bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic Growth of Hydraulic Fracturingin High Perm Reservoirs – Asset M Case Study
Authors: Kindi O. , Ahmed M. , Al Riyami S. M. , Konwar A. A. , Ghaithi A. , Kindi S. 
Published: September 2023

AbstractHydraulic fracturing has proven success to unlock Hydrocarbon production from tight reservoirs in Petroleum development Oman for many years since 1990s. however given the high cost and extensive operation footprint, the Frac was not a favorable option in the South assets where sandstones can vary in permeability between 0.1- 4 Darcy permeability. The objective of this work to is show case Asset M organic growth in Hydraulic fracturing application and the enablers that supported this journey.Hydraulic fracturing is considered an expensive technology compared to other stimulation techniques and it requires a lot of technical work to screen the right candidates, plan and design the Frac operation. Asset M is a mix of over 20 fields ranging in size, reservoir qualities and Oil properties. This introduces additional challenge in frac candidate selection and design. To overcome these constrains the team have looked at potential techniques that could reduce the cost and accelerate the technical evaluation and frac program maturation. In this paper, the cost saving initiatives will be highlighted along with the frac design and execution simplification done. High level performance compared to baseline of each well will also be shared.The Organic growth of Hydraulic fracturing in Asset M is truly astonishing. The Asset started with 2 candidates only in 2019 to assure success and based on the outcomes, Hydraulic fracturing has been growing since with 12 wells stimulated with Hydraulic fracturing in 2022. The increase is also linked to the simplified operational approach and the high oil gain associated to these activities where in some of the wells oil gain exceeded 400%.The work presented here will be the first time to show case Asset M frac journey both from technical and commercial impact. It is a very good case study for replication across other E&P operators which are looking for more oil production beyond the easy oil gain portfolio.
Cyclic Injection Scheme to Reduce Breakdown Pressure in Hydraulic Fracturing Wells: Case Study
Authors: Salah Mohamed , Al Hammadi Mohamed Thani , Al Marzooqi Afnan , Alshehhi Hajer Mohamed Ali J. 
Published: September 2023

Abstract
Globally, the development of unconventional resources has drastically played a pivotal role in the energy supply. The economic production from the unconventional reservoirs is a great challenge where these tight producing zones often exhibit extremely high in-situ stress with low permeability conditions, necessitating the hydraulic fracturing stimulation of each horizon to define fluid and assess productivity. This extreme in-situ stress condition poses a considerable high breakdown pressure, making the hydraulic fracturing techniques challenging when implemented to these types of reservoirs and often treatment parameters approach the equipment capabilities and operational limits without breaking down the formation or creating any fractures. Consequently, conventional techniques have yielded unsatisfactory outcomes, rendering the wells economically unviable. In this paper, a new approach has been developed to help reduce the formation breakdown pressure during the hydraulic fracturing treatment. The new approach encounters injection of hydraulic fracturing fluid in a series of hydraulic pulses schemes to induce fatigue failure damage and weaken rock tensile strength. This paper discusses the fatigue damage mechanism and constitutive relationship for rock subjected to cyclic stress. The mechanical response of rock under both monotonic and cyclic stress loading will be examined. The rate of fatigue damage evolution is influenced by the number of load cycles, stress amplitude and accumulated plastic deformation. This case study presents hydraulic fracturing technique, to reduce rock tensile strength, and induce fatigue damage to one of extremely in-situ stressed reservoirs which could not be broken-down by conventional hydraulic fracturing technique. The results of cyclic fracturing technique are summarized. The cyclic injection scheme fatigue response of rock reduces formation breakdown pressure by 16% compared to the results obtained in conventional hydraulic fracturing.
Integrated Pressure Transient Analysis of Hydraulically Fractured Wells in Tight Gas Condensate Reservoirs in the Sultanate of Oman
Authors: Zhan Lang , Al-Sulaimi Saleh , Liu Mankit , Abdulkadir Ramzi 
Published: September 2023

Abstract
We present an integrated approach that combines pressure transient analysis (PTA) of multiple hydraulically fractured wells and additional measurements from other disciplines to deliver consistent results of formation and fracture properties. PTA for Multi-Fractured Horizontal Wells (MFHW) has greater uncertainty than that of their vertical counterparts. Utilizing complementary characteristics and information from multiple wells reduces the non-uniqueness in parameter estimations of tight gas condensate fields. This paper features a methodology to sequentially estimate fracture conductivity, fracture height, fracture length and formation permeability for MFHWs. First, this new method separates fracture conductivity from fracture geometry using Fracture Radial formation linear (FRFL) flow regime, resulting in a significant reduction of uncertainty in fracture conductivity estimations. Then, fracture height can be estimated by analyzing the end time of FRFL flow because fracture height dictates the termination time of the FRFL flow. Using the end time of the FRFL flow to estimate fracture height is a novel technique in the industry and has significant value because a MFHW can rarely drain hydrocarbon resources beyond fracture height in tight and shale reservoirs while the fracture height is almost always an unknown. After both fracture conductivity and fracture height are determined for MFHWs, formation permeability can be estimated from bilinear flow and/or pseudo-radial flow regimes, if existing. Finally, fracture length can be estimated using the conventional approaches with much less uncertainty because the other three key parameters are known. The proposed sequential interpretation workflow and fracture height estimation will be demonstrated using field examples. The estimated results provide valuable insights into formation features, reservoir quality and completion effectiveness, which help hydraulic fracturing design, reservoir modeling and forecast, and field development optimization.
First Implementation of Nano-Proppant Technology in Middle East
Authors: Buijs H. , Nuriakhmetov R. , Bulekbay A. , Alam A. , Ao Taliwati , Singh Anil , Vazquez Alejandro , Basioni M. , Alloghani J. A. , Al Hammadi A. E. , Al Kindi R. K. , Al Aryani F. M. , Bregar U. B. , Hassan A. M. , Saldungaray P. , Annovi Enrico 
Published: September 2023

AbstractThis paper describes the first application of nano-proppant technology in Middle East that was additionally combined with tailored-made smart-proppant to unlock hard to recover reserves in the first successful hydraulic fracture treatment pumped offshore Abu Dhabi. The primary target reservoir is the Pre-Khuff Clastics Fm., a deep tight gas sandstone that can be found at depths exciding 16,000 ft with temperatures above 350º F.Given the reservoir characteristics, primarily its low permeability, hydraulic fracturing is required to achieve commercial production rates. The design of the fracture stimulation treatment presented several challenging conditions including high formation temperature, high closure stress, poroelastic effects and, among others, the potential for post treatment proppant flowback in an offshore environment. The implementation of tailored-made proppant technologies provided the means to overcome such challenges while providing key information to optimize fracture treatments as wells were completed.The primary objectives of nano-proppants were centered on sustaining production performance by propping the formation natural fracture network, mitigation of near wellbore entry friction pressures and fissure leakoff control to assure the successful placement of the frac treatment. In turn, smart-proppant technology was utilized to obtain an accurate fracture height measurement to reduce the uncertainty and non-uniqueness of pressure matching, better determining the placed frac length and width by properly understanding containment. Resin coated proppant was engineered to lock-in conductivity in a high stress and temperature environment based on expected temperature heat-back profiles required to achieve a targeted proppant pack unconfined compressive strength.This paper will provide insights on the results and lessons learned from the application of state-of-the-art proppant technologies that paved the way to reach stable commercial rates after the first fracture treatment by improving production performance by over 500%.
Fracturing and Production Characteristics of Tight Gas Reservoir: A Case Study from Thrace Basin, Turkey
Authors: Kilicaslan U. , Mengen A. E. , Ozcan O. , Sevinc S. , Belhoucine S. , Boudissa R. , Mironov V. S. , Khlopkov A. V. 
Published: September 2023

AbstractDuring the last three years, Turkish Petroleum Corporation, state owned oil company of Turkish Republic, has put significant efforts to develop its shaly sandstone reservoirs located in the Thrace Basin by-utilizing hydraulic fracturing technology. In this paper, a comprehensive review of operational and modelling aspects in the development of tight gas reservoirs were presented as a real field case study.Fracturing an over-pressured tight gas reservoir deeper than 3,000 meters (true vertical depth), in a tectonically active area, was the main challenge of the project. The initial priority was performing fracturing operations in a safe, proper, environmentally friendly way. In the post-frac phase, substantial difference observed in the individual well performances and post-frac assessment of estimated ultimate recovery (EUR) have become the main criteria in evaluation of the success of the current stimulation campaign as well as the identification of possible potential infill opportunities.Diagnostic fracture injection tests showed high closure stresses (up to 1 psi/ft gradient), which resulted in high treating pressures. To prevent screen-out, proppant concentration was increased by 0.25 ppg at each step and considerable sweeps between main stages were carried out. Different type of proppants were employed during the treatments in order to ensure having better fracture initiation and conductivity. The created fracture properties estimated from stimulation software as well as the values from rate-transient analysis were not well aligned. EUR predictions from the decline curve analysis and history matched simulation model only agreed for the first well, after having 2 years of production history, but not for other more recent wells. Image logs were also very helpful to explain different initial flow rates seen in the wells, due to the inferred presence of natural fractures.This case study summarises the efforts to overcome challenging hydraulic fracturing conditions and to analyse varying production behaviours between the hydraulically fractured wells by means of different methods; to assist the efficient development of the company's tight gas reservoirs in the Thrace Basin, Turkey. It was observed that natural fracture intensity increases as the well locations approach major faults, at which point the complex stress regime may then begin to expose the fracturing operations to a risk of early screen-out. Therefore, any proposed infill wells should be located in those areas at a safe proximity from faults for enhanced production.
Reproductive biology of Acer caesium Wall. ex Brandis (Sapindaceae): a dioecious tree species from Northwestern Himalayas
Authors: Roy Sudip Kumar , Khanduri Priyanka , Bhatnagar Ashok Kumar , Pandey Arun Kumar 
Published: September 2023

Abstract
Acer caesium, commonly known as Himalayan maple, is a tree species endemic to Central and Western Himalaya. This multipurpose tree species has undergone a decline in its natural population number due to overexploitation over the years. Any attempts for conservation of this species will require understanding its reproductive behaviour in natural ecosystems. However, there is hardly any information on pollination ecology of this species. To bridge this gap, we studied the floral biology and pollination ecology in natural populations growing at Kedarnath Wildlife Sanctuary, Uttarakhand, India. In addition, whether the species is experiencing any pollen limitation was examined using hand-pollination experiments. A. caesium is a dioecious tree species with male biased sex ratio in the studied populations. Both male and female flowers exhibit typical characters of a wind pollinated plant. Interestingly, pollination experiments revealed ambophily in the species, with wind as the primary means of pollination and a small percentage of fruit set through insects. Pollen limitation experiments showed that natural fruit set in A. ceasium is pollen limited as pollen supplementation augmented the fruit set. The probable reason for low fruit set in natural pollination conditions seems to be sparse distribution of the male plants around female plants in the population. Thus, for optimal conservation efforts, it is recommended that spatial structure of male and female individuals in the population must be considered for better outcrossing opportunities.
Robust Training of Machine Learning Interatomic Potentials with Dimensionality Reduction and Stratified Sampling
Authors: Ong Shyue Ping , Qi Ji , Ko Tsz Wai , Wood Brandon , Pham Tuan Anh 
Published: September 2023

Abstract
Machine learning interatomic potentials (MLIPs) that enable accurate simulations of materials at scales beyond conventional first-principles approaches have played increasingly important roles in understanding and design of materials. However, MLIPs are only as accurate and robust as the data they are trained on. In this work, we present DImensionality-Reduced Encoded Clusters with sTratified (DIRECT) sampling as an approach to select a robust training set of structures from a large and complex configuration space. By applying DIRECT sampling on the Materials Project relaxation trajectories dataset with over one million structures and 89 elements, we develop an improved materials 3-body graph network (M3GNet) universal potential that extrapolate more reliably to unseen structures. We further show that molecular dynamics (MD) simulations with universal potentials such as M3GNet can be used in place of expensive ab initio MD to rapidly create a large configuration space for target materials systems. For demonstration, we combined this scheme with DIRECT sampling to develop a reliable moment tensor potential for titanium hydrides without the need for iterative optimization. This work paves the way towards robust high throughput development of MLIPs across any compositional complexity.
Association of cognitive impairment with the interaction between chronic kidney disease and depression: Findings from NHANES 2011-2014
Authors: Zhou Tong , Zhao Jiayu , Ma Yimei , He Linqian , Ren Zhouting , Yang Kun , Tang Jincheng , Liu Jiali , Luo Jiaming , Zhang Heping 
Published: September 2023

Abstract

Background: Cognitive impairment (CoI), chronic kidney disease (CKD), and depression are prevalent among older adults and are interrelated, imposing a significant disease burden. This study evaluates the association of CKD and depression with CoI and explores their potential interactions.
Method: Data for this study were sourced from the 2011-2014 National Health and Nutritional Examination Survey (NHANES). Multiple binary logistic regression models assessed the relationship between CKD, depression, and CoI while controlling for confounders. The interactions were measured using the relative excess risk of interaction (RERI), the attributable proportion of interaction (AP), and the synergy index (S).
Results: A total of 2,666 participants (weighted n=49,251,515) were included in the study, of which 700 (16.00%) had CoI. After adjusting for confounding factors, the risk of CoI was higher in patients with CKD compared to non-CKD participants (odds ratio [OR]=1.48, 95% confidence interval [CI]:1.11–1.97). The risk of CoI was significantly increased in patients with depression compared to those without (OR=2.23, 95% CI: 1.68–2.94). Furthermore, there was a significant additive interaction between CKD and depression in terms of the increased risk of CoI (adjusted RERI=1.88, [95% CI: 0.27–3.48], adjusted AP=0.49 [95% CI: 0.24–0.75], adjusted S=2.97 [95% CI: 1.24–7.13]).
Conclusion: CKD and depression synergistically affect CoI, particularly when moderate-to-severe depression co-occurs with CKD. Clinicians should be mindful of the combined impact on patients with CoI. Further research is needed to elucidate the underlying mechanisms and assess the effects specific to different CKD stages.
Coverage and Factors associated with utilization of Pyrethroid-Piperonyl Butoxide treated nets in Malaria Endemic Region, Western Kenya
Authors: Aricha Stephen Akuma , Owiny Maurice , Odhiambo Fredrick , Mangeni Judith , Oyugi Elvis 
Published: September 2023

Abstract
Background: Increased resistance to pyrethroid based Long-Lasting Insecticidal Nets (LLINs) informed WHO recommendation to deploy Piperonyl Butoxide (PBO) based LLINs. Kenya adopted use of PBO nets in endemic areas, though coverage is not known. We determined coverage and factors associated with utilization of PBO nets in a malaria endemic county.
Methods: A cross-sectional study was conducted with multi-stage sampling in Matayos Sub-County, Busia County. Data were collected using questionnaire from June-July 2022. Data was analyzed by Stata version 16. Universal coverage was defined as ownership of one PBO net for two household members. Proper utilization was defined as sleeping under a mosquito net the previous night, net usage on all days of the week, hanging the net adequately. Data was collected on net ownership, access, utilization. Proper utilization of nets was the dependent variable. We calculated measures of central tendency and dispersion for continuous variables and proportions for categorical variables. Odds ratio with 95% confidence intervals was used to test for association between dependent and independent variables and variables with a p-value< 0.05 were considered to be statistically significant.
Results A total of 402 participants were interviewed; mean age was 41.2 years (±16.7 years), 268 (66.7%) resided in rural areas, 77.9% (313) were female, 71.4% (287) were married, 45% (181) had at least 8 years of formal education and 86.6% (348) had informal occupations. Among all respondents, 86.3% (347) had bed nets, 92.8% (322/347) were PBO nets. A total of 64.9% (261) households attained universal coverage for bed nets. The utilization of PBO treated LLINs was significantly lower in households with heads in informal occupations compared to those in formal occupations (aOR = 0.29, 95% CI = 0.11-0.78). Additionally, households without universal coverage for bed nets had significantly lower odds of utilizing a PBO-treated LLIN compared to those with universal coverage (aOR = 0.01, 95% CI = 0.01-0.03).
Conclusion: Universal coverage of PBO nets was below the national target (80%). Occupation and universal coverage were associated with the utilization of PBO nets. We recommend for continuous PBO nets distribution through additional innovative channels.
Seroprevalence of SARS-CoV-2 antibodies among healthy blood donors: a systematic review and meta-analysis
Authors: Ukwishaka Joyeuse , Fotabong Mela Cyril , Aseneh Jerry Brown Njoh , Ettaj Malak , Ilboudo Dieudonné , Danwang Celestin , Samadoulougou Sekou , Kirakoya-Samadoulougou Fati 
Published: September 2023

Abstract

Introduction: The development of a potent immune response and antibodies against SARS-CoV-2 is important for attaining herd immunity. This serological response could be due to past infection or vaccines. Healthy blood donors could represent and provide information on the immune status of the general population. Hence, we estimated the global and regional prevalence of SARS-CoV-2 antibodies among healthy asymptomatic blood donors.
Methods: We systematically searched PubMed, Scopus, and ProQuest for eligible articles published between December 1, 2019, and January 12, 2023, without language restrictions. After critical appraisal and quality assessment, a qualitative synthesis of the identified pertinent articles was performed. The random-effect model was used to estimate the pooled prevalence of SARS-CoV-2 antibodies. Funnel plots and Egger’s test were used to assess publication bias. Sensitivity analysis was performed, and heterogeneity was quantified using I2 statistics.
Results: A total of 70 peer-reviewed articles were selected and included 2,453,937 blood donors. The global estimated pooled prevalence of SARS-CoV-2 antibodies among healthy blood donors was 10.9% (95% CI: 5.0 – 18.8%, n=68). A high seroprevalence of SARS-CoV-2 was observed in Asia (20.4%, 95% CI: 10.1 – 33.1%, n=24), followed by Africa (16.1%, 95% CI: 6.8 – 28.3%, n=7). The seroprevalence of SARS-CoV-2 in studies conducted before the introduction of the vaccine was 6.5% (95% CI: 4.9 – 8.3%, n=50), while that of studies conducted after the vaccine was 27.6% (95% CI: 12.4 – 46.2% n=18). High seroprevalence was observed in studies that measured antibodies against the S protein of the virus (16.2%, 95% CI: 11.4 – 21.8%, n=27), while it was 12.5% (95% CI: 5.3 – 22.1%, n=16) in those that measured antibodies against the N protein. A high seroprevalence of SARS-CoV-2 was observed in studies that only measured IgG antibodies (17.2%, 95% CI: 10.5 – 25.1%, n=33) and in studies that measured total antibodies to SARS-CoV-2 (6.2%, 95% CI: 0.7 – 16.5%, n=33).
Conclusion: In view of all evidence, there is variation in the prevalence of SARS-CoV-2 antibodies among healthy blood donors globally. Noticeably, there is a regional difference that could depict differences in transmission and vaccination rates. Based on the results of our analysis, we recommend evidence-based booster vaccination strategies informed by seroprevalence trends and waning immunity and reinforcing seroprevalence surveillance for outbreak management. It is advisable to mitigate socioeconomic disparities through inclusive health policies coupled with adaptable public health measures given local seroprevalence rates. These will contribute to informed policy decisions to build community resilience during the post-PHEIC phase of the COVID-19 pandemic.