bluuebunny/crossref_metadata_2025 huggingface dataset:
ANALISIS STATUS DAYA DUKUNG AIR DI SUB DAS CIKERUH MENGGUNAKAN METODE SOIL CONSERVATION CURVE NUMBER (SCS-CN)
Authors: Pramadita Kania Gita , Suryadi Edy , Kendarto Dwi Rustam
Published: December 2021

Sub DAS Cikeruh merupakan kawasan dengan laju pertumbuhan penduduk yang tinggi, yang mana hal tersebut mengakibatkan alih fungsi lahan terjadi di beberapa kecamatan sehingga berimplikasi terhadap menurunnya ketersediaan air dan meningkatnya kebutuhan air di Sub DAS Cikeruh. Penelitian ini bertujuan untuk mengetahui status daya dukung air di Sub DAS Cikeruh melalui perbandingan rasio antara kebutuhan dan ketersediaan air. Kebutuhan air dihitung dengan menggunakan standar yang ditentukan oleh SNI 19-66728.1, 2002; SNI 67281-2015; dan Ditjen Cipta Karya Dinas PU tahun 1996, adapun sektor yang dihitung adalah domestik, non domestik, industri, pertanian, peternakan, dan perikanan. Ketersediaan air dihitung dengan mengestimasi volume aliran yang terjadi di Sub DAS Cikeruh menggunakan metode Soil Conservation Service Curve Number (SCS-CN) dari USDA dengan melibatkan data hidrologi dari tahun 2011 hingga 2020. Hasil penelitian menunjukkan bahwa ketersediaan air di Sub DAS Cikeruh pada tahun 2020 adalah sebesar 351.852.088,9 m3/tahun, sedangkan kebutuhan air di Sub DAS Cikeruh mengalami perubahan yang dinamis setiap tahunnya. Kebutuhan air di Sub DAS Cikeruh pada tahun 2011 adalah sebesar 545.250.212 m3/tahun, tahun 2015 sebesar 711.121.596 m3/tahun, sedangkan tahun 2020 sebesar 520.638.257 m3/tahun. Hasil perhitungan menunjukkan bahwa terjadi defisit air di Sub DAS Cikeruh, dimana nilai kebutuhan air lebih tinggi dibandingkan ketersediaan air, adapun rasionya sebesar 0,641, yang artinya daya dukung lingkungan telah terlampaui (overshoot) karena nilai rasio < 1.
Velocity field in the McMurdo shear zone from annual ground penetrating radar imaging and crevasse matching
Authors: Ray Laura , Jordan Madeleine , Arcone Steven , Kaluzienski Lynn , Walker Benjamin , Koons Peter Ortquist , Lever James , Hamilton Gordon
Published: December 2021

The McMurdo shear zone (MSZ) is strip of heavily crevassed ice oriented in the south-north direction and moving northward. Previous airborne surveys revealed a chaotic crevasse structure superimposed on a set of expected crevasse orientations at 45 degrees to the south-north flow (due to shear stress mechanisms). The dynamics that produced this chaotic structure are poorly understood. Our purpose is to present our field methodology and provide field data that will enable validation of models of the MSZ evolution, and here, we present a method for deriving a local velocity field from ground penetrating radar (GPR) data towards that end. Maps of near-surface crevasses were derived from two annual GPR surveys of a 28 km² region of the MSZ using Eulerian sampling. Our robot-towed and GPS navigated GPR enabled a dense survey grid, with transects of the shear zone at 50 m spacing. Each survey comprised multiple crossings of long (> 1 km) crevasses that appear in echelon on the western and eastern boundaries of the shear zone, as well as two or more crossings of shorter crevasses in the more chaotic zone between the western and eastern boundaries. From these maps, we derived a local velocity field based on the year-to-year movement of the same crevasses. Our velocity field varies significantly from fields previously established using remote sensing and provides more detail than one concurrently derived from a 29-station GPS network. Rather than a simple velocity gradient expected for crevasses oriented approximately 45 degrees to flow direction, we find constant velocity contours oriented diagonally across the shear zone with a wavy fine structure. Although our survey is based on near-surface crevasses, similar crevassing found in marine ice at 160 m depth leads us to conclude that this surface velocity field may hold through the body of meteoric and marine ice. Our success with robot-towed GPR with GPS navigation suggests we may greatly increase our survey areas.
PCOS and Hyperprolactinemia: Conflicting Conditions or Comorbidities?
Authors: Atalyan Alina , Sharifulin Eldar , Lazareva Lyudmila , Nadelyaeva Yana , Suturina Larisa
Published: December 2021

Currently, hyperprolactinemia is considered as a condition to be excluded during the diagnosis of polycystic ovarian syndrome (PCOS), because it often demonstrates clinical signs similar to PCOS. However, some publications have reported “the prevalence of hyperprolactinemia in PCOS,” which does not agree with the statement above statement. The publications presented in this review demonstrate conflicting approaches to considering the association of hyperprolactinemia and PCOS. On the one hand, the current consensus on the diagnosis of PCOS assumes the exclusion of patients with hyperprolactinemia, and on the other hand, some authors consider hyperprolactinemia as an acceptable condition and estimate its prevalence in PCOS. Based on the analysis of the literature, we have demonstrated a contradictory attitude towards the association between hyperprolactinemia and PCOS. To overcome the contradiction, we consider it appropriate to use the term "potential PCOS" before the final assessment of the contribution of hyperprolactinemia to the development of symptoms similar to PCOS. The final diagnosis of PCOS in the presence of hyperprolactinemia is possible only after its correction and reassessment of all symptoms.
The Role of Physical Aerobic Activity in Controlling Exercise-Induced Bronchoconstriction in Children and Adolescents with Asthma
Authors: Abdelbasset Walid , Elsayed Abbas
Published: December 2021

Asthma, one of the major widespread chronic disorders among children and adolescents, has become more prevalent recently. The common manifestations of this disorder are caused by inflammatory airways that lead to airway restriction and lung hypersensitivity causing dry coughing, wheezing, and shortness of breath, all of which are combined with sleep disturbance, impaired physical activity, and reduced quality of life. The main goal of this brief review was to identify the associated variables that affect the management of asthma disease in children and young adolescents and to identify the role of physical aerobic exercise in the treatment of asthmatic children. The current review was based on prior research published in English databases such as Google Scholar, PubMed, and Embase in scientific articles published between January 2010 and October 2021 with the keywords "asthma," "children," "adolescents," "breathing episodes," "physical activity," and "physical exercise." Regular physical aerobic exercise training with moderate intensity has been shown to improve pulmonary functions, life quality, psychological conditions, and reduce asthma symptoms and EIB in children and adolescents with bronchial asthma.
The Frequency Detection of Opportunistic Sexually Transmitted Infections among HIV-Infected Women Planning Pregnancy
Authors: Belyaeva Elena , Genich Eleva , Leshchenko Olga
Published: December 2021

The purpose of our study was to determine the frequency of detection of opportunistic sexually transmitted infections (Chlamydia trachomatis, Trichomonas vaginalis, Ureaplasma spp, Human papillomavirus) in HIV-infected women planning pregnancy. Methods and Results: We examined 31 HIV-positive Caucasian women. They sought pregnancy planning advice at the Scientific Center for Family Health and Human Reproduction Problems in Irkutsk during 2014-2015. The average age of the women was 30.9±4.5 years (20-39 years). A clinical diagnosis of HIV was made at Irkutsk Regional AIDS Center. All HIV-infected women were tested for the presence of DNA of pathogens of bacterial and viral sexually transmitted infections in the epithelium of the cervical canal. Chlamydia trachomatis was detected in 1(3.2%) participant, Trichomonas vaginalis in 1(3.2%), Ureaplasma spp. in 14(45.2%), and HPV in 22(71%). Co-infection of HPV and Ureaplasma spp. was observed in 35.5% of HIV-positive women. Conclusion: the prevention and detection of sexually transmitted infections in HIV-infected individuals remain a public health priority and an integral component of HIV primary care.
Microbiological Study of Vaginal Microbiota and Endometrium in Women with Chronic Endometritis
Authors: Voropaeva Natalia , Lazareva Lyudmila , Danusevich Irina , Belkova Natalia , Nemchenko Uliana , Grigorova Ekaterina
Published: December 2021

The research objective was to study the spectrum of the vagina and endometrium microorganisms in women with chronic endometritis (CE) in order to take adequate therapeutic measures. Methods and Results: We did a cross-sectional study in 47 women (average age of 35.38±5.19 years) with histologically confirmed CE. The vaginal microbiota and endometrial biopsies were assessed using microbiological research methods in accordance with the medical technology "Integral assessment of the state of the vaginal microbiota." To identify the share of different types of microorganisms in the structure of the biocenosis, the coefficient of constancy of the species (C) was used. Only 19% of patients had a titer of Lactobacillus spp. within the age norm, while the deficit was observed in 80% of women. Among the representatives of Enterobacteriaecae, Escherichia coli and Klebsiella aerogenes were sown, which are considered to be random species (C=11% and C=2.1%, respectively). The average titer for E. coli was 3.6±1.3 lg CFU/swab and for K. aerogenes - 2.14 lg CFU/swab. An atypical variant of E. coli with hemolytic properties was found in only one sample. All isolates of the genus Staphylococcus were also random species (C did not exceed 25%). Coagulase-negative staphylococci (CoNS) were detected in 7 patients (C=15%), while the average titer was 2.1±0.4 lg CFU/swab. S. aureus was isolated from only one patient at a titer of 5 lg CFU/swab. Corynebacterium spp. were isolated in 11% of cases (C = 11% - random species), in a titer of 3.2±0.8 lg CFU/swab. Enterococcus spp. also belonged to random species (C=23.4%). At the same time, E. faecalis was inoculated in 19% of cases and E. faecium was sown in 4.3%, the average titer of which was 3.1±0.9 and 5 lg CFU/swab. Streptococcus spp. were recorded in only one case at a concentration of 5 lg CFU/swab. Fungi of the Candida were isolated as a random species in 8.5% of cases. The growth of microorganisms in endometrial samples was obtained only in 3 examined women with CE (6.4% of cases). The endometrial microbiota were represented only by random species, for which the C index ranged from 2.1% to 4.3%. Conclusion: The microbiological study of the microbiota of vaginal discharge showed the presence of dysbiotic disorders with a significant deficiency of lactobacilli (80%) without the dominance of representatives of the Lactobacillus spp. In the structure of opportunistic microflora, Escherichia coli, coagulase-negative staphylococcus, Enterococcus spp., and E. faecalis prevailed as random species. Representatives of the microbiota in endometrial biopsies were identified only in 6.4% of cases, and are represented by random species.
Neuropeptide Y and Asthma Clinical Course
Authors: Shkatova Yanina , Budnevsky Andrey , Ovsyannikov Evgeniy , Prozorova Galina , Volynkina Anna , Olysheva Irina
Published: December 2021

Background: The spectrum of clinical manifestations and pathogenetic mechanisms of bronchial asthma (BA) is very wide. Given the complex pathogenesis and syndromic nature of BA, it is not surprising that there is no single universal biomarker. The objective of this study was to evaluate levels of neuropeptide Y (NPY) and its association with levels of leptin, adiponectin, oxidative damage, antioxidant status, spirometry parameters, and asthma control in BA patients. Methods and Results: Overall, 140 patients [35(25%) men and 105(75%) women; mean age of 57.0±9.34 years] with moderate asthma participated in the study. According to body mass index, all patients were divided into three groups. The asthma diagnosis was based on the integral assessment of symptoms, medical history, health status, and spirometry values according to the Global Strategy for Asthma Management and Prevention. (GINA, 2017 REPORT). The Asthma Control Test (АСТ) was used to assess asthma control. NPY was measured in blood serum in EIA. The NPY level was significantly higher in overweight patients and patients with obesity than in patients with normal body weight. The NPY level significantly correlated with leptin (r=0.44; P<0.05), adiponectin (r=-0.24; P<0.05), ImanOx (r=-0.40; P<0.05), PerOx (r=0.58; P<0.05), ACT (r=-0.41; P<0.05), VC (r=-0.31; P<0.05), FEV1 (r=-0.41; P<0.05), FEF25% (r=-0.26; P<0.05), FVC (r=-0.23; P<0.05), Tiffno index (r=-0.36; P<0.05), FEF50% (r=-0.22; P<0.05), and PEF (r=-0.23; P<0.05) Conclusion: The severity of the asthma clinical course is associated with different factors, including oxidative stress, levels of leptin, adiponectin and NPY. NPY seems to be associated with worse asthma control and higher levels of leptin and oxidative damage.
Molecular Predictors of Effective Implantation and Live Birth in IVF Programs
Authors: Chukhnina Elena , Kazachkov Evgeny , Voropaeva Ekaterina , Kazachkova Ella , Polina Miroslava , Douglas Natalya
Published: December 2021

The aim of the study was to improve the possibilities of predicting blastocyst implantation and live birth of ART programs in women of late reproductive age with tubal-peritoneal infertility based on immunohistochemical markers of the endometrium. Methods and Results: The results of IVF and IVF/ICSI programs were analyzed in 68 patients of late reproductive age (36-44 years of age) with tubal-peritoneal factor of infertility. Morphological examination of the endometrium was performed on Day 7 after confirmed ovulation in the cycle preceding ART. The expression of vitamin D receptors (VDR) and HOXA11 in endometrial stromal cells was assessed by immunohistochemical method. The effectiveness of using the endometrial markers VDR and HOXA11 as potential predictors of ART programs efficiency was confirmed by prognostic models. The levels of the stromal expression of VDR<8.7% and HOXA11<6.1% (probability >0.27) were determined to be favorable for successful blastocyst implantation. The expression levels of VDR<8.3% and HOXA11<6.1% in endometrial stromal cells are prognostically favorable for live birth (probability >0.19) in women of late reproductive age with tubal-peritoneal infertility who undergoing ART treatment with their own oocytes.
Socio-Demographic Factors and Epidemiological Characteristics of HIV-Positive Pregnant Women with High Risk of Vertical Transmission of the Immunodeficiency Virus
Authors: Vanyarkina Anastasiya , Petrova Alla , Rychkova Lyubov , Moskaleva Ekaterina , Novikova Evgeniya
Published: December 2021

The purpose of this study was to determine the features of the course of pregnancy, delivery, and the postpartum period in HIV-positive women with a high risk of HIV vertical transmission. Methods and Results: A retrospective, longitudinal cohort study of mother-child pairs for the period from 2017 to 2019 was conducted in the Irkutsk City Perinatal Center (level III). The clinical observation group included HIV-positive women (n=213) and their newborn children with a high risk of perinatal immunodeficiency virus transmission (n=214). The findings of the conducted study demonstrated that most HIV-seropositive women with a high risk of HIV vertical transmission had an aggravated social history, a high prevalence of pelvic inflammatory diseases, and a high incidence of opportunistic and AIDS-defining conditions. Evaluation of PMTCT preventive complex showed that the target parameters in women with a high risk of HIV transmission were not reached: the first stage was performed for 49.3% of pregnant women with good ART adherence, the second stage – for 97.1% of obstetric patients, the third stage – in 100% of HIV perinatally exposed children. HIV RNA was detected in 3.7% of children, which evidences their antenatal infection. Conclusion: Development of efficient communication with HIV-positive women aimed at preservation of their health and decrease of logistic barriers to access to medical care.
Comparison of a Portable and Non-Portable Ultrasound Machine in the Evaluation of Children with Sickle Cell Disease: A Pilot Study
Authors: Alsaadi Mohammed , Widdup Joanne , Aslam Mohammed , Chakravorty Subarna
Published: December 2021

Background: Transcranial color Doppler (TCCD) ultrasound is used to identify children with sickle cell disease (SCD) at high risk of developing stroke. There is anecdotal evidence to suggest that different ultrasound equipment can give different blood flow velocities. The purpose of this study was to compare two different TCCD ultrasound machines. Methods and Results: A flow phantom was used to compare PSV measurements from a Philips IU-22 and Zonare Z-One ultrasound machine. Twenty-five children with SCD (aged between 2 and 16 years) attending the outpatient clinic at St. Mary’s Hospital, Imperial College Healthcare NHS Trust, as part of the NHS Sickle Cell & Thalassaemia (SC&T) screening program were studied. The two ultrasound machines compared the TAMM velocities in the middle cerebral artery and stroke risk categorization. PSV measurements using a flow phantom were underestimated by Philips IU-22 (31%) and Zonare Z-One (53%). TAMM velocities varied considerably between machines, with a poor agreement in stroke risk categorization. As a result, three children identified at increased risk of stroke by Philips IU-22 were not identified by Zonare Z-One. Conclusion: Two ultrasound machines were found to underestimate PSV using a flow phantom. The two ultrasound machines were shown to positively correlate, and this was statistically significant. However, there was variation in the TAMM velocities recorded by the machines which resulted in the different categorization of the stroke risk of a small number of the subjects. This pilot study confirms the feasibility and clinical significance of this investigation.
Contribución de la economía creativa al desarrollo local del Centro Histórico de La Habana Vieja
Authors: Piloto-Chávez Richard Osmel , Ruíz-Acosta Verónica
Published: December 2021

El Centro Histórico de la Habana Vieja posee un modelo de gestión propio que condiciona un escenario propicio para el desarrollo de las economías creativas. Esta investigación se propone analizar los desequilibrios en los procesos de desarrollo de las industrias creativas del sector no estatal en este territorio. Se seleccionaron dos de sus consejos populares, con diferencias socioeconómicas sustanciales, y se tomó una muestra representativa de 150 emprendimientos del sector privado con el fin de identificar aquellos que se encuentran asociados a la economía creativa. Además, se identificaron las potencialidades y las barreras que presentan estas dos áreas para el desarrollo de las economías creativas privadas y se elaboraron las posibles líneas de acción para desarrollar en estos territorios. A pesar de estar en una zona con un desarrollo artístico de excelencia, son pocos los negocios por cuenta propia que pueden clasificar como economías creativas, pues existe una gran cantidad de propuestas repetitivas, sin valores culturales diferenciados y una marcada incultura sobre el tema. Se confirmó que los consejos populares estudiados presentan diferencias en cuanto a la diseminación de estas industrias, por lo que se analizó la importancia de trazar políticas que tributen al desarrollo equitativo de estas economías en todo el Centro Histórico de La Habana Vieja.
Efficient Modeling of Unconventional Well Performance with Millions of Natural and Hydraulic Fractures Using Embedded Discrete Fracture Model EDFM
Authors: Yu Wei , Gupta Anuj , Vaidya Ravimadhav N. , Sepehrnoori Kamy
Published: December 2021

The complexity of dynamic modeling for naturally fractured reservoirs has increased in recent years to incorporate more data and physics, as well as to handle advanced completion designs and development scenarios. While these complex models can provide more insight to difficult problems, they come with higher computational costs. Such a limitation prohibits an asset team from working with a large number of well/fracture scenarios that correctly represent geological uncertainty. This study presents a powerful non-intrusive Embedded Discrete Fracture Model (EDFM) method to efficiently handle millions of natural and hydraulic fractures with hundreds of horizontal wells, which has never been modeled in the literature. Specifically, we built a 3D geological model using a black oil reservoir simulator with 100 square miles in the horizontal area and 11 layers of 165 ft thickness. The total number of matrix cells without considering fractures is over 3 million. In total, 400 horizontal wells with well length of 6000 ft were modeled in two target layers. Each layer contains 200 wells. Each well has 112 hydraulic fractures with cluster spacing of 50 ft. The total number of hydraulic fractures is 44,800. In addition, we generated three cases with 10K, 100K and 1 million 3D natural fractures with dip angle from 70 to 90 degrees. For the case with 1 million natural fractures, the total number of cells is over 42 million. Well performance for the field example, with and without natural fractures, was investigated. This work adds significant value to the well and fracture spacing optimization process during field development planning. The non-intrusive EDFM method has been proven to be an efficient fracture modeling tool for simulating million-level complex hydraulic/natural fractures, which significantly improves accuracy and reduces computational time.
A Novel Machine-Assisted Technique for Extracting Multiscale Vugs and Fractures in Heterogeneous Carbonates Sequence
Authors: Parashar Sarvagya , Wu Ivan Zhia Ming
Published: December 2021

Predicting petrophysical properties in carbonate reservoirs is challenging due to the deposition and diagenetic history, which creates pore-scale features and heterogeneity at multiple-length scale. Non-fractured carbonate rocks with monomodal pore distribution often provide weak transportation properties compared to carbonates with multimodal pore system. The behaviour of such formations is subject to percolation effect where the connectivity of vug clusters control the poro-perm relationship which can be explained with high-resolution microresistivity images and nuclear magnetic resonance (NMR) data. A machine-assisted processing technique, defined as "thresholding," was applied to high-resolution microresistivity images, resolving vugs and fractures with similar resistivity. Other objects of interest are removed using object-oriented filters and thresholding, resulting in a "sculptured image" containing only vugs and fractures. The image is analysed to quantify formation porosity. A Laplacian of Gaussian filter is used to avoid highlighting features of no interest. Step two analyses T1 and T2 relaxations allowing portions of signal from a pore-size group to spill across the discrete boundaries. The pore-size takes on a fuzziness near the discrete relaxation time cut-offs corresponding to pore radii breakover points. High poro-perm layers of grainstone in overall thinly bedded sequences of packstone and wackestone were successfully identified and subsequently shed light upon the ambiguities observed in mobility values obtained from formation tester across the same lithocolumn. This novel technology helps in deciphering high-resolution integrated lithofacies. The histogram from the image porosity binning demonstrates a different response within vugular zones compared to fractured zones. Where the vugs sizes are variable, they exhibit a multi-pore system nature in NMR. For the fractured interval, the images and NMR exhibit weak distribution. The resistivity independent image pixel-based filtration technique helps to define interesting features on images which can be enhanced and measurable at various scales. Machine assisted technique in NMR complement the results in aiding to characterize the heterogeneous carbonate rocks.
Value Oriented Engineering Solutions for Business Continuity
Authors: Delgado Rivera Jose Luis
Published: December 2021

This paper presents a systemic approach using Engineering and analytics methods to avail the fastest and safest responses to recovering business operations after Abqaiq Plants major disruption after the 2019 September 14th incident. This new approach using value and agile engineering, risk management methodologies combined with the business continuity model suggested was successfully applied to recover Abqaiq Plants Operations after catastrophic events occurred.

This paper pretends to serve as example about how the business continuity plan should response to a major emergency and how this planning activity could be effectively supported using a Value Oriented Engineering Solutions (VOES). This VOES approach is based on Business continuity framework and adapted for use during emergency situations to generate effective and urgent responses to recover one of the most strategical operations in the Oil and Gas Industry worldwide ahead of the last year significant disruption.

VOES approach vastly implemented during Abqaiq Plants Restoration allowed a 100% functional recovery on 9 days, 5 days in advance to the most optimistic scenario. This paper shows a case study implemented for major instrumentation and electrical equipment activities performed in UA Spheroids plant, one of the most affected area and responsible to process the 100% of the Abqaiq Plants Oil Production rate.

This paper pretends to contribute with the research and practice on business continuity management. Considering a particular approach to BCM, incorporating value-oriented engineering solutions in the developing of continuity plans; we apply model-based techniques to provide quality assurance in the elaboration process, and to automate the generation/update of a BCP. On the practical side, this study converts Operational, Maintenance, Safety and Reliability perspectives in a holistic view provided from Engineering solutions responsible to generate the guidelines for an agile, effective and realizable recovery plan.
Application of a Drilling Simulator for Real-Time Drilling Hydraulics Training and Research
Authors: Skenderija Jelena , Koulidis Alexis , Kelessidis Vassilios , Ahmed Shehab
Published: December 2021

Challenging wells require an accurate hydraulic model to achieve maximum performance for drilling applications. This work was conducted with a simulator capable of recreating the actual drilling process, including on-the-fly adjustments of the drilling parameters. The paper focuses on the predictions of the drilling simulator's pressure losses inside the drill string and across the open-hole and casing annuli applying the most common rheological models. Comparison is then made with pressure losses from field data.

Drilling data of vertical and deviated wells were acquired to recreate the actual drilling environment and wellbore design. Several sections with a variety of wellbore sizes were simulated in order to observe the response of the various rheological models. The simulator allows the input of wellbore and bottom-hole assembly (BHA) sizes, formation properties, drilling parameters, and drilling fluid properties. To assess the hydraulic model's performance during drilling, the user is required to input the drilling parameters based on field data and match the penetration rate. The resulting simulator hydraulic outputs are the equivalent circulation density (ECD) and standpipe pressure (SPP).

The simulator's performance was assessed using separate simulations with different rheological models and compared with actual field data. Similarities, differences, and potential improvements were then reported. During the simulation, the most critical drilling parameters are displayed, emulating real-time measured values, combined with the pore pressure, wellbore pressure, and fracture pressure graphs. The simulation results show promise for application of real-time hydraulic operations.

The simulated output parameters, ECD and SPP, have similar trends and values with the values from actual field data. The simulator's performance shows excellent matching for a simple BHA, with decreasing system's accuracy as the BHA design becomes more complex, an area of future improvement.

The overall approach is valid for non-Newtonian drilling fluid pressure losses. The user can observe the output parameters, and by adding a benchmark safety value, the simulator gives a warning of a potential fracture of the formation or maximum pressure at the mud pumps. Thus, by simulating the drilling process, the user can be trained for the upcoming drilling campaign and reach the target depth safely and cost-effectively during actual drilling.

The simulator allows emulation of real-time hydraulic operations when drilling vertical and directional wells, albeit with a simple BHA for the latter. The user can instantly observe the output results, which allows proper action to be taken if necessary. This is a step towards real-time hydraulic operations. The results also indicate that the simulator can be used as an excellent training tool for professionals and students by creating wellbore exercises that can cover different operating scenarios.
Simulation of Pressure- and Temperature-Dependent Fracturing Fluid Loss in Multi-Porosity Multi-Permeability Formations
Authors: Liu Chao , Phan Dung , Abousleiman Younane
Published: December 2021

In this paper, the multi-porosity multi-permeability porothermoelastic theory is used to derive the analytical solution to calculate the pressure- and temperature-dependent fracturing fluid loss. A triple-porosity triple-permeability source rock formation is selected as an example to illustrate the model. The effects of fracturing fluid temperature and natural fractures on the fluid loss rate are systematically illustrated. The model successfully accounts for the varying leak-off rates in the multi-permeability channels through the hydraulic fracture faces. Furthermore, thermal diffusion near the hydraulic fracture faces contributes to a variation of pore pressure whose gradient at hydraulic fracture faces directly controls the fracturing fluid leak-off rate. The model shows that thermal effects bring almost 27% variation in the leak-off rate. Comparison study indicates that the single porosity model without considering multi-permeability systems or thermal effects significantly underestimates the rate of fracturing fluid loss and predicts nearly 84% and 87% lower leak-off rate, compared to the dual-porosity dual-permeability and triple-porosity triple-permeability models, respectively. Two case studies using published laboratory measurements on naturally fractured Blue Ohio sandstone samples are conducted to show the performances of the model. It is shown that the model presented in this paper well captures the total leak-off volume during the pressure-dependent fluid loss measured from laboratory tests. Matching the analytical solution to the laboratory data also allows rocks’ double permeabilities to be estimated.
Deterministic Modeling to Predict the Natural Gas Density Using Artificial Neural Networks
Authors: Shreif Mariam , Kalam Shams , Khan Mohammad Rasheed , Khan Rizwan Ahmed
Published: December 2021

During the past decades, several research studies have been made to unfold the immense and diversified benefits of the innovative applications of machine learning (ML) techniques in the petroleum industry. For instance, machine learning algorithms were applied to estimate the various physical properties of natural gas. Natural gas density is considered an indispensable metric that influences the determination of several variables necessary for analyzing natural gas systems. In this work, the Artificial neural network (ANN), a machine learning technique, was applied to estimate natural gas density incorporating the influencing factors. The ANN model was also compared with another ML technique, namely the Adaptive Neuro-Fuzzy Inference System (ANFIS). A mathematical form has been also presented using ANN. A real data set was taken from the literature, comprised of about 4500 data points assimilating three influencing input variables, including pseudo-reduced pressure (PPr), pseudo-reduced temperature (TPr), and molecular weight (Mw). The PPr and TPr are obtained by calculating the averages of the sample gas critical pressures and critical temperatures. A complicated nonlinear relationship exists between the three influencing variables and the gas density. The data set was divided into a 70:30 ratio for training and testing the model, respectively. Adaptive Neuro-Fuzzy Inference System (ANFIS) and Artificial Neural Networks (ANN) were applied to train and test the model. Absolute average percentage error (AAPE), coefficient of determination (R2), and root mean squared error (RMSE) were considered in the error metrics to acquire the best possible model. Levenberg–Marquardt backpropagation algorithm was employed for ANN, while subtractive clustering was used for ANFIS. Results showed that natural gas density can be well correlated with numerous inputs using machine learning tools (ANN and ANFIS). The input parameters include Ppr, Tpr, and Mw, as mentioned above. ANN performed better than ANFIS. The network was adjusted against the training sub-set to set-up weights and biases covering each node. R2 for both testing and training data was more than 99%, while AAPE was around 4% for both cases. Moreover, a detailed mathematical scheme for the ANN model is also provided in this paper.
Fracturing Fluid Design: A Closer Look at Breaker and Surfactant Selection
Authors: Alfakher Basil , Al-Taq Ali , Aldarweesh Sajjad , Alhamad Luai
Published: December 2021

Guar and its derivatives are the most commonly used gelling agents for fracturing fluids. At high temperature, higher polymer loadings are required to maintain sufficient viscosity for proper proppant carry and creating the fracture geometry. To minimize fracturing fluids damage and optimize fracture conductivity, it is necessary to design a fluid that is easy to clean up by ensuring proper breaking and sufficiently low surface tension for flow back. Therefore, breakers and surfactants must be carefully selected and optimally dosed to ensure the success of fracturing treatments.

In this study, two fracturing fluids were evaluated for moderate to high temperature applications with a focus on post-treatment cleanup efficiency. The first is a guar-based fluid with a borate crosslinker evaluated at 280°F and the second is a CMHPG-based fluid with a zirconate crosslinker evaluated at 320°F. The shear viscosities of both fluids were tested with a live sodium bromate breaker, a polymer encapsulated ammonium persulfate breaker and a dual breaker system combining the two breakers. Different anionic and nonionic surfactant chemistries (aminosulfonic acid and alcohol based) were investigated by measuring surface tension of the surfactant solutions at different concentrations. The compatibility of the surfactants with other fracturing fluid additives and their adsorption in Berea sandstone was also investigated. Finally, the damage caused by leak-off for each fracturing fluid was simulated by using coreflooding experiments and Berea sandstone core plugs.

Lab results showed the guar and CMHPG fluids maintained sufficient viscosity for the first two hours at baseline, respectively. The encapsulated breaker proved to be effective in delaying the breaking of the fracturing fluids. The dual breaker system was the most effective and the loading was optimized for each tested temperature to provide the desired viscosity profile. Two of the examined surfactants were effective in lowering surface tension (below 30 dyne/cm) and were stable for all tested temperatures. The guar broken fluid showed better regained permeability (up to 94%) when compared to the CMHPG (up to 53%) fluid for Berea sandstone.

This paper outlines a methodical approach to selecting and optimizing fracturing fluid chemical additives for better post-treatment cleanup and subsequent well productivity.
Assessment of Foamed Fluids Based on Surfactants and Nanoparticles for Fracturing and Acidizing Applications
Authors: Alarawi Abeer , Al Moajil Abdullah , Alrustum Abdullah , AlMahri Waddah
Published: December 2021

Foamed fluids are commonly used in acidizing and fracturing applications to minimize formation damage, improve fluid recovery, and as diverting-agents. However, significant concerns with foamed fluids are poor stability and low viscosity. The study objectives include evaluating the commercially available surfactants’ foamability and stability when mixed with and without nanoparticles. The prepared foamed fluid characteristics such as rheology, morphology, stability, and proppant suspension were evaluated.

Foam loop rheometer experiments were conducted at 1500 psi and 70% N2 quality to assess foam-stability and rheological properties. Foam decaying time was detected by half-life-time measurements (measuring foam-height as a function of time). Turbiscan was used to study the proppant settling using backscattering light. A high-resolution optical microscope was used to observe foam morphology and stability.

The surfactant C-nanoparticles-based foamed fluid demonstrated stable foam with a high viscosity value that reached >110 cP at 100 S-1 77 °F and 70% N2 quality. Compared to the surfactant-based foamed fluid, combining the surfactant with nanoparticles as a foam-stabilizer increased the foam-half-life-time by nearly 35-75%. Foam bubbles size of surfactants A and B (with/without NPs) were large with an irregular shape and tended to rupture intermittently within 50 and 8 minutes, respectively. Bubbles average size of surfactant C (with/without NPs) based foams was small, and the count was higher than the foams of surfactants A and B. surfactant C (with/without NPs) based foams demonstrated bubbles with a spherical shape.

Turbiscan stability index values of several surfactants-nanoparticles-based foamed fluids were almost comparable at 77 and 122 °F. Lastly, the foam fluids’ proppant settling velocity prepared with nanoparticles was lower than pure surfactant-based foams.
Successful Mitigation of Excessive Backreaming in Troublesome Vertical Applications in the Sultanate of Oman
Authors: Pranava Ananda , Ali Hassan Albalushi Humaid , Mamari Zakaria , Al Zeidi Badar , Newman Tom , Mounzer Fadi
Published: December 2021

Drilling through some of the reactive shale formations in the western gas fields in the Sultanate of Oman has proven challenging and often troublesome. Frequently, time spent on backreaming would exceed the time required to drill the related hole sections. In addition, the carbonate Natih sequence has also proven problematic. High levels of vibrations are often encountered. Such drilling dysfunctions are known to be destructive to both bit and bottom hole assembly (BHA). Different mud systems, drive systems and reamer types were used in separate attempts to alleviate the faced dysfunctions to little avail. This paper illustrates a trial campaign introducing an alternative design stabilizer (ADS) and reamer (ADR) to the drilling BHA with the aim of addressing and resolving the aforementioned limiters.

Based on a set of agreed-on key performance indicators (KPIs), and following a methodical approach, a 4-well trial was conducted in order to introduce a unique stabilizer-reamer design while simultaneously scrutinizing and optimizing the BHA configuration accordingly. Two of the candidate wells targeted the 17-1/2" section while the other 2 wells targeted the 12-1/4" sections. The main goals were to reduce the time spent on backreaming by 50% and minimize the experienced levels of vibrations in order to extend bit runs and reliability of the different BHA components. For further comparisons, the same approach was tested on a rotary BHA as well as a steerable motor BHA in the larger hole sections.

Both 17-1/2" sections were each drilled in a single run similar to the second 12-1/4" section. The first 12-1/4" also proved smooth and required 2 runs due to bit hours, still noting a record section distance run for a single bit. All BHAs were optimized around the placement of the new design stab and reamer design combination. The optimized BHA configuration enabled pulling out of hole (POOH) on elevators for all 4 sections almost fully eliminating the hard backreaming experienced in past wells. In addition, it was also noted that in all cases the levels of vibrations were significantly reduced compared to what is typically experienced and recorded in the offset wells. This enabled a record setting bit run for that particular section and field.

The authors detail the historical challenges encountered drilling such wells then present the applied benchmarking exercise and the adopted systematic approach to tackle those challenges. Following, the unique design characteristics of the deployed technology are highlighted and how this is applied in each of the runs in view of optimizing casing point to casing point section delivery times. Finally, the achieved results and gains are underlined together with a roadmap forward.
Emerging Techniques in Measuring Capillary Pressure and Permeability Using NMR and AI
Authors: Ghamdi Ahmed , Isah Abubakar , Elsayed Mahmoud , Garadi Kareem , Abdulraheem Abdulazeez
Published: December 2021

Measurement of Special Core Analysis (SCAL) parameters is a costly and time-intensive process. Some of the disadvantages of the current techniques are that they are not performed in-situ, and can destroy the core plugs, e.g., mercury injection capillary pressure (MICP). The objective of this paper is to introduce and investigate the emerging techniques in measuring SCAL parameters using Nuclear Magnetic Resonance (NMR) and Artificial Intelligence (Al).

The conventional methods for measuring SCAL parameters are well understood and are an industry standard. Yet, NMR and Al - which are revolutionizing the way petroleum engineers and scientists describe rock/fluid properties - have yet to be utilized to their full potential in reservoir description. In addition, integration of the two tools will open a greater opportunity in the field of reservoir description, where measurement of in-situ SCAL parameters could be achieved. This paper shows the results of NMR lab experiments and Al analytics for measuring capillary pressures and permeability.

The data set was divided into 70% for training and 30% for validation. Artificial Neural Network (ANN) was used and the developed model compared well with the permeability and capillary pressure data measured from the conventional methods. Specifically, the model predicted permeability 10% error. Similarly, for the capillary pressures, the model was able to achieve an excellent match. This active research area of prediction of capillary pressure, permeability and other rock properties is a promising emerging technique that capitalizes on NMR/AI analytics. There is significant potential is being able to evaluate wettability in-situ. Core-plugs undergoing Amott-Harvey experiment with NMR measurements in the process can be used as a building block for an NMR/AI wettability determination technique. This potential aspect of NMR/AI analytics can have significant implications on field development and EOR projects

The developed NMR-Al model is an excellent start to measure permeability and capillary pressure in-situ. This novel approach coupled with ongoing research for better handling of in-situ wettability measurement will provide the industry with enormous insight into the in-situ SCAL measurements which are currently considered as an elusive measurement with no robust logging technique to evaluate them in-situ.
Micromechanics of Drilling: A Laboratory Investigation of Formation Evaluation at the Bit
Authors: Koulidis Alexis , Mohamed Fahd , Ahmed Shehab
Published: December 2021

Challenging drilling applications and low oil prices have created a new emphasis on innovation in the industry. This research investigates the value of drill bit based force sensing at the rock-cutter interface. For this purpose, a laboratory-based mini-rig has been built in order to recreate a scaled drilling process. The work aims to build a better understanding of the collected force and torque data despite the semi-continuous drilling process. This data is then used to estimate the formation strength.

A scaled drill bit with two cutters was designed with sensors integrated into the drill bit cutter, drill string and the mini-rig structure. The mini-rig design allowed the accurate control of depth of cut by utilizing a comprehensive data acquisition and control system during the experiments. Initially, fifty-five samples were prepared with various water/gypsum ratios for a uniaxial compression test, scratch test, and for testing in the mini-rig. Prior to the mini-rig experiments, the results of the uniaxial compression and scratch tests were used as a benchmark to extract rock properties and the state of stress behavior.

The experiments under atmospheric conditions revealed that the mini-rig could accurately estimate formation strength from a few rotations. The force data at the bit-rock interface was correlated with the torque measurements, and the results indicate that the tangential force has similar trends and relatively similar values.

The groove created by the drill bit's rotating trajectory has a 14.45 cm circumference. This allows for a significant amount of data to be captured from a single rotation. The circular cutter geometry's influence is crucial for a continuous process since the active cutting area is continuously changing due to the pre-cut groove. The performed depth of cuts ranged from 0.1 to 1 mm in the same groove, and thus the active cutting area can be accurately calculated in real-time while conducting the experiments.

Tangential and normal force data from the scratch test was analyzed in order to provide insights for correlation with the mini-rig data. The analysis shows that both tests give similar trends to the force measurements from the mini-rig. Moreover, the benchmark value of formation strength that was obtained from the uniaxial compression test was also in the same range. This illustrates the potential viability of drill bit based formation strength measurement due to the similarity between mini-rig test results and those using more classical testing practices.

The experimental setup can provide a continuous cutting process that allows an accurate estimation of formation strength during a semi-continuous drilling operation with analogous application in the field. This can lead to an in-depth understanding of drilled formation properties while drilling and possibly assist in evaluating cutter wear state in-situ.