bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wide Azimuth seismic: azimuthal analysis in offset vector domain for velocity and amplitude
Authors: Boelle Jean-Luc , Lecerf Didier , Navion Sylvain , Belmokhtar Ahmed , Ladmek Abdeljebbar 
Published: May 2016

Abstract
In 2005 a 3D high density wide-azimuth seismic survey was shot over the Irharen area (south east of Timimoun, Algeria). This acquisition was designed to better image the structure but also to improve fracture characterization and mapping, recognized as key in the description of this tight sand reservoir. The use of the offset vector binning concept, introduced by Cary (1999) and Vermeer (2002), on dense wide azimuth datasets is well suited for preserving the azimuthal information. An azimuthal residual velocity analysis based on semblance optimisation by scanning isotropic and anisotropic components of a parabolic elliptical model is proposed and tested successfully. The significant imaging improvement achieved with this land data case demonstrates the accuracy of the extracted azimuthal parameters for a better post-PSTM azimuthal residual moveout. After this correction, Common Image Gathers are ready for an azimuthal analysis of amplitudes. Taking advantage of the good sampling in offset and azimuth directions, the present study investigates the potential of Fourier analysis for describing the azimuthal variations of seismic amplitude.

Introduction
The description of fracturation is a key information to optimize tight or carbonate reservoirs production, as a consequence many studies have been undertaken to get this information from seismic. In particular, anisotropic models have been proposed to link the fracturation to seismic anisotropy, Hudson (1980,1981), Schoenberg et al. (1980, 1995). P wave velocity is then depending on fracture orientation, which may cause azimuthal variation in the seismic velocity field. On the other hand, coefficients of anisotropy may be estimated from azimuthal variations in reflected P wave amplitude (Rüger, 2001).
Wide azimuth seismic acquisitions, which provide a full azimuthal illumination of the structures for a more accurate image, may additionally offer information on fractures orientation through the azimuthal analysis of the seismic response.
To meet these objectives, it is essential that the 3D wideazimuth character of the data be preserved throughout the processing sequence in order to get full benefit from the use of true 3D algorithms. In this perspective, the use of the offset vector binning concept, introduced by Cary (1999) and Vermeer (2002), on dense wide azimuth datasets is advantageous as it preserves offset and azimuth information, even after migration. In the present paper, we show how the Common Offset Vector (COV) processing is used to point out azimuthal variations in the velocity field and analyze the azimuthal variations of the reflected amplitude at a given horizon.
Use of Automated Mineralogical Scanning and Magnetic Anisotropy Techniques to aid Permeability Predictions in Fine Grained Carbonates and Micro-Porous Reservoirs
Authors: Watson Paul , Matthews Anna , Hailwood Ernie 
Published: May 2016

I Introduction
The Upper Cretaceous - Danian Chalk Group of northwest Europe is an important producing reservoir in the North Sea. Chalk is a soft fine grained rock composed primarily of calcium carbonate (principally coccoliths), and is highly porous (20% plus porosity values), although most of the pores are sub 1micron in size. Traditionally, silica has been recognised either as fossil tests within this calcareous matrix or as distinct chert layers. Recently, however, XRD analyses revealed unexpectedly high levels of silica in chalk samples that show no obvious presence of silica in SEM and petrological studies. The assumption from these analyses is that the silica is distributed throughout the sample at the microscopic level. As with other fine grained microporous rocks, improved recovery depends on establishing the mineralogical constituents of the rock and the ability of reservoir engineers to extract the hydrocarbons contained within the micropores or microfractures.
In chalk reservoirs, recovery by injection of water depends on the wetting conditions of the rock and compaction by overburden due to water weakening the formation. Recent studies (Strand et al 2007) have concluded that the silica content of chalk is related to differences in wetting conditions and mechanical properties. It is also suggested that silica content may have affected the retention of porosity by inhibiting clay formation, and can also form intra-reservoir barriers.
In order to understand the relationship between permeability and mineralogy (in particular silica content) in chalk reservoirs, two well sections from the North Sea have been studied: Well A and Well B. Core samples studied from these wells span the Ekofisk and Tor Formations. In addition to standard carbonate sedimentological methodologies, samples have also been analysed by QEMSCANTM and MagporeTM techniques. Preliminary results of this ongoing study are presented here.
QEMSCANTM is an automated mineralogical scanning tool which uses a combination of SEM and EDS to evaluate the mineralogy of rock samples. MagporeTM uses magnetic anisotropy to evaluate the pore fabric of the lithologies. By combining these two techniques, it has been possible to define the 3D pore orientation data and relate these to bedding structures and mineralogy. It has also been possible to define various levels of silica within each sample, to map these mineralogically, and then to provide downhole plots which quantify silica concentrations through the well sections.
HSE in Design and Operation for Sour Gas Facilities
Authors: Al-Abri Ahmed Abdullah , Blyth Abi , Jewitt Ian 
Published: May 2016

Abstract
HSE challenges are substantial in sour gas projects; the poisonous nature of H2S introduces the risk of a toxic release with potential to cause multiple fatalities both inside and outside the site boundary.
Learning from recent sour projects emphasises a "keep it in the pipe" philosophy: appropriate materials selection, use of high-integrity components for facilities, wells and flow lines, and removal of as many leak sources as is practicable. Effort is also required to reduce personnel exposure, either through minimum intervention / minimum manning, or by spacing facilities to minimise the impact of a toxic cloud. However, the implementation of these apparently simple elements involves a complex balance of HSE goals against operability, maintainability, availability and Capex/Opex targets. Conflicting factors include:• Very high costs associated with corrosion-resistant materials.• Potential maintainability / operability hindrance associated with removal of leak sources (valves, flanges, instrumentation).• Availability losses imposed by prohibiting online maintenance (forcing turnaround maintenance shutdowns).• Costs and operability difficulties associated with large-scale plant spacing.
The solution lies in a design that optimises these elements to achieve risk levels that are as low as reasonably practicable, or ALARP. In doing so, it is important that the HSE Risk Assessment methodology aligns with the Reliability, Availability and Maintainability (RAM) premises, and that both are underpinned by the Operations Philosophy. This critically requires Operations input from a very early stage of the project.
Emergency Response capability also needs to be considered early in sour projects, since this too will underpin fundamental design and Operations Philosophy decisions such as layout spacing and requirements for cascade air systems and safe refuges. As a result, H2S release detection mechanisms; personnel H2S response training and respiratory protective equipment will also play a critical role in the ALARP demonstration.
Critically, Sour Gas developments should take an asset lifecycle view to understand the feasibility of incremental facility changes, field Simultaneous Operations (SimOps) and replacement of aging equipment.
Finally, there must be a consistent and integrated approach to HSE in sour projects all along the value chain, since the chain is only as strong as its weakest link, and there are no second chances with H2S. "Sour Mindset" responsibility must be demonstrated during design, throughout construction and commissioning, and into operations, by both Company and Contractor personnel. Only by this means can ALARP really be achieved.
Case Study: High Angle Directional Drilling with 9-5/8-in. Casing in Offshore Qatar
Authors: Van Zyl Daniel , Stephens Jeffrey Tod , Turki Mounir , Abed Malek , Al-Athbah Hamad Rashid 
Published: May 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

Abstract
In Qatar, Occidental Petroleum is faced with the task of drilling high angle wells through an unstable formation before entering the productive zone. Casing while drilling is becoming a powerful tool in mitigating both lost circulation as well as wellbore stability issues. The unstable Nahr Umr formation lies directly above the Shuaiba payzone and is typically drilled with 12-1/4-in. bits. The Nahr Umr shale tends to slough in shortly after drilling, leading to stuck BHA's and difficulty running 9-5/8-in. casing. Exposure time with the Nahr Umr is increased due to the requirement of continuous angle building and turning to land near horizontal. This paper details the case history of directional casing drilling (DCD) that have been utilized in offshore Qatar and the lessons learned.
Issues & Design Trends In Onshore Gas Reception Facilities
Authors: Zomerman Jannes Jan , Bradley Adam , Sikkenk Jan , Bras Ed 
Published: May 2016

Abstract
In pursuit of greater safety, lower environmental impact and lower capital expenditure, it is desired to reduce (or preferably eliminate) upstream offshore processing. Specifically for offshore platforms, the biggest capital expenditure savings can be achieved by either designing the offshore production facilities to be unmanned platforms or having subsea completions without a platform. In both cases all produced wellhead fluids will need to be transported untreated to shore in trunklines.
A major contributor to HSE incidents in the upstream oil and gas industry is the logistics of bringing people to and from the platforms by boat or helicopter transport. Being able to avoid the necessity of this people transport will greatly improve the overall safety performance of the gas production.
Furthermore, zero-effluent discharge offshore can be achieved by sending all of the produced fluids to the onshore plant for processing and disposal, as an alternative to the standard offshore processing and reinjection.
A further trend in recent developments is that of poorer-quality feedstock gas. Amongst others gas is becoming more sour, containing up to 40% H2S and up to 70% CO2. This, coupled with the elimination of offshore processing facilities requires the injection of chemicals to combat trunkline corrosion and formation of hydrates. The higher quantities of acid gases, free water (condensed and formation water), injected chemicals and increased corrosion products all have to be handled by the onshore gas-reception facilities that have to produce acceptable quality gas for the downstream facilities.
The onshore facilities also have to be robust for transient conditions like receiving significant slugs of production water during pigging and start up. As the gas and condensate specifications are getting more and more stringent stable operation of the units downstream the slugcatcher is essential to ensure on specification products. To realize this the downstream condensate stabiliser train needs a continuous feed of condensate even when water slugs enter the slugcatcher. Furthermore, potential water breakthrough to the condensate stabiliser train brings challenges to the design of the stabiliser column.
These trends require the onshore gas-reception facilities to do more, and in more difficult circumstances. This in turn is leading to more complex gas-receiving facilities and an increase in the unit's cost. As the experience with the onshore gas-receiving facilities without offshore platform is still building up, it is essential that sufficient time and effort is spent in the design phase to identify the possible risks and challenges.
Fracture characterization of a tight gas reservoir using seismic attributes derived from singular value decomposition of azimuthal AVO data.
Authors: Chao Gabriel , Maultzsch Sonja , Cadoret Thierry , Deplante Christian , Varela Isabel 
Published: May 2016

Abstract
This work presents a pilot study of the application of a seismic inversion technique for fracture density and fracture orientation in an area where available well data revealed the presence of open fractures. The inversion method is based on a singular value decomposition of azimuthal AVO data. This decomposition allows us to calculate seismic attributes which are linked to the fracture density of the fracture network through anisotropic rock physics modeling. The outcome of this pilot study is promising since the obtained results are consistent with existing image log data; however, further testing and research on a larger area are needed to assess if the fracture characterization results are consistent with geological interpretations and other analysises of fracture networks in the reservoir.

Introduction
The characterization of fracture networks in naturally fractured reservoirs can potentially play an important role in the optimization and enhancement of hydrocarbon production. Accurate maps of fracture density can aid in identifying areas of high occurrence of fractures and sweet spots. However, the determination of fracture density is a difficult and challenging problem that often involves the integration of different types of data at different scales. At the log scale, image logs and dipole sonic logs are employed to characterize fractures locally, while at the seismic scale azimuthal AVO and shear wave splitting techniques are used in seismic fracture characterization studies.
In this work we study the application of an inversion method to obtain the distribution of fracture density and fracture orientation in a pilot study covering a small area of a tight gas sand reservoir known to be fractured at least at one well location. The inversion method is based on a singular value decomposition (SVD) of the representative azimuthal AVO responses for the target reservoir. By means of singular value decomposition it is possible to calculate seismic attributes that provide a direct mapping with fracture density. This mapping is then used in the inversion of fracture density. The singular value decomposition method was originally implemented by Causse and coauthors for conventional AVO inversion (Causse et al., 2007). Varela and coauthors extended this methodology to invert for fracture density using azimuthal AVO and applied it both to synthetic data (Varela et al., 2007) and to laboratory experiments in a geological scale model (Varela et al., 2009). It is worthwhile to mention that one of the main advantages of this inversion method is that it is based on exact solutions of the AVOAz response calculated according to a full anisotropic modelling of the fractured reservoir and does not rely on the standard AVOAz approximations (Ruger et al., 1997). The seismic modelling in this work is based on the anisotropic rock physics model of Chapman (Chapman, 2003).
Petroleum Resource Assessment Methodologies and Petroleum Systems Modeling
Authors: Wygrala Bjorn 
Published: May 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

Abstract
Petroleum resource assessments are used to quantify discovered and undiscovered ('yet-to-find') petroleum that is technically and economically recoverable within a certain time frame, typically 30 years. The importance and economic impact of these assessments is enormous, especially in the light of globally dwindling resources. Resource assessments are however made using a range of methods, none of which can be described as being scientifically rigorous, especially in applications in frontier areas or areas with sparse data. Petroleum resource assessment methods can be subdivided into those that are applicable vs. those that are not applicable in frontier areas with only limited or no data. Methods that require detailed production data and therefore cannot be used in frontier areas include material balance, historical performance and reservoir simulation methods. Those that can be used in frontier areas include analogies, volumetric, delphi and Petroleum Systems Modeling methods. The latter is already recognized by leading assessment agencies such as the USGS as providing the most rigorous approach. According to the USGS, "Petroleum Systems Modeling incorporates the geoscience data required for resource assessments in ways that strengthen the assessment process" and "quantitatively extend the 'total petroleum systems' (TPS) that is employed in USGS resource assessments". Petroleum systems modeling can require more effort to compile and structure the data, however it provides clearly superior results as they are based on all of the available G&G data, conceptual models can be used if no data is available, uncertainties can be included in the analysis, all of the controlling parameters are coupled and geologic processes and time are included in the assessment. They offer the only resource assessment workflow which is documentable, logical, repeatable, quantitative and consistent within the contraints of the available data. In this presentation, the authors use both conceptual and real applications to illustrate how petroleum systems modeling is applied to petroleum resource assessments and what the benefits of the methodology are.
Leveraging Emerging Technologies to Increase Production from Unconventional Reservoirs: Case Study of India
Authors: Choudhary Yogesh Kumar , Bhat Sumit , Kumar Arunesh 
Published: May 2016

Abstract
With a sustained growth rate of 6.2%, India is set to become the third largest economy following the USA and Chinaby 2035. In accordance with the growth rate, it is estimated that India's import dependence is likely to increase from the current level of 72% to approximately 90% by 2035. With a large dependency on imports to meet commercial energy requirements, the demand/supply gap in oil and gas in India will inevitably grow. Unconventional energy resources are becoming increasingly more important in the quest for energy security because of the continuing decline of production from proven reserves (4 to 6% decline has been observed in mature fields), accompanied by the increasing price of crude oil and natural gas. Potential sources of unconventional energy in India, proven or speculated, are coal bed methane (CBM), shale oil/gas, tight gas, and gas hydrates.
With the recent advancement in 3D seismic analysis and technologies developed to analyze core samples, these have enabled a better understanding of CBM fields and other unconventional reservoirs. Because of the low permeability of these formations, economical production from unconventional reserves can only be obtained using a hydraulic-fracturing stimulation technique. Advancements in fracturing techniques from the conventional "perf-and-plug" method to multistage fracturing have enabled stimulation treatments in long intervals in a rapid and cost-effective manner. The use of advanced and proven numerical simulators in designing hydraulic-fracturing treatments has exponentially increased the success of treatments. Development of cleaner and environmentally acceptable fluids for stimulation treatments has reduced formation damage and is critical for effective stimulation of these unconventional sources of energy.
Case studies from Indian fields where such emerging and effective technologies are being implemented are presented. Best practices developed to exploit CBM reservoirs and lessons learned from the mature fields in overcoming several operational challenges are discussed.

Introduction
India, an emerging economy, has undergone unprecedented levels of economic expansion, along with countries like China, Russia, Mexico, and Brazil. With a gross domestic product (GDP) growth rate of 8.8% in Q1 2010, by 2035 India is set to become the third largest economy following the USA and China, assuming the forecasted compounded annual growth rate (CAGR) of 6.2%. The GDP of India grew from USD 36 billion to 1.25 trillion over the last five decades. This expansion increased primary energy consumption in India by about 5% (CAGR) over the last two decades; whereas, for the rest of the world, this increase was only 2% (CAGR). India comprises 16% of the total world population and, with a CAGR of 1.54%, it is expected to cross 1.5 billion by 2035; therefore, energy will be one of the most critical aspects supporting the economy and human development.
Integrated Reservoir Characterization And Development Through An Improved Workflow Approach To Couple A Three Dimensional Seismic Study Results And Reservoir Numerical Simulation: Revealing The Effect Of Structural Features In La Victoria Field
Authors: Castillo Karilys , Urdaneta Marisely , Askoul Yamal Eduardo 
Published: May 2016

Abstract
A detailed seismic interpretation for reservoir characterization is a powerful tool to obtain information in the inter-well area for the purposes of field management and development. This paper presents a workflow approach to characterize La Victoria Field reservoirs, which belongs to Apure State in the Southwest of Venezuela, particularly Escandalosa M Sand of Escandalosa Formation. The available 3D seismic data have been used to predict small-scale faults as well as presence of internal compartments where undrained zones or bypassed oil might be located in a mature oilfield. Additionally, reservoir engineering techniques as numerical simulation helped to verify reservoir parameters estimated by history matching in a black oil simulator, such as the sealing character of some faults, identified from seismic interpretation.

Introduction
La Victoria Oilfield is located in Apure State, Southwest of Venezuela, specifically at 60 km to the Southwest of Guasdualito Village and 6 Km to the West of Colombian - Venezuelan boundary, between Uribante - Apure Rivers (North) and Arauca River (South). This oilfield produces from Tertiary and Cretaceous reservoirs.
The Escandalosa M Sand is a cretaceous unit, which highly homogeneous; consequently, the structural characterization is the key in order to find drilling opportunities in this field. Seismic attributes reveal features and patterns; which can be useful to understand the geological structure and to build a robust 3D geomodel. Also, this reservoir represents a mature reservoir, in consequence is necessary to do a detailed geological and geophysical and reservoir engineering analysis to find undrained zones or bypassed oil to propose an optimal placement of a well.
The aim of this work is to present a methodology for creating an Integrated Structural Geological Model from seismic attributes and well logs in order to build a 3D geomodel that reproduces as exactly as possible the small geological features, and finally create the simulation model which allows identifying undrained zones. Although this work was made along of all oilfield, we will focus this article on the northern part of the field, because was there where the locations were proposed and drilled with excellent results, confirming the results of this study.