bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quality Assurance and Control of Surfactants for Field Scale EOR Pilot Projects
Authors: Barnes J. R. , van Batenburg D. W. , Faber M. J. , van Rijn C. H. , Geib S. , van Kuijk S. R. , Perez Regalado D. , King T. E. , Doll M. J. , Pretzer L. E. 
Published: November 2015

Abstract
Alkaline Surfactant Polymer (ASP) flooding is an enhanced oil recovery (EOR) technique that involves the injection of a solution of surfactant, alkaline, and polymer into an oil reservoir to mobilize and produce the remaining oil. There are several pattern-flood pilots in progress or about to be executed to evaluate ASP at a scale relevant to commercial scale application. The quantities of surfactants needed for these pilots and potential future commercial scale applications are large (100s to 10,000s of ton) and necessitate large scale manufacture using existing processes and plants for the different manufacturing steps. These operate under slightly different process conditions than those used to make the smaller quantity (ca. 50 kg) of the reference blend, used to design the formulation in the laboratory. The upscaling of the surfactant production itself is an essential step to enable field scale implementation of ASP. In order to ensure and control the quality of the surfactants produced for pilots with Shell interests, a stage gated Quality Assurance/Control (QA/QC) programme was designed and executed. The application of the QA/QC process for a high and a low active matter surfactant blend concentrate (around 60% and 20% active, respectively) is used to illustrate the process.
The early definition of the QA/QC programme provided a framework with clearly defined stages for upscaling from laboratory to large scale production. The definition of analytical and performance based laboratory experiments with up front defined specifications (minimum and maximum values) and repeatability allowed for clear, unambiguous decisions. Correlations between composition and performance that were developed based on pilot scale production were essential to assure the performance of the larger scale production. Core floods, used as the ultimate performance check, showed virtually identical performance for pilot scale prepared surfactants and surfactants from different large scale batches.
The paper illustrates that consistent industrial scale production of surfactants for application in chemical EOR is feasible. To ensure the quality of such surfactants requires a detailed QA/QC programme. The successful execution of the QA/QC programme for the surfactants for the pattern pilots ensures that the produced large scale surfactant blend performs as the reference blend used to design the formulation.
Chloride Stress Corrosion Cracking (Cl-SCC) of Stainless Steel Piping and Equipment in Condensate Stabilization Unit
Authors: Choudhary Satish 
Published: November 2015

Abstract
The purpose of this paper is to present a condensed summary of the work done by Dolphin Energy on chloride stress corrosion cracking (Cl-SCC). Stress corrosion cracking poses a serious threat to the integrity of a natural gas plant and the company responded to this threat by launching a comprehensive initiative to determine the cause(s) and to adopt best practices for preventing future failures.
This paper provides a valuable engineering insight into the ways and means adopted by the company for tackling Chloride Stress Corrosion Cracking issues in an operational plant without jeopardizing safety while maintaining the production targets at the same time. Included in this paper are various monitoring tools as well as interim and permanent preventive measures that were employed by Dolphin Energy following the first reported instance of chloride cracking in one of the stainless steel pipe works carrying hydrocarbon mixed with H2S.
One of the sources of the chlorides responsible for the corrosion/cracking failures was believed to be from hydrolysis of Ca/Mg/Na chloride salts generated in the hot stabilizer bottom and/or from left over hydrochloric acid (from well stimulations) in the well head production fluid. This condition was not considered during the design phase.
Interim and permanent preventive measures were identified for tackling the Cl-SCC issues. Key recommendations to address Cl-SCC included a reduction in operating pressure / temperature at vulnerable sections of the unit, use of various non-destructive testing (NDT) techniques to identify and monitor the cracks and generation of an Integrity Operating Window (IOW) to keep the key operating parameters within thresholds. It was determined that a material upgrade was the permanent solution for avoiding Cl-SCC in the Condensate Stabilization Unit.
A metallurgical investigation confirmed the mode of cracking to be intergranular as well as transgranular unlike conventional chloride cracking, which is primarily transgranular in nature. The reasons for observed mixed-mode cracking could be ascribed to certain combination of Chlorides, H2S, CO2 and partially oxidized sulfur species that are present in the service apart from the degree of cold work that material has undergone during fabrication.
It is important that within one year of commissioning the unit, a detailed review is made to verify process and operating parameters (design assumption versus actual operating conditions).
The Key Factors Affecting the Deliverability and OGIP of Multi-layer Gas Reservoirs
Authors: Yujin Wan , Yong Hu 
Published: November 2015

Abstract
For multi-layer gas reservoirs, the dynamic performance, especially the deliverability and OGIP (Original Gas In Place) of comingled gas wells, is seriously affected by the interlayer heterogeneity. The gas well production rate, if we set it as (1/3 to 1/5) of the absolute open flow potential (AOFP) by empirical method, will decline soon. There exists obvious difference between the OGIP, calculated by using the early period of production data, and the volumetric reserves. By integrating the experimental tests, gas reservoir engineering investigation and typical well dynamic performance analysis. Firstly, the experimental test of two parallel sets of full diameter core samples was carried out to simulate two-layer comingled producing, and the results show that the higher permeability layer produced more gas and its pressure decreased more quickly. Secondly, well test design model is used to simulate the dynamic performance of single layer and two-layer comingled wells, and the AOFP and OGIP calculated by the simulated results has been investigated. Finally, the dynamic performance of typical multi-layer comingled gas wells in Sebei gas field has been analyzed. The results of above all show us, the AOFP of comingled gas wells is mainly dominated by the higher permeability layer, the interlayer permeability differential and the layered reserves are the key factors to affect the AOFP and OGIP of comingled gas reservoirs.
Enhancements in Modeling Gas Sweetening
Authors: Sheikh Saifuddin 
Published: November 2015

Abstract
Acid gas removal is an important process in various branches of the hydrocarbon processing industry, primarily in natural gas processing and refining. Acid gas removal is also an essential part of other processes, such as coal gasification where carbon dioxide, hydrogen sulfide, carbonyl sulfides, mercaptans, and other contaminants need to be removed.
Acid gas is defined as gas containing significant amounts of contaminants, such as hydrogen sulfide (H2S), carbon dioxide (CO2), and other acidic gases. Sour gas is gas contaminated with H2S. This term comes from the rotten smell due to sulfur content. Thus, "gas sweetening" refers to H2S removal, because it improves the odor of the gas being processed, while "acid gas removal" refers to the removal of both CO2 and H2S.
Acid gases need to be removed in order to comply with sales gas quality regulations. These regulations are in place to minimize environmental impact and ensure gas transport pipeline integrity, avoiding undesired occurrences, such as corrosion caused by H2S and CO2 in the presence of water. Acid gases also need to be removed due to the toxicity of compounds, such as H2S, and the lack of the heating value of CO2. Typically, "pipeline quality" or sales gas is required to be sweetened to contain concentrations of H2S that's no more than 4 parts per million (ppm), and a heating value of no less than 920 to 1150 Btu/SCF, depending on the final consumer requirements.
Corrosion Under Insulation Technologies - High Performance Solutions
Authors: Pedersen Lars Thorslund 
Published: November 2015

Abstract
It has been recognized by most facility owners that corrosion under insulation is a phenomena which needs special attention during design and construction. If the pipes and vessels are left uncoated or if the wrong type of coating has been applied before the insulation material is wrapped around – the result will often show up in a few year times in form of heavy corrosion under the insulation material or even break down due to leaking pipes or vessels.
Selecting the correct coating to protect the vessel or pipe before insulation can be a challenge especially when we see a lot of new coating technologies reaching the market. This paper will discuss the reason for have different coating technologies available and what to look for when specifying coatings under insulation.
Application of CO2 Micro Bubble for the Innovative CO2-EOR
Authors: Akai Takashi , Xue Ziqiu , Yamashita Yuji , Yoshizawa Minoru 
Published: November 2015

Abstract
CO2-EOR is one of the proven enhanced oil recovery (EOR) techniques and has been used commercially. However, in field applications, unfavorable sweep efficiency is often reported. In order to improve the sweep efficiency of CO2 flooding, we investigated an applicability of CO2 micro bubbles.
To evaluate the applicability of CO2 micro bubbles for CO2-EOR, we conducted core flooding experiments using CO2 micro bubbles and the results were compared with the normal CO2 flooding. Previous study confirmed the generation of CO2 micro bubbles by using a specially developed porous filter. Using this filter, core flooding experiments were conducted. During the experiment, flooding behavior was monitored by a medical X ray CT system, and recovered oil and water were collected to make a quantitative comparison with normal CO2 flooding.
From the images taken by the medical X ray CT, we observed that CO2 micro bubbles flowed over both upper and lower parts of core samples, while normal CO2 flowed only upper part of core samples. As a result, a delay of CO2 break-through was confirmed in CO2 micro bubble flooding case. The time series of medical X ray CT images indicates improvement in sweep efficiency by using the CO2 micro bubbles. In addition to this, the material balance calculation during the core floodings revealed 3% of additional oil recovery compared to the normal CO2 flooding. From the experiments, differences in flooding behavior were clearly observed between the normal CO2 and the CO2 micro bubbles injection. We consider the differences would lead to the improvement of both vertical and areal sweep efficiencies.
Although this technique is still in a stage of fundamental research, since the technique only requires the special filter and it is considered that it can be easily installed at the down hole, it may provide a novel option to improve the CO2-EOR performance.
Consideration on Shape of Hydraulic Fracture Based on Laboratory Experiment
Authors: Akai Takashi , Yano Shunsuke , Kurosawa Isao , Chen Youqing , Ishida Tsuyoshi 
Published: November 2015

Abstract
In development of unconventional reservoirs such as tight and shale oil/gas reservoirs, hydraulic fracturing has been applied to enhance reservoir productivity. In spite of active applications of hydraulic fracturing, a shape of induced fractures is not fully understood. This paper presents the result of laboratory visualization experiment of hydraulic fracturing, which was conducted to visualize the shape of induced factures with cylindrical shale sample through the fluorescent method. An acrylic resin mixed with a fluorescent agent was used as a fracturing fluid. The resin is solidified and fixed within the samples by heat. The shape of the induced facture reveals based on different brightness under ultraviolet light irradiation. Many associated microfractures were observed around the main fractures. The fracturing fluid can be trapped in these types of microfractures by capillary force and these fractures cause lower recovery of fracturing fluid in the actual field operations. Acoustic emission (AE) was also monitored by the 16 sensors mounted the rock samples. Result from the path of main fractures identified by the resin mixed with a fluorescent substance and distribution of AE indicates good agreement between two. This helps us to examine which particular failure generates microseismicity. Although the scale difference between laboratory experiments and field operations needs to be taken into account, the shape of induced fractures is successfully characterized. We interpret the fluid leak off zone, main fracture, and branch fractures can be a source of the AE while no AE is observed at the area of the fracture with large aperature based on overlaying AE hypocenters with visualized induced fracture. This work helps engineers to make a proper model of hydraulic fractures for the estimation of well productivity.
Enhanced Security for Oil and Gas Facilities in a Volatile World
Authors: Aspden Albert 
Published: November 2015

Abstract
Oil and gas facilities are usually situated in remote locations. These areas are often geo-politically sensitive areas, with infrastucture that has little, if any, protection.
Nonetheless, these facilities often represent several billions of dollars of an investment portfolio, making them high in both monetary and strategic value, and at risk of sabotage or attack..
A client requested a solution to provide protection systems for a vast gas field from such malicious threats. The objective was to design a system that would: DETECT a potential threat;ASSESS the threat (friend or foe);ACT on the threat
This paper discusses the technology options considered and the prescribed solution: Using access control systems and closed-circuit television (CCTV) surveillance to protect numerous facilities and major gas pipelines across a geographic area of some 1,300 square km.
Integration of Evolving Petrophysical and Formation Testing Measurements for Enhanced Characterization of Tight Gas Reservoirs
Authors: Mohsin Labib , Sassi Khaled H. , Yaarubi Azzan H. , Daungkaew Saifon , Yu Dai G. , Lawatia Redha H. 
Published: November 2015

Abstract
Tight unconventional reservoirs have become an increasingly common target for hydrocarbon production in Oman. Exploitation of these resources requires a comprehensive reservoir description and a characterization program to estimate reserves, identify properties that control production, and account for fracturability. It is becoming evident, however, that any single technology by itself is unable to address all the key challenges, and the integration of technologies is crucial to answer all the questions to reduce key subsurface uncertainties.
This paper discusses in detail a case study in which the integration of advanced petrophysical logs has enabled successful downhole sampling and provided a comprehensive reservoir and fluid characterization despite the very challenging lithologies and very tight formation. The comprehensive logging suite included advanced measurements of dielectric dispersion, nuclear magnetic resonance (NMR), and spectroscopy. The reservoir fluids and dynamic properties were also characterized by a series of formation testing measurements.
Dielectric dispersion logs clearly identified the hydrocarbon-bearing zones despite the characterless resistivity profile, taking advantage of its resistivity-independent saturation approach. The accuracy of the measurement was key to estimating water- filled porosity down to 0.5 p.u. regardless of the formation water salinity and changes in the rock electrical parameters. The integration of dielectric and NMR measurements, reflecting the pore structure, has played a major role in identifying the "best" reservoir intervals and indicating the type of fluid (hydrocarbon or water) filling the free pore space. The NMR unimodal and bimodal T2 distributions revealed the pore structure along with polarization effects on light hydrocarbons, helping to gain insight on the reservoir quality. The NMR was also combined with the microimaging measurements to indicate pore connectivity and formation heterogeneity. This integrated approach was applied to a deep tight-gas exploration well and has contributed to achieving successful formation sampling that provided an in-situ fluid characterization despite the tightness of the rocks, with only 4 p.u. average porosity. Integrated logging measurements along with fluid sampling resulted in both enhanced formation and fluid characterization in this exploratory well, shedding light on the hydrocarbon potential over the region.
Improvement of the Compositional Model to Represent a Complex Fluid System of a UAE Carbonate Reservoir
Authors: Alejandra Khan Karem , Uchida Miho , Noah Awolayo Adedapo , Olawale Olayiwola Saheed , Al Hammadi Khaled Eissa 
Published: November 2015

Abstract
The studied field is located in Abu Dhabi and has been identified as faulted anticlines structure with associated local fractures. The reservoir is characterized by lateral and vertical variations in reservoir rock and fluid properties ranging from a gas condensate at the top of the structure to undersaturated black oil down the reservoir. A substantial compositional gradient has been identified from over 50 fluid samples taken at different depths over the thick fluid column of about 1500 feet. The field is presently under miscible hydrocarbon WAG (HC-WAG) injection, water injection and future consideration for CO2-WAG injection.
The field has been characterized using an Equation of State (EOS) model and compositional mapping with areal changes of saturation pressure. Therefore, the aim of this study is to improve the compositional model that can replicate the areal and vertical variation in the fluid thermodynamic. This presents a huge task considering the vast number of laboratory experiments. Hence, the updated EOS will be used to improve the reliability of reservoir modeling, production forecasts and operational requirements.
All the fluids analyses studies were compiled and validated. These data were analyzed areally and vertically down the fluid column. Correlations of saturation pressure, gas-oil ratio, formation volume factor and compositions were generated with depths across the formation. The data showed a large variation of saturation pressure, all fluids parameters and composition with depth especially close to the gas oil contact. Then the compositions and saturation pressures were validated using a 1-D vertical model and obtained results were compared with the experimental values at various depth.
The obtained result proved that a single EOS and fluid representation could model the complex thermodynamic behavior of all the reservoirs in the field. Considering that part of the field has been under HC-WAG injection and future consideration for other WAG processes, the generated EOS would allow the numerical simulation to have a better representation of the fluids and predict the impact of these processes on the ultimate oil recovery.
Evaluation of Water Saturation in a Low-Resistivity Pay Carbonate Reservoir Onshore Abu Dhabi: An Integrated Approach
Authors: Uchida Miho , Salahuddin Andi Ahmad , Ashqar Ayham , Awolayo Adedapo Noah , Olayiwola Saheed Olawale , Eissa Al Hammadi Khaled 
Published: November 2015

Abstract
Characterization and fluid quantification of Carbonate reservoirs looks more challenging than those of sandstone reservoirs. The determination of accurate hydrocarbon saturation is more tasking due to their complex and heterogeneous pore structures, and mineralogy. Traditionally, resistivity logs are used to identify pay intervals due to the resistivity contrast between oil and water. However, when pay intervals exhibit low resistivity, such logs exhibit low confidence in the precise determination of the hydrocarbon saturation. Few Middle-Eastern reservoirs are categorized as low resistivity pay, where resistivity based log analysis results in high water saturation. However, downhole fluid analysis identifies mobile oil, and the formation flows dry or nearly dry oil during production tests. This makes resistivity based saturation computation questionable.
Because of the complexity of low resistivity pay (LRP), its cause should be determined prior to applying a solution. Several reasons were identified to be responsible for this phenomenon- among which are the presence of micro-porosity, fractures, paramagnetic minerals, and deep conductive borehole mud invasion. Integration of Thin section, Nuclear magnetic resonance (NMR) and Mercury injection capillary pressure (MICP) data from the studied formation indicated the presence of micropores network.
This paper discusses the observed variations in quantifying water saturation in LRP interval and the related discrepancies between the resistivity and non-resistivity based techniques. The non-resistivity based methods, used in the course of this study, are coined from sigma log measurement and core data, either capillary pressure-based (MICP, Centrifuge, and Porous plate), or direct from Dean-Stark measurements. The interpretation process considered water saturation derived from resistivity measurement and core data combined with production test information.
The combination of several water saturation determination approaches captured the uncertainty and improved our understanding of the reservoir properties. This enhanced our capability to develop a robust and reliable saturation model. The integration of data from these various sources added confidence to the estimation of water saturation in the studied field and thus, improved reserves estimation and reservoir simulation for accurate history matching, production forecasting and optimized field development plan.