bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased Asphaltenes Surface Aids Fuel Formation with the Presence of Clays during In-Situ Combustion
Authors: Ismail Norasyikin B. , Hascakir Berna 
Published: October 2017

Abstract
Increased surface area of reservoir rock due to the presence of clays and the catalytic impact of clays are known to enhance the in-situ combustion (ISC) performance. But the basics behind these mechanisms are still not known. In this study, we investigated the role of clays on ISC in microscopic scale.
Six one-dimensional combustion tube experiments were conducted on three different crude oil samples. The combustion performance of each crude oil was evaluated with two combustion runs; reservoir rock prepared with sand-oil and with sand-clay-oil mixtures. Each combustion tube test was evaluated in terms of cumulative oil production, combustion front propagation, and characterization of the produced oil samples. Activation energy and heat of combustion were calculated empirically. Quality of the produced oil samples was determined through viscosity measurements. Saturates, aromatics, resins, and asphaltenes (SARA) fractions of initial and produced oil samples were compared. To better understand the fuel formation mechanism, asphaltenes surfaces were visualized by a Scanning Electron Microscope (SEM) and SARA fractions with Fourier Transform Infrared (FTIR).
Combustion tube experimental results highlight that crude oil type affects the process performance the most. Clay presence in the rock expedited the combustion front velocity by increasing the oxygen utilization rate. Activation energy was reduced drastically with the presence of clays, however, the heat of combustion has not changed. Thus, the generated heat has been consumed more effectively with the presence of clays. Produced oil quality has been increased significantly in terms of viscosity, more viscosity reduction was observed with the presence of clays. Since saturates acts like an ignitor during ISC, the amount of saturates fraction was decreased in produced oil when compared to initial oil. While the amount of aromatics fraction was increased significantly, the asphaltenes fraction is decreased with the presence of clays when compared to the aromatics and asphaltenes fractions of the initial oil. The reduction in viscosity is mainly due to increased aromatics content of produced oil with high solvent power. With the SEM images taken on asphaltenes surface, the role of clays has been observed clearly on fuel formation. With the presence of clays, the asphaltenes surface have created cribriform structures. Without clays, asphaltenes surfaces were observed as smooth surface. Those holes should increase the surface area on asphaltenes surfaces and increase the effective transformation of asphaltenes into fuel.
Case Studies of Optimizing the Artificial Lift Strategy for Reactivating Abandoned Wells in a Mature Field
Authors: Patron Katherine Escobar , Villarreal Paola Martinez , Leon Jorge Luis 
Published: October 2017

Abstract
At a time when oilfield economics preclude new drilling, one way to achieve economic goals is to strategically reopen abandoned wells. Choosing the artificial lift strategy that best suits the economic constraints for the reactivation of abandoned wells is a challenge. This paper uses real-world field data examples to introduce a new methodology that replaces opinion and guesswork with objective and quantifiable comparisons to drive strategic decisions that balance technical and economic concerns. A new method to simplify and quantify the development of that strategy can have wide-ranging impact for mature fields around the world. The study uses a sample of 10 wells initially completed with electrical submersible pumps (ESPs) with different production characteristics and well profiles from a mature field in South America.
Reactivating abandoned wells is particularly challenging because the reasons for abandonment are complex; production challenges ranging from deep installations, low production rates as well as flow assurance related problems lead to premature equipment failures and final well abandonment. As economic conditions change and new technology is developed, the abandoned wells' value potential may also change. This paper uses the sample wells to demonstrate a new method of selecting optimal artificial lift systems for highly complex projects.
A new method of artificial lift system selection provides a quantifiable, objective means of studying well and field economic and technical potential. The method balances economic factors with specific well application considerations to optimize performance to suit an operator's strategic plan. The data in the paper demonstrate that the method can give a solution for a challenging environment of previous abandoned wells by selecting the artificial lift method that maximizes reliability and performance under specific operating conditions. After the workflow implementation, the sample data was classified into two groups where: Group 1: Wells where the ESP systems are the best strategy—with to special design considerations and equipment configuration to manage production challenges.Group 2: Wells where hydraulic pumping units are the best solution—with special attention to rod design and downhole equipment to meet the production challenges.
An Analysis of Classroom Inversion in the Corporate Environment
Authors: Thompson Analise J , Flores Daniel V , Pauls Ralph 
Published: October 2017

Abstract
This paper compares instructor led training versus classroom inversion for two courses taught at Exxon Mobil Corporation ("ExxonMobil"). We discuss training elements such as total training hours, pre/post-test results, and student satisfaction surveys. The most important findings are: Student and supervisor behaviors need to change when learning is transformed from an event to an extended journeyGreater effort is required to prepare for and monitor the progress of studentsClassroom efficiencies can be realized and the quality of instruction enriched with inversionThe effectiveness of learning was comparable to that of a conventional classroom
Successful Sand Blockage Removal from Sealine Using an Innovative Plastic Coiled Tubing
Authors: Pelucchi M. , Mantica D. B. , Piemontese M. , Restuccia G. , Mackenzie H. 
Published: October 2017

Abstract
Sand accumulation occurs in subsea infrastructure and pipelines, also called sealines, when the fluid carrying capacity isn't sufficient. Once this situation degenerates, the maximum achievable production rate decreases till complete stop: a sand blockage is formed and production lost.
The first worldwide subsea application for a plastic coiled tubing for sand removal demonstrates the opportunity to think for alternatives and use an innovative technology to avoid expensive pipeline replacement and to restore the production in a quicker and cheaper way.
With space upon FPSO units inherently limited, a complex engineering solution involving workover rig or intervention vessel is typically required to support the removal of sand plug or line section replacement. Those options, are inherently expensive, and could shut down the production for a long period and generate additional HSE risks.
A preliminary analysis is necessary to identify the sand plug dimension and plan the proper remedial job.
In 2014, Operator decides to think for alternatives and performed a smart intervention using an innovative Plastic Coiled Tubing directly from FPSO, washing down the riser and the subsea flowline till complete sand blockage removal.
The use of a standard coiled tubing unit isn't an applicable solution for severe limitations in transport and rig/up operations; so the decision is to select and develop a customized ultra-lightweight, highly flexible pipe compared to conventional coiled tubing.
On board of the FPSO unit, a continuous improvement process is necessary to optimize equipment layout and configuration. Adjustments in operative procedures and some troubleshooting actions maintain higher the efficiency during the washing and cleaning job through riser and subsea flowline.
The final result is the complete sand blockage removal and the hydraulic continuity re-establishment inside the pipeline.
The overall process successfully validates the so performed analysis, screening and equipment selection, demonstrating that plastic coiled tubing is a valid and innovative tool for sealines washing and production restoration in a quicker way.
Quantitative Assessment of the Impact of Sparse Data and Decision Bias on Reservoir Recovery Forecasts
Authors: Meddaugh W. S. , Meddaugh W. , McCray B. 
Published: October 2017

Abstract
Nandurdikar and Wallace (2011) industry-wide lookback summary showed that recovery forecasts made prior to project sanction averaged about 25-50% higher than actual observed reservoir performance. This study has examined the potential quantitative impact of sparse data and "decision" bias on reservoir recovery forecasts using a synthetic data set. The approaches utilized included statistical analysis of forecasts derived from a synthetic analog data set as the number of analogs was reduced from the full set of reservoirs to as few as 25% of the available reservoirs using random as well as biased selection criteria. The latter bias experiments allowed some inference to be made as to the potentially large impact of management "decision" bias. Statistical results obtained from the synthetic and actual case histories suggest that sparse data "impact" may account for up to 10-25% of the observed optimism and that decision bias for up to 15-25% of the observed optimism. Although not investigated in detail in this study, prior work (Meddaugh, 2015) suggested that other sources of potential bias such as stochastic geological model parameters (e.g. the semivariogram model) and upscaling are generally small with the possible exception of static/dynamic model grid parameters (particularly dynamic model cell size) and well location optimization workflows. Improved quantitative understanding of the potential impact of sparse data and decision bias on reservoir forecasts will enable the industry to reduce the forecast optimism noted by Nandurdikar and Wallace (2011) and will likely improve capital efficiency in the industry.
New Development of Multi-Detector Pulsed Neutron Instrument for Quantitative Gas Saturation Monitoring in Air- or Gas- filled Boreholes: Physics, Modelling and Application
Authors: Zhang Qiong , Chace David , Inanc Feyzi , Wu Jianghui , Yuan Peng , Gade Sandeep , Kim Yonghwee 
Published: October 2017

Abstract
One important application of a multi-detector pulsed neutron instrument is to detect gas response for determining quantitative gas saturation in the formation. Obtaining this saturation value is achieved by differentiating the gas response from the liquid response. The maximum formation sensitivity to gas and liquid is observed when the wellbore is filled with liquid. When the wellbore is filled with gas, however, the separation between formation gas and liquid responses is reduced. This reduced separation results in increased uncertainty in the log analysis. The current operational solution is to set a plug and the fill the borehole with water. Although this technique helps to obtain the desired formation gas-liquid sensitivity, it incurs increased operational expenses, potential damage to fragile formations, reinvasion effects, etc.
To overcome these challenges, a sleeve has been designed to deploy with the pulsed neutron instrument. The sleeve imitates the presence of water in the borehole around the tool and increases the dynamic range to the levels seen with the boreholes filled with water and oil-based fluids. This technique extends the application of multi-detector pulsed neutron instrument to provide solutions in airor gas-filled boreholes. It avoids the potential damage to the formation, diminishes HS&E hazards, and reduces operational expenses by eliminating the operation of loading the borehole with water or brine.
The sleeved pulsed neutron instrument has been evaluated using Monte Carlo nuclear modelling for design and validation. Prior to any deployment, a sensitivity analysis is conducted using Monte Carlo N-particle (MCNP) transport code to evaluate the formation sensitivity improvement due to the presence of the sleeve. The impact of various tool-sleeve positions and the performance of various sleeve materials have also been studied. A case study is presented to demonstrate how the sleeved pulsed neutron tool significantly improves formation gas sensitivity as compared to the standard tool in gas-filled boreholes.
Hydrate Plug Remediation in Deepwater Well Testing: A Quick Method to Assess the Plugging Position and Severity
Authors: Zhao Yang , Wang Zhiyuan , Yu Jing , Pan Shaowei , Zhang Jianbo , Sun Baojiang 
Published: October 2017

Abstract
Gas hydrates can form during deepwater well testing, resulting in serious flow assurance problems. Once plugs form, remediation operations must be carried out to remove the plugs. We developed a method to quickly locate the plugging position and assess the severity of hydrate plugs. The proposed method was developed based on hydrate thermodynamics, kinetics, and hydrate particle transport & deposition dynamics. The application procedure was established. Flowrate, pressure and temperature data in well testing was collected and used as input data for hydrate plugging development analysis, from which the plugging location and severity could be quickly assessed. The plugging position and severity under various water depth, gas production rate and inhibitor concentration conditions were obtained. It indicates that hydrates generate and attach to the tubing wall and form a growing hydrate layer, which narrows the effective flow area of the tubing. As the hydrate layer becomes thicker, the plugging becomes more severe and bring a greater interference to well testing operations. A significant choking effect is encountered when the hydrate layer thickness increases to a critical value, resulting in distinct pressure drop increase in the testing tubing. It indicates the occurrence of conduit blockage. The plugging position is found at the site where the maximum subcooling is encountered, rather than where the lowest ambient temperature presents. For a typical deepwater gas well, the plugging position is at 150 m below the sea surface. The effects of gas production rate, inhibitor concentration and water depth on plugging position are studied. It is found that the plugging position becomes deeper as the water depth increases and/or the production rate decreases. More severe plugging can be encountered when the gas production rate is lower, the water is deeper, and/or the inhibitor concentration is lower. The proposed method can help operators locate the plugging position and assess the severity of hydrate plugs in a shorter time compared to traditional methods. This study provides key instructions and helps reduce uncertainties involved in removal work. Therefore the operational risk and duration can be significantly cut down.
Extension of Capacitance-Resistance Model to Tracer Flow for Determining Reservoir Properties
Authors: Naudomsup Nuntha , Lake Larry W. 
Published: October 2017

Abstract
Several tools and techniques exist to understand distributions of reservoir properties. Interwell tracer testing is one ofthe most common methods to obtain reservoir information from the amount of tracer produced. The capacitance-resistance model (CRM) is an analytical tool to estimate connectivity between producer-injector pairs from historical rates and (when available) bottom hole pressure data in waterfloods.Because the CRM is a physically based, simple input-output model, its combination with tracer testing can provide insight into reservoir features.
To enable the CRM application to tracer flow, we incorporated tracer models,based on miscible displacement theory, into the CRM. Reservoir properties are estimated as a result of the model fitting to produced tracer data. In this paper, we present three tracer models:a dispersion-only(short range autocorrelation) model, a Koval (long-range) model, and a combination of the two. To incorporate the tracer models into the CRM, we used two methods, serial fitting (CRM then tracers) and simultaneous fitting (CRM and tracers).
We applied these techniques to tracer data from 10 injectors and 10 producers of the Lawrence field. Results suggest that interwell connectivity obtained from the CRM is in good agreement with the observed peak tracer concentrations. All tracer models are able to give a good fit in most of the cases. Comparing among the tracer models, the combined model can better represent a tracer flow than the other two models alone. We also found that the simultaneous fitting method gives the best fit to total producer rate data and tracer data. Simultaneous fitting mitigates the non-uniqueness of the fits, leading to an improvement of tracer matching. The reservoir properties obtained in this study (Koval factor and dispersion coefficient) were also analyzed and compared to those from previous measurements.
Downhole Multiphase Flow Monitoring Using Fiber Optics
Authors: Fidaner Onur 
Published: October 2017

Abstract
Distributed Acoustic Sensing (DAS) technology has been used in an increasing number of applications in the petroleum industry.Multiphase flow rate measurement is an important DAS application. In this work we provide a forward model relating multiphase flow rates and two-phase flow patterns in the wellbore to the DAS data. Modeling consists of a series ofanalytical relationships between various physical parameters, which allows for simulating DAS data efficiently based on various assumptions regarding the flow and wellbore. The forward model also allows us to characterize various mechanisms that introduce uncertainty to DAS data and various parameters estimated from DAS data. We also discuss methods to analyze DAS data to find the speed of sound and flow rates in the wellbore. The forward model enables us to develop efficient algorithms for the inverse model, including the wavelet transform and artificial neural networks to analyze DAS data in real time and calculate the flow rate and flow patterns in the wellbore.
Integration of Pressure and Rate Transient Analysis for Transverse and Longitudinal Multistage Fractured Horizontal First Unconventional Gas Well in Egypt
Authors: Ibrahim Mazher , Salah Mohamed 
Published: October 2017

Abstract
Recent advancements in technologies pertaining to the drilling of horizontal well and multistage hydraulic fracturing have made it possible to get significant hydrocarbon production even from extremely low permeability formations. Evaluation of the economics is becoming increasingly essential before committing to any big investment. In this scenario, production forecasting plays an important role by not only evaluating the economic feasibility of the project, but also helping in the selection of the most optimal development strategy (Shivam et al. 2017).
This paper presents an integrated workflow that has been applied in one of unconventional gas bearing formation which is a common reservoir in Egypt’s Western Desert. It does form a reasonable reservoir size and spread over several hundred sq.kms. It is characterized as a low permeability carbonate (0.2 mD) in soft chalk reservoir. Many vertical wells were drilled and completed in the appraisal program for collecting the required data to evaluate reservoir performance before the completion of horizontals, but economical target production rates could not be achieved. To help optimize field development strategy and further increase production, a full field development plan was initiated by drilling horizontal wells with multistage fracturing stimulation. Horizontal pilot wells were drilled and completed along and perpendicular the minimum horizontal in-situ stress direction to enable both transverse and longitudinal fracture propagation patterns for the best completion option.
The objective of this paper is to present an integrated approach to evaluate an unconventional resource, improve the completion efficiency, improving the future fracture design and understand the productivity enhancement specifically in the Western Desert of Egypt, through a detailed analysis of production data and pressure transient analysis.
The conclusions from this study will help in evaluating the behavior of multistage fractured horizontal with different fracture azimuth direction and generate production forecast for different development scenarios. The stimulated rock volume estimation will help in planning the future fracture design to increase well EUR. The proposed workflow and lessons learned formed the basis for subsequent development of various unconventional plays in Egypt.
An Engineered Approach to Design Biodegradables Solid Particulate Diverters: Jamming and Plugging
Authors: Shahri Mojtaba P. , Huang Jian , Smith Clayton S. , Fragachán Francisco E. 
Published: October 2017

Abstract
Fluids introduced into a reservoir for stimulation typically take the path of least resistance and therefore frequently go into areas where there are open flow paths. In many cases, those are neither the areas you would want to stimulate for increased production nor areas from which formation damage will need to be removed. The success of a hydraulic fracturing or an acidizing operation depends on maximizing the contact between the fracturing fluid (or acid) and intact rocks. To achieve this goal, existing fluid paths must be effectivelyplugged to divert the fluid towards intact rock for an efficient application.
A typical fluid diversion application can be divided into three major steps; i.e., displacement from surface to downhole, downhole plugging/diversion and corresponding stimulation and production efficiency.The aim of this paper is to review and identify the criticalparameters controlling the downhole plugging and diversion step. In addition, an analytical solution is used for predicting minimum required concentration of solid-particulate diverting agent. The proposed model incorporates multiple operational parameters such as flow rate, fluid viscosity, particle size, and opening size. The validity of the proposed solution is checked byusing experimental testswith single slot-opening. In addition, a coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) model has also been used to verify the proposed analytical solution.The findings will have beneficial implications for acidizing, multistage hydraulic fracturing, and refracturing operations.
By using a scientific approach, better understanding of the controlling parameters along with the verified analytical solution,we can better design and achieve efficient fluid diversion and necessary pressure buildup.The analytical solution verified against both experimental data and advanced numerical simulations (CFD-DEM) can significantly and reliably enhance the diversion job efficiency. Using the analytical solution along with the thorough understanding of underlying mechanisms, we can optimize the particulate system characteristics for a successful diversion process. As an example and by selecting the minimum required concentration, we can eliminate the excessive use of diverting agents, which would reduce costs and adverse effects on equipment resulting from high concentrations.