bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanosensitivity of cell membrane may govern creep-strain recovery, osmotic expansion and lysis.
Authors: Pawłowski Piotr H
Published: March 2019

A simple theoretical model considering cell membrane mechanosensitivity can accurately describe published experimental data on membrane area creeping and recovery, and on osmotic expansion and rupture. The model to data fit reveals real values of membrane tension and elasticity modulus, and the parameters describing membrane organization and kinetics of mechanosensitive membrane traffic, including small solute transport, water permeability, endocytosis, exocytosis, and caveolae formation. This estimation allows for separation and quantitative analysis of the participation of different processes constituting the response of plasmalemma to short time-scale membrane load. The predicted properties of the model were verified for membrane stretching at different osmotic pressures. Finally, a simple hypothesis concerning stressed cell membrane breakdown is postulated.
Bradykinin-related peptides up-regulate the expression of kinin B1 and B2 receptor genes in human promonocytic cell line U937.
Authors: Guevara-Lora Ibeth , Florkowska Magdalena , Kozik Andrzej
Published: March 2019

Kinins, universal mediators of inflammation, are recognized by two kinds of receptors, B1 and B2, which have been found to be expressed in numerous cell types of several species. However, the knowledge of the regulation of these receptors in leukocytes is still not satisfactory. In the current work, we have demonstrated a constitutive production of B2 receptor mRNA in the human promonocyte U937 cells and its two-fold augmentation after cell differentiation with retinoic acid and phorbol ester. Bradykinin and des-Arg(10)-kallidin induced the expression of both B2 and B1 receptors in cells before and after differentiation. Generally, the undifferentiated cells were more susceptible to bradykinin-dependent induction of kinin receptors (increases by approximately 250% and 200% for B2 and B1 receptors, respectively). The induction, by approx. 200%, of B1 receptor by des-Arg(10)-kallidin was detected on both mRNA and protein levels. In addition, an unexpected strong induction of B2 receptor by this compound was observed in the retinoic acid- and phorbol ester-differentiated cells (by 150% and 200%, respectively) that suggests a possible autoregulation of kinin receptors by own agonists during the inflammatory state. On the other hand, a strong enhancement of the expression of both receptors by interleukin 1beta, especially in the phorbol ester-differentiated cells, indicates the involvement of kinin receptors in the propagation of the inflammatory processes.
A newly identified Thr99fsX110 mutation in the PMP22 gene associated with an atypical phenotype of the hereditary neuropathy with liability to pressure palsies.
Authors: Moszyńska Izabela , Kabzińska Dagmara , Sinkiewicz-Darol Elena , Kochański Andrzej
Published: March 2019

Hereditary neuropathy with liability to pressure palsies (HNPP) is manifested by a spectrum of phenotypes, from the classical HNPP course associated with intermittent nerve palsies to a neuropathy resembling Charcot-Marie-Tooth type 1 (CMT1) disease. The majority of HNPP cases are associated with submicroscopical deletions in the 17p11.2-p12 region containing the PMP22 gene, while PMP22 point mutations are rare, representing about 15% of HNPP cases. In this study, we present a patient manifesting with atypical HNPP phenotype associated with a new Thr99fsX110 mutation in the PMP22 gene. We conclude that all patients who fulfill the electrophysiological criteria of HNPP, even if they lack the typical HNPP phenotype, should be tested for point mutations in the PMP22 gene.
Gelsolin in human colon adenocarcinoma cells with different metastatic potential.
Authors: Litwin Monika , Mazur Antonina J , Nowak Dorota , Mannherz Hans G , Malicka-Błaszkiewicz Maria
Published: March 2019

Gelsolin, one of a major actin-binding proteins, is involved in the regulation of actin cytoskeleton organization by its severing and capping activity towards actin filaments. Human colon adenocarcinoma cell line LS180 and its selected variants of different metastatic potential were used to check for a correlation between gelsolin level, its subcellular localization and the invasive capacity of cells. Based on immunoblotting experiments, a decreased level of gelsolin was detected in the most invasive 5W subline when compared to the parental cell line LS180. The intracellular distribution of actin filaments and gelsolin in colon adenocarcinoma cells was examined by confocal microscopy. In the 5W subline, unlike in the other examined cells, gelsolin was colocalized with filamentous actin at the cell periphery. In summary, in human colon adenocarcinoma cells, gelsolin level and its subcellular distribution seem to correlate with their metastatic potential.
Diphenyl diselenide and diphenyl ditelluride increase the latency for 4-aminopyridine-induced chemical seizure and prevent death in mice.
Authors: Brito Verônica B , Rocha João Batista T , Folmer Vanderlei , Erthal Fernando
Published: March 2019

In this work was investigated the effect of pre-treatment with (PhSe)(2) and (PhTe)(2) on chemical seizure and 4-aminopyridine-induced lethality in mice. Additionally, lipid peroxidation levels of whole brain after treatment with 4-aminopyridine and effect of pre-treatment with (PhSe)(2) and (PhTe)(2) on these levels were investigated. Mice were pre-treated with (PhSe)(2) or (PhTe)(2) (50, 100, or 150 micromol/kg) 30 min before 4-aminopyridine (12 mg/kg) administration. The treatment with 4-aminopyridine caused a significant incidence of seizures (clonic, tonic) and death. Pre-treatment with (PhSe)(2) and (PhTe)(2) significantly increased the latency for clonic and tonic seizures, and prevented 4-aminopyridine-induced death. Significantly, the pre-treatment with (PhSe)(2) or (PhTe)(2) increased the latency for clonic seizures in a dose-dependent manner. Additionally, a significant increase was observed in the brain lipid peroxidation level after treatment with 4-aminopyridine, which was significantly inhibited by pre-treatment with 150 micromol/kg (PhSe)(2) or (PhTe)(2). These results demonstrate that (PhSe)(2) and (PhTe)(2) counteract the harmful effects of 4-aminopyridine. It is possible that this effect results from modulation of the redox state of N-methyl-d-aspartate receptors and/or of Ca(2+) channel activity with subsequent alteration in neurotransmitter release. Importantly, this study provides evidence for anticonvulsant and antioxidant properties of (PhSe)(2) and (PhTe)(2), which indicates a neuroprotective activity of these compounds.
Reseña: Guerrero, María Paz. (2018). Dios también es una perra.
Authors: Carvajal Franklin Juan
Published: March 2019

Reseña: Guerrero, María Paz. (2018). Dios también es una perra.
Application of Machine Learning Techniques to Predict Mechanical Properties for Polyamide 2200 (PA12) in Additive Manufacturing
Authors: Baturynska Ivanna
Published: March 2019

Additive manufacturing (AM) is an attractive technology for manufacturing industry due to flexibility in design and functionality, but inconsistency in quality is one of the major limitations that does not allow utilizing this technology for production of end-use parts. Prediction of mechanical properties can be one of the possible ways to improve the repeatability of the results. The part placement, part orientation, and STL model properties (number of mesh triangles, surface, and volume) are used to predict tensile modulus, nominal stress and elongation at break for polyamide 2200 (also known as PA12). EOS P395 polymer powder bed fusion system was used to fabricate 217 specimens in two identical builds (434 specimens in total). Prediction is performed for XYZ, XZY, ZYX, and Angle orientations separately, and all orientations together. The different non-linear models based on machine learning methods have higher prediction accuracy compared with linear regression models. Linear regression models have prediction accuracy higher than 80% only for Tensile Modulus and Elongation at break in Angle orientation. Since orientation-based modeling has low prediction accuracy due to a small number of data points and lack of information about material properties, these models need to be improved in the future based on additional experimental work.
Entropic Description of Gravity by Thermodynamics Relativistic Fluids and the Information Theory
Authors: Baudrimont Roman
Published: March 2019

The purpose of this paper is to show a new approach to unify the theory of general relativity and quantum physics. For this, we rely on thermodynamics, fluid mechanics and the theory of information. We will then see that the Shannon entropy, Boltzmann and Von Neumann can be the source of gravity, which would be a form emerging. For this, we will study at first what is lacking for the unification of general relativity and physics. Secondly, we will explain the concept of entropic gravity by introducing calculations Erik Verlinde. Then we will explain the concept of entropy Boltzmann, Shannon, Von Neumann and the links between them. Then, we will modify Einstein's equations by transforming the tensor of perfect fluid in terms of entropy. Finally, we will link our theory with experience already carried out as part of a link between gravity and quantum theory.
¿POR QUÉ EL CIRUJANO DE PARED ABDOMINAL DEBERIA OPERAR LA DIASTASIS DE RECTOS?
Authors: Cuccomarino Salvatore
Published: March 2019

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THD and Compensation Time Analysis of Three-Phase Shunt Active Power Filter Using Adaptive Spider Net Search Algorithm (ASNS) for Aircraft System
Authors: Khalid Saifullah
Published: March 2019

A novel Adaptive Spider Net Search Algorithm (ASNS) has been presented, which has been used for the optimization of conventional control scheme used in shunt active power filter for aircraft system. The superiority of this algorithm over existing Genetic Algorithm results has been presented by analyzing the THD and compensation time of both the algorithms. The simulation results using MATLAB model ratify that algorithm has optimized the control technique, which unmistakably prove the usefulness of the proposed algorithm in aircraft supply system.
Machine Learning Application for Oil Rate Prediction in Artificial Gas Lift Wells
Authors: Khan Mohammad Rasheed , Alnuaim Sami , Tariq Zeeshan , Abdulraheem Abdulazeez
Published: March 2019

Well production rate is one of the most critical parameters for reservoir/production engineers to evaluate performance of the system. Given this importance, however, monitoring of production rates is not usually carried out in real time. Some cases flowmeters are used which are known to carry their own inherent uncertainties. The industry, thus, relies on the use of correlations to allocate production to wells. Over time, it has been realized that the generally used correlations are not effective enough due to multiple technical and economic issues.

The focus of this work is to utilize machine learning (ML) algorithms to develop a correlation that can accurately predict oil rate in artificial gas lift wells. The reason for using these algorithms is to provide a solution that is simple, easy to use and universally applicable. Various intelligent algorithms are employed, namely; Artificial Neuro Fuzzy Inference Systems (ANFIS), and Support Vector Machines (SVM), along with the development of Artificial Neural Network providing a usable equation to be applied on any field, hence demystifying the black-box reputation of artificial intelligence. In addition, non-linear regression is also performed to compare the results with ML methods.

Data cleansing and data-reduction were carried out on the dataset comprising of 1500 separator test points. This practice yielded in only the common wellhead parameters to be used as input for the model. All ML models were compared with the non-linear regression model and with previously derived empirical models to gauge the effectiveness of the work. The newly developed model using ANN shows that it can predict the flow-rate with 99% accuracy. This is an interesting outcome, as such accuracy has not been reported in literature usually.

The results of this study show that the correlation developed using ANN outperforms all the current empirical correlations, moreover, it also performs multiple times better in comparison to previously developed AI models. In addition, this work provides a functional equation that can be used by anyone on their field data, thereby removing any ambiguities or confusion related to the concept of artificial intelligence expertise and software. This effort puts forth an industrial insight into the role of data-driven computational models for the production reconnaissance scheme, not only to validate the well tests but also as an effective tool to reduce qualms in production provisions.
The Geology and 3D Modelling of the Cliff Head Oil Field, Australia
Authors: Eshmawi Yosuf
Published: March 2019

The Cliff Head is one of the most significant discoveries in the offshore Northern Perth Basin. Hence, understanding the structure and geology of the field is essential to further evaluate the offshore region in the basin. Two structural models were developed with the objective to achieve a better understanding of this field. The first model is focused on the Permian and older strata, while the second model is for the overburden. In addition, reservoir properties models (e.g. porosity model and water saturation model) were developed to better understand the reservoir facies and hydrocarbon distribution. Examination of the structural models has shown that there are two main sets of faults within the Cliff Head area, which can be categorized into the following: the deep Permian faults that are truncated against the Late Permian unconformity, and younger Cretaceous faults that were developed during the Early Cretaceous rifting. It has also shown that the oil accumulation within the field is structurally trapped within Permian aged set of horsts and is mainly reservoired within the Irwin River Coal Measures. The secondary target (e.g. the underlying High Cliff Sandstone) is mostly beneath the regional oil-water contact of −1257.8 m TVDss, except in the highest structural point in the field, where Cliff Head-6 was drilled. The Irwin River Coal Measures in the study area contained four high resolution depositional sequences that displayed a finingupward pattern as depicted by the Gamma Ray log response and are interpreted to have mainly deposited in a fluvial depositional system. The High Cliff Sandstone, in contrast, contained two high resolution depositional sequences that displayed a coarsening upward sequences as supported by Gamma Ray log response and were interpreted to have mainly deposited in marginal marine settings. Reservoir properties modeling was also conducted utilizing the 3D models, where a 3D porosity model was calculated and shows that the Irwin River Coal Measures, in general, exhibit higher porosity distribution than the underlying High Cliff Sandstone, even though the later has coarser and more laterally extensive sand sheets. This is probably attributed to diagenetic porosity reduction within the High Cliff Sandstone caused by the formation waters. The calculated 3D water saturation model also confirms the presence of a single regional oil-water contact within the field and hence, reservoir heterogeneities and fault seal capacities did not affect the hydrocarbon distribution within the field. Finally, all the calculated models (e.g. lithofacies model, porosity model, and water saturation model) were integrated to estimate the recoverable hydrocarbons in place, where the Cliff Head is estimated to contain a total of 15.2 million barrels.
Research and Application of Rod/Tubing Wearing Prediction and Anti-Wear Method in Sucker Rod Pumping Wells
Authors: Zhao Ruidong , Li Jinya , Tao Zhen , Liu Meng , Shi Junfeng , Xiong Chunming , Huang Hongxing , Sun Chengyan , Zhang Yufeng , Zhang Xiaowen
Published: March 2019

With the development of many kinds of oilfields, deep well, high deviated well and cluster well are increasing rapidly. Sucker rod pumping still remains a major artificial lift method. There are such problems as severe rod/tubing wearing and shortened rod/tubing life in high deviated rod-pumped wells, and the mechanism and prevention of rod/tubing wearing have not been understood properly.

In order to understand the mechanism of rod/tubing wearing, a lateral load calculation model of rod/tubing is solved in this paper. The calculation results show that both the magnitude and direction of lateral force change dynamically with time and space in one stroke cycle. To better describe the rod/tubing wearing phenomenon, the lateral load is divided into two parts: the primary normal vector related to wellbore trajectory and axial force, and the secondary normal vector only related to wellbore trajectory and invariant with time.

The three-dimensional and dynamic nature of lateral force can account for the rod/tubing wearing partially. The results of mathematical model show that the magnitude of lateral force at the same depth may differ greatly at different times, and its direction may also change periodically. It is likely to be bidirectional rod/tubing wearing when the primary normal force direction changes periodically. Simulation results show that the direction of lateral force is very likely to change periodically below the neutral point of rod string. This finding has accounted for the common double-faced and multi-faced rod/tubing wearing on the lower rod string. The periodic change of lateral force direction will cause rod/tubing collision, which is also an important cause for the rod/tubing wear below the neutral point. It is assumed qualitatively that the production parameters such as pump depth, stroke, stroke frequency and pump diameter are the major factors of the rod/tubing wearing according to field experience. In this paper, mathematic model is used to analyze the impact of these parameters on lateral force and the quantitative analysis is also conducted which provide theoretical foundation for the design of anti-wear production parameters.

The mathematic model and method proposed in this paper are favorable to better accounting for the important phenomenon of rod/tubing wearing in rod-pumped deviated wells. They are capable of the quantitative calculation of lateral forces under different parameter conditions and the anti-wear design. This model has been applied to hundreds of highly deviated wells at Jidong Oilfield, prolonging rod/tubing life 58 days in average.
Drilling Process Digitalization Using Advanced Machine Learning Techniques – Case Study
Authors: Shayaa Adel Al , Tamimi Khaled Al , Bakhti Sara , Arnaout Arghad , Thonhauser Gerhard
Published: March 2019

The digital era is upon us in the oil and gas industry, enforcing the importance of integrating this novel concept of digital transformation is mandatory to improve the overall efficiency of the drilling process. The advances in Artificial Intelligence for the industry, and the methodology of how these solutions can be implemented will be addressed in this paper.

The digital transformation of drilling will provide an unprecedented stream of high-quality information that has never been accomplished in the industry, through the utilization of automated real-time drilling downhole tools, data analytics and predictive analysis.

Therefore, a real-time measurement and processing technology based on automated rig activities detection was established to improve the performance of the rig crew and drilling operations of an international operating company. A monitoring process was implemented for all drilling operations and benchmarked against operational Key Performance Indicators (KPIs).
Assessing the Effect of Micronized Starch on Rheological and Filtration Properties of Water-Based Drilling Fluid
Authors: Elkatatny Salaheldin
Published: March 2019

Drilling Fluids rheological properties play a vital role in controlling the success of the drilling operation. Rheological parameters such as effective (or apparent) viscosity, yield point (YP), gel strength, and plastic viscosity (PV) are very important for rig hydraulic calculations and hole cleaning efficiency. The water-based drilling fluid (WBDF) consists of a mixture of different solids and polymers which are used to optimize the rheological properties. Starch is a resistance-solid additive which is used mainly to control the filtration properties and at the same time to increase the viscosity of the drilling fluid.

The main goal of this research is to evaluate the effect of using micronized starch (1 μm) on the rheological and filtration properties of water-based drilling fluid. Field emission scanning electron microscope (FESEM) was used to evaluate the starch at different particle size. Rheological properties for the drilling fluid with different starch sizes were measured at ambient condition using Fan VG rheometer while the high-pressure high-temperature (HPHT) filter press was used to conduct the filtration experiment at 200°F.

It was noted that micronized starch (1 μm) had a vital effect on the rheological and filtration properties of WBDF. The PV of the WBDF with micronized starch was increased by 158% while the YP was increased by 125% as compared with the starch of conventional size (60 μm). The apparent viscosity (AV) was increased by 137% after reducing the starch sized to 1 μm. Adding the micronized starch for the WBDF resulted in flat rheology behavior where there is no increase in the gel strength between 10 seconds and 10 minutes. The filter cake thickness was reduced by 63% while the cumulative filtrate volume was decreased by 52% when 1 μm starch is used.

This study introduced a new drilling fluid formulation that contains a micronized starch as an additive, which will help the drilling engineers to avoid many drilling issues especially the formation damage by forming an ideal filter cake.
Fundamental Behaviors and Borehole Deformation on Wellbore Stability and Sand Production in Conventional and Hydrates-Bearing Gas Reservoirs
Authors: Wang Yarlong
Published: March 2019

A general formulation for a coupled Thermal-Hydraulic-Mechanical with hydrate Dissociation (THMD) system is developed and applied to sand prediction for conventional gas and gas hydrate bearing sediments (GHBS). Two-phase fluid and conductive heat flow are coupled to an elastoplastic geomechanics model. Series of solutions for simplified models are presented. Fundamental geomechanics behaviors before and after plastic yielding, sanding, and gas hydrate dissociation are defined, discussed, and simulated differently and sanding onset for both conventional gas formations and GHBS are defined by an effective plastic strain (EPS) criterion. The accuracy and reliability of the proposed conventional model are verified by comparing the model prediction with the results of hollow cylinder tests on two different types of sandstone. The advantages of using the EPS over stress-based criteria as an indicator for onset of borehole collapse and sand production are discussed. Introducing a moving gas hydrate dissociation zone (front), the fundamental geomechanics behaviour and elastoplastic deformation of the skeleton formation are highlighted. The effects on sand prediction due to the characteristics of non-linear plastic yielding criteria and gas flow in porous media are also emphasized.
Surfactant-Polymer Feasibility for a Sandstone Reservoir in Kuwait. Successful Integrated Approach from Laboratory to Pilot Design
Authors: Al-Murayri Mohammed , Hassan Abrahim , Hénaut Isabelle , Marlière Claire , Mouret Aurélie , Lalanne-Aulet David , Sanchez Juan-Pablo , Suzanne Guillaume
Published: March 2019

This study presents an integrated approach to design a fit-for-purpose surfactant-polymer process for a major sandstone reservoir in Kuwait. The adopted procedure is described covering core flood experiments through pilot design using a reservoir simulation tool that was calibrated using laboratory results.

The surfactant-polymer formulation design was already described in another publication (SPE-183933). In this paper, further optimization of the chemical formulation is described, including core floods to minimize the quantity of the injected chemicals while maintaining high oil recovery. Formulation robustness and its impacts on water-oil separation at the surface are also evaluated. Furthermore, reservoir simulation was utilized to design a field trial. At first, the parameters that were used to model surfactant-polymer performance were calibrated using core flood results. Then, the reservoir simulation model was used at a larger scale to identify the most appropriate injection sequence for field implementation.

The performance of the designed surfactant-polymer formulation is promising. Core flood experiments demonstrate that the injection of the chemical formulation recovers more than 85% of the remaining oil after waterflooding, while having relatively low adsorption values. The designed formulation was also found to be quite resilient to variations in divalent cations concentration, water-oil ratio and oil composition. It was noticed that rock facies heterogeneity has a limited effect on surfactant adsorption. Favorable phase behavior properties were maintained around reservoir temperature and the formulation exhibited good aqueous stability between reservoir and surface temperatures. EOR parameters including salinity-dependent surfactant adsorption, capillary desaturation and polymer-induced water mobility reduction were calibrated in the reservoir simulation model using core flood data. Larger scale reservoir simulation enabled the design of a suitable injection sequence including a main surfactant-polymer slug followed by a polymer slug. The main variables of the design, including slug injection durations, chemical concentrations and pattern size were optimized through numerous sensitivity scenarios. Using a 5-spot pattern with a spacing of 75 m, surfactant-polymer injection effects should be observed within a short timeframe of around 14 months.

This paper describes a successful approach to design a surfactant-polymer process, integrating laboratory experiments and reservoir simulation. This work paves the way for a 5-spot EOR pilot involving a major sandstone reservoir and will undoubtedly provide valuable insights for chemical EOR applications in similar reservoirs elsewhere.
Increase in Oil Production: Methodology & Best Practices for Hydraulic Fracturing Candidate Selection and Execution in Assam-Arakan Basin
Authors: Mukku Vinil , Lama Tshering , Verma Sanjay , Kumar Pankaj , Bordeori Krishna , Chatterjee Chandreyi , Kumar Arvind , Mishra Siddharth , Sharma Lovely , Batshas Siddhanta , Shah Arpit , Prasad C. B. , Pathak Digantha , Saikia Partha Protim
Published: March 2019

Hydraulic fracturing can establish well productivity in tight and unconventional reservoirs, accelerate production in low- to-medium permeability wells and revamp production in mature wells. However, not all wells are suitable candidates for hydraulic fracturing and the technique can be detrimental if the right candidate is not chosen. An integrated approach is required to select the wells that are the most-suitable candidates for hydraulic fracturing.

This paper discusses the hydraulic fracturing candidate selection workflow and execution carried out in the year 2015 to 2016, which has unlocked reservoir production potential of Upper Assam basin fields of Oil India Ltd. (OIL). Wells which showed poor/no inflow prior to hydraulic fracturing operations, exceeded operator expectations during post fracturing production. Better reservoir management through hydraulic fracturing, rejuvenated ceased wells with an incremental oil production rates of 1380 bopd cumulative rate from six wells, post fracturing. The candidate analysis workflow described in this paper, can serve as the best practices guide for any operator investigating workover candidates among multiple fields, with an objective of production enhancement.

A customized candidate selection methodology was developed to identify the 10 best candidates from a pool of 70 vertical/deviated wells in two phases of the hydraulic fracturing campaign. In the absence of dynamic reservoir analysis, offset well data analysis assisted in filling the data gaps by enabling geological and reservoir level understanding. Well production models were calibrated with the production history, geo-mechanical models were prepared and used in the fracture modelling to generate optimum fracture geometry and predict post-fracturing production. Wells were ranked according to incremental hydrocarbon production coupled with risk factors including completions integrity. In the execution, fracturing model was validated by performing fracturing diagnostics tests such as Step Rate and Minifrac injection. The final calibrated model was then used to design the optimum fracturing treatment. Given the age of wells and traditional completions architecture, best practices were developed to counter challenges of high pressures and rate limitations in wells with depth greater than 3500 m.

As stimulations and well preparation in completed wells are expensive, it was critical to identify the most-suitable candidates with the available dataset before attempting well preparation and further acquisition. This was addressed through a customized workflow to perform production rate transient analysis for reservoir dynamic flow properties, create synthetic geomechanical models for stress profile & fracture vertical growth estimation.
Integrating Production and Formation Pressure Testers Analysis for Field Development in Complicated Carbonate Reservoir
Authors: Matar Omar , Al Janahi Ahmad , Engineer Yusuf , Ali Eyad
Published: March 2019

For mature oil fields with complicated reservoir architecture, reservoir surveillance is key to track reservoir performance. Reservoir surveillance may include various monitoring tools from complicated horizontal production logging tools down to regular well tests. One of the main surveillance methods is running formation pressure measurement tools such as Formation Pressure Testers (FPT) or as historically known to the industry, Repeated Formation Tester (RFT). This paper describes the use of this important tool integrated with production data to understand reservoir production and depletion behavior and hence support the Bahrain Field development plan.

A study was conducted on the Ostracod and Magwa reservoirs; complicated carbonate reservoirs in the Bahrain Field. The Ostracod Zone is a sequence of inter-bedded limestone and shale in the upper Rumaila formation of the middle Cretaceous Wasia group. It is over 200 feet thick and consists of three main units: B0, B1, and B2. The Magwa reservoir is the lower member of the Rumaila Formation. It is 120 feet thick and conformably underlies the Ostracod reservoir. It consists of three main units: M1, M2, and M3.

The main objectives of this study are:

Evaluating pressure depletion from the initial reservoir pressure for each unit in both reservoirs, which defined the existence of flow barriers in this inter-bedded complicated carbonate. Evaluating the relationship between pressure depletion in each unit and the spacing between offset wells to the FPT location. Evaluating the Ostracod/Magwa pressure depletion per unit with time. Linking the pressure depletion to the cumulative production from the area offset by the FPT data.

The results of this study helped define the depletion risk on the future infill opportunities in such complicated reservoirs. It also helped in locating highly depleted units and determining the optimal locations for the new infill wells.
Beyond Steel Casing: Detecting Zonal Isolation in the Borehole Environment
Authors: Eltsov T. , Patzek T. W.
Published: March 2019

Electrically resistive composite casing materials are being introduced to the oil & gas industry. Resistive casing enables electromagnetic logging for exploration and reservoir monitoring, but it requires development of new logging methods. Here we present a technique for the detection of integrity of magnetic cement behind resistive casing. We demonstrate that an optimized induction logging tool can detect small changes in the magnetic permeability of cement through a non-conductive casing in a vertical (or horizontal) well. We can determine both integrity and solidification state of the cement filling annulus behind casing. Changes in magnetic permeability influence mostly the real part of the vertical component of magnetic field. The signal amplitude is more sensitive to a change of magnetic properties of the cement, rather than the signal phase. Our simulations show that optimum separation between the transmitter and receiver coils ranges from 0.25 to 0.6 meters, and the most suitable magnetic field frequencies vary from 0.1 to 10 kHz. A high-frequency induction probe operating at 200 MHz can measure the degree of solidification of cement. The proposed method can detect borehole cracks filled with cement, incomplete lift of cement, casing eccentricity and other borehole in homogeneities.
New Approach of Synergizing Advanced Well Test Deconvolution, Rate Transient Analysis and Dynamic Modeling in Evaluating Reservoir Compartmentalization Uncertainty at K Field in Sarawak Basin; A Case Study
Authors: Hj Azlan Ali Al-Amani , Wan Muda Wan Mohd , Mubaraki Alireza Hajizadeh , M Khir Khairul Ezee , M Sahid Norhayati , M Zakei Amran
Published: March 2019

This paper presents the result of synergizing advanced well test deconvolution, rate transient analysis and detailed reservoir modeling to answer the compartmentalization uncertainty demonstrated by downhole pressure data in K field located offshore Sarawak, Malaysia. The gas reservoir is well distributed within approximately 10 × 20 km area and divided into two fault blocks, east and west. The development only focused at eastern area. Based on earlier assessment during Field Development Plan (FDP) stage, no fault has been seen from seismic data interpretation within east area. However, the six years actual performance of the field address different understanding which suggesting possible compartmentalization. Several assumptions were made to reconcile the connected hydrocarbon initially in–place estimated from conventional material balance and static volumetric calculation, however it has led to inconclusive results. The paper draws on the strength of an integrated reservoir engineering studies that include analytical and numerical analysis. The general framework covers advanced well test deconvolution analysis which multiple Pressure Build Ups (PBUs) and flowing duration were interpreted. This helps in guiding reservoir characterization understanding further from the well and type of fault setting within the reservoir. In addition, Rate Transient Analysis (RTA) has been conducted to estimate the connected volume. Several interesting findings will be shared in this paper as well.

The combination of these deconvolution and RTA works enhanced the understanding of reservoir compartmentalization which guided the history matching process done through dynamic model. The newly established workflow has reduced the efforts required in history matching process and gave clearer picture of the uncertainty of reservoir compartmentalization.
Reservoir Pore-Throat Characteristics Evolution During Waterflooding: A Theoretical Study
Authors: Lei Gang , Liao Qinzhuo , Patil Shirish
Published: March 2019

During waterflooding, pore-throat structure of the porous media in the reservoir changes continually, which causes the great challenge in reservoir modeling and simulation. However, through the evolution mechanism of pore-throat characteristics for the reservoir during waterflooding has been intensively investigated in the past several decades, the essential controls on pore-throat structure evolution of reservoir rocks are not studied much. It is of theoretical and practical significance to use analytical methods to study the evolution of pore-throat characteristics of porous media during waterflooding. However, because of the disordered and extremely complicated microstructures of porous media, the theoretical model for stress sensitivity is scarce. The objective of this work is to establish a novel and reasonable quantitative model to determine the essential controls on pore-throat structure evolution of reservoir rocks. The theoretical model is derived from the fractal geometry. The predictions from the proposed model agree well with the available experimental data presented in the literature, which verified the novel quantitative model. There is no empirical constant and every parameter in the model has specific physical significance. In addition, the evolution rule for the pore-throat structure parameters has been obtained. The results show that the pore-throat structure of porous media becomes more complex and more heterogeneous after waterflooding. The pore-throat parameters (e.g. porosity, permeability, the maximum pore-throat radius, average pore-throat radius and sorting coefficient, etc.) will change during waterflooding. This work presents accurate and fast analytical models to perform the evolution rule of pore-throat characteristics of porous media during waterflooding. The proposed models can reveal more mechanisms that affect the coupled flow deformation behavior in porous media.
Palynological Correlation of the Late Cambrian to Middle Ordovician Saq Formation in Saudi Arabia and Equivalent Strata in Oman Manuscript Title
Authors: Vecoli Marco , Cesari Christian
Published: March 2019

The Cambro-Ordovician succession of Saudi Arabia comprises dominantly siliciclastic sediments deposited in a passive margin intracratonic setting and includes the fluvial to marginal marine Saq Formation (Late Cambrian to early Middle Ordovician), the marine Qasim Formation (late Middle to Late Ordovician) and the glaciogenic Sarah Formation (Hirnantian, latest Ordovician).

The Saq Formation is subdivided into the Risha Member (Late Cambrian) and the Sajir Member (Early to Middle Ordovician). Palynological age-control in the Risha Member is provided by a characteristic acritarch assemblage (CB1 Palynozone) which contains well-known Furongian (Late Cambrian) diagnostic taxa (e.g., Trunculumarium revinium, Timofeevia phosphoritica and Ninadiacrodium dumontii), as recorded in one subsurface locality in the Arabian Gulf. This typical assemblage occurs worldwide in Furongian-aged strata and not only permits a confident age- attribution, but also indicates an open marine facies within the predominantly fluvial to marginal marine lower Saq Formation. In Oman, the same assemblage occurs in the Al-Bashair Member of the Andam Formation. In the lower part of the Sajir Member, one acritarch assemblage characterized by the presence of Acanthodicaodium angustum and Vulcanisphaera spp., was described from a subsurface section in Eastern Saudi Arabia, indicating an earliest Ordovician (Tremadocian) age. This assemblage forms the O6 Palynozone and suggests correlation with the Mabrouk Member of the Andam Formation in Oman.

The top of the Sajir Member of the Saq Formation is characterized by mud-rich bioturbated deposits which typically yield a distinct palynological assemblage (O5 Palynozone), characterized by dominance of morphologically distinctive sporomorphs (e.g., Virgatasporites spp., various hilate sporomorphs) and characteristic acritarch species such as ?Clypeolus sp., ?Cymatiosphaera sp., ?Retialetes sp., and Barakella spp. The assemblage is also characterized by the first occurrence of some typical Middle Ordovician acritarch taxa such as Arkonia, Striatotheca, and Frankea. Among the chitinozoan, Siphonochitina formosa is typically represented. The age of this assemblage spans the Dapingian to earliest Darriwilian, in agreement with faunal evidence. The assemblage indicates a marginal marine, restricted paleoenvironment. Virtually identical palynological assemblages occur in Oman in the Saih-Nihayda Formation, considered of late Dapingian to Darriwilian age. More specifically, it is suggested here that the O5 Palynozone of Saudi Arabia permits correlation of the upper Sajir Member of the Saq Formation with the lower, sand-prone, part of the Saih Nihayda Formation in Oman.
Towards Identifying the Mechanisms of the Modified-Salinity Waterflooding by a Novel Combination of Core flooding and Mathematical Modeling
Authors: Taheri Mirhossein , Bonto Maria , Eftekhari Ali Akbar , M. Nick Hamidreza
Published: March 2019

Our objective is to find an alternative approach to the history matching of the modified salinity water flooding tests in secondary and tertiary mode. Instead of matching only the recovery factor and pressure drop history, we give a higher priority to matching the different ion concentrations and oil breakthrough times. Based on these analyses, we suggest the predominant mechanisms for the modified-salinity water flooding in carbonates.

The work is done in three steps: 1) Studying a large data-set of modified-salinity water flooding experiments in carbonates. 2) Quantifying the adsorption of potential determining ions (PDIs) on the carbonate surface using an optimized in-house surface-complexation model 3) Adjusting the relative permeability parameters to history-match the experimental data using different analytical solution of water-flooding (with and without ionic adsorption) combined with modern search-based optimization algorithms. The optimization algorithm gives a high weight factor to the breakthrough time of oil and PDIs.

Having too many parameters in the relative permeability (6 parameters for Brooks-Corey type) make it possible to match any type of recovery curves. However, we found out that matching the breakthrough times, especially in the tertiary modified salinity waterflooding, can only be achieved by considering the wettability change due to the adsorption of PDIs on the carbonate surface. This observation, combined with our ability to accurately model the adsorption of PDIs on the carbonate surface, helped us to identify the important PDIs that cause the wettability change in carbonates. For instance, we observe that a model that considers the wettability change due to the adsorption of calcium ions on the chalks surface matches perfectly to the tertiary flooding of the Stevns Klint outcrop chalk with seawater. The second important observation is that the lag between the start of the injection of the modified-salinity brine and the oil breakthrough time is not always due to the adsorption of ions and sometimes can be explained by the wettability change due to the lower salinity of the injected brine. It must be noted that this new approach is still semi-empirical, and needs to be combined with more fundamental studies to identify the actual mechanisms.
Enzyme Enhanced Oil Recovery EEOR: A Microfluidics Approach
Authors: Rahayyem Maher , Mostaghimi Peyman , Alzahid Yara A. , Halim Amalia , Evangelista Lucas , Armstrong Ryan T.
Published: March 2019

Enzyme Enhanced Oil Recovery (EEOR) has recently been categorized as one of the most effective EOR mechanisms. Laboratory and field studies have reported up to 16% of incremental oil recovery rates. EEOR recovers oil mainly by two main mechanisms: lowering the interfacial tension between brine and oil and altering the wettability on rock grains to a more water-wet condition. Therefore, EEOR would promote mobilization of capillary-trapped oil after regular waterflooding. Since capillary-trapped oil resides at the micro-scale, it is essential to assess EEOR fluid-fluid interaction at that scale. To further investigate the ways in which these enzymes contribute to EOR, an experimental micro-scale approach was developed in which EEOR was analyzed using polydimethylsiloxane (PDMS) microfluidic devices. The PDMS microfluidics device was based on X-ray micro-CT images of a Bentheimer sandstone with resolution of 4.95 μm. We first compared the IFT reduction capabilities of one class of enzyme (Apollo GreenZyme ®) and a commercial surfactant (J13131) obtained from Shell Chemicals. For GreenZyme concentrations of 0.5, 1.5 and 2 wt%, the IFT values between GreenZyme solution and oil are 4.2, 0.7 and 0.6 mN/m, respectively. Whereas the IFT values for 0.5 wt% surfactant solutions and deionized water are 1.1 and 32 mN/m, respectively. We then compared the oil recovery of the two systems using the aforementioned sandstone PDMS microfluidics device. Recovery values up to 92% of oilwere obtained using GreenZyme. Surfactant and waterflooding on the same PDMS chips had recovery values of 86 and 80%, respectively. This study provides insights and direct visualization of the micro-scale oil recovery mechanisms of EEOR that can be used for design of effective EEOR flooding.
Smart Dual ESP Completion To Develop Stacked Reservoirs
Authors: Alsafadi Ghassan , Siyabi Saud
Published: March 2019

Drilling less wells to produce more oil is the ultimate goal that any oil producing company operator is chasing especially during economic hurdles, in fields with stacked reservoirs, producing long term arrested oil behind casings due to un-ability to commingle two formations at the same time is one of the worldwide production challenges faced oil industry which is always looking for methods that allow producing two reservoirs simultaneously and independently from the same wellbore utilizing one production tubing.

The Smart Dual ESP Completion provide an innovative solution for this common production challenge in fields with stacked reservoirs, this Smart Completion has been tested successfully in one of Alghubar wells in PDO, the results was superior as it reduces the UTC by 74% as well maximize the NPV by approximately 200% (adding new formation and save drilling new dedicated well for each formation)

Alghubar field has a multi–highly- fractured carbonate reservoirs (Natih-A/B, Natih-E and Shuaiba), where the main production is from Natih-E and Shuaiba, the majority of the wells in this field used to be completed with dual gas lift strings in 9 5/8" casing. However due to high operating cost of running an aged gas lift compressor, decision was made to phase it out and start ESP conversion campaign instead. Therefore, producing both Natih-E and Shuaiba formations separately and simultaneously from same wellbore was raised as a key challenge.

The project consists of running Smart Dual ESP in parallel separated by a packer (to separate the two reservoirs) in one completion string with a modified Y-tool (to carry the weight of lower ESP and Packer). They are both producing through one string in the wellbore to surface starting from Y-tool block; both ESP's can be optimized separately and controlled by VSD at the surface, while other completion jewelry were introduced based on the reservoir conditions and well control requirements, the trial supported by detailed simulation analysis using a hybrid model from Prosper and GAP (IPM) to design both ESP's capacity and calculate required motor loads at a different reservoir, wellbore and operation conditions.

This successful trial of smart ESP completion design and the sophisticated installation would open a new horizon in production optimization through reducing the total number of development wells to be drilled in the fields of stacked reservoir from one wellbore. Further value were also obtained such as commercialization of marginal layers through existing wells and utilizing one of the ESP as a backup while waiting for workover in case of break down, subsequently further reduction in UTC and additional project value.