bluuebunny/crossref_metadata_2025 huggingface dataset:
TÉCNICA DE RIVES-STOPPA PARA LA REPARACIÓN DE HERNIAS INCISIONALES DE LÍNEA MEDIA: RESULTADOS EN 100 PACIENTES CONSECUTIVOS.
Authors: De Andrés Gómez Alejandra , Bruna Esteban Marcos , Báez de Burgos Celia , Navarro Moratalla Carla , Oviedo Bravo Juan Miguel , Albors Bagá Pilar , Vázquez Prado Antonio , Puche Pla José Julian
Published: March 2019

INTRODUCCIÓN: Se han descrito múltiples técnicas quirúrgicas para el tratamiento de las hernias incisionales buscando reducir las complicaciones postoperatorias y la tasa de recurrencia, siendo la de Rives-Stoppa una de las más empleadas actualmente. Se presentan los resultados obtenidos con esta técnica para el tratamiento de las eventraciones de línea media.MÉTODOS: Se intervinieron 10 pacientes con hernias incisionales  (Abril 2009-Octubre 2016), recopilando datos epidemiológicos, características de las hernias y técnica quirúrgica. Se evaluó el grado de satisfacción y el dolor postoperatorio mediante una escala visual analógica (EVA), siendo controlados al mes y al año postquirúrgico.RESULTADOS. Se incluyeron 58 mujeres y 42 hombres con una edad media de 62,32±12,6 años. 38 pacientes presentaban eventroplastias previas. Las localizaciones y tamaños más frecuentes, según la European Hernia Society (EHS) fueron M3 (23%) y M4 (21%), y W2 (49%) y W3 (40%). Se empleó malla de polipropileno de baja densidad en el 93%, con overlap de 5 cm (RIQ: 4-6). La estancia hospitalaria fue de 2 días (RIQ: 2-4), morbilidad del 20% y mortalidad del 4%. La puntuación álgica el primer día postoperatorio fue 5 (RIQ: 2-7), reduciéndose a 0 (RIQ: 0-2) al mes. La tasa de infección de herida fue de un 8% y de recidiva al año del 13,2%. El 91% resultaron satisfechos tras la cirugía.CONCLUSIONES: En los pacientes intervenidos de hernia incisional de línea media mediante la técnica de Rives-Stoppa se obtienen buenos resultados de dolor, grado de satisfacción, tasa de recurrencia y complicaciones de herida.
NUESTRA EXPERIENCIA EN LA TECNICA SAC DE CARBONELL-BONAFE EN EVENTRACIONES COMPLEJAS
Authors: Gonzalez sanchez Juan Antonio , VALDERRABANO GONZALEZ SANTIAGO , HERAS GARCEAU MARIA ALEXANDRA , ALVAREZ PEÑA ESTIBALIZ , FERNANDEZ FRANCOS SILVIA
Published: March 2019

RESUMEN : El objetivo de la reparación de las eventraciones complejas de pared abdominal es obtener una reconstrucción anatómica y funcional,  cuyos resultados se mantengan con el tiempo. La técnica de SAC de Carbonell-Bonafé nos pareció muy atractiva para el tratamiento de estos casos y presentamos nues­tra experiencia  con la misma y con seguimiento a largo plazo.Material y métodos: Presentamos nuestra serie de 50 pacientes con eventraciones  complejas, intervenidos en nuestra unidad desde noviembre del 2009 hasta octubre de 2017. En 34 casos se trataba de eventraciones primarias, y recidi­vadas en 16 .La técnica realizada ha sido la descrita por Carbonell-Bonafé como nivel I en 11 ocasiones y de nivel II en 39.Hemos seguido la evolución de los pacientes durante los pri­meros 5 años, por lo que el seguimiento medio de la serie es de 49 meses, con mínimo de 2 y máximo de 60.Resultados: – Mortalidad: 1 paciente (2%). Complicaciones quirúrgicas: 4 pacientes (8%) desarrollaron ne­crosis cutáneas, de las cuales 3 requirieron desbridamiento quirúrgico; 6  pacientes  (12%) tuvieron infecciones de herida quirúrgica , manteniéndose  la prótesis en todos ellos.– Recidivas: En eventraciones no asociadas a ostomías (44 casos) hemos tenido 2 recidivas, 1 de SAC 1 y otra de SAC 2, ocurrida 6 años tras la reparación inicial (4.5 %). Conclusiones: La técnica SAC de Carbonell Bonafé  ha producido muy buenos resultados en la reparación duradera de eventra­ciones muy complejas con escasa morbimortalidad.
Problemas en la identificación del nervio femoro cutáneo lateral: variante de trayecto largo. Implicaciones quirúrgicas
Authors: Moreno Egea Alfredo
Published: March 2019

Introducción: el nervio femorocutáneo lateral puede lesionarse durante el abordaje laparoscópico de la hernia inguinal o seccionarse de forma inadvertida durante la triple neurectomia como tratamiento del dolor crónico postquirúrgico. El objetivo de este trabajo es presentar una variante y realizar una revisión de la literatura.Material y método: disección de cadáveres adultos formolizados al 10%, en la Cátedra de Anatomía de la Facultad de Medicina de la Universidad Católica de Murcia. El trayecto del nervio femorocutáneo lateral, y de todo el plexo lumbar, fue analizado en base a sus relaciones locales, tanto a nivel retroperitoneal como inguinal anterior.Resultados: en la mayoría de los casos, el nervio femorocutáneo lateral es único cruzando el espacio retroperitoneal desde el borde lateral del psoas a la a la espina ilíaca anterosuperior y pasar al muslo en una zona media del ligamento inguinal. Variantes descritas son: bifurcación temprana, posición epifascial, origen de la rama femoral del genitofemoral, del ilioinguinal o su ausencia. Describimos una variante de trayecto largo sobre el músculo cuadrado lumbar de difícil diferenciación clínica del ilioinguinal.  Conclusión: 1) La cirugía del retroperitoneo no puede identificar con certeza los diferentes nervios del plexo lumbar. 2) Nunca se debe seccionar un nervio sin verificar craneal y caudalmente los adyacentes. 3) El nervio femorocutáneo puede presentar variantes que dificulten su reconocimiento, sobre todo respecto al Ii, y deben tenerse presentes en cualquier cirugía laparoscópica para evitar una morbilidad indeseable.
Reconstruction of the Proximal Aspect of the Radius After Desmoplastic Fibroma Resection
Authors: Lans Jonathan , Chebib Ivan A. , Castelein René M. , Chen Neal C. , Lozano-Calderón Santiago
Published: March 2019

Case:

Desmoplastic fibromas are tumors of fibrous tissue that rarely are diagnosed. We present the case of a 27-year-old man who presented with pain of the forearm that was initially diagnosed as a muscle strain. A computed tomography-guided core biopsy revealed a desmoplastic fibroma. Consequently, the patient was treated with a resection of the proximal aspect of the radius followed by reconstruction with use of a vascularized fibular autograft.

Conclusion:

At the 2-year follow-up, radiographs showed integration of the autograft; additionally, good results were noted with the Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity and Physical Function Short Form T-score and the QuickDASH (an abbreviated version of the Disabilities of the Arm, Shoulder and Hand Score [DASH]) questionnaire, along with good range of motion.
Analizando la gobernanza urbana mediante la aplicación del análisis de redes sociales (ARS): el caso del Segundo Plan Estratégico de Málaga
Authors: Merinero Rodríguez Rafael , Ledesma González Oswaldo
Published: March 2019

La gobernanza entendida como una red de actores se ha convertido en el elemento central que caracteriza la elaboración e implementación de políticas públicas y se han identificado multitud de instrumentos que permiten su aplicación entre los que está la Planificación Estratégica Urbana. En este trabajo se propone un análisis del sistema de gobernanza del Segundo Plan Estratégico de Málaga mediante la aplicación del Análisis de Redes Sociales (ARS) que hace posible una caracterización estructural de la gobernanza y su vinculación con el nivel de ejecución de las políticas públicas.
Aportaciones del análisis pedoantracológico al conocimiento paleoecológico de Pinus Pinaster en el sur de España: el caso de Sierra Bermeja
Authors: Olmedo Cobo José Antonio , Cunill Artigas Raquel , Gómez Zotano José , Pardo Martínez Rubén
Published: March 2019

Pinus pinaster es una conífera nativa del Mediterráneo Occidental que ocupa una amplia área corológica, apareciendo en gran diversidad de hábitats. En el caso de Sierra Bermeja (provincia de Málaga, sur de España), la especie integra, junto con los abetales de Abies pinsapo, las formaciones forestales predominantes en la actualidad sobre suelos serpentiníticos. Sin embargo, esta conífera también ha sido considerada por ciertos autores una especie introducida en este territorio. Este hecho y la aparición aislada de distintas especies de Quercus arbóreos han justificado diversas teorías fitosociológicas defensoras de la marginalidad de P. pinaster frente a los árboles latifolios. Este trabajo, mediante el análisis pedoantracológico y posterior datación radiométrica C14 de muestras de carbón, ha permitido establecer el origen natural de la especie sobre los sustratos ultramáficos y su presencia en el macizo a lo largo de gran parte del Holoceno. Asimismo, de los resultados obtenidos parece inferirse además el rol de refugio –probablemente el más meridional de Europa– que pudo tener este macizo para P. pinaster durante el último máximo glaciar, en un contexto en el que parece que el fuego tuvo un papel destacado en la configuración del paisaje vegetal bermejense a lo largo del Holoceno.
La dimensión geográfica de las invasiones biológicas en el Antropoceno: el caso de Xylella fastidiosa
Authors: Gutiérrez Hernández Oliver , García Luis V.
Published: March 2019

Xylella fastidiosa es una bacteria potencialmente dañina para un gran número de cultivos leñosos y especies arbóreas, y está considerada una de las bacterias fitopatógenas más peligrosas del mundo. En este artículo, combinamos modelos de nicho ecológico para estimar la distribución potencial global de X. fastidiosa y, complementariamente, técnicas de evaluación multicriterio para estimar regionalmente la exposición de la península Ibérica e islas Baleares a la entrada y difusión del patógeno. A nivel global, nuestros modelos estimaron una distribución potencial de X. fastidiosa con un amplio radio potencial de expansión en climas templados (Grupo C, según la clasificación climática de Köppen). A nivel regional, nuestros resultados revelaron que la península Ibérica se halla muy expuesta a la entrada y propagación de este organismo invasor, cuya presencia es ya generalizada en las islas Baleares. En el Antropoceno, la Geografía desempeña un papel crucial en el manejo de los riesgos biológicos. El éxito en la gestión de los mismos depende, en gran medida, de nuestra capacidad para predecir los rangos geográficos potenciales de los organismos invasores e identificar los factores que promueven su propagación.
Real Time Call Monitoring System Using Spark Streaming and Network Intrusion Detection Using Distributed WekaSpark
Authors: V S Darshan , Raphael Ria
Published: March 2019

With the increase of calls in industries it is very difficult to identify the calls made in a huge organization. The study and developing analytics out of the call history generated in terms of real time or the information stored helps in the improvement of the quality of calls in terms of network failure analysis, analysing call usage pattern from minimal to maximum to increase server efficiency, analyse user level pattern. The capability to process, analyse and evaluate real time data in a system is a challenging task, the test of building up an adaptable, shortcoming tolerant and flexible observing framework that Can deal with information continuously and at a huge scale is nontrivial. We exhibit a novel framework for real time processing and batch processing by using spark streaming and spark, also an ensemble model is used with distributed weka-spark for intrusion detection.
Characterization and Modeling of the Geo-Body Geometries and the Reservoir Properties: An Outcrop Analog Study of Jurassic Carbonate Reservoirs in Central Saudi Arabia
Authors: Yassin Mohamed A. , Abdullatif Osman M. , Makkawi Mohammad H. , Yousif Ibrahim M. , Osman Mutasim S.
Published: March 2019

Well exposed Jurassic outcrops belt in central Saudi Arabia provides good outcrop analogs which can be utilized to capture the high resolution facies types and architecture that might help to fill the inter-wells gap in the subsurface. This study is focused on the characterization and modeling the facies types, body geometries deposited in geomorphic elements of carbonate ramp system and the distribution of the reservoir properties on it. Three-dimensional models for the different facies-body geometries were conducted to provide accurate stochastic representation. This study was conducted at a selected Jurassic outcrop reservoir analog that exposed around Riyadh area. The Mesozoic carbonate strata of central Saudi Arabia are interpreted to have been deposited in ramp systems and exposed in hundreds of kilometers in the strike and dip direction of palaeoshoreline. The study integrates detailed sedimentological and stratigraphic analysis from outcrop strata to capture facies-body geometries and their petrophysical properties on the ramp system. Nine lithofacies were interpreted from the stratigraphic sections. Spatially, the porosity and permeability show different ranges of heterogeneity from micro to meso and macro scales. Laterally, the reservoir properties show steady variations in contrast with the abrupt change vertically. This variation seems to be related to the sedimentary structure, grain size, and degree of cementation. Different pore types were recognized in the studied intervals, which include fracture, intraparticle, moldic and intercrystalline porosities. Several 3D facies models were constructed using sedimentological and stratigraphic data that collected from the field. These models express the complex and heterogeneous relationship between facies-body geometries in the outcrop precisely. Integration of these data to subsurface equivalent reservoirs will provide qualitative and quantitative information useful for understanding and predicting reservoir quality and architecture in carbonate ramps.
Unified Field Compositional Fluid Model for the Bahrain Field
Authors: AL-Muftah Ali
Published: March 2019

The Bahrain Field is characterized by large lateral and vertical variations in fluid properties, with oil gravity ranging between −9 and 80 °API. The lower API crudes are encountered mostly on the structural flanks and within the upper reservoir units, while the highest API crudes are condensates from deeper formations such as Hith and Arab. The deepest reservoir is the gas-bearing Khuff. It has 50 °API condensate and forms a separate fluid type from the rest of the Bahrain Field.

The objective of this paper is to derive a single compositional predictor for the entire range of crude gravities. Excluded from this unified model are bitumens from Aruma and Khuff condensates, which are compositionally different. One outcome of this study was to predict the reservoir fluid as a function of well test Gas Oil Ratio (GOR) and API gravity by mathematical recombination of averaged data from abundant well tests across the Bahrain Field. A strong trend of methane fraction in the reservoir fluid versus saturation pressure has been observed, and thus it has been possible to construct the recombined reservoir fluid and then predict saturation pressures, Formation Volume Fraction (FVF), and viscosity. This fluid model was used to initialize compositional models for gas plant evaluations, miscible flood evaluations, and to determine the maximum GOR at which saturation pressure equals reservoir pressure. Another outcome of the unified fluid model was to construct a reservoir fluid composition given a target saturation pressure and API. This information is used to construct representative fluids for laboratory synthesis of crudes and gas for live oil experiments.

As part of the process, a number of quality checks were constructed to determine if the fluid encountered is in range of historic produced crudes (e.g. contamination by air or lift gas) and enable construction of fluids for reservoir simulation.
A More Sustainable Approach: Nanofiltered Seawater-Based High-Temperature Fracturing Fluids
Authors: Li Leiming , Chang Fakuen F. , Saini Rajesh K.
Published: March 2019

In recent decades, the widespread implementation of horizontal drilling and multistage hydraulic fracturing in unconventional plays has increased the use of fresh water in oilfield operations. The formulation of fracturing fluids with non-fresh water sources such as seawater or produced water are attracting more attention due to the long term sustainability of non-fresh water use.

Fracturing fluids using seawater are available in the industry. But the compatibility between the composition of local seawater and reservoir brine can add complication in the formation damage consideration. For example, if a seawater rich in sulfate comes in contact with formation brine rich in calcium or barium, severe scale can be expected if the proper caution is not taken. Treated seawater with nano-filtration to removal sulfate is a good practice to eliminate this problem. This paper describes a fracturing fluid formulated by using nanofiltered seawater for high temperature applications at 300 to 325°F. The crosslinked fracturing fluid formulation was optimized in the lab to accommodate the nanofiltered seawater, resulting in satisfactory fluid performance thereby enabling the fracturing operations to conserve fresh water.

A high-temperature crosslinked fracturing fluid system was prepared with the nanofiltered local seawater. The fluid system showed robust stability at high temperatures. For example, the fluid viscosity stayed above 400 cP (at 100 sec−1 shear rate) for 2 hr at 300°F, with 45 ppt of the polymer loading. At 325°F, the fluid maintained viscosity above 300 cP for 2 hr with 60 ppt of the polymer loading. The nanofiltered seawater-based fluids was found to be compatible with a number of commonly used fluid additives including biocide, surfactant, and clay stabilizer. The fluid system also showed low formation damage and scaling tendencies. In the coreflow tests at 300°F, a regained permeability of greater than 95% was obtained. In the scaling tests without the presence of scale inhibitor at 300°F, traceable (<0.01 wt %) amount of scale was observed in the mixture of the nanofiltered seawater and high total dissolved solids (TDS) formation brine. Overall, it was found using the nanofiltered seawater can lead to better fluid stability at elevated temperatures, better fluid cleanup, and reduced downhole scaling tendency.

By careful selection of the fluid components, the nanofiltered seawater-based fluid relieve the burden of needing fresh water for hydraulic fracturing treatment, allowing for a more sustainable approach. This paper discusses the technical functions of the key fluid additives used in the fracturing fluid preparation.
New Artificial Neural Network Model for Predicting the TOC from Well Logs
Authors: Sultan Abdullah
Published: March 2019

The key factor for characterizing unconventional shale reservoirs is the total organic carbon (TOC). TOC is estimated conventionally by analysis cores samples which requires extensive lab work, thus it is time-consuming and costly. Several empirical models are suggested to estimate the TOC indirectly using conventional well logs. These models assume the TOC and well logs are linearly related, this assumption significantly reduces the TOC estimation accuracy.

In this work, the design parameters of the artificial neural network (ANN) were optimized using self-adaptive differential evolution (SaDE) method to effectively predict the TOC from the conventional well log data. A new correlation for TOC calculation was developed, which is based on the optimized SaDE-ANN model. 460 data points of different well logs from Barnett formation were used to learn and validate the optimized SaDE-ANN model. The predictability of the SaDE-ANN correlation was compared with the available correlations for predicting the TOC using 29 data point from Duvernay formation.

The TOC was estimated using the optimized SaDE-ANN model with an average absolute percentage error (AAPE) and correlation coefficient (R) of 6% and 0.98, respectively. The SaDE-ANN correlation developed for TOC prediction outperformed the recent models suggested by Wang et al. (2016) and Mahmoud et al. (2017). The new empirical equation reduced the AAPE in predicting the TOC by 67% compared to Mahmoud et al. (2017) model in Duvernay formation.
Large-Scale Chemically Pulsed Fracturing Stimulation of Unconventional Reservoir Using Hybrid FEM-DEM Approach
Authors: Alruwaili Khalid , Han Yanhui , Al-nakhli Ayman , Bataweel Mohammed
Published: March 2019

In this paper, FDEM simulation approach was used to simulate the chemically-induced pulse fracturing of a large-scale wellbore confined by far field stresses. The mesh near wellbore is refined to maximize the model resolution in the critical regions, while coarser mesh elements are used in the regions away from the borehole to minimize the run time. The buildup of gas pressure generated by the reactive chemicals injected inside the borehole is applied to the borehole surface as a time-dependent surface pressure.

Simulation showed that mixed tensile and shear fractures initiate from the borehole extending randomly towards the maximum horizontal stresses. These fractures continue to nucleate and eventually form an elliptical-shaped fracture region around the borehole. As the model undergoes more mechanical damage, shearing along the tip of the created fractures generate new shear fractures. As the pressure loading propagates, radial fracture is created and extended to into the model domain. Explicit deformation of rock near the wellbore is observed during the drilling process.

The computational cost of large-scale dynamic simulation can be prohibitive. In this study the chemically pulsed fracturing processes in a large reservoir is investigated using FDEM approach, which optimizes the computational load while still accurately capturing an explicit deformation response of large rock rocks in the near-well regions using DEM and elastic dynamic response of rocks in the far-field using FEM.
Ultrasound Tomography Based Flow Measurement System; Field Experiences
Authors: Arsalan Muhammad , J. Ahmad Talha , Li Weichang , Adams Robert , Deffenbaugh Max
Published: March 2019

Multiphase flow meters are available from sometime, however, there still remain unresolved challenges. Dependable flow sensing is essential for reservoir management and production optimization. Most commercial water-cut and multiphase flow meters have limitations while measuring over the full range of flow conditions. Exiting meters need recurrent calibration, and have significant capital and operational overheads. In this paper an ultrasonic tomography based meter for water hold-up measurement is presented and the the experiences and challenges of testing the system in the field are shared. The designed system has the potential to resolve the shortcomings of available multiphase metering solutions.
Strategy Towards Unlocking and Accelerated Development of Low Permeability, Microporous Reservoirs-II
Authors: Kumar Kamlesh , Awang Zaidi , Azzazi Mohamed , Hamdi Abdullah , Hughes Brendan , Abri Said
Published: March 2019

The microporous rock types in Upper Shuaiba are low permeability (~ 1mD) rocks occurring in thin (2-5 m) formations within the extensive Upper Shuaiba carbonate formations in Lekhwair. These microporous rocks constitute a significant volume of hydrocarbon in-place. Unlike the higher quality rudist-rich and grainstone rock types, appraisal pilots in the microporous areas have shown poor performance with waterflood development, which is the preferred development concept in the entire Lekhwair field. Two work streams are active in parallel to identify a technically and commercially feasible development option: Phase 1, technology trials to enable a successful waterflood implementation, and Phase 2, further studies to screen the potential of enhanced oil recovery (EOR) techniques and other light tight oil development.

The technology trial work stream, initially considered four initiatives targeting injectivity improvement. To date, trials are complete for abrasive jetting and designer acid stimulation, early results are available for Directional Acid Jetting, and evaluation of Fracture Aligned Sweep Technology (FAST) is ongoing with hydraulic fracturing evaluation accelerated to Phase 1 due to synergies with the FAST evaluation. Trial results to date:

Abrasive Jetting: 7 trials complete, limited success in improving injectivity. Designer Acid Stimulation: 1 trial complete, no to limited injectivity improvement Directional Acid Jetting: implemented in 3 wells, injectivity improvement in early injection FAST: trial planning ongoing Hydraulic Fracturing: trial planning ongoing

This paper discusses the encouraging results and learnings to date with regard to these new technology trials, and the early screening results for the implementation of gas injection as an alternate recovery mechanism.
Efficient Large Volume Acid Fracturing in Openhole Horizontal Well with Pre-Created Circular Notches
Authors: Kayumov Rifat , Arias Urbina Rommel , Bander Khateeb , Aidagulov Gallyam , Chang Fakuen
Published: March 2019

Tight carbonate reservoirs often require acid fracturing stimulation treatments to exploit them economically. In a horizontal well with a long openhole interval across a tight carbonate reservoir, multiple acid fracturing stages might be desirable, however this typically requires permanent completion devices to isolate discrete target intervals into specific stages. Multistage completions face many complications, such as hole-shape dependence, risk of communication between stages, completion deployment risks, and cost. A simplified completion technique was proposed to enable placement of multiple fractures along the openhole reservoir section without a complex completion.

The main challenge in fracturing long openhole horizontal wellbores is limited or lack of control in positioning and orienting initiated fractures. One way to lower the fracturing pressure and force the hydraulic fracture to initiate at one or more desired target depths is to mechanically weaken the formation at specific points along the wellbore. An example of such a weak point is a cavity in the shape of a circular notch cut into the openhole wall. This technique was implemented in a multilateral horizontal water injector well drilled in a tight carbonate reservoir. Four circular notches were cut at predefined depths before stimulation with a goal of creating four separate fractures during one pumping operation. The volume of treating fluids required for the operation was significantly larger compared to a conventional acid fracturing job with only a single fracture propagating. To increase the effectiveness of stimulating all four intervals, degradable particulate diversion material was used during the treatment to temporarily isolate already stimulated fractures and divert treating fluids into less stimulated intervals.

The stimulation treatment was successfully placed after the circular notches were created by coiled tubing using a rotational jetting tool with hydrochloric acid. As the primary result of the circular notching and acid fracturing stimulation, the injectivity index of this well increased almost four times. Temperature, caliper, production, and saturation logs were taken before and after fracturing to evaluate the applied completion approach. These measurements confirmed improved overall injectivity and highlighted areas for further improvements to the new technique, mainly related to preventing overstimulation of untargeted laterals in a multilateral well.
Methodology to Identify Presence of Resin During Post-Fracturing Flowback
Authors: Al-Hulail Ibrahim , Al-Abdullatif Abeer
Published: March 2019

Proppant flowback can cause equipment damage and restrict hydrocarbon production, making it an expensive issue. In response to industry demands for a solution, this paper presents a methodology designed to identify and help prevent flowback issues and to exhibit high cohesive strength to increase the stability of proppant packs.

Liquid resin proppant coating applied during pumping operations shows significant conductivity enhancement and fines control in hydraulic fracturing operations, as compared with traditional curable resin-coated proppant (CRCP). The concentration of resin applied follows proven industry standards. Placement technique and concentration of resin can delay the cure time if needed, which enables the proppant pack to consolidate after placement in the fractures. In addition, it enables the proppant to obtain better grain-to-grain contact in the fracture, and capillary action pulls the liquid resin coating to the contact points of the proppant grains. This process provides a highly cohesive, consolidated proppant pack.

The liquid resin system was designed to be mixed with the proppant immediately before it is added to the fracturing fluid during pumping operations, to consolidate after it is carried into the fracture. Laboratory analysis demonstrates that the resin will prevent fines from flowing back, and it will remain coated on the proppant in the fracture. During the post-treatment cleanout process, a flowback sample was collected and sent to the laboratory to verify that there was no resin content present. The sample was analyzed using Fourier transform infrared (FTIR) spectroscopy, and the resulting spectra were compared to the original resin chart. No resin was present. To confirm the results, a sample of the resin used on the treatment was mixed and analyzed for comparison in FTIR spectra.

This paper describes the methodology to identify the presence of resin during well cleanout and to evaluate the proppant consolidations expected. A new methodology is presented to compare the fluid returned during well cleanup and to evaluate samples in laboratory experiments.
A Novel Method to Determine Kerogen Content of Tight Gas Shale
Authors: Lawal Lateef Owolabi , Mahmoud Mohamed , Adebayo Abdulrauf Rasheed , Syed Rizwanullah Hussaini
Published: March 2019

Reservoir evaluation of source rock is still a challenge because the geochemical assessment of the kerogen content is complicated and time consuming. Existing traditional methods to characterize kerogen involves the removal of inorganic minerals which is a critical preliminary step. The incomplete isolation of kerogen may introduce some errors and uncertainties in kerogen content estimation. The alteration of kerogen microstructure during this process has also been documented. The current approach still requires input from geochemical measurement of total organic carbon (TOC) while the conversion of TOC to kerogen volume requires the precise value of a conversion factor and kerogen density. Overall, there is yet a standard lab or field scale approach to characterize kerogen content. These difficulties and uncertainties prompt the motivation to attempt a new methodology to quantify the kerogen content of unconventional shale from porosity measurements.

Porosity is the basic rock property that is related to the volumetric average of pore space. The distinction between the total and effective porosity is meaningless for shale and this characteristic property has enabled the preservation of its organic content. The recent popularity and growth of different measurement techniques is in part closely tied to the near zero porosity of shale. Two special cases of practical interest are NMR and density porosity measurements which can both be measured in the rock physics lab and well logs. NMR porosity is sensitive to 1H which is naturally enriched in kerogen whereas density porosity must be calibrated to the mineral matrix.

Based on porosity measurements, the emerging aproach is that the kerogen volume fraction is the contrast between NMR and density porosity. Although, the theoretical basis of this approach is not satisfactory, it is straightforward and far less complicated than the existing approaches to quantify kerogen content. We investigate this concept further based on laboratory measurement. We conducted laboratory measurements of NMR porosity, bulk density, grain density and TOC on Qusaiba shale to characterize its kerogen content. In our approach, we conducted the NMR experiment on the shale samples in the dry state without fluid saturation.
Machine Learning in Oil & Gas Industry: A Novel Application of Clustering for Oilfield Advanced Process Control
Authors: Patel Kalpesh , Patwardhan Rohit
Published: March 2019

Data Analytics is an emerging area that involves using advanced statistical and machine learning algorithms to discover information & relationsips present in different types of data. The work described in this paper illustrates the application of machine learning techniques to an Oilfield Advanced Process Control (APC) project involving deployment of APC at a large onshore conventional oilfield in Saudi Aramco. APC implementation enables better control and optimization of the production from hundreds of oilwells.

APC rollout at the large oilfield involved APC deployment on 300+ oil wells. Using conventional APC implementation methodology, the rollout would be very difficult to manage and would have taken about 3 man years which was not practical. Use of innovative data analytics techniques was essential to ensuring the timely deployment of such a large scale APC project. A machine learning algorithm used to cluster similarly behaving wells, enabled significant (80%) reduction in the engineering effort and operator involvement in developing the models for each well. This allowed the implementation to be completed one year in advance thus realizing the APC benefits earlier than planned.
How Over 60% Recovery Achievable in a Multi-Layer, Heterogeneous Sandstone Reservoir
Authors: Lu Xiaoguang , Xu John , Feng Lijing , Yang Qing , Li Guoqiang , Lin Lihua
Published: March 2019

The XB Field in China contains more than 100 thin sand units deposited in a non-marine environment, which results in an extremely heterogeneous sandstone reservoir. Comparison with global field analogs of similar reservoir characteristics indicates that the >60% ultimate recovery in the XB Field is much higher than average. This paper reviews the over 50 years of production history and summarizes its development strategies, successful reservoir management practices, key IOR/EOR technologies and lessons learned, which can benefit efforts of maximizing recovery in other reservoirs.

This paper begins by summarizing the basic reservoir and fluid characteristics as well as the production performance history. This is followed by a benchmarking analysis focused on reservoir heterogeneity, fluid properties and recovery factor against global analog reservoirs. Finally, the authors highlight the development strategy, key IOR/EOR methods, and integrated reservoir management practices based on fit-for-purpose reservoir and remaining oil characterization studies.

The benchmarking study against global analogs shows the XB reservoir to possess much higher heterogeneities and poorer fluid properties than average. The field is expected to achieve an ultimate recovery of more than 60%, which is substantially higher than the average of 36.7% and P50 value of 36% based on global reservoir analog in C&C Reservoirs DAKS. The key IOR methods applied include pressure maintenance through water injection starting at early development stage, infill drilling, and chemical EOR methods. Water injection and infill drilling have helped improve recovery by 30% and 20%, respectively. Water injection optimization has been applied throughout the 50-year production history, focused on by-passed oil or poorly swept areas. Zonal water injection, subdivision of injecting-producing unit, modification injection pattern and cyclic water injection are methods of this category. Other IOR methods, such as horizontal well targeting by-passed oil, profile modification, and fracturing of low permeability reservoir sands also contribute to the high recovery factor. When the field entered the mature production stage, field-wide polymer and ASP flooding have been implemented based on numerous laboratory studies and pilot tests. The chemical EOR application in this field is one of the most successful cases in the world. Polymer flood and ASP flood are expected to achieve incremental recovery factor of 10% and 20%, respectively.

The XB Field case suggests that many mature fields in the globe have the potential to further improve their recovery. Most of the technologies discussed in this paper are well established, conventional, inexpensive and readily available. The key point is that detailed reservoir characterization, remaining oil identification and application of lessons learned from global analogs are of prime importance.
Beyond One-Dimensional Evaluations: The Search for Genetic Reservoir Regions through Time & Space
Authors: Hadidi Shahab , Yaarubi Hilal , Baaske Uwe , Suwannathatsa Sakharin , Farsi Shadia , Bazalgette Loic , Hamdoun Lana
Published: March 2019

The infill potential of one of the most complex fractured carbonate reservoirs in the Sultanate of Oman has been evaluated through the integration, visualization and analysis of different data sources. The field has been split into different simplified genetic geobodies which contain the culmination of facies changes that define rock quality, fluid fill, oil saturation distribution and fracture network, amongst other properties that affect fluid flow. The long production history of more than 45 years, along with the large number of logged long horizontal wells scattered around the field, were key enabler for the analytical methodology.

Production data, coupled with resistivity logs in horizontal wells, viewed through time were the backbone of the analysis. Data analysis was achieved by combining these data in a single platform and performing the analysis at different slices of time. At each timeslice, different interpretations were inferred that explain the observed production behaviour and remaining oil saturation from the logged wells. The interpretations were narrowed down into a minimum number of realizations by combining interpretations from the same area gathered from different slices of time.

The analysis has resulted in the identification of four genetic performance regions in the field. Each region approximates a primary depositional facies belt and has a general defined relative behaviour of initial wells potential, water-cut development, initial and remaining oil saturation and, most importantly, infill wells potential. The analysis has aided in narrowing the subsurface uncertainties and has given a promising explanation for the large variations in wells behaviour. Infill wells opportunities have been identified, selected and ranked relatively in each of the regions.

The value of data analytics on large volumes of acquired information normally not used was demonstrated. Visualization of different data sources in one platform is a challenging task that usually stops engineers from experimenting. The team has found fit for purpose solutions to visualize different data sources through time. The shift of mind-set from uncertain complex models and evaluations into finding simple genetic performance regions of the reservoir was vital in unravelling infill potential.
A Review of Pulse Fracturing Treatment: An Emerging Stimulation Technique for Unconventional Reservoirs
Authors: Tariq Zeeshan , Mahmoud Mohamed , Abdulraheem Abdulazeez , Al-Nakhli Ayman , Bataweel Mohammed
Published: March 2019

The enormous resources of hydrocarbons hold by unconventional reservoirs across the world along with the growing oil demand make their contributions to be most imperative to the world economy. However, one of the major challenges faced by oil companies to produce from the unconventional reservoirs is to ensure economical production of oil. Unconventional reservoirs need extensive fracturing treatments to produce commercially viable hydrocarbons. One way to produce from these reservoirs is by drilling horizontal well and conduct multistage fracturing to increase stimulated reservoir volume (SRV), but this method of increasing SRV is involved with higher equipment, material, and operating costs.

To overcome operational and technical challenges involved in horizontal wells multistage fracturing, the alternative way to increase SRV is by creating multiple radial fractures by performing pulse fracturing. Pulse fracturing is a relatively new technique, can serve as an alternative to conventional hydraulic fracturing in many cases such as to stimulate naturally fractured reservoirs to connect with pre-existing fractures, to stimulate heavy oil with cold heavy oil production technique, to remove condensate banking nearby wellbore region, and when to avoid formation damage near the vicinity of the wellbore originated due to perforation. Pulse fracturing is not involved with injecting pressurized fluids into the reservoir, so it is also a relatively cheaper technique.

The purpose of this paper is to present a general overview of the pulse fracturing treatment. This paper will give general idea of the different techniques and mechanisms involved in the application of pulse fracturing technique. The focus of this review will be on the comparison of different fracturing techniques implemented normally in the industry. This study also covers the models developed and applied to the simulation of complex fractures originated due to pulse fracturing.
Development of A New Chemical Treatment for Removing Water Blockage in Tight Reservoirs
Authors: Hassan Amjed , Mahmoud Mohamed , Al-Majed Abdulaziz , Alade Olalekan , Al-Nakhli Ayman , BaTaweel Mohammed , Elktatany Salaheldin
Published: March 2019

In petroleum industry, great challenges are associated with producing hydrocarbon from unconventional reservoirs. Tight reservoirs are characterized with low permeability which reduces the hydrocarbon flow into the wellbore. Water blockage is considered as a potential damage issue in tight reservoirs due to increasing the water saturation around wellbore region and eventually decreasing the relative permeability of hydrocarbons. Acid fracturing or hydraulic fracturing are required to remove the damage and enhance the formation conductivity. The objective of this paper is to propose a new technique to remove the water blockage from tight formations using thermochemical treatment. Chemicals that generate pressure and heat at reservoir conditions are used to remove the water bank from tight core samples.

Coreflooding experiments, capillary pressure and NMR measurements were conducted as well as routine core analysis. The impact of thermochemical treatment on improving the formation productivity was quantified. The effect of thermochemical injection on rock integrity was analyzed by evaluating the pore geometry before and after the chemical treatment. Thermochemical treatment resulted in a significant improvement in the core conductivity. NMR indicated that, tiny fractures were created in the core samples due the thermochemical flooding. Capillary pressure measurements showed that, the capillary pressure was reduced by 55.6% after the chemical treatment.

The results of this study highlight that water blockage is great challenge in tight gas reservoirs. Injecting thermochemical fluids into tight samples reduces the capillary forces significantly, which leads to remove the water accumulation. Therefore, considerable enhancement was observed in the rock conductivity. This study provides a novel approach for removing the water blockage from tight formations using environmentally friendly chemicals. Chemicals that generate heat and pressure at downhole conditions were used to create tiny fractures. This treatment was able to remove the water blockage from tight sandstone cores and improve the productivity index by reducing the capillary forces.
The Role of Transient Perturbations and Heterogeneities in Subsurface Wave Propagation - A Scalable Numerical Solution
Authors: San-Roman-Alerigi Damian
Published: March 2019

The objective of this work is to present the development of a numerical model for wave propagation in materials with time-varying, heterogeneous, and non-linear properties. Materials change with time as the result of complex linear and non-linear processes, which can occur due to natural causes or induced. Wave phenomena in this context brings about an interesting and complex problem, which involves the solution to coupled equations which describe interlinked multiphysics phenomena. Thus, understanding the dynamics of this interaction is beneficial to numerous applications across different industries and applied research; e.g. acoustic characterization of moving fluids, laser-fluid interaction, distributed optical fiber sensing, photonic integrated systems, among others. Numerical models, therefore, are indispensable to gain a deeper insight about the physical dynamics of the process and, ultimately, purvey a platform to design and test new applications and technologies.

Over time some numerical models have been proposed to simulate wave phenomena in these situations. The method and solution reviewed in this work provides a unique solution to develop and optimize multiple applications. For example, it can be used to model the interaction of electromagnetic waves with travelling Bragg mirrors produced by temperature or pressure changes in optical fibers, which is the basis of fiber-based distributed fiber sensing; the scattering of acoustic waves by transient disturbances in fluid flow that may arise from gas bubbles or variations in the density of fluids; and the propagation of an electromagnetic pulse in a rapidly moving and varying fluid.

The mathematical description of the process was derived originally for electromagnetics; yet, the numerical solver and mathematical treatment is generic and can be applied to other wave phenomena. The derivation departs from physical principles to write a generalized set of equations that describe wave propagation in time-varying, heterogeneous, and non-linear materials. The resulting set of hyperbolic partial differential equations (PDE) includes diffusive and convective terms that fully describe the wave interaction and process. Linear and nonlinear spatial and time heterogeneities in the material are assimilated into the convective terms of the hyperbolic wave equation. The solver was implemented using a semi-discrete and multidimensional scheme based in the finite-volume method which is highly scalable. Extension to other wave phenomena is discussed by analyzing the parameter correspondence for the acoustic and electromagnetic case.