bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facilitating feedbacks between field measurements and ecosystem models
Authors: LeBauer David S. , Wang Dan , Richter Katherine T. , Davidson Carl C. , Dietze Michael C. 
Published: October 2012

Ecological models help us understand how ecosystems function, predict responses to global change, and identify future research needs. However, widespread use of models is limited by the technical challenges of model–data synthesis and information management.To address these challenges, we present an ecoinformatic workflow, the Predictive Ecosystem Analyzer (PEcAn), which facilitates model analysis. Herein we describe the PEcAn modules that synthesize plant trait data to estimate model parameters, propagate parameter uncertainties through to model output, and evaluate the contribution of each parameter to model uncertainty. We illustrate a comprehensive approach to the estimation of parameter values, starting with a statement of prior knowledge that is refined by species‐level data using Bayesian meta‐analysis; this is the first use of a rigorous meta‐analysis to inform the parameters of a mechanistic ecosystem model.Parameter uncertainty is propagated using ensemble methods to estimate model uncertainty. Variance decomposition allows us to quantify the contribution of each parameter to model uncertainty; this information can be used to prioritize subsequent data collection. By streamlining the use of models and focusing efforts to identify and constrain the dominant sources of uncertainty in model output, the approach used by PEcAn can speed scientific progress.We demonstrate PEcAn's ability to incorporate data to reduce uncertainty in productivity of a perennial grass monoculture (Panicum virgatum L.) modeled by the Ecosystem Demography model. Prior estimates were specified for 15 model parameters, and species‐level data were available for seven of these. Meta‐analysis of species‐level data substantially reduced the contribution of three parameters (specific leaf area, maximum carboxylation rate, and stomatal slope) to overall model uncertainty. By contrast, root turnover rate, root respiration rate, and leaf width had little effect on model output; therefore trait data had little impact on model uncertainty.For fine‐root allocation, the decrease in parameter uncertainty was offset by an increase in model sensitivity. Remaining model uncertainty is driven by growth respiration, fine‐root allocation, leaf turnover rater, and specific leaf area. By establishing robust channels of feedback between data collection and ecosystem modeling, PEcAn provides a framework for more efficient and integrative science.
Improved Health, Safety and Environmental Profile of a New Field Proven Stimulation Fluid
Authors: Braun W. , de Wolf C. A. , Nasr-El-Din H. A. 
Published: October 2012

Abstract
Acidizing treatments can help significantly improve the productivity of a well. Safe handling of commonly used corrosive acids, however, is a significant challenge to properly manage during the execution of the treatments. The additives, such as corrosion inhibitors, iron control agents, etc., typically used to mitigate the corrosive impact of acids and other un-wanted reactions during the treatments adds to the complexity of safe handling, while further aggravating the environmental impact of the overall treatment. Higher dosages of additives that are needed at higher treatment temperatures and pressures further compound the challenge. With the industry needs trending to high temperatures & pressures, and stricter health, safety & environmental (HSE) considerations, an alternative stimulation fluid that is suited for all the challenging conditions and be globally applicable with an acceptable environmental profile would be ideal.
Recent studies and field applications with a new stimulation fluid based on glutamic acid diacetic acid (GLDA) has shown that GLDA can improve permeability in carbonate and sandstone formations even at tough field conditions and can maintain the integrity of wells made of various tubular metallurgies. In the present paper the health, safety and environmental profile of GLDA is reviewed and compared against conventional stimulation fluids such as hydrochloric acid, acetic acid, hydrofluoric, etc., along with the commonly used additives.
GLDA is to a large extent based on a natural amino acid made from sustainable resources. It is biodegradable in both fresh and seawater. GLDA has a very favorable eco-tox profile and very low toxicity levels. In contrast to other stimulation fluids and frequently used additives, GLDA does not have any hazard classification and therefore requires no adverse safety labeling. GLDA can be handled easily and safely in the field with just standard chemical handling precautions in place. Overall, GLDA is a safe, environmentally friendly and effective stimulation solution that can help improve productivity of a well with the least possible well integrity or HSE concerns.
Design and Status of the Only Underground Gas Storage Project in Turkey after Three Years of Operation
Authors: Sahin Secaeddin , Abravci Suleyman , Tirek Ali 
Published: October 2012

Abstract
More than ninety eight percent of natural gas used in Turkey is imported predominantly from Russian Federation, Azerbaijan and Iran by pipeline, and Algeria and Nigeria as LNG. As in most developing gas consuming countries, Turkey's natural gas consumption varies in seasonal basis. Therefore, the country has had to work consistently to develop its transmission and storage systems. As a solution to this, Turkish Petroleum Corporation (TPAO) decided to convert the producing two gas fields, Kuzey Marmara (off-shore) and Degirmenkoy (on-shore) into underground gas storage facilities to accommodate seasonal variations in natural gas consumption.
The main reasons in choosing the Kuzey Marmara (K. Marmara) and Degirmenkoy fields as gas storage are the proximity of the fields to the gas pipeline network and Istanbul, and their suitability for gas storage because of their reservoir characteristics. The project area, however, is located in an environmentally sensitive region, which is also popular with its recreational and residential areas. Authority requirements regarding emissions, noise and other aspects were extremely severe.
The Silivri (K. Marmara and Degirmenkoy fields) underground natural gas storage (UGS) facilities with a storage capacity of 1.9 billion m3 were became operational on 13th of April 2007. Gas from the existing supply pipeline is currently being injected into the storage reservoirs and subsequently reproduced into the supply pipeline during the periods of high demand.
This paper provides the design and development process of the first and the only underground gas storage project of Turkey and also presents the status quo after the first three complete cycles.
Case Study of an East Siberian Field: A Holistic Review of Drilling Performance Enhancement
Authors: Buchan Andrew , Fazletdinov Marat , Okafor Zimuzor , Shulga Vladimir 
Published: October 2012

Abstract
The Verkhnechonskoye (VCNG) oilfield located in Eastern Siberia is developed on pad clusters, with in excess of 200 wells drilled to date. Typical well geometry consists of a vertical 13 3/8in. conductor followed by directional 12 ¼ in. and 8 ½ in. sections ran with subsequent 9 5/8in. and 7in. casing strings. Production hole is drilled in 6in. with a 4 ½in. liner set prior to completion. The predominant well design incorporates a double build profile which lands horizontally in the Verknechonskiy reservoir with an approximate 600m lateral drilled in the productive zone.
VCNG field has evolved of key strategic importance to deliver oil through the Eastern Siberia Pacific Ocean (ESPO) pipeline from Russia to the vast Asia-Pacific market located to its South East. Increasing production targets have been required to deliver hydrocarbons to fulfill aggressive pipeline commitments. Meeting these requirements have in turn initiated a relentless drive to enhance operational efficiency since the inception of development drilling phase in 2007; leading to a significant increase in drilling performance and reduction in overall well construction time in the period to date. This improvement has been achieved against the backdrop of an environment which is extremely challenging on several distinct fronts; remoteness of the project with &gt;600km from the nearest major conurbation, harshness of an extreme continental climate with temperatures seasonally dropping to -50°C and coupled with a unique and problematic lithological column all serve to make drilling, logistics and general operations a complex undertaking.
The purpose of this paper will be to take a holistic review of drilling performance in the field and to chronicle the numerous incremental technological and procedural advancements which have led to a reduction in average well construction time from 58 to 21 days between 2007 and 2011. Incorporated into this dramatic efficiency improvement includes a 465% increase in average well ROP along with a corresponding increase in meters drilled per circulating hour (MPCH) of 390%.
A Glass Micromodel Experimental Study of Hydrophilic Nanoparticles Retention for EOR Project
Authors: Hendraningrat Luky , Shidong Li , Torsœter Ole 
Published: October 2012

Abstract
A number of researchers put on attention on nanoparticles suspension (nanofluids) as part of nanotechnology application in enhanced oil recovery (EOR) nowadays. This experimental study is preliminary stage of nanofluids for EOR project at NTNU. This paper presents the investigation of interfacial tension reduction, nanoparticles retention and permeability impairment in porous media by injecting nanoparticles suspension into glass micromodel. The deposition and pore-blockage of nanoparticles in glass micromodel were investigated and microscopically visualized by taking sequential images. A hydrophilic nanoparticles and synthetic seawater (brine, NaCl 3 wt. %) as base fluid were chosen in this study. The nanofluids were made with various concentration from 0.1 to 1.0 wt. %. The sonicator as liquid homogenization tool was used just before injecting the nanofluids into glass micromodel to avoid agglomeration.
A dynamic interfacial tension (IFT) phenomenon has observed during this experiment. Introducing dispersed nanoparticles in brine has reduced dynamic IFT. It will decrease when increasing nanoparticles concentration. Theoretically, it makes oil easier to move out since the friction force between water-phase and oil-phase will also decrease (Afrapoli, 2010).
Based on microscopic visualization from glass micromodel, it observed nanoparticle has deposited and adsorbed at surface pore network. In permeability measurement, it reduced 41–72% after injected with nanoparticles. Dynamic light scattering analysis is also performed for nanoparticles entrapment analysis. Another nanoparticles which has bigger average size and lower specific surface area, showed similar behavior with previous nanoparticles suspension. However the permeability reduction is less around 17–21% at similar nanofluids concentration.
In conclusion, this phenomenon of nanoparticles transport process possibly occurs due to its deposition on pore surface and blockage in pore throat of glass micromodel. This study provides essential knowledge for us of nanoparticles behavior in pore media before going further experiment stage to as EOR method.
Building a Roadmap for Enhanced Oil Recovery Prefeasibility Study
Authors: Lefebvre Ch. , Lemouzy P. , Sorin D. , Roy G. , Serbutoviez S. 
Published: October 2012

Abstract
This paper describes an easy-to-use and fast-track roadmap for Enhanced Oil Recovery (EOR) Prefeasibility Study including (1) screening of EOR suitable methods 2) estimating of additional recovery with mechanistic 3D models 3) evaluating preliminary economics (NPV) for field scale application 4) assessing the main uncertainties to reservoir, fluids and economical parameters.
Oil-production from EOR projects represents currently about 4% of the worldwide production; this ratio is expected to increase significantly in the near future. EOR projects require in general important investments often in matured fields. It is therefore important for a decision maker to have a global view of the main technical and economical expectations and risks ahead of an EOR project decision.
This roadmap helps identify ahead of an EOR project the main technical and economic challenges and provides a first Go/No-Go taking into account the main uncertainties and risks associated to this type of project.
The main results of this roadmap are a set of pre-defined mechanistic 3D models with different reservoir geometries and suitable for 7 EOR methods (polymer, surfactant, SP flooding, steam injection, SAGD, in situ combustion, gases injection) and a simple but robust economic model providing a set of default technical and economical input values. Risk analysis is performed on these technical and economical results using either a deterministic or a probabilistic approach.
The outcome of this roadmap is at field scale, for a given EOR method, an expected additional recovery factor and the corresponding discounted NPV with an uncertainty analysis on the main technical and economical parameters.
New Coiled-Tubing-Deployed Multizone Hydraulic Fracturing: An Unconventional Process for Unconventional Reservoirs
Authors: van Gijtenbeek Klaas , McNeil Fraser , Massaras Leon 
Published: October 2012

Abstrac
Operators in the US have been producing from shale for decades, which places Europe and other continents with shale reservoirs in a unique position to benefit from the sharing of knowledge and technology already in use. However, Europe is faced with unique challenges that include the following: Rapid production decline.Water usage/disposal.Small pad size.Equipment limitations.High cost of nonproductive time (NPT).
To truly optimize a multizone stimulation treatment of unconventional reservoirs, one should not adopt the premise that the speed of the operation and initial production are all that determine success. Formation evaluation should be the primary determining factor in selecting the optimum completion technique, which must also provide a low-risk, operationally efficient solution designed to increase the reservoir contact and ultimately improve long-term production.
This paper discusses a new coiled-tubing (CT-) deployed hydraulic fracturing process, which is expected to have a considerable impact on advancing economic recovery of shale gas in Europe by fracturing one interval at a time using downhole mixing of proppant into the fracturing fluid. The downhole mixing rate can be manipulated in real-time to customize the placement and downhole-proppant concentration instantly. The combination of downhole mixing and microseismic fracture mapping provides unprecedented control of the fracturing treatment execution to facilitate branch fracturing. At the end of the final treatment stage, the well is simply cleaned out, with the entire operation completed with only one CT trip in hole. This paper reviews this technique, comparing it directly to conventional processes. In addition, background information is supplied from a combined CT/jointed-tubing (CT/JT) deployed hydraulic fracturing process.
Ranking of Hydrocarbon Reserves for the Management Them
Authors: Shandrygin A. N. , Smagina T. N. , Diakonov I. I. , Dubrovskiy D. A. 
Published: October 2012

Abstract
A method for ranking hydrocarbon reservoir with the zoning objects on the basis of geological knowledge and the economic efficiency of hydrocarbons production is proposed. For a ranking of hydrocarbon reserves, they are conventionally divided into four categories: profitable, contingently profitable, potential and non-commercial. Hydrocarbon reserves of reservoirs and fields are allocated to the categories, taking into account the geological, technological and economic criteria. The result is a ranking of information about the structure of the reserves for the planning of drilling, well intervention and the allocation of areas for pilot projects. The same information can be used to calculate the possible profiles of oil production in a different order involvement in the development zones of various categories of reserves and, thereby, to determine the optimal scenario of field development.
Petrophysical Base of Reservoir Saturation Type Prediction in Interwell Space
Authors: Kozhevnikov Dmitry , Kovalenko Kazimir , Deshenenkov Ivan 
Published: October 2012

Abstract
The integration of petrophysical and seismic data is a key technology for reservoir characterization and subsurface fluids monitoring. Rock physics as a link between seismic and logging data, it's applied to predict reservoir parameters, such as lithologies and pore fluids, from seismically derived attributes. Fluid substitution procedure is the rock physics technique for understanding how seismic velocity and impedance depend on pore fluids. The conventional fluid substitution model (Gassmann's model, 1951) assumes homogeneous water saturation without dividing on free and residual water shares.
On the base of petrophysical model of effective porosity we establish a new way of Gassmann's relation application for fluid effect on elastic properties simulation. This fluid substitution model takes into account free and residual water volumes and properties separately and cement swelling as well. Developed model was applied for Western Siberia sandstones and Eastern Siberia carbonates investigations. Seismic responses on oil and gas reservoirs characteristics were modeled with presented approach. Reservoir parameters such as saturation type, residual water features, reservoir properties were studied in seismic field with AVO modeling and simultaneous inversion of synthetic seismograms. The determination of conventional and developed model accuracy characteristics is carried out with Monte-Carlo technique. The outcomes indicate that the estimated error of proposed model is in 1.3–1.5 times less than conventional one.
The results of stated work could be the petrophysical base of the technique for reservoir saturation type prediction from seismic data, which provides identification of pay-zones, reservoir saturation mapping and three-dimensional modeling in order to drill for oil and gas.
Additional Acoustic Method for Measuring Formation Permeability in the Presence of Mudcake Achieved
Authors: Sinev A. V. , Dorovsky V. N. , Romensky E. I. 
Published: October 2012

Abstract
The interest in Stoneley waves in wellbores drilled through porous media comes from the dependence of its attenuation on formation permeability. This property makes the Stoneley waves an important tool for measuring the permeability of the porous medium [Xianyun, Hezhu, 2007; Dorovsky V. et al. 2010]. Drilling technology induces mudcake buildup between the borehole fluid and the porous formation with permeability of the latter being our main subject of this paper. Therefore what are the distinguishing properties of mudcake buildup during the permeability-measuring process while using the Stoneley wave properties, and what influence does mudcake thickness and rheology have on the attenuation length? There seems to be no obvious answer to these questions. Another important fact is dependence of the characteristics of the radial oscillations of the borehole fluid on formation permeability [Dorovsky et al. 2010; Dorovsky V. et al. 2012]. This fact allows one to measure formation permeability, and it should be evaluated for the case of mudcake presence. An issue of changes in the measuring procedure for permeability in the presence of radial oscillations of the borehole fluid arises in case of radial oscillations. The main property of radial oscillations is the dependence of the relative velocity of the formation matrix and formation fluid on the permeability of the porous medium at the interface between the media. Measuring the relative velocity at the interface between the media on the borehole side, one can use this dependence to calculate formation permeability. In the presence of mudcake, relative velocity dependence on permeability is retained, but only between the formation and mudcake, which cannot be measured directly on the side of the "mudcake-borehole fluid" interface. However, because the relative velocity in the formation beyond the borehole retains its dependence on permeability, it serves as a means of effective attenuation of borehole fluid waves. This can also serve as a tool for measuring formation permeability in the presence of mudcake and seems to be the foundation for numerical attenuation studies of the Stoneley waves and radial waves in the presence of mudcake. Therefore it should be noted that the influence of mudcake on the Stoneley waves was investigated by Liu, Maximov, etc. [Liu, Johnson, 1997; Maximov, Merkulov, 2002] drew the conclusion based on the theoretical analysis within the framework of the Biot theory that mudcake appears to reduce the influence of permeability on the attenuation length of the Stoneley waves.
Fluid Mechanical Aspects of Wet Gas Metering
Authors: Gryzlov A. , Nyfors E. , Jordaan L. , Undheim E. , Braaten N. A. , Gregersen S. E. , Steinsland E. 
Published: October 2012

Abstract
Current trends in hydrocarbon production are driven by improved oilfield management with various control and optimization strategies. These strategies rely on the efficiency of monitoring equipment which is used to obtain real-time oil and gas production rates with sufficient spatial and temporal resolution. Consequently considerable efforts have been put in the development of reliable flow measurement techniques dedicated to real-time monitoring of hydrocarbon flow rates without separation of the phases.
Multiphase metering at an upper limit of gas volume fraction (mostly above 95% GVF) is referred to as wet gas metering. Usually the metering of a wet gas flow is performed using standard dry gas meters which are supplemented by additional corrections in order to account for the impact of a liquid phase. These correction algorithms use explicit information on the measured fractions of oil, water and gas and can either be based on empirical correlations or employ mechanistic flow models. In contrast, issues related to installation effects of various components (such as pressure/temperature gauges and ad-hoc sensors) cannot usually be handled using simple flow models and should be assessed using extensive experimental analysis.
As a general solution, more fundamental physical background is put into the design and development of a new generation of a wet gas meter. The usage of general flow models both on micro and macro scales reduces uncertainty relevant to empirical modelling and promises more robust flow metering performance. In this work, the issues related to the optimal salinity sensor location have been studied via computational fluid dynamics. In particular, different variants of sensor placement scenarios have been analyzed in order to identify the location, which will have the maximum water volume fraction to achieve as high sensitivity as possible.