bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Machine Learning in Transient Surveillance in a Deep-Water Oil Field
Authors: Chang Oliver , Pan Yan , Dastan Aysegul , Teague David , Descant Frank
Published: April 2019

There are on-going efforts in digital transformation in different aspects of hydrocarbon recovery. For well performance surveillance, we have developed the key elements of a Transient Data Surveillance Machine to efficiently process and analyze all transient data from continuous measurements at the wells, allowing for full utilization of the available data. The workflow has been applied at wells in a deep-water oil field in Gulf of Mexico and proved to be effective.

We developed Machine Learning (ML) algorithms and techniques to efficiently process and analyze pressure-rate transient data. Following the automatic workflow, K-mean clustering is used to identify shut-in periods, maximum-slope method is used to synchronize pressure and rate data, Supported Vector Machine algorithm combined with Kernel method is used for transient flow-regime recognition, followed by Non-Linear Regression using physical models to estimate reservoir and well properties and assess uncertainty.

Through synthetic case and field data testing, we demonstrated that the ML method is tolerant to data noise. Even at 15% of noise level, which is much higher than standard pressure gauge data, the successful rate is 98% in flow-regime identification. However, it is sensitive to data outliers, and we need to include other techniques, such as wavelet data processing, in the workflow. Adding real field data with associated reservoir models that are validated by experts into the training data set could increase the accuracy of pattern recognition 10% more than training with only analytical solutions. The application of our workflow in a deep-water oil field in Gulf of Mexico, which started oil production in 2009 with all wells with permanent downhole pressure gauges, helped to process and analyze transient data from shut-in’s (70% planned transient tests and 30% operation related) efficiently, and derived information about well productivity changes, interference among wells, and permeability reduction due to rock compaction. This enabled continuous well monitoring and effective identification of well productivity issues.

The novelty of our Transient Data Surveillance Machine is its capacity in handling huge amounts of dynamic data and its efficiency using real-time data diagnosis for operation decisions and reservoir management.
Pressure Transient Analysis in Fractured Horizontal Wells with Fracture Networks
Authors: Chen Z. , Liao X. , Liu Q. , Wang L. , Wang S. , Tang X. , Zhang J.
Published: April 2019

Drilling fractured horizontal well is now a common practice to improve the productivity of unconventional wells. With the reactivated natural fractures, the technique of fractured horizontal wells can generate a large amount of complex fracture networks of hydraulic fractures (HF) and micro fractures (MF) in unconventional reservoirs. In this paper, an efficient semi-analytical model is developed for pressure transient analysis in horizontal wells by considering hydraulic fracture networks as well as natural fracture networks. During the model development, we develop the diffusivity equation for fluid flow in formation matrix using line source function. With the nodal analysis technique, the flow interplay at fracture intersections is eliminated and the diffusivity equations for fluid flow in hydraulic fractures are built. The pressure transient solution of these diffusivity equations is obtained by using Laplace transforms and Stehfest numerical inversion (Stehfest, 1970).

The results show that different from a single "dip"––the classical dual-porosity feature of naturally fractured reservoirs ––in the pressure derivative, the reservoir system exhibits many other different pressure behaviors like "fluid feed", "pseudo-boundary dominated flow", etc. All these pressure behaviors are associated with the properties and geometries of natural/hydraulic fractures. What's more, the pressure response for fracture network horizontal wells with natural fracture networks can be divided into some flow regimes, which include: (1) the first bilinear flow, (2) "MF-HF" support, (3) the second bilinear flow, (4) formation linear flow, (5) cross flow, and (6) pseudo-radial flow. Model reliability is demonstrated by a numerical verification. The efficient semi-analytical model in this work can substantially reduce the computational burdens of numerical simulators for transient pressure analysis in shale reservoirs with hydraulic and/or natural fracture networks.
Multiphase Permeability Evolution in Low Permeability Sandstones from Surfactant-Treated Fractring Fluids
Authors: Abaa Kelvin , Yilin-Wang John , Elsworth Derek , Ityokumbul Mku
Published: April 2019

Improper selection and design of surfactant treatments intended to remove damage aqueous phase trapping often ends up causing other types of formation damage. This is due to our limited understanding of the processes that govern rock-fluid and fluid-fluid interactions between surfactants, fracturing fluid and the formation during invasion and flowback of the injected fluids in the rock matrix. This study focuses on the laboratory investigation of the processes governing multiphase permeability evolution during invasion of fracturing fluids treated with surfactants in low permeability sandstones.

Two surfactant chemicals, Triton X-100, a hydrocarbon surfactant and Novec FC-4430, a fluorosurfactant, were used to treat filtrate from slickwater, linear gel and borate crosslinked gel fluids. Multiphase experiments were conducted on sandstones cores flooded with the treated fluids. The experiments consist of steady state gas displacements and pulse decay permeability measurements. The obtained data include gas flow rate, pore volumes of liquid expelled and gas relative permeability curves.

Experimental results indicate that treatments with fluorosurfactant improved liquid and gas permeability recovery for all fracturing fluids. Additionally, maximum liquid and gas permeability recovery was achieved when the core was pretreated with fluorosurfactant. Our results show that multiphase permeability evolution with surfactant treatment is driven by wettability alterations rather than reduction in interfacial tension.

Multiphase permeability data could be used in modeling of post fracture well performance and formation damage assessment in low permeability sandstones. The new findings will serve as a guide for optimizing fracturing fluid/surfactant treatment in tight gas reservoirs.
Slickwater, Hybrid, Self-Suspending Proppant: Practical Use of Data Analytics to Determine Hydraulic Fracture Fluids
Authors: Sedillos Lia , Saxena Jayant , Convers Carlos , Dean Elio , Roundtree Russell
Published: April 2019

Utilizing fluids that have friction reducing qualities and/or viscosity building properties are desirable for hydraulic fracturing in multi-stage horizontal wells. Horizontal wells targeting the Middle Bakken used various fluid types for stimulation were analyzed in this study. This paper uses data analytics to show that the answer to "which fluid type is better?". By applying statistical methods of k-means clustering, t-tests as well as multivariate analysis, a more robust answer was obtained in the comparison between slickwater, crosslinked gel, linear gel, hybrid systems, and Self-Suspending proppant. The first part of the analysis compared independent variables (lateral length, true vertical depth (TVD), liquid loading, sand loading, and fluid type) to well productivity in 532 Middle Bakken wells. Multivariate analysis was conducted to determine the dominant variables. Based on those, the data were filtered in two different ways: first on sand loading and secondly on lateral length and TVD.

The second part of the analysis applied distinct k-means clustering. A multivariate model was built to accommodate the influence of each variable in each cluster. Having found inconclusive results, ANOVA (Analysis of Variance) analysis was conducted to analyze which fluid type resulted in the best overall well production. Several conclusions are demonstrated in this paper. First, industry stimulation treatment data are rarely crafted with thorough Design of Experiment rigor. This challenges many of the assumptions in statistics and data analytics to provide for unbiased analysis. Second, while lateral length, TVD and total sand are all seemingly independent variables physically, they were found to have a certain degree of statistical collinearity; a measure of variable dependence. Third, it was shown that wells using slickwater and 1Self-Suspending Proppant outperform wells using other proppant types in terms of overall production in the Middle Bakken. Hence, while the perfect frac job still eludes us, establishing a framework of unbiased analysis provide us with a robust approach to answer one of the key questions of our day: which fluid type is better? The novel thing about this type of analysis is that it takes thousands of different types of data points and narrows down what the most important variables in the data are. In an age where data is king, this approach follows statistic principles designed for handling such data.
Prescriptive Analytics for Completion Optimization in Unconventional Resources
Authors: Gharib Shirangi Mehrdad , Oruganti Yagna , Wilson Thomas , Furlong Edward , Winter Eric , Martin Joel , Yancy Robert
Published: April 2019

In this work, we present and apply a comprehensive prescriptive analytics framework for well completion optimization in unconventional resources. The methodology involves 1) data processing, ingestion into databases, and data cleansing 2) application of AutoML for generating an accurate machine learning model, and 3) numerical optimization of decision parameters for minimizing an economic objective. Input parameters to the machine learning model include system parameters (such as well location and trajectory, existence and type of artificial lift) and decision parameters (such as number of stages, amount of stimulation material). The AutoML process automatically searches among various machine-learning algorithms (e.g., neural networks, random forest), to find the best algorithm and the best associated hyper-parameters. In the third step, a multi-objective optimization process is implemented to simultaneously optimize the 12-month oil producton (Qoil) and the completion cost divided by Qoil. The methodology is applied to a real case in the Permian Basin, in collaboration with Diamondback Energy. The results demonstrate that the two objectives are conflicting. The construction of the Pareto front, which shows a set of optimal solutions, provides a visual trade-off for decision makers and enables them to select a strategy that minimizes the cost, but does not sacrifice too much of the 12-month oil production.
Evaluation of a New Treatment to Remove Calcium Sulfate Scale: Lab Studies and Field Application.
Authors: Farid Ibrahim Ahmed , Nasr-El-Din Hisham , Abd El-baqi Mohamed , Abdelhay Ahmed , Farouk Hossam , Aref Ahmed , Reda Ahmed , Rafaat Mohamed , Gamal Mohamed
Published: April 2019

Scale deposition has been a significant problem in the oil and gas industry. Scale deposition has an adverse impact on production and injection operations. The precipitation of scale in the near-wellbore area will diminish the productivity of the production wells and loss of the injectivity of water injection wells. This paper presents a new non-corrosive agent to remove calcium carbonate, and calcium sulfate scales.

Two sets of coreflood experiments were conducted to evaluate the chemical to remove anhydrite depositions. Coreflood experiments were conducted by using the new scale remover to stimulate dolomite cores with anhydrite content of 30 wt% at 250°F. Other experiments were conducted with the Bandera sandstone cores. Calcium sulfate was precipitated inside the pores and then the chemical was used to treat the cores to remove this damage. Effluent samples were collected and analyzed with ICP for sulfur and calcium concentrations. CT scan was used to detect the dissolution and the deposition of scale inside the cores. The chemical was applied on several oil wells from the Nukhul sandstone formation.

Coreflood results show increasing the permeability of the dolomite core to 4 times of its initial value and ICP results show 1:1 calcium to sulfur concentrations. The second coreflood experiments showed the ability of the dissolving agent to remove the precipitated scale completely with (final permeability =initial permeability) with no effect on clays. In the field case, the treatment was conducted and placed using a coiled tubing without using additional additives such as corrosion inhibitors, intensifiers, and iron control agents. The success of this treatment was realized by increasing the well production 4 times its initial oil production per day.

Field data and the lab results highlight that the de-scaling solution is an effective fluid for calcium sulfate scale.
The Use of Asphaltenes Precipitants and Environmentally Friendly Solvents During Solvent-Steam Processes
Authors: Ng Alwin , Vishnumolakala Narendra , Hascakir Berna
Published: April 2019

Steam flooding is the most widely used thermal enhance oil recovery (EOR) process to recover bitumen and heavy oil. This process has been proven to be reliable, thus, establishing itself as a favorite among other thermal EORs. However, the excessive water usage to generate steam causes environmental concerns such as air and water pollution. Thus, a noble idea to reduce the sole dependency on steam alone is to co-inject solvent with steam. Solvent will aid the oil recovery process by improving miscibility aside from the oil displacement mechanisms from steam itself.

Three core flooding experiments were conducted on a heavy oil sample from Texas; namely, steam flooding (E1), CO2 -steam flooding (E2), and CO2 - MS- steam flooding (E3). MS is a corn based environmentally friendly solvent which is tested for the first time for heavy oil extraction via solvent-steam injection process. Because CO2 is known as asphaltene insoluble solvent, asphaltene precipitation was also investigated on spent rock samples to determine the formation damage occurring during the process. An ASTM method was used to determine the amount of asphaltenes in initial oil sample, on produced oil samples, and on residual oil samples. Another flow assurance problem is emulsion formation which occurs widely in any steam processes. Hence, the emulsions formed during solvent-steam and steam experiments and the role of asphaltenes on emulsion formation are investigated.

It has been observed that CO2 enhances the asphaltene precipitation and results in consolidation of core samples which reduced significantly the oil production. The use of asphaltene insoluble solvent CO2 with an asphaltene soluble solvent (MS) enhanced the oil production, increased the sweep efficiency and decreased the water-in-oil formation.

With this study for the first time asphaltene soluble and insoluble solvents co-injected together with steam to recover a heavy oil from Texas. We also analyzed the oil displacement mechanism through asphaltene precipitation and emulsion formation.
Predicting and Applying Wellhead Temperatures for Steamflood Field Operation and Production Performance Monitoring
Authors: Yang Zhengming
Published: April 2019

Producer flow line temperatures (FLT) can be measured automatically with a thermistor on an emergency shut-down system (ESD), or manually on a specified spot on flow line with a hand-held unit. Measured FLTs can usually be mapped to represent the formation temperature distribution for steamflood reservoir management purposes (Hong, 1994). In the meantime, predicting the long-term flow-line temperature trend in steamflood operation is necessary for designing surface facilities for both oil dehydration/separation and produced water recycling. This predicted temperature will also be applicable for production performance monitoring. In addition to FLT, wellhead temperature (WHT) is another surface temperature. FLT and WHT are comparable for their close typical distance of 5-10 ft.

To predict the wellhead temperature, Hasan, Kabir and Wang (2009) derived a steady state analytical solution for calculating WHT from bottom hole temperature (BHT) under flowing conditions of a multiple section slant wellbore for the isothermal primary depletion process with both WHT and BHT being time independent for a given gross rate. This steady-state analytical solution has been extended to calculate steamflood producer WHT from BHT (both are time-dependent) by approximating WHT and monthly average of FLT measurements to a steady state solution consecutively. The monthly averaged FLTs are seasonally variable and higher in the summer months of July to September and lower in the winter months of December to February. Both WHTs (if measured) and monthly averaged FLT measurements depend on an annual ambient temperature cycle within the depth needed for reaching undisturbed ground temperature (typically 30-50 ft, Gwadera, Larwa and Kupiec, 2017). WHT prediction, however, are only process dependent and not seasonally variable due to the inability in describing seasonally undisturbed depth in the geothermal gradient. Therefore, WHT prediction can be validated with the monthly average of measured summer month FLTs. BHTs in this analytical approach is predicted by Lauwerier's analytical model (1955) and improved by calibrating with the available reservoir simulation model or several years’ FLT measurements for steamflood response timing.

A field case study for the South Belridge diatomite steamflood was investigated. WHT prediction is compared with FLT measurement for diagnosing and understanding the production performances such as water or steam premature breakthrough, interference by the waterflood on the steamflood boundary producers, as well as the FLT variation related to steam injection target rates. This diagnostic analysis approach combined with the Buckley-Leverett theory based displacement efficiency analysis, and injection pressure and rate signal, will help to develop an improved understanding of the displacement detail and form a decision base to optimize the production performance.
Polymer Flooding in Oil-Wet, 2D Heterogeneous Porous Media
Authors: Singh Robin , Song Haofeng , Mohanty Kishore K.
Published: April 2019

The displacement of viscous oils typically involves unstable immiscible flow. The microscopic and volumetric efficiency is further exacerbated if the reservoir is oil-wet and heterogeneous, respectively. The goal of this work is to systematically compare the performance of secondary vs. tertiary polymer flooding for viscous oil recovery in an oil-wet 2D, layered, heterogeneous system. It focuses on performing flow visualization to capture the effect of cross-flow and viscous fingering in both modes. First, contact angle experiments were performed to ensure that the reservoir crude oil results in oil-wet sand. Second, rheological analysis of HPAM polymer solution was performed to find the optimal injection concentration. Third, oil displacement experiments were performed in an in-house, custom-built 2D sandpack with the front face made of a transparent acrylic sheet for flow visualization. It was packed with two communicating layers of silica sand — bottom layer with 20-30 mesh and a top layer with 100-120 mesh, which resulted in a permeability contrast of 8:1. The system was vacuum-saturated with a viscous crude oil with a viscosity of 157 cp. Polymer floods were conducted in secondary and tertiary modes and the oil displacement profiles were continuously monitored using a camera. At the end of the experiments, the sandpacks were cut in 16-equal zones and were analyzed for the amount of crude oil using UV-Spectroscopy to quantify the residual oil saturation achieved in each zone. Finally, the results were compared with analogous floods in 1D sandpacks to understand the effect of heterogeneity. The contact angle experiments revealed that the reservoir crude oil used in the present work resulted in highly oil-wet sand after aging. In the oil displacement experiments in the layered sandpack, the secondary waterflood recovery after 1 PV was low (∼25% OOIP) due to channeling in the bottom high-permeability region, leaving the top low-permeability region completely unswept. Tertiary polymer flooding leads to improvement in sweep efficiency in both regions. It resulted in an incremental oil recovery of 53% OOIP with an ultimate recovery of 78% OOIP. Conversely, polymer flooding in secondary mode resulted in 46% OOIP in 1 PV injection. But the overall recovery was 69 % OOIP which was less than the tertiary mode. Different flow phenomena, such as, cross-flow, gravity segregation, and viscous fingering, were observed in these visualization experiments.
Integrating Machine Learning in Identifying Sweet Spots in Unconventional Formations
Authors: Tandon Saurabh
Published: April 2019

Productive zones or "sweet spots" in unconventional reservoirs depend on their geomechanical and petro-physical rock properties. Machine learning algorithms can significantly improve workflows used for evaluating sweet-spots in such complex reservoirs. The objectives of this paper are to: (i) quantity the effects of rock mechanical properties on fracturing treatments using data analytics and (ii) use regression-based machine learning algorithms and improve sweet-spot assessment in complex mudrock reservoirs.

We used a hydraulic fracturing simulator that couples fluid-flow with fracture deformation in discrete fracture networks to model field-scale hydraulic fracturing treatments. First, we selected several geomechanical properties related to rock fracability. We obtained wide variation in aforementioned properties using a quasi-random design approach. Then, we performed 200 slick-water fracturing simulations with quasi-random distribution of design parameters using the hydraulic fracturing simulator. We quantified the performance of fracture treatments by calculating the effective short- and long-term Stimulated Reservoir Volume of the reservoir (SRV). We finally analyzed the results of numerical simulations by applying regression analysis to improve the assessment of sweet-spots in complex reservoirs.

The regression analysis involved the following simulation variables: shear modulus, poisson's ratio, fracture friction coefficient, principal horizontal stress anisotropy, fracture toughness, fracture closure stress, shear dilation angle, and initial fracture aperture. The SRV results were analyzed using: linear regression, linear regression with beta coefficients, ridge and lasso regression, and principal component regression algorithms. The regression analysis revealed that linear models can explain 73.1% and 59.2% variance in short- and long-term SRV values, respectively. The ridge and lasso regression and beta linear regression analysis revealed that stress anisotropy, fracture dilation angle, and fracture friction coefficient show the highest effect on the aforementioned SRV values. In all the regression models, shear modulus and critical fracture toughness did not have a significant effect on SRV but these parameters are important as they are correlated to other parameters that directly impact fluid flow.

The results of using data analytic approaches demonstrated that factors related to unpropped fracture conductivity play a critical role in success of hydraulic fracturing treatments. We have also introduced and compared the performances of different machine learning algorithms that might be used to assess the impact of geomechanical properties on fracturing treatments. Such supervised and unsupervised machine learning algorithms can help in integrating legacy field data in the analysis of productive zones in complex reservoirs. Such analysis can also be used to develop data-based models that might improve the study of sweet-spot and fracturing treatment performance assessment in complex reservoirs.
Saturation Dependent Errors in Interpreting Waterflood Diagnostic Plots
Authors: Wu Jun , Ershaghi Iraj
Published: April 2019

Various diagnostics plots related to examining injection pressure gradient requirements for maintaining injectivity have been used in waterflood management. Among these plots, Hall plots and the derivative of Hall plots are the most common approaches used in the industry. This paper includes an analysis of some errors associated with interpreting Hall plots and the derivative of Hall plots in monitoring waterfloods.

Based on observations from several waterfloods in California, in this paper we demonstrate by numerical modeling, that the cause of slope flattening can also be dependent on the state of saturation history around injection wells. We also show that the flattening can be compensated by skin build up resulting in misleading trends.

We conducted a series of numerical modeling work to examine these issues. From such modeling experiments, we considered cases of injection well behavior in virgin reservoirs as well as in mature waterfloods. We show that when new injectors are drilled, water saturation buildup tends to flatten the slope observed on the Hall Plot or the derivative of Hall plot. For new floods, drops in the slope observed can be associated with water saturation buildup caused by limited flooding history. When injection wells are drilled in flooded segments of a field, such saturation dependent flattening may not be observed.

This is a significant issue as it affects decisions related to restriction limits on injection gradient as well as unnecessary stimulation work. In summary, we conclude that interpretation of Hall plots without consideration of water saturation history can be misleading.
Pore Structure Characterization of a Shale Sample Using SEM Images
Authors: Zhang Yixin , Ghanbarnezhad Moghanloo Rouzbeh , Davudov Davud
Published: April 2019

We analyze a compiled stack of Scanning Electron Microscopy (SEM) images of an Eagle Ford shale sample to assess pore structure and complex pore connectivity. In recent years, shale and tight oil formations have played an important role as energy resource. However, uncertainties associated with pore structure and pore connectivity as an important parameter controlling the well productivity remain to be resolved; that is why, high-resolution image processing has been an emerging research tool.

In this study, 600 contiguous high-resolution SEM images of a 6 μm Eagle Ford sample is analyzed using an image processing software. We obtain 2D and 3D porosity and pore size distribution. In addition, we map out the connected pores to obtain the connected porosity from 3D volumetric fraction. Next, we analyze total and connected porosity as a function of sample size in both forward and backward sequences. Finally, results obtained from the shale sample is compared with a sandstone sample to determine differences in their pore structure properties.

We conclude that the connected porosity is 6.1% for the shale sample, smaller than that of the sandstone (19.6%). The attributed pore size distribution ranges from 0.01μm to approximately 0.1μm, while the sandstone’s pore radius size ranges from 1 μm up to 12.7 mm. Through evaluation of sandstone sample, it turns out that 3D total porosity of the sandstone sample is almost the same as the connected porosity. Moreover, although the connected porosity of the stacked images gradually and slightly decreases as the sample size increases. However, for the shale sample, total porosity remains almost constant as a function of sample size while the connected porosity significantly decreases from 13.3% to 6.1%. More interestingly, if the images are analyzed in the backward sequences, then both porosity and the connected porosity increase. Overall, the results suggest that for the studied shale sample, Representative Elementary Volume (REV) describing pore connectivity is around 4 μm.

The results from this study will provide a new insight into complex pore structure and help better understand the production performance of shale reservoirs. In addition, the outcome of this paper would have some implications on research work related to fluid flow in shale.
A Correlation for Estimating Biot Coefficient
Authors: Li Qi , Aguilera Roberto , Cinco Ley Heber
Published: April 2019

The objective of this paper is to develop an easy to use correlation for estimating Biot coefficient. This is important as Biot coefficient plays an important role in solving many practical petroleum engineering problems, including for example, design of hydraulic fracturing jobs and estimation of in-situ closure stress on proppant.

The procedure for developing the proposed empirical correlation uses data from various lithologies including limestone, sandstone, shale, marble and granite. Thus, the correlation has application in conventional and unconventional petroleum reservoirs. Use of the correlation requires knowledge of permeability and porosity, data commonly available in petroleum engineering (on the other hand Biot coefficient data is almost never available). The ratio of permeability and porosity, commonly known as process or delivery speed and pore throat aperture (rp35), are input for estimating Biot coefficient from the correlation proposed in this paper. The correlation is useful in those cases where sophisticated experimental work needed for estimating Biot poroelastic coefficient is not available.

Testing against various data sets indicates that the proposed correlation provides reasonable results. In the past, methods with different complexity levels have been used for estimating Biot coefficient. These have included, for example, (1) a method that requires knowledge of bulk modulus of the rock mineral and bulk modulus of the skeleton with no fluids in it, parameters that are not usually available for petroleum reservoirs, (2) a method that is based on knowledge of only porosity, (3) a method that is based on knowledge of only permeability, and (4) an approach that simply assumes that Biot coefficient is equal to 1.0 or some other number. The proposed correlation falls somewhere in the middle. It is not as simple as saying that Biot coefficient is equal to 1, or saying that it depends on only porosity, or only permeability. On the other hand, it is not as complex as requiring sophisticated laboratory work of the type mentioned in item (1) above.

The novelty of this work is the development of an original easy to use correlation for estimating Biot coefficient in conventional and unconventional (tight and shale) reservoirs based on knowledge of k/ϕ and rp35. The correlation is developed in such a way that it has also application for estimating Biot coefficient in the case of unconsolidated petroleum reservoirs and oil sands. The overall approach allows integration of geomechanics with flow units, geology, petrophysics, and reservoir engineering.
Improving Water Efficiency in the Wilmington Field Using Streamline-Based Surveillance
Authors: Kwong Ryan R. , Kellogg Ryan P. , Thiele Marco R. , Simmons David M.
Published: April 2019

This paper describes application of a streamline-based surveillance methodology to define injector-centered-patterns using streamlines, calculate pattern efficiencies, and propose target rates for injectors and producers to improve oil production, lower WOR, and reduce water cycling in the Wilmington Field.

The Wilmington Field is a faulted anticline structure in the Los Angeles Basin with alternating sand/shale sequences, which straddles offshore and onshore locations in Long Beach, California. It has been actively waterflooded since 1953 and currently injects over 1.6 million barrels of water injected (BWIPD) and produces at ~98% water cut. Due to the industrial port environment and history of subsidence, a minimum voidage replacement ratio (VRR) is required to sustain stable surface elevations. Given the scale of the Wilmington field, we focused on implementing two pilots to improve the flood performance by targeting different fault blocks/reservoirs: Fault Block 2 Tar Reservoir (Tar 2) and Fault Block 7 Ranger Reservoir (Ranger 7) which together represent 5% of total Wilmington oil production. Both surveillance models used a multi-layered numerical grid with geologic properties from existing 3D geomodels. The key objective for Tar 2 and Ranger 7 was to redistribute the current injected water volumes to improve oil production while maintaining VRR targets. Injection into the Tar 2 model was vertically refined to per-sand using pseudo-injectors in the modeling approach. Injection wells for the Ranger 7 model used a single path and injection volumes were allocated into each sand using permeability-height (kh) values. Rate changes suggested by the surveillance model for both pilot areas were made through choke adjustments and/or well shut-ins and required no pump size changes or workovers.

The Tar 2 and Ranger 7 pilots were monitored over a 6-month and 17-month period, respectively. The Tar 2 pilot area resulted in a decrease from 20% to 2 % annual oil decline rate while keeping a constant injection rate, while the Ranger 7 pilot area new rate target resulted in WOR from 52 to 47 and a decrease in annual oil decline from 15% to 5%. With the success of the waterflood management approach seen in Tar 2 and Ranger 7, a larger area in the Wilmington Field, Fault Block 6 Ranger (23% of total production) is now under a similar evaluation with the goal of reducing WOR and oil decline using the same surveillance methodology.
Perioperative management of patients receiving long-term antithrombotic therapy. Russian Federation of anesthesiologists and reanimatologists guidelines
Authors: Zabolotskikh Igor B. , Kirov M. Yu. , Afonchikov V. S. , Bulanov A. Yu. , Grigoriev E. V. , Gritsan A. I. , Zamyatin M. N. , Kurapeev I. S. , Lebedinskii K. M. , Lomivorotov V. V. , Lubnin A. Yu. , Ovechkin A. M. , Potievskaya V. I. , Roitman E. V. , Sinkov S. V. , Subbotin V. V. , Shulutko E. M.
Published: April 2019

The review presents the clinical guidelines of the Federation of Anaesthesiology and Resuscitation specialists of Russia, revised in 2018. The recommendations are based on a review of publications and modern international guidelines of the British Hematology Standards Committee (BSH, 2016), the European Society of Cardiology in partnership with the European Society of Cardiothoracic Surgeons (ESC and EACTS, 2018), the American Society of Regional Anesthesia and Pain (ASRA, 2018), The European Society of Anesthesiologists (ESA, 2010), as well as a consensus document of an interdisciplinary group of experts of the Russian Federation.
Perioperative management of patients receiving long-term antithrombotic (antiplatelet and / or anticoagulant) therapy may be problematic, as they often need to interrupt antithrombotic therapy before surgery. In this, it is necessary to maintain a balance between the effectiveness of antithrombotic therapy and its safety by minimizing the frequency of both hemorrhagic and thrombotic complications. The recommendations presented in the review are aimed at achieving the strategic goal of perioperative antithrombotic therapy — minimizing the risk of bleeding subject to the minimum necessary antithrombotic potential.
Identifying Most Influential Land Use Parameters Contributing Reduction of Surface Water Bodies in Rajshahi City, Bangladesh: A Remote Sensing Approach
Authors: Kafy Abdulla-Al , Islam Muhaiminul , Khan Abdur Rouf , Ferdous Lamia , Hossain Md. Mamun ,   Department of Urban and Regional Planning, Rajshahi University of Engineering and Technology (RUET), Rajshahi-6204, Bangladesh.,   Department of Urban and Regional Planning, Rajshahi University of Engineering and Technology (RUET), Rajshahi-6204, Bangladesh.
Published: April 2019

Surface water bodies are one of the irreplaceable natural resources for human survival, and it extensively reduces with increasing the world population. This study modeled the spatiotemporal changes of land use / land cover (LULC) and identified the most influential LULC parameters, which contributes in the reduction of surface water bodies using the Landsat 4 and 5 TM and Landsat 8 OLI images (1992-2017). Rajshahi City Corporation is situated in the Northern piece of Bangladesh. A maximum likelihood supervised images classification algorithm was used for detection of changes in LULC. Matrix union technique was used for identifying the prominent LULC parameters. About 14% of water bodies were filled up in twenty-five year (1992-2017) due to rapid urbanization in Rajshahi City Corporation area. This study can provide an essential move towards necessary actions for preservation of surface water bodies to maintain the ecological balance and environmental sustainability.
MOBILIDADE URBANA: ESTUDO DA IMPORTÂNCIA DE SERVIÇOS BASEADOS EM TECNOLOGIA PARA OS GÊNEROS
Authors: Cassita Hino Marcia Regina Martelozo , Cunha Maria Alexandra Viegas Cortez da
Published: April 2019

No fenômeno de urbanização, a mobilidade urbana é uma das principais áreas afetadas. O Brasil apresenta um cenário de urbanização acelerada, intensificando a redução da mobilidade. Pouco se conhece sobre o reflexo desse crescimento para os diferentes gêneros, mas sabe-se que a tecnologia pode ser um aliado para a redução das diferenças de gênero nos serviços de mobilidade urbana. Nesse cenário, o artigo busca investigar a existência de diferença de perspectivas de gênero em relação à importância de tecnologia em serviços de mobilidade urbana. A análise se desenvolve com uma abordagem quantitativa com dados secundários. Tendo o Brasil como pano de fundo deste artigo, utilizou-se dados coletados de 14 cidades, no período de 2014/15. Resultados sugerem a existência de diferença de perspectivas de gênero em relação à importância de tecnologia em alguns serviços de mobilidade urbana, mais especificamente em transporte público inteligente, gestão de frotas, veículo elétrico e bicicletas.
O PAPEL DA UNIVERSIDADE NA CONSTRUÇÃO DE CIDADES INTELIGENTES E HUMANAS
Authors: Neves Ana Regia De Mendonca , Sarmanho Kaê U. , Meiguins Bianchi S.
Published: April 2019

As universidades desempenham um papel fundamental para o desenvolvimento das cidades inteligentes e humanas. Iniciativas de smart campus tornaram-se uma tendência crescente com o objetivo de melhorar a infraestrutura e vivência dentro dos campi universitários, bem como para promover soluções que impulsionem a inovação urbana. Nesse sentido, o presente artigo descreve o projeto Smart Campus UFPA, um estudo em progresso para a construção de um smart campus na Universidade Federal do Pará. Também, apresenta o primeiro resultado dessa iniciativa, o aplicativo móvel para Android, denominado Smart UFPA, o qual tem seu foco inicial na área de mobilidade. O projeto tem como objetivo engajar a comunidade para discutir e desenvolver soluções alternativas para os problemas encontrados no campus universitário, que possam ser, posteriormente, ampliadas para ajudar a melhorar o contexto urbano da cidade.
SERVIÇOS DE EMERGÊNCIA EM CIDADES INTELIGENTES: O PROBLEMA DE ACIONAMENTO DE UNIDADES MÓVEIS
Authors: Hernandes Sediane Carmem Lunardi , Calsavara Alcides , Pellenz Marcelo Eduardo , Lima Júnior Luiz Augusto de Paula
Published: April 2019

Cidades inteligentes buscam melhorar a qualidade de vida dos cidadãos por meio do uso das Tecnologias da Informação e Comunicação (TICs). Esforços vem sendo realizados para que sistemas computacionais sejam desenvolvidos para tratar os grandes problemas das cidades. Um dos serviços importantes é o atendimento a chamados de emergência (ex.: polícia e hospitais), o qual demanda o deslocamento de unidade móveis. O problema consiste em realizar o acionamento das unidades móveis mais adequadas para atuar em uma situação em particular, considerando, entre outros fatores, o tempo necessário para se chegar ao local da emergência. Um middleware pode ser utilizado nesse contexto para oferecer suporte a esse acionamento, gerenciando, desta forma, a notificação de eventos relacionados a situações de emergência. Vários middlewares baseados em eventos foram analisados para verificar sua adequação quanto ao suporte para o acionamento das unidades móveis mais adequadas para atuar em situações de emergência em cidades inteligentes. Entretanto, se mostraram pouco flexíveis em relação ao envio somente para as unidades móveis mais adequadas. Assim, este artigo apresenta e formaliza o problema de acionamento de unidades móveis, bem como sua solução, avalia middlewares baseados em eventos e propõe um novo middleware baseado em eventos que pode ser utilizado como suporte para serviços de emergência em cidades inteligentes, apresentando a implementação de uma das abordagens propostas.
USANDO O CLASSIFICADOR NAIVE BAYES PARA GERAÇÃO DE ALERTAS DE RISCO DE ÓBITO INFANTIL
Authors: Da Silva Cristiano Lima , Alves Joyce Quintino , Braga Oton Crispim , Pereira Júnior José Wellington , Monteiro de Andrade Luiz Odorico , Barbosa de Oliveira Antônio Mauro
Published: April 2019

GISSA é um sistema inteligente para a tomada de decisões em saúde focado no cuidado materno infantil. Neste sistema, vários alertas são gerados nos cinco domínios da saúde (clínico-epidemiológico, normativo, administrativo, gestão do conhecimento, conhecimento compartilhado). O sistema se propõe a contribuir para a redução da mortalidade infantil no Brasil. Este artigo apresenta o LAIS, um mecanismo inteligente que usa aprendizado de máquina para gerar alertas de risco de mortalidade infantil no GISSA. Para tanto, este trabalho usa uma metodologia baseada na mineração de dados para alcançar um modelo de aprendizagem capaz de calcular a probabilidade de um recém-nascido morrer. Os testes mostram que o classificador Naive Bayes é o mais adequado para este propósito, apresentando bons resultados, com área da curva ROC de 92,1%. O trabalho reúne bases de dados do Ministério da Saúde, SIM e SINASC, para o treinamento de algoritmos de classificação, identificando relações entre dados de nascimento e de morte de crianças com menos de um an. Durante o processo metodológico foi utilizado o algoritmo spread subsample, que aplica sub-amostragem, melhorando os resultados do modelo.
O MODELO ABERTO DE DESENVOLVIMENTO DE SOFTWARE EM PEQUENAS EMPRESAS BRASILEIRAS
Authors: Bono Milan Luiz Fernando Albertin , Meirelles Fernando De Souza
Published: April 2019

Nas últimas décadas, o modelo aberto de desenvolvimento de software foi de passatempo de programadores, para inimigo de empresas de tecnologia e, mais recentemente, passou a ser uma estratégia destas. Sob o paradigma filosófico do Realismo Crítico, o estudo tem o objetivo de identificar os mecanismos envolvidos na decisão de adoção do modelo aberto de desenvolvimento de software por pequenas empresas brasileiras. Utilizando estudo de casos múltiplos, os dados contemplam quatro empresas brasileiras de tecnologia. O material qualitativo foi analisado utilizando técnicas indutivas e dedutivas, buscando evidências para suportar um modelo preliminar de pesquisa baseado na literatura e a identificação de novos fatores. O principal resultado do estudo foi a identificação de três fatores não endereçados pela literatura utilizada como base para o estudo, são eles: o receio de uso oportunista do código; o custo envolvido na adoção do modelo aberto de desenvolvimento; e, a instabilidade política. Aos gestores do mercado, permite a reavaliação de suas estratégias em relação ao desenvolvimento de software.
GOVERNANÇA DE TECNOLOGIA DA INFORMAÇÃO: A MEIO CAMINHO ENTRE O ISOMORFISMO E A COMODITIZAÇÃO
Authors: De Moura Jr Pedro Jácome
Published: April 2019

A gestão da tecnologia da informação (TI) na Administração Pública Federal (APF) no Brasil passa por profunda reforma, conduzida primordialmente por exigências de órgãos de regulação e controle externo, sob o emblema da governança. Não obstante a contemporaneidade das soluções e os potenciais ganhos sociais obtidos por esta implantação, meios e fins não têm sido discutidos à altura dos desafios interpostos. Este estudo foca o fenômeno nas Instituições Federais de Ensino Superior (IFES), fundamentado de um lado nas teorias da agência e neo-institucionalismo e, de outro, em observação participante decorrente da vivência do autor como gestor de TI em uma IFES. Discutem-se implicações da implantação de um modelo de governança de TI em IFES brasileiras, procurando indicar posicionamentos estratégicos para os gestores de TI dessas instituições por meio do questionamento ao modelo em implementação. Do ponto de vista teórico, este estudo valida a aplicação da teoria neo-institucional à análise do comportamento da TI na APF e propõe relação causal entre governança, isomorfismo e “comoditização” da TI na administração pública, o que parece ser uma combinação teórica pouco explorada até o momento.
Infection in pulmonary vascular diseases: Would another consortium really be the way to go?
Authors: Butrous Ghazwan , Mathie Alistair
Published: April 2019

[first paragraph of article]There has been a clear engagement by the medical community with pulmonary hypertension after the approval of targeted therapies and the introduction of more therapeutic modalities in the last 18 years. The increasing number of scientific sessions and conferences was inevitable. Major initial interest was from the developed countries, which concentrated on prevalent etiologies: primary (later called idiopathic) pulmonary arterial hyposecretion and secondary to connective tissue disorders currently both classified as Class I. Unfortunately, a lesser consideration was given to other causes of pulmonary hypertension such as secondary to left heart failure (Class II) or hypoxic pulmonary disease (Class III). This is presumably due to both the complexity and the multifactorial etiologies of these causes and the lack of availability of targeted therapies.
The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT): Lower is better, but is it good enough?
Authors: Bouhout Ismail , El-Hamamsy Ismail
Published: April 2019

Due to their durability, mechanical prostheses are frequently used for aortic valve replacement (AVR) in young adults. However, these valves are thrombogenic and require lifelong anticoagulation. Over the last few decades, efforts have been made towards the lowering of INR targets in an effort to reduce bleeding events without influencing the thromboembolic risk. The Prospective Randomized On-X Valve Anticoagulation Clinical Trial (PROACT) was designed to compare standard versus low anticoagulation targets in high-risk patients undergoing mechanical AVR with the ON-X prosthesis.
Towards tailoring blood pressure control in HFpEF: Lessons from OPTIMIZE-HF
Authors: Hassan Mohamed
Published: April 2019

[first paragraph of article]Heart failure (HF) with preserved ejection fraction (HFpEF) represents approximately 50% of the world's HF population, and this proportion is increasing over time. The diagnosis of HFpEF is more challenging than HF with reduced ejection fraction (HFrEF). Patients with HFpEF are significantly older, more likely to be female, and more likely to have hypertension, obesity, anemia, atrial fibrillation, renal disease, and pulmonary disease compared to those with HFrEF. In observational studies, rates of hospitalization and death among patients with HFpEF approach those with HFrEF, however in clinical trial populations, outcomes are better in patients who have HFpEF. Death from non- cardiovascular causes is more common in patients who have HFpEF than in those with HFrEF, and a smaller percentage of patients with HFpEF die from CVD-related causes.
Repair of degenerative mitral regurgitation: An update
Authors: Richens David , Boulemden Anas , Skinner Henry
Published: April 2019

The recent development of catheter-based therapies for structural valve disease, such as mitral-TAVI, MitraClip and left atrial appendage occlusion devices, makes a review of surgery for degenerative mitral valve disease timely. In this personal perspective we discuss the evolution of mitral valve repair, the core principles involved and the evidence base behind it through the lens of a single UK-based surgical team operating for a quarter century, illustrating the techniques, outcomes and some of the pitfalls of intervention.