bluuebunny/crossref_metadata_2025 huggingface dataset:
MethylExtract: High-Quality methylation maps and SNV calling from whole genome bisulfite sequencing data
Authors: Barturen Guillermo , Rueda Antonio , Oliver José L. , Hackenberg Michael
Published: October 2013

Whole genome methylation profiling at a single cytosine resolution is now feasible due to the advent of high-throughput sequencing techniques together with bisulfite treatment of the DNA. To obtain the methylation value of each individual cytosine, the bisulfite-treated sequence reads are first aligned to a reference genome, and then the profiling of the methylation levels is done from the alignments. A huge effort has been made to quickly and correctly align the reads and many different algorithms and programs to do this have been created. However, the second step is just as crucial and non-trivial, but much less attention has been paid to the final inference of the methylation states. Important error sources do exist, such as sequencing errors, bisulfite failure, clonal reads, and single nucleotide variants.

We developed MethylExtract, a user friendly tool to: i) generate high quality, whole genome methylation maps and ii) detect sequence variation within the same sample preparation. The program is implemented into a single script and takes into account all major error sources. MethylExtract detects variation (SNVs – Single Nucleotide Variants) in a similar way to VarScan, a very sensitive method extensively used in SNV and genotype calling based on non-bisulfite-treated reads. The usefulness of MethylExtract is shown by means of extensive benchmarking based on artificial bisulfite-treated reads and a comparison to a recently published method, called Bis-SNP.

MethylExtract is able to detect SNVs within High-Throughput Sequencing experiments of bisulfite treated DNA at the same time as it generates high quality methylation maps. This simultaneous detection of DNA methylation and sequence variation is crucial for many downstream analyses, for example when deciphering the impact of SNVs on differential methylation. An exclusive feature of MethylExtract, in comparison with existing software, is the possibility to assess the bisulfite failure in a statistical way. The source code, tutorial and artificial bisulfite datasets are available at http://bioinfo2.ugr.es/MethylExtract/ and http://sourceforge.net/projects/methylextract/, and also permanently accessible from 10.5281/zenodo.7144.
Diachronic Changes in Jazz Harmony
Authors: Broze Yuri , Shanahan Daniel
Published: October 2013

The present study examines both gradual and rapid changes occurring in 20th-century jazz harmonic practice. A newly-assembled corpus of 1,086 jazz compositions was used to test the idea that jazz music exhibits a mid-century decline in traditionally “tonal” chord usage. Evidence was found for slow, incremental changes in zeroth-order chord quality distributions, consistent with gradual, unconscious changes in harmonic usage. Typical tonal chord-to-chord transitions became less common between the 1920s and the 1960s, consistent with the hypothesis of tonal decline. Finally, use of root motion of an ascending perfect fourth dropped suddenly in the 1950s, suggesting that chord-to-chord transitions might be more susceptible to rapid change than chord frequency. Possible constraints on stylistic evolution are discussed.
Nocardia brasiliensis Infection Mimicking Juvenile Idiopathic Arthritis in a 4-Year-Old Girl
Authors: Kapur Nitin , Adib Navid , Grimwood Keith
Published: October 2013

Nocardia are ubiquitous environmental saprophytes that cause pneumonia and disseminated disease in immunocompromised patients. They can also cause localized cutaneous and soft tissue infections in healthy people after direct percutaneous inoculation. Nocardia arthritis is rare in both forms of the disease. Here we present the first published case of a child with septic arthritis caused by N brasiliensis. Importantly, this otherwise well 4-year-old girl had no known history of trauma but presented with transient cutaneous lesions and a 6-week history of arthritis involving the right fourth digit proximal interphalangeal joint without accompanying fever or raised systemic inflammatory markers. She received a diagnosis of juvenile idiopathic arthritis and underwent antiinflammatory and immunosuppressant therapy. After 2 months she developed frank septic arthritis, which necessitated a surgical joint washout, from which an intraoperative swab grew N brasiliensis. The patient received 6 months of high-dose trimethoprim–sulfamethoxazole and remains well more than 4 years after treatment. This unusual case highlights the importance of considering an indolent infection from slow-growing organisms, including Nocardia, when diagnosing the oligoarthritis subtype of juvenile idiopathic arthritis. This is especially relevant when a single joint is involved and response to antiinflammatory therapy is suboptimal because antiinflammatory agents may mask evolving signs of infection.
Improving Depression Screening for Adolescents With Type 1 Diabetes
Authors: Corathers Sarah D. , Kichler Jessica , Jones Nana-Hawa Yayah , Houchen Andrea , Jolly Mary , Morwessel Nancy , Crawford Peggy , Dolan Lawrence M. , Hood Korey K.
Published: October 2013

OBJECTIVE:

Depression is common among adolescents, but rates increase significantly in the presence of chronic health conditions. Outpatient screening for depression is recommended but rarely formally conducted due to barriers of implementation.

METHODS:

To provide a model for depression screening of youth with chronic health conditions, a standard process using a self-administered electronic version of the Children’s Depression Inventory (CDI) was developed. Quality improvement methodology and traditional analytic approaches were used to test the feasibility and outcomes of routine screening in patients 13 to 17 years of age with type 1 diabetes.

RESULTS:

Of the 528 eligible adolescents, 509 (96%) received at least 1 depression screen during the first year. The process was tested and refined in over 1200 patient encounters, which resulted in an increase in depression screening rates from <5% to a median of 85% over the initial 12 months. Both patients and staff reported acceptance of screening on qualitative surveys. Elevated CDI scores (≥16) were found in 8% of the sample; moderate scores (10–15) in 12% of the sample. Low risk scores were found in 80% of the sample. Higher CDI scores correlated with lower blood glucose monitoring frequency and higher hemoglobin A1c, confirming the link between more depression symptoms and poorer diabetes management and control. Suicidal ideation was endorsed in 7% of the population.

CONCLUSIONS:

Systematic depression screening in adolescents with type 1 diabetes can be reliably implemented with clinically significant results. A systematic approach, such as described in this study, can serve as a model for other chronic health conditions.
Higher-Hazard, No Benefit Research Involving Children: Parental Perspectives
Authors: Sachdeva Tanya , Morris Marilyn C.
Published: October 2013

OBJECTIVES:

US regulations allow local institutional review boards to approve greater than minimal risk, no-benefit research when the research enrolls children with the condition under study but not when it enrolls healthy children. We aim to describe the opinions of parents regarding higher-hazard, no-benefit research

METHODS:

Quantitative and qualitative interviews with parents of children without heart disease or chronic medical conditions (no heart disease [noHD], n = 30), children with fully correctable heart disease (FCHD, n = 30), and children with life-altering heart disease (LAHD, n = 30).

RESULTS:

Parents of children with heart disease endorse higher-hazard, no-benefit heart disease research more strongly than noHD parents. Eight of 30 noHD parents, 19 of 30 FCHD parents, and 26 of 30 LAHD parents reported willingness to enroll their children in a heart disease research study involving an otherwise unnecessary chest radiograph (P < .01). There was no difference among groups in willingness to enroll their children in a similar study focused on childhood cancer. Twenty-two of 30 FCHD and 30 of 30 LAHD parents reported that parents have a responsibility to enroll their children in medical research to help future children with heart disease. Twenty-one of 30 noHD parents, 29 of 30 FCHD parents, and 30 of 30 LAHD parents feel able to evaluate the risks of medical research (P = .01).

CONCLUSIONS:

Parental opinions regarding higher-hazard, no-benefit research align with federal regulations. Parental willingness to enroll their children in higher-hazard, no-benefit research is driven in part by a sense of obligation to a community of families affected by childhood heart disease.
Complementary and Conventional Medicine Use Among Youth With Recurrent Headaches
Authors: Bethell Christina , Kemper Kathi J. , Gombojav Narangerel , Koch Thomas K.
Published: October 2013

OBJECTIVE:

To identify prevalence and patterns of complementary and alternative medicine (CAM) use among youth with recurrent headaches (HA) and evaluate associations with co-occurring health problems and limitations as well as with the use and expenditures for conventional medical care.

METHODS:

Variables were constructed for youth aged 10 to 17 by using linked data from the 2007 National Health Interview Survey and the 2008 Medical Expenditures Panel Survey. Bivariate, logistic, and 2-part regression analyses were used.

RESULTS:

Of the 10.6% of youth experiencing HA, 29.6% used CAM, rising to 41% for the many HA sufferers who also experienced difficulties with emotions, concentration, behavior, school attendance, or daily activities. Biologically based products (16.2%) and mind-body therapies (13.3%) were most commonly used, especially by the 86.4% of youth with HA experiencing at least 1 other chronic condition. Compared with non-CAM users, youth with HA who used CAM also had higher expenditures for and use of most types of conventional care.

CONCLUSIONS:

CAM use is most common among youth with HA experiencing multiple chronic conditions and difficulties in daily functioning. Associations among CAM use, multiple chronic conditions, and higher use of conventional care highlight the need for medical providers to routinely ask about CAM use to meet the complex health needs of their patients and facilitate the optimal integration of care. Research is needed to identify models for coordinating complementary and conventional care within a medical home and to understand the health benefits or risks associated with CAM use in conjunction with conventional treatments for patients with HA.
Hydrocarbon Potential Of The Enisei-Khatangsk Region With In The Taimyr Autonomous District (TAD) And The Extent Of Its Development
Authors: Dmitrievsky A. N. , Eremin N. A. , Shabalin N. A.
Published: October 2013

The geological studies carried out on the territory of the Taimyr autonomous district of the Krasnoyarsk Krai during the period of 1930–1950 by the Glavsevmorputi subdivisions, the USSR Mingeo organizations and the institutes of the USSR Academy of Sciences (AS) show a considerable thickness of sedimentary deposits perspective for oil and gas, the availability of the Paleozoic salt-bearing sections, the prolongation of the continental tectonic structures into the water area of the marginal seas followed by the increase of the sedimentary deposits The TAD borders on three oil and gas bearing provinces of Siberia such as the West-Siberian, the Khatango-Vilyuisk and the Leno-Tungussk the limits of which allocate the Enisei-Khatangsk OGR and partially the Pur – Tazovsk OGR. (20). The total area of the oil and gas potential lands is over 550 th square km (13).
Cost Efficient Decrease Of Risks Due To Additional Geological Information
Authors: Balaban I. J. , Gutman I. S.
Published: October 2013

The paper presents methods for the economic evaluation of additional geological information obtained through a variety of field-geological studies in the presence of geological risks. This is particularly important in the Arctic where the risks associated with the development of hydrocarbons are extremely high. The evaluation is based on the ability to make the right decision that is reduced to the choice of two options: to continue the project or abandon it. We consider Monte Carlo method for economic evaluation of the information. The paper also suggests to express the economic effect of information in equivalent amounts of hydrocarbons instead of monetary units. This in some cases will greatly simplify the calculations using practical formulas to estimate the economic impact of additional information based on fairly standard data available to the companies.
Influence of Permafrost on Seismic Imaging in Alaska
Authors: Matson Rick , Wolf Kevin , Yancey Daniel
Published: October 2013

A layer of permafrost, approximately 500m thick, lies immediately beneath the surface of Arctic Alaska’s Central North Slope. This frozen layer of unusually high seismic velocity overlies more than twenty producing fields containing over 60 Billion in place barrels of light and heavy oil. Multiple reservoir levels ranging in depth from 1000m to 3000m are nominally imaged using conventional surface 3D seismic technologies. Natural arctic surface features and man-made sub-surface activities produce local bodies of unfrozen sediment with anomalously low velocity in the surrounding high velocity permafrost. Abrupt lateral and vertical velocity variations detrimentally affect the conventional surface seismic image at reservoir depths, thereby negatively impacting our ability to describe the reservoirs and maximize production of this vast resource.

BP-Alaska, as operator of many of these fields, is motivated to apply optimal seismic acquisition and processing techniques to minimize permafrost-related image distortions. We are therefore developing a permafrost velocity characterization of both the offshore and onshore environments on the Arctic Central North Slope to guide the appraisal of available geophysical techniques. Our characterization is underpinned by: 1) physical properties of frozen and unfrozen sediments taken from the literature, 2) regional and local morphologies of the permafrost based on well log measurements, 3) the application of numerous geophysical techniques for the widespread measurement of shallow (upper 600m) velocities, and 4) a dynamic model for thawing of the permafrost caused by either naturally occurring or man-made circumstances to help predict the extent, shape, and depth of local velocity anomalies.

BP-Alaska is making progress in understanding the permafrost velocity field on the Central North Slope; but gaps in our ability to characterize a large portion of the permafrost interval still persist. Some techniques show promise but may not be economic in a brown field business environment located in an arctic acquisition environment.
Integration of a Complex Log Data Suite for the Evaluation of Pokurskaya Formation in Western Siberia
Authors: Ezersky D.. , Vishnevskaya I.. , Tukhtaev R.. , Charupa M.. , Latypov A.. , Weinheber P.. , Bikeev E.. , Pasynkov A.. , Tikhomirov E..
Published: October 2013

The maintenance of Western Siberia oil production levels has required the industry to evaluate and develop ever more complex reservoirs. In this case study we look at the evaluation of the heavy oil bearing field located in the north part of Western Siberia and specifically the unconsolidated Pokurskaya formation of the Cenomanian age. The specific evaluation requirements included an understanding of the oil properties, especially viscosity and its variations, and an understanding of recovery factor by an analysis of residual oil saturation. In order to accomplish these objectives an extensive suite of log data as acquired including standard triple combo data, cross-dipole acoustic, NMR, micro-images, spectroscopy and formation tester samples and pressures.

In this paper we show how an innovative use of NMR data allowed us to improve the fluid model and irreducible water saturation calculations. Combining NMR with standard data allowed a prediction of the residual oil saturation. Additionally, from the NMR data we were also able to extract oil viscosity information, however we needed a calibration point and for that a formation oil sample was required.

Unconsolidated formations saturated with viscous oils are notoriously difficult to sample with formation testers. Sand production can lead to contaminated samples, tool plugging and even borehole collapse. To avoid these issues we included dipole sonic data to estimate formation strength in order to select the optimal sampling locations. Additionally a new ‘dual intake’ straddle packer configuration was used to optimize the fluid sampling. As a result of these precautions samples were successfully acquired and the resulting PVT data was used in field development planning as well as calibration points for a continuous NMR-derived viscosity curve.
Engineering Protection for Permanent Offshore Platform against Ice Impact in the Arctic Shelf
Authors: Kutvitskaya N. B. , Ryazanov A. V.
Published: October 2013

Construction solutions, construction technology and exploitation conditions of protection facilities, keeping the floating platforms at a designed location, are proposed in this scientific paper. They have been developed and proved by thermal calculation and strength prediction.

Protection structure includes a pile row, made of metal pipes, and special all-year cooling (freezing) devices, located inside the metal pipes. The piles are installed into the sea floor sediments or on the bedrock, depending on soil conditions. A compressor unit runs the cooling system during the construction on floating platform. The agent inside the cooling system is circulating which causes ice (in water) and ice-ground (below sea bottom) cylinders to grow around pipes. Ice cylinders form piles of big diameter. These piles may interlock fully or partially, forming a shockproof wall, which can withstand ice loads.
Optimizing Underground Thermal Reserves By Insulating The Wellbore Monitoring And Modeling Wellbore Temperature In The Kharyaga Field’s Arctic Tundra Environment
Authors: Danquigny J.. , Semenov A.. , Eropkin E..
Published: October 2013

The Kharyaga oil field is located beyond the polar circle in northeastern Europe, and since 1999, has needed first-class thermal insulation for its ESP-lifted wells to produce. In these Arctic conditions, the permafrost typically reaches thickness of up to 300 meters. And with the wax appearance temperature (WAT) or pour point as high as 50°C and 30°C for some geological objects, managing wells in order to minimize wax scraping operations is a real challenge. Especially during shut-in periods, as the produced fluids cool down the risk of wax totally plugging the tubing is significant.

To combat that risk, the production or injection annuli are systematically filled with gelled diesel. Permanent real-time temperature monitoring by fiber optic sensors has been deployed in the production annulus of six wells so far, to measure temperature distribution along the wellbore across the permafrost layer, down to the reservoir. And thermal modeling, using the Enthalpy Balance thermal model, shows a good match with the temperatures thus measured. It also confirms the fine thermal quality, as per expectations, of the gel deployed.

For the purposes of further development of the Kharyaga field, which includes wells with liquid expected rates less than 1,000 bpd, well modeling flags up the necessity for additional thermal insulation. Using 3½" instead of 4½" tubing is a first solution: trials on two wells have shown a gain of up to 12°C. The benefit and design of field proven double-wall tubing was also assessed for the many additional development producers planned. One set of vacuum-insulated tubing (double-wall tubing with vacuum inside) is already on the spot ready for a field trial on a future work-over in the Kharyaga environment.
Environmentally Compatible Drilling Fluids
Authors: Pilgun Sergei , Aramelev Aleksey
Published: October 2013

Well drilling under arctic conditions affects the ecological situation in the region. At the same time, specific climatic conditions have additional requirements for designing, equipments and technologies. There are also particular specifications for drilling highly tortuous offshore wells. Making drilling fluids is a main task to ensure both technical capability and safety in case of oil spill.

The Arctic Region is the world storage of energetical reserves. Significance of offshore mining is increasing from day to day, especially on the background of depletion of easily accessible hydrocarbon reserves. Exploration of a shelf plate is an essential component of economic and strategic development of Russia.

Shelf plate exploration is carried out under harsh weather conditions: vast time period of storms, hard ice situation, change of stream velocities. All this creates additional requirements for the design, choice of applied equipment and technologies. Well drilling under arctic conditions is relevant to the environmental safety in the region. Restoration of the ecological balance in the zone of ecological catastrophe takes a lot of time. And major disasters are capable to tilt the ecological balance of our planet at all.

The main objective of exploration of the arctic shelf plate is development and implementation of high performance technologies that are security-wise and applicable to use in the Arctic region.

The important link of the technological chain of modern well construction is the drilling fluid that performs a lot of functions when carrying out drilling operations.
Improved Geomagnetic Referencing in the Arctic Environment
Authors: Poedjono Benny , Beck Nathan , Buchanan Andrew , Borri Luca , Maus Stefan , Finn Carol A. , Worthington E. William , White Tim
Published: October 2013

Geomagnetic referencing uses the Earth’s magnetic field to determine accurate wellbore positioning essential for success in today’s complex drilling programs, either as an alternative or a complement to north-seeking gyroscopic referencing. However, fluctuations in the geomagnetic field, especially at high latitudes, make the application of geomagnetic referencing in those areas more challenging. Precise crustal mapping and the monitoring of real-time variations by nearby magnetic observatories is crucial to achieving the required geomagnetic referencing accuracy. The Deadhorse Magnetic Observatory (DED), located at Prudhoe Bay, Alaska, has already played a vital role in the success of several commercial ventures in the area, providing essential, accurate, real-time data to the oilfield drilling industry. Geomagnetic referencing is enhanced with real-time data from DED and other observatories, and has been successfully used for accurate wellbore positioning. The availability of real-time geomagnetic measurements leads to significant cost and time savings in wellbore surveying, improving accuracy and alleviating the need for more expensive surveying techniques. The correct implementation of geomagnetic referencing is particularly critical as we approach the increased activity associated with the upcoming maximum of the 11-year solar cycle. The DED observatory further provides an important service to scientific communities engaged in studies of ionospheric, magnetospheric and space weather phenomena.
Solid Polymer Prevents Gas Migration into Cement Slurry in Subzero Conditions
Authors: Isgenderov Islam , Bogaerts Martijn , Docherty Kevin , Osayande Victor , Kanahuati Alia Iza
Published: October 2013

Cementing formations with medium to high gas migration severity in cold conditions is considered a very challenging operation for major operators in Turkmenistan. The liquid gas migration agents used in Turkmenistan for the above mentioned severities incur additional operational and technical challenges, particularly during the winter months as the ambient temperature falls below zero. In addition to the climatic challenges, Turkmenistan drilling activity often encounters the additional challenges of high pressures and narrow pore / frac windows.

This paper focuses on case studies to analyze the application of both liquid and solid gas migration prevention additives compared with conventional slurry systems in overcoming challenges encountered while cementing across gas bearing formations. To address such challenges, a solid polymer gas migration prevention additive has been field tested successfully in environments such as Canada, USA and Russia having similar conditions as Turkmenistan. A description is then given of a successful method of combining a special solid polymer based gas migration prevention system with good cementing practices, in order to not only achieve the primary objective of the cementing operation, but also yield improved logistics in terms of storage, handling, and no associated mix fluid aging or detrimental effect of thawing. Field case histories are presented, illustrating the versatility of the system in solving gas migration problems in seasonal climate changes.

Above all, solid gas migration prevention polymers are considered the best cost effective solution compared to the liquid gas migration agents of the same family which is considered as the key value for commercial oil and gas production.
Technology of Productive Horizons Casing Perforation by Drilling of Branched Channels With Midget Diameter and Curvature Radius
Authors: Aleksandrovich Lyagov Ilya , Aleksandrovich Lyagov Marina
Published: October 2013

Maintaining a high level of production volume means the maximum use of the opportunities of each well. The application of a number of ways to intensify well productivity, such as hydraulic fracturing, acid treatment, heat treatment, etc. is not always possible due to a number of geological and technological reasons. In addition, each of these methods has a negative component effect on the reservoir properties. The effectiveness of these methods, the impact on the bottom zone (producing zone) is often limited by the lack of reliable hydrodynamic connection between wells producing formation, which may be caused by deterioration of reservoir properties over time, the lack rock permeability, reservoir heterogeneity, insufficient length of perforations, etc. [1].

The new technology is designed to increase the perforation production flow rates and increase injection capacity of injection wells (by increasing filtration area producing zone), reduce water cut (by reducing the drawdown), as well as improving the turnaround time for well operation (by increasing the hydraulic perfection of producing zone) [2].

The technology involves the removal of the casing of the first stage of research and development project (hereinafter – drilling through the casing with change bit without lifting oriented capture and anchors for drilling in rock shown in Figure 2. The extension of the main trunk, injecting insulating special gelling agent, the creation of cement plug, drilling out its auxiliary barrel, drilling super long channels according to the predicted trajectory in one run [2, 3, 6].
Increasing the Frost- Resisting Properties of Cement Stone in Casing and Cementing of Wells Through the Use of Magnesia Cement Material
Authors: Pastuhov A. M. , Tolkachev G. M. , Kozlov A. S. , Anisimova A. V.
Published: October 2013

In 2012 by request of JSC"TNK-BP Management", in the Scientific laboratory "Technological liquids for well drilling and casing" of the Perm National Research Polytechnic University (PNRPU) works on assessing the properties of the cement materials developed by three foreign and one Russian service companies were carried out. These blends were announced as the cementing materials that had been specially designed for oil and gas well casing and cementing in the areas of Western Siberia and the Far North, where the presence of permafrost (PFR) in well profiles have made their use more complicated. The received testing results of the presented cement slurry – stone indicate that the signs of failure in the samples being tested for frost resistance are first indicated after 2 to 4 cycles of freezing and thawing. The samples showed fractures, flaking or chipping off. The maximum number of the "freeze and thaw" cycles prior to decreasing of cement stone strenght in the most frost-resistant of the blends presented for testing was 5, which is not enough to be able to predict a long-term integrity of cement stone incorporated in casing and cementing of the well.

To increase the quality of casing cementing within the intervals of permafrost rock formation, the employees of the PNRPU developed a new cementing blend with higher frost-resistance properties of cement stone. This special cement material is based on a highly active cementitious agent – magnesium oxide. The major advantage of this newly designed magnesia cement slurry is the higher frost resisting ability of cement stone as compared to those being tested. The reason for this is low capillary fluid content. The cement stone in such cementing material endures over 15 cycles of the "freeze" and "thaw" test. Among the positive characteristics of the cement slurry-stone which is viewed as perspective when used for casing cementing in the continuous permafrost zones are as follows: –possibility to achieve a lightweight cement slurry;–zero ice-thawing during putting the slurry into casing string annulus;–low rates on water separation and cement-water sedimentation of cement slurry;–good harden ability of cement slurry and strength development of cement stone at lower temperature;–adhesive bond formation between cement stone and ice.

The achieved magnesia cement blend can be used for experimental and industrial testing during casing cementing, when the casing strings extend through the perennially frozen rock deposits.
Improving Multistation Analysis of MWD Directional Magnetic Surveys
Authors: Bulychenkov Konstantin
Published: October 2013

Multistation analysis (MSA) is a technique widely used in the industry to correct systematic errors of magnetic MWD surveys associated with drillstring interference (DSI). However, to ensure an acceptable uncertainty of the correction we must understand the geomagnetic reference accuracy.

One of the main problems for magnetic MWD surveys is that the inaccuracy of the BGGM (BGS Global Geomagnetic Model) from the British Geological Survey (BGS), does not allow for correction of axial DSI for wells with inclination more than 55° in the west/east direction by the MSA method. If there is a local magnetic reference error, the BGGM does not have the required resolution to map it. This may mean that the azimuth error from the MSA correction will be significantly greater than the error caused by DSI. Thus, both a compensation for DSI and a good magnetic reference value are required to accurately position wells with MWD tools.

A modification of the MSA algorithm uses a model of distortion caused by DSI when a trajectory deviates. Within residual uncertainty, the results thus calculated are combined with the conventional MSA. That allows the possibility of avoiding the current limitation of DSI correction uncertainty.

The described algorithm avoids errors caused by geomagnetic reference inaccuracy in the case of a trajectory with changing direction and inclination. For cases with enough variation of the trajectory, we can correct axial DSI for horizontal wells in the west/east direction with high accuracy. Also, the method can be used for calculation of actual reference offsets from values derived from a geomagnetic model like the BGGM.

The developed method is an evolution of MSA that keeps all the advantages of the conventional method and avoids the limitation caused by geomagnetic reference inaccuracy. Application of this algorithm is most beneficial in regions where BGGM accuracy is low, as it is in Russia. In addition, the method allows greatly improving the correction of surveys for horizontal wells near an east/west direction in the case of a deviated trajectory.
Choosing Oil Spill Response Method to Protect Sensitive Coastal Areas in the Russian Arctic
Authors: Belkina Natalia
Published: October 2013

Once oil has been spilled, urgent decisions need to be made concerning response options, so that environmental impacts are kept to the minimum. Options for protection of shorelines include containment and recovery, in-situ burning, use of dispersants or just leaving the oil to dissipate and degrade naturally. All response options have both limitations and benefits which need to be compared with each other. This process is known as Net Environmental Benefit Analysis (NEBA).

A NEBA for protection of coastal areas in the Russian part of the Barents Sea and the White Sea was performed by Ramboll in the framework of the UNEP/GEF project "Improvement of the emergency oil spill response system under the Arctic conditions for protection of sensitive coastal areas (case study: the Barents and the White seas)". The analysis was based on the results from modeling of spills of oil and oil products which are transported through the Barents and the White seas, oil spill sensitivity mapping as well as assessment of available oil spill response (OSR) resources in the region.

The analysis shows that coastline protection methods such as using dispersants or in-situ burning lack methodological and regulatory framework and at the moment they cannot be used in the Russian part of the Barents Sea and the White Sea. The optimal available technique in case of a spill of fuel oil or crude oil will be mechanical containment and recovery (use of booms and skimmers). However, mechanical methods will be both inefficient and extremely hazardous to combat spills of gas condensate or naphtha due to high explosion and fire risk until full evaporation of the volatile fractions has taken place. In such a case it is recommended to observe the slicks and await natural dissipation.

Challenging logistics in the region and harsh climatic conditions can significantly impede timely response to offshore oil spills and use of traditional mechanical recovery that creates need for adapting alternative tactics such as in-situ burning and dispersants.
Oil Spill Response in the Arctic
Authors: Pilipenko Natalja , Lerondeau Benjamin , Vial Eric
Published: October 2013

The context of the Oil Spill Inconvenience of the existing oil spill recovery solutions Problems that we face during the recovery operation 5 important recommendations The Technology The Arctic solution

Despite the significant methods employed, very few- if any- hydrocarbons are recovered at sea. The existing solutions are not capable to recover Oil Spill at difficult weather conditions, rapidly and efficiently, especially in the Arctic. This paper will talk about the patented innovative technology to fight Oil Spill at sea and especially in Artic extreme environments.

First of all we will go through the main disadvantages of the existing solutions to fight oil spill pollution. We will see images and drawings that will explain us the reason of its bad functioning. Then we will put in advance few very important points which must be considered while choosing the solution of oil spill response at sea. And finally we will see in details the technology that permits to recover oil spill at any sea without creating emulsion.
Promising Physical-Chemical IOR Technologies for Arctic Oilfields
Authors: Altunina L.. , Kuvshinov V.. , Kuvshinov I..
Published: October 2013

The results of laboratory and field tests of physicochemical technologies for enhanced oil recovery are presented for oil fields developed by flooding and thermal-steam stimulation. These technologies can be used in extreme climatic conditions of the Arctic. A promising concept has been developed using reservoir energy or that of the injected heat carrier to generate oil-displacing fluid, gels and sols in situ. Physicochemical bases for EOR have been developed involving chemical intelligent systems: gel-forming and oil-displacing systems based on surfactants self-regulating a complex of properties, optimal for oil displacement, in a reservoir for a long time. Pilot tests of EOR technologies were successfully carried out in oil fields of Russia, China, Vietnam, Oman and Germany using gel-forming systems and surfactant compositions developed at IPC SB RAS. Such systems are commercially produced in Russia and China. The results of pilot tests and commercial application of the technologies for enhanced oil recovery and water shutoff are presented for oil fields with difficult-to-recover reserves including deposits of high-viscosity oils. For effective development of difficult-to-recover oil reserves and further increase in oil production it seems promising large-scale use of advanced complex technologies for enhanced oil recovery combining basic reservoir treatment by water or steam injections with physicochemical methods increasing reservoir sweep and oil-displacement factor at simultaneous intensification of the development. The achieved scientific and technical level of the works enables to create new EOR technologies for hydrocarbon deposits located in the Arctic shelf of Russia, in the Urals and Siberia, as well as reagents adaptable to works in the extreme climatic conditions.
Selection of Subsea Production Systems for the Field Development in the Arctic Environment
Authors: Pribytkov E. A. , Zolotukhin A. B. , Gudmestad O. T.
Published: October 2013

In this paper an analysis of the selection of integrated template structures for the arctic environment is presented. First of all, an analysis of several actual projects has been carried out, where their specifics were thoroughly studied. One of the important parts of the work was devoted to the requirements to integrated template structures conceived in relevant NORSOK, ISO and DNV standards. Arctic metocean conditions that can affect selection, installation and the operational conditions of templates are analyzed. The Main elements of Subsea Production Modules are considered in the work, their specific characteristics and components.

Operations and installation of subsea modules in Barents Sea are considered in the paper. Four scenarios with different numbers of integrated template structures (2, 3, 4 and 6) and different numbers of wellslots in each were analyzed. For each scenario an analysis of related marine operations for the subsea modules installation was carried out. A program for installation cost estimates was built that enabled us to find the optimal scenario for the integrated template structures design. Various parameters affecting the cost of subsea infrastructure were analyzed and studied from different perspectives, e.g. geometrical well pattern system, the distance between drilling centers, drilling and construction costs, etc. Risk analysis regarding the threats and consequences is also performed; risk assessment matrices and mitigation actions are established. As a result, a model for selecting an optimal Integrated Template Structure for the arctic/subarctic regions was built.
Russkoye Heavy Oil Field: Complexity and Exploration Prospects
Authors: Svarovskaya M. G. , Schmidt S. A. , Edelman I. Y. , Zolotukhin A. B.
Published: October 2013

Russkoye field is a unique field containing strategic volumes of hydrocarbon reserves. The pilot projects that lasted more than 20 years show its complexity and ambiguity: high viscosity oil, unconsolidated reservoir, thick gas cap, bottom water, location in the Arctic environment determine the objectives of the seismic, geophysics, development, production and exploitation studies.

This paper announces the key uncertainties that exist in the field and were taken into account to form the current vision of the project solutions for its development: determine principal production profiles, count and mutual location of production and injection wells, consider lateral heterogeneity through an adaptive development system, meeting the critical operating conditions.
Development History Case of a Major Oil-Gas-Condensate Field in a New Province
Authors: Grinchenko V. A. , Anuryev D. A. , Miroshnichenko A. V. , Gordeev Y. I. , Lazeev A. N.
Published: October 2013

The paper describes approaches of the Verkhnechonskoye field development design under uncertainty. Data integration examples for design of the full field development plan are given. Risk management strategy is described. Efficiency analysis of initial reservoir development decisions is made. Approaches to the field development scientific and engineering support are described. Greenfield project typical and unique problems and solutions examples are given (i.e. full field development strategy design, salty sandstone reservoir waterflooding).
The Features of Building the Integrated Model for Development of Two Gas-Condensate Formations of Urengoyskoe Field
Authors: Ignatyev A.. , Bikbulatov S.. , Mukminov I.. , Romashkin S.. , Buchinskiy S.. , Vikulova E..
Published: October 2013

Most of oil and gas companies are building simulation models for its assets to planning reservoir development. However, even in those cases when the models are reliable and well calibrated to the production history, they do not always reflect the interaction between the different parts of a single system "reservoir-well-gathering system-processing facilities". In other cases when hydrodynamic models are the parts of an integrated model (IM), the models become too complex and require a long time of simulation, what mostly is not very convenient.

This article provides an example of the IM building for the two formations of one of the largest oil-gas-condensate field in the world. Two large gas-condensate reservoirs are in the pilot stage. Full-field development of these reservoirs will increase hydrocarbon production by 5 times (Figure 1). To develop and optimize production plans and the development of the asset, it was decided to use the integrated model. Figure 1Planned production profiles for gas. Formations Ach3–4 and Ach52–3

There were considered different methodologies for constructing the unified model, which combines the reservoir models, models for wells and gathering systems and for processing facilities. Finally the best approach for this project has been selected. The initial compositional hydrodynamic models, which was matched to the production history, have been successfully converted to the Black-Oil models, while giving identical forecasts for gas and condensate and significantly reducing the simulation time. Well models were calibrated to historical data. The formation fluid in the gas gathering network was modelled using a simplified description, while in the models of processing facilities the fluid was modelling with the detailed composition. Despite of the differences in the approaches to the description of PVT properties of gas condensate in different simulators (Eclipse, Gap, Hysys), the developed Integrated Model has demonstrated consistency in the description of fluid PVT-properties. A significant reduction in time of simulation was obtained during the forecast calculations. The results of the Integrated Model were very important for the field development plan optimization, the development of which was previously limited to disparate models of reservoirs and ground infrastructure.
Method of Energetic Interconnected Junction of Large-Scale Inflow to SmartWells Constructed in Elaborated Reservoirs
Authors: Popkov V.I. , Zatsepina S.V. , Khamitov I.G. , Shakshin V.P.
Published: October 2013

Introduction

There are few people who have doubts concerning the important role of crest faults in migration and formation of oil/gas deposits. The increased fracturing and vags capacity in these zones creates the useful space which under favorable conditions that serves as subsurface storage of hydrocarbons (HC). Complex phase trajectories with the development of fractured reservoirs by numerous wells and rock pressure (stresses) related to them and the seismic emissions of condensed matrix cannot be described by parabolic equations of geological-hydrodynamical simulation. The geophysical and the related hydro-dynamic fields of HC genesis and accumulation, facies and phase borders of porous space in well inflow cases are characterized by the following general abnormal features:

Complicated self-organizing feature of scaled macro-world/micro-world space with no strict structural monitoring; Fluctuations of inflow profiles from zero up to several hundreds of cubic meters per day, that are not coordinated to low porosity and permeability values; Restrictions of deposits by faults, replacements, tidal wave depositions, condensation, and for the wells - by segments with zero inflow from low-permeable, stagnant zones with jammed capillaries and counter-flow impregnation; Tangential pressures, non-equilibrium temperature, viscosity and difficulty (sometimes impossibility), inversion in saturation and pressure, defining the OWC; Convectual/diffusional shear deformations, non-equilibrium lithology, suffusion.

We submit two ways for decisions with multi-scaled regional task: «on a flow basis» from a well towards petro-physics and from lithology of rock space - to a well, by methods of evolutionary transformation of the equations for mass preservation up to energy-steady solutions of Navier-Stoks's equation. We have received analytical and numerically integrated decisions on the interaction of rock pressure (stress) inside the porous space and viscous drain of a well.

Theoretical Substantiation of a Problem

The forecasting of saturation character for sedimentary HC traps is one of most complicated items inn seismic exploration, geo-physics and geological hydro-dynamic modeling of deposits as well as the processes of their development. The problems while simulating these systems is related to the arrangement of various areas inside the formation, which act differently with the actions applied towards them, depending upon the stage of development. With this in mind the model of interaction it substantially different depending upon the type of effect and the distance from the center of this effect. As a result the actual behaviour of the system deviates from model one, giving the solutions that are "asymmetrical?? in specific models.
Problems of Oil and Gas Production in the Verkhnechonskoye Oil and Gas Condensate Field Associated with Halite Depositing
Authors: Chertovskikh E. O. , Lapoukhov A. S. , Kachin V. A. , Karpikov A. V.
Published: October 2013

The paper provides data on chemical composition of formation water and injected water of the Verkhnechonsky Horizon and reviews differences between them. It describes results of in-field observations of inflow of formation and injected waters into producing wells and associated halite depositing during oil and gas production. A summary of causes for halite plugging in the downhole equipment is provided. Estimation of skin factors and productivity ratios are done for cases of halite redeposition in bottomhole zones of the formation. Technological solutions for assurance of halite deposition control during oil and gas production in the Verkhnechonskoye Oil and Gas Condensate Field are described. The actual data are compared to data available from publications on the problem of halite/chloride depositing during oil production. A theoretical basis is proposed for understanding of geochemical processes of halite depositing in the bottomhole zones in the Verkhnechonskoye Field.

The Verkhnechonskoye Oil and Gas Condensate Field (hereafter the VC Filed) is located in Katanga District of the Irkutsk Region in East Siberia (Extreme North Area). The main oil and gas reservoirs are placed in the Verkhnechonsky Horizon (83% of recoverable reserves). (Figure 1). Figure 1Scheme of faults and formation borders in the Verkhnechonskoye Field