bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure Property Relationship of Novel Nano-Hybrids for Hydraulic Fracturing Applications
Authors: Kalgaonkar Rajendra , Baqader Nour , Alnoaimi Khalid , Sahu Qasim 
Published: October 2019

Abstract
The unique properties of polymer nano-hybrids, which not only make them obvious technology materials, but also provide a convenient macroscopic system to study fundamental scientific issues concerning confined and tethered polymers, have sparked the attention of material developers. Studying the formation, structure and dynamics of polymer nano-hybrids can lead to a better understanding of organic-inorganic hybrids, polymers in confined environment or at a solid interface. Proppant are an integral part of hydraulic fracturing operations. Resin coated proppants are widely used in hydraulic fracturing applications to increase the strength of proppant material to withstand closure stresses and to mitigate any proppant flowback. In this paper we showcase the development of novel nano-hybrid materials that enhance the proppant physico-chemical properties.
We present an investigation of novel polymer nano-hybrids based on emulsified resin and nanofillers having one dimension in nanoscale. The resins used for proppant coating are introduced as a water external emulsion, thus making them compatible with the aqueous fracturing fluids. We show that by using a solid resin-based emulsion system as proppant coating material we could introduce this system on the fly, along with the fracturing fluid without facing any incompatibility issues between the hydrophobic resin and the aqueous fracturing fluid. We further show that by using tactoid-based filler materials dispersed within the emulsified resin we could tremendously enhance the overall physico-chemical properties of the proppants. It is also shown that this property enhancement is dependent on the structure of the nano-hybrid.
In polymer nano-hybrids using tactoid based nano-fillers, better dispersion of nano-fillers in the polymer matrix can be achieved by organic modification filler surface, rendering the filler surface hydrophobic, thereby facilitating the delamination of the tactoid individual layers into nanoscale platelets by the polymer chains. The dispersion of nano-size layers in the resin matrix, markedly improves physico-chemical properties as compared to pristine resin. We have shown that the delamination of the individual tactoid layers and their uniform dispersion in the resin matrix was the key aspect that governed the tremendous property increment in the nano-hybrid coated proppants. A microstructural evaluation of these nano-hybrid coated proppants is presented and correlated to the proppant property enhancement.
Novelty of this paper is the development of new nano-hybrid based proppant coating materials that lead to tremendous physico-chemical property enhancement as well as on-the-fly deployment of the proppant coating material along with fracturing fluid due to enhanced compatibility.
Wettability Measurements of Mixed Clay Minerals at Elevated Temperature and Pressure: Implications for CO2 Geo-Storage
Authors: Fauziah Cut Aja , Al-Khdheeawi Emad A. , Barifcani Ahmed , Iglauer Stefan 
Published: October 2019

Abstract
Wettability of CO2/brine/clay has an important role in CO2 geo-sequestration efficiency as it highly affects the fluid flow through a porous medium. In this context, it is vital to measure the wettability of the clays. In addition, many previous studies have been conducted to investigate the wettability of pure clay minerals. Thus, in this study, we systematically measured the wettability of a mixture of different clay minerals (i.e. 14 wt% kaolinite, 48 wt% illite and 38 wt% montmorillonite). Both advancing and receding contact angles were measured at four different pressures (ranging from 5 MPa to 20 MPa) and two different temperatures; 305 K and 333 K. Then, for each clay minerals suspension with the brine, the zeta potential analysis was conducted to examine the clay's correlation to macroscopic contact angle. The results illustrate that the advancing and receding contact angles increased with increasing pressure (i.e. the wettability of the mixed clay has been altered from weakly water-wet to intermediate-wet with the pressure increased from 5 to 20 MPa). However, the results show that mixed clay minerals contact angle was a slight decrease with increasing temperature from 305 K and 333 K. Therefore, we conclude that the mixed clay minerals contact angle is highly affected by reservoir pressure and that higher pressures lead to reduce the CO2 storage capacity and contaminate security of the mixed clay minerals. This study has various significant implications for CO2 flow in porous media, CO2 entrapment in the deep geological reservoirs for CO2 geo-sequestration, and CO2 dynamics and spreading in geological formations for CO2 injection of methane recovery.
Semi-Analytical Analysis of Peak Production Rates in Unconventional, Boundary-Dominated Gas Reservoirs with Adsorptive Storage
Authors: Alzaabi Abdulla , King Gregory 
Published: October 2019

AbstractThe objective of this study was to develop tools to analyze the production profile of unconventional gas reservoirs where adsorption is a dominant storage mechanism. Specifically, the research is focused on analyzing the conditions that affect the time needed to achieve peak gas production rate. To this end, we have successfully derived the analytical expressions for the reservoir pressures at which peak gas production occurs under various operating scenarios.The methodology involves the development of a system of generalized two-phase material balance equations for boundary dominated flow in unconventional gas reservoirs where adsorption is a dominant storage mechanism. The resulting analytical ODEs are then solved numerically (Runge-Kutta) which yields a semi-analytical solution for pressure and saturation versus time. Once the pressure and saturations are determined numerically, gas and water production rates, along with their derivatives, are determined analytically and used to analyze the production profiles. Through the analytical derivatives, reservoir and fluid parameters can be modified to observe their effects on the time to peak gas rate.In this study, three different well specifications were investigated (constant flowing well pressure, constant well drawdown, and constant water production rate) with only two of the three well specifications resulting in a peak gas production rate - no peak gas production rate was observed for the water rate specified wells. Furthermore, the developed semi-analytical model, under appropriate conditions, gives results comparable to numerical reservoir simulator. The paper will discuss conditions at which the material balance results are comparable to full reservoir simulation.Through this research, a new material balance method has been developed that can be presented in different domains (pressure, time, and cumulative produced fluids domains). Also, the novel use of derivatives from the generalized material balance equations was applied in this research to analytically and graphically analyze the production profile. Furthermore, in addition to the peak gas production rate, additional inflection points were observed that have not been reported in the current literature.
Setting the Standard for Safety in the Offshore Access Industry
Authors: Nacheva Mina , Silianova Krissi , Mulders Tim 
Published: October 2019

Abstract
This paper is a combined review of the literature on the safety culture in the offshore industry as a whole and safety in the offshore access industry. As well as a review on best practices to incorporate new technologies and systems into an organisation. Safe offshore access is a challenge that all players in the offshore energy industry face, and setting the standards requires the continuous implementation of new technologies and higher managements' hands-on involvement in its implementation.
Finally, this paper looks at three key criteria that could bring the safety culture from being responsive to preventive and ultimately to proactive. It does so by evaluating the safety culture using the Hudson's safety culture ladder. In the end, it is always important to note that safety is the responsibility of everyone.
An Experimental Investigation of Polymer Performance in Harsh Carbonate Reservoir Conditions
Authors: Alfazazi Umar , Thomas Nithin Chacko , AlAmeri Waleed , Al-Shalabi Emad W. , Shaik Abdul Ravoof 
Published: October 2019

AbstractPolymer flooding is a well-established enhanced oil recovery (EOR) technique for mobility control. However, several factors affect a successful application of polymer at field-scale including injectivity and retention. The latter two parameters can lead to poor polymer performance. This work investigates the flow behavior of an HPAM-based polymer (SAV10) in carbonate reservoirs under high-temperature and high-salinity (HTHS) conditions. Formation water sample as well as three-outcrop carbonate cores were utilize in this work. Rheological studies and injectivity tests were conducted on SAV10 at two different temperatures of 20 °C and 90 °C. Polymer dynamic retention tests were also conducted to assess polymer loss in porous media.The results showed that the HPAM-based polymer has a good tolerance to salinity with a shear thinning behavior at reservoir flow rates and shear thickening behavior at well flow rates under temperature condition of 25 °C. The rheological studies also showed that this viscoelastic behavior disappears at higher temperatures of 90 °C. From injectivity tests, with increasing flow rate, resistance factor increases at 25 °C and decreases at 90 °C, which is related to polymer rheological behavior and in particular in-situ viscosity. In addition, resistance factor at 90 °C was lower than that of 25 °C due to the decrease in SAV10 retention as temperature increases. This paper recommends the use of polymer taper prior to brine postflush to better characterize resistance factor as well as the removal of backpressure to better describe polymer degradation. The paper provides more insight into the applicability of synthetic polymers (SAV10) in reservoirs with harsh conditions. The study also helps in better understanding of polymer flow behavior for designing successful field projects.
Building More Accurate Models for Different Reservoir Types and Oil Water Delineation
Authors: Zeybek Murat 
Published: October 2019

AbstractBuilding accurate reservoir models can be quite challenging, especially highly stratified thick intervals in hydraulic communication in reservoir. Presented methodology is based on comprehensive Interval and Interference Pressure Transient Testing (IIPTT) for classified reservoir types with a systematic approach. Classification of reservoir types is based on layering, thickness, and hydraulic communication of layers in the reservoir.The methodology describes building more accurate anisotropic reservoir models, providing well performance assessment based on integrated comprehensive IIPTT solving with efficient non-linear parameter estimation and modeling with numerical simulation for different reservoir types. The number distributed IIPTTs are optimized to ensure to achieve coverage across total thickness depending on the reservoir type.It is demonstrated that high resolution accurate reservoir models can be built for relatively thick highly layered reservoirs in a feasible manner. In addition, field examples with classified reservoir types including flow tests supported the methodology.
Miscible Gas Injection as a Key Development Scenario for the Complex Reservoir with Low Permeability
Authors: Mukhametzyanov Iskander , Glavnov Nikolay 
Published: October 2019

AbstractCurrently, for the most oil companies it is possible to identify a general tendency that the reservoir permeability for the new prospects is decline. Reserves quality deterioration increases the risk of the future oil production failure. This paper describes the organization of an integrated approach to source data analysis, simulation model constructon and miscible displacement design in a low-permeable reservoir.At the first stage, a reservoir fluid model is constructed. Based on the lack of a qualitative oil sample from the well (original sample was significantly depressurized during testing) and on the analysis of the fluid properties of the analog fields, the prediction of the main oil parameters was made. At the second stage, using static parameters of a low-permeable reservoir, probabilistic simulation models of the field was constructed, providing a coverage of the main spectrum of reservoir uncertainties. Further, import gas resources were estimated for the injection implementation.The main result is an integrated assessment of the impact of uncertainties for oil properties and gas import resources on key economic indicators for a miscible displacement at the field with a low-permeable reservoir using the reservoir simulation model. The analysis verified the key parameters that have the greatest impact on the economy of the project, determined the threshold values for the volume of gas imports, and based on the feasibility study made recommendations on the choice of the pilot area for injection. A program for conducting additional laboratory experiments was also prepared, this study will allow the narrowing of the oil composition uncertainties and its interaction with injection gas. In addition, a program is developed to carry out special core experiments on gas injection, which will make it possible to correct the behavior of phase permeabilities for a miscible displacement.This paper shows that on the basis of reservoir simulation an integrated approach organization for the verification, accounting and analysis of uncertainties on reservoir characteristics, fluid properties and volume of imported third-party gas allows to search for and select an economically viable and sustainable option to develop an oil field using miscible gas injection technology. An implementation of this approach provides a recovery factor increase from 7% to 25%.
Effect of Water/CO2 Ratio on Performance of CO2-Based EOR in a Sandstone Reservoir – Insights from Core Flood Tests and Simulations
Authors: Pourafshary Peyman , Al Khanbashi Iman , Mosavat Nader 
Published: October 2019

Abstract
Injection of water and gas are considered to be effective approaches in improving recovery from sandstone oil reservoirs. Different combinations of water and gas injection (such as continuous gas injection after water-flooding, simultaneous water and gas injection, and carbonated water injection) are used in oil fields to increase the recovery. The selection of the injection method and optimization of practical parameters, such as the water/gas ratio, improves the performance of this approach. Comprehensive experimental modeling techniques help specialists in the oil industry to design the most effective gas/water based enhanced oil recovery methods to produce more oil in a cheaper way.
In the first stage of this research, different experiments (such as core flooding) were carried out to study the performance of CO2-water EOR methods. Other parameters, such as gas solubility in oil and brine, oil swelling factor, oil viscosity reduction, gas diffusion coefficient, and gas utilization factor were measured and analyzed to investigate the mechanisms. At the next stage, gas/water injection in porous media was modeled. The model was in good agreement with experimental data. The confirmed model was used to analyze the main parameters of fluid flow in porous media, such as relative permeability. From the model, the optimized gas-based EOR method was selected to achieve the highest oil recovery.
In our study, oil recovery reached about 50% through water-flooding. Hence, a successful EOR approach is essential for a case with this amount of residual oil. Our experiments and models showed that simultaneous injection of water and gas with a water/gas ratio of 2.4:1 had the highest oil recovery factor (36%) in the studied sandstone formation, which makes the total recovery more than 85%. Compared to gas flooding, the gas/water injection schemes have a lower gas utilization factor, which reduces the operational cost in the fields.
Our comprehensive simulation studies, based on different experiments at core scale, provide an accurate and reliable approach to selecting the best gas injection scenario in the porous media. This methodology helps the industry to optimize the process from a technical and an economic point of view.
Characterization of Formation Damage and Fracture Choking in Hydraulically Induced Fractured Reservoirs Due to Asphaltene Deposition
Authors: Khurshid Ilyas , Al-Shalabi Emad W. , Al-Attar Hazim , Al-Neaimi Ahmed K. 
Published: October 2019

Abstract
Hydraulically induced fractures provide a significant fraction of oil supply to the world from unconventional reservoirs due to their high permeability. However, these fractures might choke because of the deposition of organic and in-organic particles. Among organic particles, asphaltene deposition severely reduces reservoir permeability causing an exponential drop in production. The objective of this study is to derive a model that characterizes formation damage and hydraulic fractures choking in unconventional reservoirs due to asphaltene deposition on fracture face and pore surface. This study also analyzes different factors affecting permeability alteration by asphaltene deposition in fractured reservoirs.
In this work, a 1D simulator is developed that predicts the performance of fractured reservoirs by solving the fluid flow governing equations for matrix and fractures. These flow equations were then incorporated with asphaltene deposition equations. The developed model considers constant temperature of the reservoir with negligible gravity and capillary forces. Sensitivity analysis was also performed to investigate the effect of three influential parameters on permeability alteration of fractured reservoirs by asphaltene deposition. These parameters include fracture-to-matrix permeability ratio, production time, and asphaltene concentration.
The study showed that asphaltene deposition could partially or completely choke fractures. This finding is in match with observations in the literature for asphaltene deposition and the consequent fracture choking. The sensitivity analysis showed that long production time and high asphaltene concentration have adverse effect on fracture permeability while matrix permeability was not much affected. On the other hand, low fracture-to-matrix ratio has a negligible effect on permeability of the simulated reservoir model. This work provides an insight into the detrimental effect of asphaltene deposition and estimates fracture choking in hydraulically fractured unconventional reservoirs with problematic oils.
Scale Prediction and Inhibition Design Using Machine Learning Techniques
Authors: Al-Hajri Nasser M. , AlGhamdi Abdullah 
Published: October 2019

Abstract
This paper will introduce a data driven methodology to predict scale formation and design its inhibition program in petroleum wells. The proposed methodology integrates and adds to the existing principles of production surveillance, chemistry, machine learning and probability theory in a comprehensive decision workflow to achieve its purpose. The proposed model was applied on a large and representative field sample to verify its results.
The method starts by collecting data such as ionic composition, pH, sample collection and inspection dates, and scale formation event. Then, collected data are classified or grouped based on production conditions. Calculation of chemical scale indexes is then made using techniques such as water saturation level, Langelier saturation index, Ryznar saturation index, and Puckorius scaling index. The machine learning part of the method starts by dividing the data into training and test sets (80% and 20%, respectively). Classification models such as support vector machine, K-nearest neighbors, gradient boosting, and decision tree classifier are all applied on collected data. Prediction results are then classified into a confusion matrix to be used as inputs for the probabilistic inhibition design model.
The scale inhibition program design is based on a probabilistic model that quantifies the uncertainty associated with each machine learning method. The scale prediction capability compared to actual inspection is presented into probability equations that are used in the cost model. The expected financial impact associated with applying any of the machine learning method is obtained from defining costs for scale removal and scale inhibition. These costs are factored into the probability equations in a manner that presents incurred costs and saved or avoided expenses expected from field application of any given machine learning model. The forecasted cost model is built on a base case method (i.e. current situation) to be used as a benchmark and foundation for the new scale inhibition program.
As will be presented in the paper, the results of applying the above techniques resulted in a scale prediction accuracy of 95% and realized three-folds of cost savings figures compared to existing programs.
Modeling of Smart Pigging for Pipeline Leak Detection: From Mathematical Formulation to Large-Scale Application
Authors: Thiberville Caitlyn , Wang Yanfang , Waltrich Paulo , Williams Wesley , Kam Seung Ihl 
Published: October 2019

Abstract
Although leak incidents continue, a pipeline remains the most reliable mode of transportation within the oil and gas industry. It becomes even more important today because the projection for new pipelines is expected to increase by 1 billion BOE through 2035. In addition, increasing number and length of subsea tiebacks face new challenges in term of data acquisition, monitoring, analysis, and remedial actions. Passive leak-detection methods commonly used in the industry have been successful with some limitations in that they often cannot detect small leaks and seeps. In addition to a thorough review of related topics, this study investigates how to create a framework for a smart pigging technique for pipeline leak detection, as an active leak detection method.
Numerical modeling of smart pigging for leak detection requires two crucial components: detailed mathematical descriptions for fluid-solid and solid-solid interactions around pig, and network modeling for the calculation of pressure and rate along the pipeline using iterative algorithms. The first step of this study is to build a numerical model that shows the motion of a pig along the pipeline with no leak, i.e., at a given injection rate, a pig first accelerates until it reaches its terminal velocity, beyond which the pig moves at a constant velocity. The second step is to construct a network model that consists of two pipeline segments (one upstream and the other downstream of leak location) through which the pig travels and at the junction of which fluid leak occurs. By putting these multiple mechanisms together and using resulting pressure signatures, this study presents a new method to predict the location and size of a leak present in pipeline.