bluuebunny/crossref_metadata_2025 huggingface dataset:
Fetal intrapericardial teratomas
Authors: Yuan Shi-Min , Lin Hong
Published: January 2020

Fetal intrapericardial teratomas are rare and benign. However, they can be life-threatening owing to the complicated massive pericardial effusions, tamponade, or cardiorespiratory distress. The purpose of this review is to give an overview on clinical features, management and prognoses of fetal intrapericardial teratomas. The materials of this study were based on a comprehensive literature retrieval of fetal intrapericardial teratomas published in the past two decades. It was noteworthy that fetal pericardial/pleural effusions or ascites were detected since 19-week gestation, and tumors could be found since 21-week gestation. A growing trend of tumors was observed in more than half of the cases. Prenatal centesis and postnatal tumor resection were required in most of the cases. Fetoneonatal deaths (including fetal demise, termination of pregnancy and neonatal death) occurred in one-third of the cases. The neonatal survival rate was 59.4%. Symptomatic fetuses usually required perinatal maneuvers, such as pericardiocentesis, or thoraco-/ pericardio-amniotic shunt in order to improve fetal hemodynamic status and prolong the pregnancy for lung maturity. Open fetal surgery and ex utero intrapartum treatment (EXIT) procedure can be considered, however, impact of EXIT procedure on later delivery remains uncertain. Postnatal operation is a curative and symptom-relieving method for those cases with prenatally diagnosed intrapericardial teratomas. As a result, the fetoneonatal outcomes are somewhat promising.
Clinical findings and genetic analysis of the patients with IL-12Rβ1 deficiency from southeast Turkey
Authors: Doğruel Dilek , Gündeşlioğlu Özlem Özgür , Yılmaz Mustafa , Alabaz Derya , Altıntaş Derya Ufuk , Kocabaş Emine
Published: January 2020

IL-12Rβ1 deficiency is an autosomal recessive disorder characterized by predisposition to poorly pathogenic mycobacteria, salmonella and candida species. We aimed to analyze the clinical manifestations, immunological and genetic features of IL-12Rβ1 deficiency in 10 Turkish patients from a single center. We retrospectively studied the clinical manifestations and genetic analysis of the IL-12Rβ1 deficiency patients from 2008 to 2016. Ten patients were diagnosed and followed for eight years. The mean age at onset and diagnosis were 24.1±42.5 (med:10.5) and 52.3±6.83 (med:20) months, respectively. Parental consanguinity rate was 81.8%. All patients were BCG vaccinated. Abscess and axillary lymphadenopathy in the vaccinated area was the most common initial presentation following the BCG vaccination, six patients had recurring oral candidiasis. Active infections were treated appropriately, in addition to prophylactic therapy with IFNɣ. We identified 6 different mutations in the IL12RB1 gene in 10 patients including 5 splice-site mutations, 3 missense, 1 frameshift, 1 premature stop codon. One of these mutations was novel. The most common mutation was IVS8+1G > A(c.783+1G > A) followed by p.R175W(c.523C > T). This study emphasizes that patients presented with abscess and axillary lymphadenopathy associated with BCG vaccination should be evaluated for IL-12Rβ1 deficiency.
Detection and molecular characterization of uncommon rotavirus group A genotype G12 among hospitalized children in Chennai
Authors: Arun Ponnambalam , Krishnasami Kaveri , Gunasekeran Palani , Fathima Gracy , Padmanabhan Vidya
Published: January 2020

Human group A (RVAs) possess genetic diversity and often newer RVA strains have been reported frequently with different G and P combinations worldwide. As the disease burden is more common in low income countries including India, monitoring and detection of the circulating strains of rotavirus needs to be monitored to understand the genetic diversity of the strains which evolve over time. This study was an attempt to provide data on rotavirus gastroenteritis prevalence in and around Chennai Tamilnadu-South India during the pre-vaccination era. Stool samples were collected and tested from 401 children less than five years of age admitted to hospitals with acute gastroenteritis. The samples were subjected to amplification for VP7 and VP4 genes by using consensus primers, followed by semi-nested type-specific multiplex PCR. Phylogenetic analysis of VP7 genes of G12 were carried out and the variations between strains isolated globally were documented. Rotavirus was detected in 167 (41.64%) samples and five were found to be the uncommon G12P[6] genotype (2.99%) tested by RT-PCR followed by G1P[8], G9P[4], G9 with P untypable and G3P[8] and combinations of G2G9P[6] and G9G2P[11] with few strains untypable. In this study we highlight the occurrence of uncommon G12P[6] strain of rotavirus infection in the community. Since rotavirus is transmitted through oral-fecal route and monitoring of environmental cleanliness is mandatory to cease the spread of this deadliest viral agent to achieve our MDG-IV. Covering single genotype will have to be modified with respect to the circulating stains.
Giant axonal neuropathy: A differential diagnosis of consideration
Authors: Edem Pınar , Karakaya Mert , Wirth Brunhilde , Okur Tuncay Derya , Yiş Uluç
Published: January 2020

Giant axonal neuropathy (GAN) is a rare neurodegenerative disorder affecting both the central and peripheral nervous systems progressively. The recessive mutations of the GAN gene are responsible for the disease. Although some clinical aspects, like coarse and kinky hair, are suggestive, other diseases may interfere with diagnosis. We describe a case who previously had been diagnosed with and treated for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP); after re-evaluation, genetic testing was received, and the patient was diagnosed with GAN.
Hemophagocytic lymphohistiocytosis associated with oxcarbazepine
Authors: Kırık Serkan , Güneş Hatice , Yurttutan Sadık , Sarışık Nafiz , Acıpayam Can , Kırık Yasemin
Published: January 2020

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening multisystem disorder. Reports of the disorder as a side effect of drugs are extremely rare. We report the case of a 3-year-old boy with a history of epileptic seizures in which oxcarbazepine was added to treatment for the last 35 days and dose had been increased. For 10 days he had a fever, hepatosplenomegaly, rash, edema and other systemic symptoms. He was diagnosed with HLH after bone marrow examination. Oxcarbazepine treatment was terminated after the intravenous immunoglobulin treatment. The next day, clinical and laboratory results had improved. This is the first HLH report of an association with oxcarbazepine. Bone marrow aspiration may be indicated to confirm the diagnosis when facing a patient with systemic symptoms after newly added antiepileptic drug treatment.
Kawasaki disease complicated by peripheral gangrene and a ventricular septal defect: An unusual association
Authors: Mohsin Muhammad , Akhtar Saleem
Published: January 2020

Kawasaki disease is an acute febrile illness associated with the vasculitis of small and medium size arteries. Peripheral gangrene is very rare but a known complication of Kawasaki disease mostly reported in the infantile age group. Early therapy is advocated for prevention of serious complications. We report a 10-month-old girl with Kawasaki disease and a small ventricular septal defect who developed peripheral gangrene despite initiation of early therapy.
Thirty years of the newborn screening program in Central Serbia: the missed cases of congenital hypothyroidism
Authors: Milenkovic Tatjana , Vukovic Rade , Radojicic Bojana , Mitrovic Katarina , Todorovic Sladjana , Zatezalo Ljubica
Published: January 2020

Newborn Screening (NS) program for congenital hypothyroidism (CH) has completely changed the natural history of this devastating disorder for the vast majority of children with CH. However, cases of missed CH do happen, and it is important to keep this possibility in mind during every day clinical practice. The objective of this study was to analyze the recognized cases of undiagnosed CH by the NS program in Central Serbia in order to evaluate the reasons for such omissions. Data regarding the recognized missed cases of CH between the years of 1983 and 2013 were collected and analyzed. During 30 years of the NS program for CH on the territory of Central Serbia, 1,547,122 newborns were screened, and during this period, 14 children with CH were missed by the NS. Five missed cases were children with athyreosis (35.8%), 8 had ectopic thyroid gland (57.1%) and one child had dyshormonogenesis (7.1%). The median age at diagnosis of CH in these missed cases was 1.12 years (range 0.08-13.5 years). In the group of children with missed diagnosis of CH, 71.4% were missed due to errors during sample collection, and 28.6% of patients were missed due to false negative screening results. Continuous education of neonatologists as well as nurses in neonatal units of maternity hospital are necessary to avoid errors in sample collection. It is of high importance to notice in a discharge list if a child is referred to the hospital before the sample is taken in a maternity hospital. On the other hand, the maternity hospital has to inform the screening laboratory about any child who was referred to another hospital if the blood samples for screening are not taken. Parents should be better informed that each child has to be included in the NS which is obligatory in Serbia. In addition, awareness amongst pediatricians in primary care should be raised regarding the possibility of missed cases of CH.
Exercise-induced anaphylaxis: a case report and review of the literature
Authors: Esenboğa Saliha , Şekerel Bülent Enis
Published: January 2020

Exercise-induced anaphylaxis (EIAn) is a rare, unpredictable, and potentially fatal cause of anaphylaxis which occurs with physical exhaustion. To the best of our knowledge, here we report the first case of EIAn from Turkey with no prior history of allergy. A detailed patient history is the most crucial point in the diagnosis of EIAn. The triggering and co-factors should be questioned in detail to determine treatment recommendations.
A novel evaluation of genetic polymorphism in BCG adenitis
Authors: Hassanzad Maryam , Farnia Poupak , Darougar Sepideh , Velayati Ali Akbar
Published: January 2020

Bacillus Calmette-Guerin (BCG) is a live attenuated vaccine which has been used to prevent tuberculosis, according to the World Health Organization (WHO) recommendation in parts of the world with an incidence of tuberculosis infection more than 1%. The incidence of BCG adverse reactions differs between regions with regional lymphadenitis as the most common presentation. The aim of this study was to detect the impact of polymorphisms causing BCG lymphadenitis in children receiving BCG vaccination at birth. Eight healthy infants with BCG adenitis from 4 to 12 months old were enrolled. All these patients underwent a thorough physical examination, abdominopelvic ultrasound evaluation to detect distant lymphadenopathies and immunodeficiency screening tests for any possible underlying immunodeficiency disorders. Then genotyping for known mutations was performed using restriction fragments length polymorphism (PCR-RFLP) assays. Sequencing was performed for IL-12 Rβ1, IFN-ϒ receptor 1, IL-10, TNF-α and P2X7. The mean age of onset of the adenitis was 6.5 months. TNF-857, IL-12Rβ1 705, IL-10 1082, and IFN-ϒ- 56 single nucleotide polymorphisms (SNPs) were common in the children studied. The most frequent polymorphism found in the patients with BCG adenitis except one, was the P2X7 -762 polymorphism. To conclude, these polymorphisms are more common in some ethnic populations but not others and make the genetic basis of immunity to BCG strains and the occurrence of post-BCG lymphadenitis in otherwise healthy children.
O TRABALHO NO CÁRCERE FEMININO
Authors: Vieira Greiceane Roza , Stadtlober Cláudia De Salles
Published: January 2020

O presente artigo discute o trabalho no contexto das mulheres privadas de liberdade no sistema prisional do Rio Grande do Sul, procurando, assim, compreender e desvelar as fragilidades adjacentes à sua normatização e ao seu papel ressocializador. Por intermédio de uma abordagem metodológica mista, procurou-se compreender de que maneira o trabalho “pode ser exercido” por pessoas privadas de liberdade, bem como descrever o panorama do trabalho prisional feminino no estado do Rio Grande do Sul, juntamente ao perfil predominante nas mulheres privadas de liberdade no estado. O resultado demonstrou que, embora o trabalho no ambiente prisional se relacione à função ressocializadora do indivíduo e, por conseguinte, diretamente imbricado com a sua reinserção social quando egresso, também opera como um mediador do regime disciplinar no interior dos estabelecimentos prisionais. Exprimiu ainda que, apesar de legalmente garantida, a previsão de trabalho não se traduz, de fato, em possibilidades para efetivação do direito ou em provisão de qualificação técnica profissional capaz de possibilitar autonomia financeira quando egressas do regime de reclusão. Reconhecendo a importância que o trabalho logra na sociedade, bem como o crescente problema do encarceramento de mulheres no Brasil, a discussão evoca a necessidade de inquirir e problematizar continuamente o trabalho e as suas formas de articulação no contexto prisional.Palavras-chave: Trabalho. Sistema Prisional. Mulheres.ABSTRACTThis article discusses about work in the context of women deprived of their liberty in the prison system of Rio Grande do Sul, aiming to understand and reveal the fragilities associated to its normatization and its resocializing role. By the means of a mixed methodological approach, it has been tried to understand how the work can be exercised by people deprived of their liberty in the State. The result showed that, even though the work in the prisonal environment is related to the resocializing function of the subjects and, consequently, directly connected with their social reintegration after leaving the system, it operates as a mediator of the disciplinary system inside prisonal facilities. It was also demonstrated that, despite legally guaranteed, the expected work is not, in fact, the same as possibilities to establish their rights or to provide professional technical qualifications, which might enable financial independence after leaving detention. Recognizing the importance the work has in society, as well as the increasing problem of women in jails in Brazil, this discussion evokes the necessity to continually question and problematize the work and its means of articulation in the prisonal context.Keywords: Work. Prisonal System. Women.
LSASF in Unconventional Sandstone Reservoirs
Authors: Al-Saedi Hasan N. , Al-Jaberi Soura K. , Flori Ralph E. , Al-Bazzaz Waleed
Published: January 2020

In order to unlock large quantities of heavy crude oil, thermal enhanced oil recovery (EOR) must keep pace with the other EOR development, such as low salinity (LS) water flooding. Injecting steam alone is accompanied by gravity override, which leads to early breakthroughs without contacting the whole heavy oil bank. Water alternating steam process (WASP) is a steam sweep efficiency improver, but using LS water provides the same feature with an extra benefit, which is wettability alteration and named low salinity alternating steam flooding (LSASF). Changing reservoir rocks wettability from oil-wet towards water-wet is highly desired during designing EOR projects. This study presents injecting steam into heavy oil accumulation in the purpose of decreasing its viscosity and ease its flow and intermitting steam with LS water flooding to improve steam sweep efficiency and to alter sandstone wettability towards being more water-wet, which unlock extra heavy oil by LS water too.

In this study, core flooding experiments have been carried out on a reservoir core plugs were taken from Bartlesville Sandstone Reservoir (located in Eastern Kansas) saturated with a heavy crude oil of 600 cp from the same reservoir. The reservoir core plugs were saturated by formation water (FW) with 104,550 ppm salinity and heavy crude oil. FW was firstly injected in the secondary stage, followed by different LS waters to examine the optimum formula of LS water that needs to be injected with steam. Each injected LS water was alternating with steam. Four kinds of LS water with 3000 ppm salinity were evaluated and named LSNaCl, LSCaCl2, LSMgCl2, and LSMix, where each subscript refers to the only salt dissolved in the LS water. Spontaneous imbibition test was also conducted to study the wettability change.

The results obtained showed that LS water and steam flooding improved oil recovery at all proposed scenarios. Still, the highest was LS water contains NaCl only (LSNaCl) followed by LS water contains CaCl2 (LSCaCl2), then LSMix, and the lowest was LSMgCl2. The spontaneous imbibition results agree with core flooding results. Based on the results of this work, it is possible to inject LSNaCl and steam that gives the lowest residual oil saturation.
Prediction of Lost Circulation Zones using Support Vector Machine and Radial Basis Function
Authors: Ahmed Abdulmalek , Elkatatny Salaheldin , Abdulraheem Abdulazeez , Abughaban Mahmoud
Published: January 2020

Drilling deep and high-pressure high-temperature wells have many challenges and problems. One of the most severe, costly and time-consuming problem in the drilling operation is the loss of circulation. The drilling fluid accounts for 25-40% of the total cost of the drilling operation. Any loss of the drilling fluid will increase the total cost of the drilling operation. Uncontrolled lost circulation of the drilling fluid can result in dangerous well control problems and in some cases the loss of the well. In order to avoid loss circulation, many methods were introduced to identify the zones of losses. However, some of these methods are difficult to be applied due to financial issues and lack of technology and the other methods are not accurate in the prediction of the thief zones.

The objective of this paper is to predict the lost circulation zones using two different techniques of artificial intelligence (AI). More than 5000 real field data from two wells that contain the real-time surface drilling parameters was used to predict the zones of circulation loss using radial basis function (RBF) and support vector machine (SVM). Six surface drilling parameters were used as an input. The data of the well (A) was divided into training and testing to build the two AI models and then unseen well (B) was used to validate the ability of AI models to predict the zones of lost circulation.

The obtained results showed that the two models of AI were able to predict the zones of circulation loss in well (A) with high accuracy in terms of correlation coefficient (R), root mean squared error (RMSE) and confusion matrix. RBF predicted the losses zones with excellent precision of R = 0.981 and RMSE = 0.088. SVM also achieved higher accuracy with a correlation coefficient of 0.997 and root mean squared error of 0.038. Moreover, the RBF model was able to predict the losses zones in the unseen well (B) that was used as a validation for the ability of the AI models with a correlation coefficient of 0.909 and root mean squared error of 1.686.
Lattice Boltzmann Method LBM for the Characterization of Pore-Scale Stress
Authors: Al-Jindan Jana , N. Noui-Mehidi Mohamed
Published: January 2020

Fluid invasion in porous media is an important factor for understanding the flow distribution at the pore-scale from mesoscopic analysis for studies related to well stability and productivity enhancement in general. To better understand these effects, experiments provide direct measurements with deep understanding; however, these are always at a high cost in terms of logistics and are limited with regard to physical modeling cases, especially when mimicking reservoir conditions.

In contrast, numerical modeling provides better alternative solutions to investigate the fluid propagation properties in a particular rock matrix. This topic was, and still is, the subject of several studies aimed at capturing the fluid flow characteristics in a porous medium (Feng Xiao, 2013).

The study of fluid flow is usually accomplished at different scale from macroscopic, mesoscopic to microscopic level to capture all flow features, and therefore the flow simulation method depends on the type of scale chosen.
Fit-for-Purpose, High-Density, Resilient Cement System for Ultra-HPHT Wells: Case Study in Brunei
Authors: Taoutaou Salim , Jaffery Maimoon Fayyaz , Jain Bipin , Abdelhamid Essam , Szakolczai Cyril , Lansot Jean-Yves , Garnier Andre
Published: January 2020

Cement sheath integrity under high-pressure and high-temperature (HPHT) conditions in the Maharaja Lela Jamalulalam (MLJ) field in Brunei is challenging to achieve because of the harsh downhole conditions. Pressures reach 15,000 psi [103 MPa], downhole temperatures rise to 165°C [330°F], and the narrow margin between the pore pressure and the fracture gradient makes mud removal and cement placement even more challenging.

In addition, pressure and temperature cycling during production means cement selection with right properties is essential to maintain long-term wellbore integrity. The cement system must deliver cement mechanical properties that can withstand the downhole stresses over time. Mechanical failure of the cement sheath would create a path for wellbore fluid migration that could result in sustained casing pressure (SCP) or interzonal communication.

This paper will discuss the challenges of cementing in the tight pore-to-fracture window in the MLJ field, and the design and placement of one of the world's heaviest (2.48SG [20.7 lb/gal]) flexible and expandable resilient cement systems.

Wells in the MLJ field reach into a deep reservoir (4500 to 5000 m true vertical depth, TVD) where the pressures can reach up to 15,000 psi with bottomhole static temperatures reaching 165°C. The well is drilled using 2.18 SG [18.2 lb/gal] mud weight, and the production string is pressure tested at 15,000 psi; during the drilling and completion, the temperature variation is on the order of 60°C [108°F].

Based on the above well conditions, advanced computer-based simulations were used to determine the cement mechanical properties required to withstand the pressure and temperature changes. To achieve the required mechanical properties, special blends were prepared with engineered particles to impart flexibility and expansion for a 2.48 SG cement system.

To manage the cement placement, state-of-the-art cementing design software was used to accurately simulate the bottomhole circulating temperatures and pressures during placement as well as to simulate pipe centralization; a 3D model for fluids displacement also proved valuable.
Assisted Field Development Planning Through Well Placement Automation
Authors: Ali Basharat , Al-Ismael Menhal , Dai Keyang
Published: January 2020

This paper highlights a systematic and robust computer assisted reservoir simulation workflow to place oil producers and water injectors in the optimum areas of hydrocarbon reservoirs. The workflow offers modeling of several types of well pattern designs, including five-spot, fork-type, line-drive, and peripheral injection, allowing the multidisciplinary subsurface team to evaluate several development plans very efficiently. The workflow relies on automating the process of well placement across areas of interest with integration of static geological and dynamic simulation models. Opportunities within the reservoir are targeted using different well types, including vertical, horizontal, and multilaterals. This process incorporates different elements of well pattern designs, including well spacing, lateral length, azimuth, dogleg severity (DLS), and completions. For example, star-shaped offshore platforms with multiple wells are placed parallel to structure contours of the reservoir honoring oil-water contact (OWC) and gas-oil contact (GOC). Multiple zone lateral placement is achieved by positioning each lateral in targeted reservoir layers. This workflow was evaluated on a conceptual tight heterogeneous reservoir with several development strategies, including star-shaped platforms with peripheral water injection. Each platform consisted of several dual and trilaterals targeting different horizons of the reservoir. The development plans were evaluated through numerical simulation and well performance was analyzed. The analysis indicated considerable improvement in field cumulative oil production and ultimate recovery. Different field development plans (FDPs) are generated in a few minutes instead of months when using traditional workflows. Overall, a 90% reduction in time has been observed in this work. The significance of this workflow increases when preparing FDPs for geologically heterogeneous reservoirs with complex well designs and challenging operational constraints. The results achieved using this workflow demonstrate a unique opportunity in creating a variety of well designs automatically to target huge and complex reservoirs under a secondary drive production mechanism. This workflow is not only valuable in early phase field development planning, but also applicable in designing multiple sidetracks and reentry wells as part of the infill drilling program in mature fields.
Experimental Study of Low Salinity Water Flooding: The Effect of Polar Organic Components in Low-Permeable Sandstone Reservoir
Authors: Al-Saedi Hasan N. , Qubian Ali , Al-Bazzaz Waleed , Flori Ralph
Published: January 2020

Low salinity (LS) water flooding in the sandstone reservoir is of pronounced interest of the prospective for improved oil recovery. In this study, laboratory experiments in low-permeable sandstone core plugs saturated with various crude oil containing different acid numbers were presented. Several low-permeable sandstone cores (1-3 mD) were taken from Bartlesville Sandstone Reservoir from Eastern Kansas were successively flooded with seawater and different LS water. The reservoir cores were cleaned and saturated with formation water (FW) and then aged in three kinds of crude oil (different acid numbers) for six weeks at 90°C. To evaluate LS water in the low-permeable reservoir core plugs, core flooding tests were performed. Contact angle and spontaneous imbibition tests were also carried out.

The results obtained from LS water flooding showed that an improvement in oil recovery up to 12% of the original oil in place when the acid number (AN) and core permeability were low. The water wetness, and in turn, the oil recovery reduced with increased crude oil's AN and as the permeability increased. The contact angle and spontaneous imbibition tests confirmed the appropriate wettability change is attainable with LS water flooding. The results were deliberated in relation to wettability change processes by LS Water.
Slow Release of Surfactant Utilizing Silica Nanosized Capsules
Authors: Alsmaeil Ahmed , Enotiadis Apostolos , Hammami Mohamed Amen , Giannelis Emmanuel
Published: January 2020

Engineering and scaling-up nanocarriers for the controlled release of surfactant are imperative for enhanced oil recovery (EOR). Herein, the use of silica-based nano-sized porous capsules to slowly release surfactant in saline water is reported. The results indicate that the silica shell ensures the stability of the protected surfactants in the cores under harsh conditions. Almost negligible release was noticed at salt-free brine (DI water). In saline brine, the particles slowly released surfactants molecules. 46% of the total surfactant encapsulated was released after 12 days as quantified by the remaining organic content after mixing with brine. Scanning Electron Microscopy (SEM) analysis confirms the stability of the surfactant incorporated particles in saline water that contains 56000 mg/L of salts.
Design, Optimization and Application of the Closed Blender for CO2 Waterless Fracturing
Authors: Yang Qinghai , Meng Siwei , Yu Chuan , Fu Tao , Chen Shi
Published: January 2020

The CO2 waterless fracturing uses the liquid CO2 to replace water as the fracturing fluid in reservoir stimulation. The continuity and reliability of the blender are key factors determining the performance of the waterless fracturing operation.

This paper proposed a novel closed blender, which introduces a vertical tanker for the operation, instead of a horizontal one. This modification can reduce the footprint and also effectively suppress the CO2 gasification. The proppant supply is controlled collectively by the short auger rotation at the bottom of the blender, the opening adjustment of the proppant dosing butterfly damper and the liquid supplement rate of the blender tanker. Such proppant transportation combing the mechanical and non-mechanical approaches is able to ensure the proppant transportation stability and meanwhile greatly lower the maintenance cost.

The effective volume of the blender is 27 m3, and the maximum output flow rate is 8 m3/min, with a rated pressure of 3 MPa and a minimum operation temperature of −40°C. On the basis of the ground testing and field practice, the overall correlation among the liquid input, output, butterfly damper opening degree and the proppant transportation intensity has been well established, which facilitates the control of the system pressure and proppant supply. So far, the blender has been stably operated at the CO2 waterless fracturing operation site for over 20 times. The pump rate can be up to 8 m3/min for a single operation, the sand transportation reaches 23 m3, and the liquid consumption amounts to 860m3. The proppant transportation is seen with good stability. The reservoir simulation performance is considerable, and the post-treatment production of the CO2 waterless fracturing is 2.4 times that of the conventional hydraulic fracturing with an identical treatment scale.

The field practice suggests that the developed closed blender combines the advantages of both the vertical and horizontal blenders, and ensures the successful implementation of the CO2 waterless fracturing operation.
Paradigm Shift in Smartwater Simulation Methods
Authors: Alshakhs Mohammed J. , BuKhamseen Nader Y. , AlGarni Saad A.
Published: January 2020

Laboratory studies of Smartwater flood have demonstrated its impact on increasing oil recovery. Smartwater refers to the injection water that is subjected to alteration of total salinity or ionic composition. Several simulation techniques are carried out to match experimental observations. The objective of the paper is to critically examine and assess the simulation practices in the industry.

Simulation strives to depict the production profiles along with the primary chemical and physical processes that take place. The simulation studies in the literature were surveyed and classified into categories based on the simulation approach. The capability of the simulation techniques to mimic the oil recovery mechanisms were evaluated. In addition, we explored the operational advantages and limitations of each technique.

Most of the simulation techniques estimate the increase in oil recovery mainly from the changes of the relative permeability curves and residual oil saturation. A correlation is often established between these data sets and certain traceable factors such as the total salinity. We identified two adopted modeling categories: single component, and mechanistic reaction models. The single component model is the most commonly used because it requires few additional input data with relatively lower uncertainty. The mechanistic reaction model is a new emerging method that accounts for oil-water-rock interactions. The main limitation of this method is that most simulators are not equipped with chemical reaction functions. In such a case, an external simulation package is required to simulate the reactions. The paper concludes that themechanistic reaction model is an excellent options to replicate the micro-scale processes. Integrating the conventional simulators with chemical reaction functions is required to improve the simulation efficiency and accuracy.

There is a gap in the literature between investigating oil recovery mechanisms associated with Smartwater flood and reflecting them in the conventional fluid-flow simulation. To motivate more efforts and bridge the gap, this review provides insights of the recent advancements in the simulation techniques and addresses the expectations from each technique.
Reliable Models for Determining the Pressure-Volume-Temperature PVT Properties Using Artificial Intelligence Technique
Authors: Hassan Amjed , Abdulraheem Abdulazeez , Mohamed Abdelmjeed
Published: January 2020

In petroleum industry, PVT properties are very important in predicting the performance of oil and gas reservoirs. Several laboratory measurements are used to determine these properties at reservoir condition. The PVT measurements are costly and time-consuming; therefore, numerous correlations were developed to predict the PVT properties based on primary inputs such as reservoir pressure, temperature and hydrocarbon gravities. However, significant deviations are reported between the actual values and the predicted results. The aim of this paper is to present reliable and rigorous models to determine the PVT properties using artificial intelligence technique.

Artificial neural network was utilized to develop the pressure-volume-temperature models. The proposed models estimate the PVT properties based on the pressure, temperature, oil and gas densities, and the solution gas-oil ratio. The developed models determine the bubble point pressure, formation volume factor and solution gas-oil ratio. Total of 250 data sets were used to develop and evaluate the model reliability. Average absolute percentage error (AAPE) and coefficient of determination (R-value) were used to evaluate the model reliability.

The new models are simple, accurate and easy to use when compared with the existing empirical equations. The obtained results showed that the developed models are able to determine the PVT properties with an average absolute error of around 7.7%. The intelligence models developed in this study outperform the popular PVT equations such as Standing and Al-Marhoun correlations. Average errors of 6.8% and 11.7% were obtained for the developed model and the popular PVT correlations, respectively. Therefore, the developed models can highly increase the quality of production management by providing an accurate estimation for the PVT properties. Also, the presented models can significantly reduce the time and cost required for conducting the PVT measurements.
Geochemical Fingerprinting of Produced Water for Enhanced Well Control and Fracturing Efficiency
Authors: Birkle Peter
Published: January 2020

The geochemical fingerprinting of produced water has been identified as a practical tool for operational applications in the petroleum industry. Provenance studies of produced water are essential to trace flow dynamics and reservoir compartmentalization in petroleum systems and to quantify fluid recovery rates from unconventional fracturing. Due to the fact that recovered oilfield water samples are frequently contaminated by operational fluids (i.e., oil-based mud, water-based mud, completion brines or stimulation fluids), representative samples for reservoir fluids have to be filtered from the geochemical data set of produced water. Besides the routine analysis of major elements (Na, Ca, Mg, K, Cl, SO4, HCO3), an enhanced geochemical monitoring program with selected minor and trace elements (i.e., B, Ba, Li, Sr), environmental isotopes (i.e., delta2H, delta18O, 87Sr/86Sr) and radiogenic isotopes (i.e., 3H, 14C) can provide in-depth information on the provenance of recovered oilfield water. Provenance studies of flowback water from hydraulic fracturing assets represent an enhanced method to assess the efficiency of the fracturing process by quantifying the recovered volume of originally injected fracturing fluid during the post-fracturing phase. The combination of gas recovery rates with geochemical flowback efficiency resulted in a practical tool to characterize the type and complexity of natural and induced fractures. Two cases studies showed that the combination of high gas recovery rates with low backflow efficiencies imply the presence of a complex system of natural and induced fractures. As a practical outcome, geochemical fingerprinting of recovered fluids can improve operational strategies for performed fracturing assets by avoiding water-pay zones, minimizing the amount of required fracturing fluids for injection purposes, and economizing the recycling process for recoverable flowback fluids. For the drilling of exploration or production wells, the presence of overpressured formations with a sudden water cut can frequently cause a technical challenge during well cementation. The design of a filtered geochemical database with regional fingerprints of formation water and groundwater zones is essential to identify the specific interval of water breakthrough for well plugging solutions. The routine geochemical analysis of reference water types, such as supply water and mud filtrate from the drilling process, is mandatory to quantify the potential flowback of applied drilling fluids.
Application of Combined Streamline Based Reduced-Physics Surrogate and Response Surface Method for Field Development Optimization
Authors: Tanaka Shusei , Onishi Tsubasa , Kam Dongjae , Dehghani Kaveh , Wen Xian-Huan
Published: January 2020

Model-based field development optimization typically requires a large number of simulations. Consequently, this process may face challenges as model size and complexities increase. The objective of this paper is to apply a reduced-physics model with response surface approach for replacing full field simulation runs to reduce the time and resources required during a search for optimal solutions.

The streamline technique is used to develop a reduced-physics model in this study. There are number of previous studies that demonstrated the use of streamlines for production optimization (e.g. well placement and/or rate allocation optimization). In a recent work (SPE 187298), an approximate equation was formulated to estimate the expected economic value based on streamlines and was applied into rate allocation optimization of a given well pattern. Our approach is to use this formulation to improve the efficiency of field development optimization by potentially screening out poor performing development designs without performing full simulations.

The streamline-based surrogate model workflow was first applied and validated using a synthetic SPE-10 case study. The workflow was then applied to the Olympus field waterflood study. The study goal is to maximize the economic value by optimizing the well count, injector and producer locations, and completion design. The validation performed using random field development designs provided a rank correlation coefficient of 0.92 between the NPV values of full field simulations and streamline-based approximation from the Olympus field application. The streamline-surrogate model was then adopted with an optimization workflow (Genetic Algorithm) and response surface method with 2-stage approach. First, Genetic Algorithm (GA) optimization was performed using the streamline-surrogate as an initial stage to screen out suboptimal field development design. Then, a second GA optimization was performed using full simulations coupled with the response surface method, starting with results from the first stage. Response surfaces that were developed using samples through GA improved the process of screening poor economic cases at later stages, as the predictability of solution improved with more training.

We demonstrated that the streamline-based surrogate formulation combined with the response surface approach will improve the optimization process of field development scenarios. The applicability of using the response surface approach by itself is limited for field applications due to the large number of simulations required for training and the risk of convergence at local minima. Multiple tests from the Olympus field development application demonstrated that the sequential combination of streamline-based surrogate formulation with response surface method had the best performance.
Effect of Molecular Architecture in Breaking Water-in-Diluted Bitumen Emulsions
Authors: Mangadlao Joey Dacula , Kailey Ishpinder , Vargas Jonathan
Published: January 2020

Oilfield emulsions are typically a mixture of oil and water stabilized by natural surfactants. Apart from the undesirable high water content, emulsions also pose several problems such as increased bulk viscosity, creating high-pressure drops in the flow lines. To resolve emulsions, chemical demulsifiers are typically used. As structure dictates function, linear and branched molecular architectures offer a variety of oil- and water-loving properties that one can exhaust to develop a much more improved demulsifier. In this contribution, we describe a systematic approach to study the effect of molecular architecture of demulsifiers as a driver of performance. Using diluted bitumen emulsions, the performance of synthesized polyethylene oxide/polypropylene oxide (EO/PO)-based demulsifier with various chemical and structural make-up were evaluated. The performance were then correlated to the demulsifier's relative solubility number, partition coefficient and interfacial properties. Results revealed that generally, branched architecture has superior performance compared to linear counterpart.
Produced Water Quality Impact on Injection Performance: Predicting Injectivity Decline for Waterflood Design
Authors: Rossini Stefano , Roppoli Giulia , Mariotti Pamela , Renna Simona , Manotti Matteo , Viareggio Alberto , Biassoni Laura
Published: January 2020

The management of produced water has become a main issue in petroleum industry due to the huge quantities to be dealt with. Produced Water Re-Injection (PWRI) allows combining disposal with Improved Oil Recovery (IOR) opportunities. Nevertheless, PWRI could damage the formation, eventually compromising field performances. Well impairment is a complex phenomenon depending on several aspects. This paper focuses on the impact of Oil In Water (OIW) in injectivity performance, validating lab predictions and field evidences.

A comprehensive review of field cases has been carried out, analyzing injection well performance with Production Data Analysis (PDA) tools together with water quality data. On a selection of field cases where OIW has been identified as main impairment reason, a workflow was established performing core flooding experiments to measure experimental loss of permeability with different content of OIW. Obtained results have been integrated by bibliographic research.

Field evidences showed a direct relationship between permeability reduction and hydrocarbon content; moreover, injectivity impairment measured on field data has been found to be comparable (same order of magnitude) with the permeability reduction measured on core flooding. Combining all data together, a common trend of injectivity reduction vs. OIW content has been extrapolated passing through the definition of Injectivity Index (II).

New water injection concept depends on several elements that could affect the overall project value, water quality requirements is one of them. Water quality rule of thumb can be found in literature, but each project basis of design is different. The proposed approach allows to preliminarily quantifying the expected well impairment as function of water quality. It can be used as a first tool to dimension treatment facilities in function of the reduction of injectivity that we can accept for any given reservoir. Obtained trend is representative of a subset of real field cases, where OIW content is the main impacting parameter on PWRI well damage.
The Most Reliable and Cost Effective Advanced Sulphur Recovery Technologies for Saudi Arabia and the Middle Eastern Region
Authors: Siu Jerry H. , Vo Ngo Bao C. , Chow Thomas K.
Published: January 2020

Gas Processing and Refining facilities in Saudi Arabia and the Middle East region are generally embracing the following design features and operation requirements for sulphur recovery facilities: Operating under hot and dry climate; lack of processing, cooling and utility water; requiring complete destruction of BTEX and Ammonia contained in gas feeds; gas feeds with higher and higher sulphur contents; requirements for expanded processing capacity in terms of sulphur contents, gas volumetric flow rates and higher overall sulphur recovery efficiency; and compliance of more stringent HSE requirements. Technologies associated with Sulphur Recovery facilities to be discussed in this paper are targeted to address these specific design features, operation and HSE requirements.

In this paper, Fluor will discuss four reliable, cost effective and commercially proven technologies as well as their respective most current improvements for new and existing sulphur recovery facility applications. These include Fluor/GAA COPE™ Oxygen Enrichment Technology, Fluor’s proprietary Hydrogenation-Amine Tail Gas Treating Technology, Fluor’s patented Low Energy Direct Contact Condenser Technology, and Fluor/GAA’s D’GAASS™ Liquid Sulphur Degassing Technology.

Advantages of each of these technologies over competing technolgies in the industry will be discussed in this paper. Their operating experience and lessons learned associated with design and operation will be addressed in terms of what improvements in design and operation are being implemented into new design practices. Comparisons in estimated CAPEX and OPEX between the original design and the new improved design will be presented for each of these technologies in the form of Case Studies.
Open Fracture Detection from the New-Generation Oil-Based Microresistivity Image Logs: A Case Study from the Bashijiqike Sandstone, Tarim Basin of China
Authors: Liu ChangXin , Wang XiaoYun , Zhang XinLei , Mo Jing , Wang Dali , Wei Guo , Pan Feng
Published: January 2020

The Cretaceous Bashijiqike formation is the main target of the tight gas production of Tarim Basin. Low porosity and low permeability were validated by core data. However, mud loss of 46.6 m3 occurred near high angle open fractures, and gas production and oil production has been tested in high angle open fracture section. It suggests that high angle open fractures can cause mud loss and they also have a positive effect on tight gas reservoirs.

Open fractures are the key point to the tight gas reservoirs of Tarim Basin. However, it was impossible to identify open fracture and cemented fracture through conventional logs and seismic data. Ultrasonic image logs and oil-based electrical image logs make it possible to oil-based mud well. The new-generation oil-based microresistivity image logs provide high resolution images with high borehole coverage. It improves the image quality of the previous oil-based microimager logs (OBI) in oil-based mud well.

A total of 39 open fractures and 33 cemented fractures in a vertical well were recognized from the new-generation oil-based microresistivity image logs. Core observation for this vertical well also validated the presence of both cemented fracture and open fracture. In addition, ultrasonic image logs were acquired in this vertical well. According to the ultrasonic image features, it only responds to large open fracture with bigger aperture and has limitation to relatively small-scale open fractures with smaller aperture. The new-generation oil-based microresistivity image logs complement the limitation of the ultrasonic logs.

The case study presents how to identify different kind of fractures by the high-resolution oil-based microresistivity image logs in oil-based mud well, especially open fracture detection. As the main gas migration pathway, the open fractures were important to tight sandstone gas reservoir quality in the Bashijiqike formation of the Tarim Basin. Better understanding of the fracture attributes was instructive for fracturing stimulation design of tight gas reservoir as well.