fluid/date, and drawdown rate management and choke size strategy. The present study eliminates these limitations by rigorously clustering 4000-plus Montney wells based on the TVD, fluid window, completed lateral length, fracturing method/fluid/date, and drawdown rate strategy to isolate the effect of each fracturing method by comparing each well’s production to that of its offsets, which use different fracturing methods but possess similar geology, fluid window, and TVD. With similar TVD, fracturing fluid, and completion date, wells completed with pinpoint fracturing method outperform their offsets completed with ball-and-seat and plug-and-perforate (PnP) fracturing methods. However, wells completed with ball-and-seat and PnP methods that outperform their offset pinpoint wells have either: (1) been fractured one to four years earlier than the pinpoint wells and/or (2) used energized oil-based fluid, hybrid fluid, and energized slickwater versus slickwater used in the pinpoint offsets. This suggests that the water-phase trapping is more severe in these pinpoint wells attributable to the use of slickwater. Previous studies often favored one specific fracturing method or fluid without highlighting these complex interplays between the type of fracturing method, fracturing fluid, completion date (regional depletion or well vintage), and the reservoir properties and hydrodynamics.


2020 ◽  
Vol 36 (S1) ◽  
pp. 11-11
Author(s):  
Patricia Aluko ◽  
Fernando Zanghelini ◽  
Oladapo Ogunbayo

IntroductionWhile horizon-scanning systems aim to identify innovative and potentially disruptive health technologies in development, a key challenge is variation in information collation and tracking of the pace of change prior to regulatory approval. An active and efficient monitoring process is crucial for timely notification of health technology assessment (HTA) stakeholders to enhance faster market and patient access. The National Institute for Health Research Innovation Observatory (NIHRIO) identifies and notifies its key HTA stakeholders in England of technologies that are within three to five-year timeframe to regulatory approval. Regular review of each technology is required to meet this remit.MethodsA standardized monitoring framework was developed based on the knowledge and experience of the evidence synthesis specialists in NIHRIO, supplemented by literature to ensure consistency of setting review periods. This framework used predefined criteria that integrated the technology innovation (advanced therapies, orphan status, regulatory awards), trial data (phase, status, completion date, preliminary results) and estimated approval timelines obtained from the company or other sources (for example, press releases).ResultsThe framework has been piloted and early findings showed improved consistency in the monitoring process between different analysts. It ensures that each technology is reviewed at least once a year; review timelines are set at three, six, nine or twelve months based on the predefined criteria. Estimated timeframes obtained from the companies are used to triangulate and streamline review periods, improving efficiency of the monitoring process.ConclusionsFindings from the pilot work with the framework demonstrated improved consistency and efficiency of the technology monitoring process, which can be easily implemented to provide early awareness in an accurate and timely manner for HTA. This framework was designed using a systematic and transparent approach that integrated different data sources to set review periods. While most of the data used in defining the criteria are publicly available, commercially sensitive information provided by companies were also used which may not always be readily available. Implications for horizon-scanning organizations will be discussed.


2020 ◽  
Vol 110 (11) ◽  
pp. 1628-1634 ◽  
Author(s):  
Calliope Holingue ◽  
Luther G. Kalb ◽  
Kira E. Riehm ◽  
Daniel Bennett ◽  
Arie Kapteyn ◽  
...  

Objectives. To assess the impact of the COVID-19 pandemic on mental distress in US adults. Methods. Participants were 5065 adults from the Understanding America Study, a probability-based Internet panel representative of the US adult population. The main exposure was survey completion date (March 10–16, 2020). The outcome was mental distress measured via the 4-item version of the Patient Health Questionnaire. Results. Among states with 50 or more COVID-19 cases as of March 10, each additional day was significantly associated with an 11% increase in the odds of moving up a category of distress (odds ratio = 1.11; 95% confidence interval = 1.01, 1.21; P = .02). Perceptions about the likelihood of getting infected, death from the virus, and steps taken to avoid infecting others were associated with increased mental distress in the model that included all states. Individuals with higher consumption of alcohol or cannabis or with history of depressive symptoms were at significantly higher risk for mental distress. Conclusions. These data suggest that as the COVID-19 pandemic continues, mental distress may continue to increase and should be regularly monitored. Specific populations are at high risk for mental distress, particularly those with preexisting depressive symptoms.


2020 ◽  
Vol 8 (11) ◽  
pp. 842
Author(s):  
Maro Car ◽  
David Brčić ◽  
Srđan Žuškin ◽  
Boris Svilicic

The global maritime digitalization reflects on navigation and paperless vessels with Paper Navigational Charts (PNC) nowadays superseded by Electronic Chart Display and Information System (ECDIS). Considering the system implementation and its acceptance as a sole navigational means, opinions of navigators differ. Although the ECDIS mandatory implementation ended in 2018, some navigators have been still favouring PNCs, pointing out their advantages over ECDIS navigation. These standpoints may have an impact on the safety of navigation in terms of acceptance, interpretation, and understanding of the system as well as on conflict of standpoints of decisive navigational ranks, the latter reason being found as one of the real problems. The presented study has focused on a specific period, soon after the transitional period completion, aiming to determine the views of traditional navigation advocates, their arguments in the present maritime navigation paperless era and to identify potential problems emerging from the conflict of two navigational means. The research has induced two independent, internationally distributed questionnaires, dedicated to navigational ranks. The first survey has referred to the period from 2012 to 2018, marking the transition to ECDIS navigation. The second survey was conducted after the implementation period completion date. The answers were analysed and discussed from the navigational ranks’ perspective, considering their competitiveness and the level of ECDIS education. The research results have indicated and confirmed that PNCs could not entirely be ruled out, at least at this stage. Besides definitive questionnaire answers, the findings have been supported with categorised comments as interpreted from the first survey questionnaire results. The paper aims to present the future of the PNCs, including possibilities of fusion with modern means. The proposed suggestions have been directed towards the benefits of maritime navigation safety, referring especially to disagreement between navigational ranks in terms of particular means acceptance.


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