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Collaborating Authors
Stø Formation
Abstract As development concepts for the Johan Castberg Field matured, new locations required soil data. A harder layer has been identified from previous soil data and mapped on seismic profiles as Seismic Unit II. This layer may cause refusal of suction anchor penetration and should ideally be avoided. Predictions of the depth to this layer both along and between seismic profiles were used to optimize suction anchor locations to be investigated during the 2018 soil investigation. This campaign was furthermore optimized by taking earlier laboratory testing into consideration. The Nkt factors were given special attention and found not to vary much in the topmost soil layers. Greater emphasis could therefore be put on acquiring CPTU data, and to use these previously determined Nkt factors to find the soil strength. The predictions of the depths to the top of Seismic Unit II were in general agreement with the data acquired during the 2018 investigation. The emphasis on collecting CPTU data and combining these with experience from the previous soil testing results saved both ship time and laboratory costs.
- North America > United States (0.68)
- Europe > Norway > Barents Sea (0.63)
- Europe > Russia > Barents Sea (0.40)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Stø Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Nordmela Formation (0.99)
- (11 more...)
Abstract The purpose of this study is to provide a technical evaluation of the feasible development concepts for selected oil discoveries in the Barents Sea, named; Goliat, Johan Castberg, Alta, Gohta, and Wisting. The study is unique to the extent that includes consideration of all required elements for a field development project; subsurface conditions, reservoir engineering, production profiles, drilling schedule, subsea and topside facilities, infrastructure (existing and planned) and environmental concerns in the Barents Sea. The selected method was based on high-level of facts, reservoir data, recoverable reserves, in place volumes and other available data, which all originates from public resources and literature. The collected data were systemized into our in-house developed profile generator tool. A predefined drilling schedule was implemented in the profile generator, and output was production rate and cumulative production. Technical and commercial evaluation on three different development concept scenarios for the selected oil discoveries has been presented. Scenarios were defined based on using available and future planned infrastructure in the region. It has been shown that the distance between discoveries and the shoreline in the Barents Sea is relatively large, and resources are lower than what is commercially needed to evaluate as a stand-alone solution. The results of the study show that discoveries may be developed through a coupled reservoir solution.
- Europe > Norway > Barents Sea > PL 537 > Block 7324/8 > Wisting Field > Sto Formation > Well 7324/8-3 (0.99)
- Europe > Norway > Barents Sea > PL 537 > Block 7324/8 > Wisting Field > Fruholmen Formation > Well 7324/8-3 (0.99)
- Europe > Norway > Barents Sea > PL 537 > Block 7324/7 > Wisting Field > Sto Formation > Well 7324/8-3 (0.99)
- (121 more...)
How to Manage Geomagnetic Field Disturbances in the Northern Auroral Zone to Improve Accuracy of Magnetic MWD Directional Surveys
Edvardsen, I.. (Baker Hughes, a GE company) | Nyrnes, E.. (Baker Hughes, a GE company) | Johnsen, M. G. (Baker Hughes, a GE company) | Hansen, T. L. (Baker Hughes, a GE company) | Aarnes, I.. (Baker Hughes, a GE company)
Abstract The auroral zone is the region surrounding the geomagnetic north and south poles and is where the largest and most frequent disturbances in the Earth's magnetic field are experienced. Since the accuracy of magnetic MWD directional surveys are affected by geomagnetic disturbances, surveying wells in the auroral zone is challenging. Development of industry practices to enable accurate surveying and safe operations in these areas is therefore important. The objective of this study is to investigate how the geomagnetic field parameters declination, dip angle and total magnetic field intensity are influenced by magnetic disturbances in the auroral zone. This is done by analysing the statistical properties of data from 20 land-based magnetic observatories and variometer stations in Alaska, Greenland, and Scandinavia, all located in the auroral zone. The results are used to estimate models for magnetic field disturbance variations as function of distance and direction. Additionally, methods and correction procedures to reduce azimuth uncertainty using data from distant monitoring stations are presented. Uncritical use of data from monitoring stations can result in uncertain azimuth measurements. In cases where data from more than one nearby monitoring stations are available, the challenge is often related to identifying which stations that provide the most accurate corrections. As will be shown, important criteria for the selection of monitoring stations are not only limited to directions and distances, but also the position of the ionospheric current relative to the rig-location. Procedures and methods for how to predict the positions of ionospheric currents are presented. The datasets analysed in this study contain measured deviations from the quiet mean for periods with low, moderate and high geomagnetic activity. Station-pairs with mutual distances ranging from 150km to 850km are considered. The general trends are that magnetic data from station-pairs located along the east-west direction are more correlated than data from stations located along north-south, and that differences in magnetic fluctuations between station-pairs are lower east-west than north-south. This accounts for all distances, directions, and disturbance levels.
- Europe > Norway (0.91)
- North America > United States > Alaska (0.36)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.46)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Stø Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Nordmela Formation (0.99)
- (41 more...)
ABSTRACT Fabrication and installation of offshore steel structures in the Arctic region will face some major challenges. Many of these challenges are well known and brought from the North Sea and the Norwegian offshore fields. Exploration in the Norwegian territory of the Arctic has taken place in the southwestern Barents Sea, i.e., in the area free of ice. So far, Snøhvit and Goliat fields have complete installations, Johan Castberg is now under planning. Therefore, there will be a gradual approach towards temperatures lower than −20°C (the lowest temperature in the current NORSOK standard is −14°C), which may represent a major challenge for the materials and structural integrity. The design temperature for Goliat is −20°C, while Johan Castberg will possibly be somewhat lower. Due to the continuous decrease in temperature the further north the field is, welded structures need focus concerning their low temperature properties. Although the initial base metal toughness may be excellent, a severe toughness deterioration occurs normally as result of fabrication welding. The present investigation summarizes results achieved in the steel part of the Norwegian project "Arctic Materials" concerning the low temperature fatigue properties in terms of crack growth, fracture toughness of steel weldments, the toughness scatter and its treatment, constraint corrections, effect of residual stresses and finally, the stress-strain behavior. The results are currently the basis for establishment of design guidelines for steel structures for the Arctic region. INTRODUCTION In Norway, research projects on materials behavior at low temperatures have been in progress since 2008 due to an expected increased oil and gas activity in the Barents Sea (e.g., Akselsen et al, 2011; Østby et al, 2011; Mohseni et al, 2012; Welsch et al, 2012; Østby et al, 2012a, 2012b; Jørgensen et al, 2013; Mohseni et al, 2013; Østby et al, 2013; Akselsen and Østby, 2014; Haugen et al, 2014; Mohseni et al, 2014; Wiklund et al, 2014; Hjeltereie, 2015; Kane et al, 2015). In the southwest area of the Barents Sea, north-northwest of the city of Hammerfest, the Snøhvit and Goliat fields are completed and in production. While Snøhvit consists of subsea production units only, the Goliat topside structure fabrication had design temperature of −20°C. This is below the minimum temperature set in existing NORSOK standards (NORSOK, 2008, 2011, 2014), which covers temperatures down to −14°C. Lower minimum design temperatures require project specific evaluations. The operator ENI accounted for this during fabrication and installation. At present, the Johan Castberg oilfield, is located about 100 kilometers north of the Snohvit-field, is under planning. Havis oilfield is another one, to be developed together with Johan Castberg due to the short distance between the two. Several other promising discoveries, e.g., the Gotha/Alta fields and many more, make the situation quite attractive. When moving further north, the temperature falls below −20°C, which means that the low temperature behavior of the structural steel becomes critical. Thus, the situation calls upon the importance of available adequate standards and guidelines for selection and design of steels for structural application in these areas. Such guidelines are now under development in the ongoing Norwegian project (Horn and Hauge, 2011, Horn et al, 2012; Østby et al, 2013; Horn et al, 2016, 2017).
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Stø Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Nordmela Formation (0.99)
- (73 more...)
Mobile Technology of Frequency-Resonance Processing and Interpretation of Remote Sensing Data: The Results of Application in Different Region of Barents Sea
Yakymchuk, N.A. (Institute of Applied Problems of Ecology, Geophysics and Geochemistry) | Levashov, S.P. (Institute of Geophysics of Ukraine National Academy of Science) | Korchagin, I.N. (Institute of Geophysics of Ukraine National Academy of Science) | Bozhezha, D.N. (Management and Marketing Center of Institute of Geological Science NAS Ukraine)
Abstract The results of application the technology of frequency-resonance processing and interpretation of remote sensing (RS) data for the hydrocarbons (HC) accumulation searching and prospecting in different region of Barents Sea are analyzed in the paper. This mobile method works within the framework of the "substantial" paradigm of geological and geophysical studies, the essence of which is "direct" searching for a particular substance such as oil, gas, gold, silver, platinum, zinc, iron, water, etc. Technology allow to detect and map operatively the anomalous zones of the "oil accumulation" and (or) "gas accumulation" type. The bedding depths of the anomalous polarized layers (APL) of gas, oil and gas-condensate type may be determined by vertical scanning of RS data within detected anomalous areas. Mobile technology allows to get a new (additional) and, more importantly, independent information about petroleum potential of the surveyed areas. This information in integration with available geological and geophysical materials can be used to select the objects for detailed studying and primary drilling. Mapped large anomalous zone of the "gas reservoir" and "gas-condensate reservoir" type on the unique Shtokman field allows to conclude, that giant and unique HC deposits in the Arctic region can be detected and mapped by used mobile method. The absence of anomalous zone over Central structure on the Fedynsky High and the relatively small anomalous zone over Pakhtusovskaya structure indicate that the probability of finding giant fields within these structures is very low. Consequently, the detailed geological-geophysical studies and drilling within these structures at this stage of prospecting are impractical due to the fact that at such a distance from the coast now is economically feasible to develop only the giant and unique HC deposits. Seven anomalous zones of the "gas+condensate" type were mapped also within area of the large Varnekskoye uplift. Seven anomalies of "oil and gas deposits" type have been discovered and mapped on the Norwegian shelf in the area of Skrugard and Havis fields' location with mobile method using. In the Norwegian part of the former "gray" zone of the Barents Sea the remote sensing data were processed within four search sites covering 39742 km2. Area of 3D seismic work within them is 13956 km2. Two anomalous zones of the "gas deposit" type and 13 anomalous zones of "gas+condensate reservoir" type with total area of 1613 km2 were detected and mapped within investigated areas. The received results show the principal possibility of remote sensing, seismic and geoelectric methods integrated application for hydrocarbon accumulations prospecting and exploration within offshore. The mobile technology of frequency-resonance processing of RS data provides a unique opportunity to operatively investigate in reconnaissance character within the Arctic region the most promising areas for the detection of giant and unique HC fields. This may significantly speed up the development of the oil and gas potential of Arctic region.
- Asia (1.00)
- Europe > Russia > Barents Sea (0.50)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (1.00)
- Geophysics > Electromagnetic Surveying (1.00)
- Europe > Russia > Northwestern Federal District > Nenets Autonomous Okrug > Timan-Pechora Basin > Khoreiver Basin > Pomorskoye Field (0.99)
- Europe > Russia > Barents Sea > East Barents Sea Basin > Shtokmanovskoye Field (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.94)
- (16 more...)
Abstract The Ganges Brahmaputra Delta and the associated Bengal Fan is the world's largest delta/submarine fan complex. The deepwater areas of the Bengal and Rakhine Basins are relatively underexplored frontier areas. In 2003 the large Shwe gas field was discovered in Lower Pliocene turbidite fan sediments with reserve estimates of 6–9 tcf. As additional blocks are licensed, new data will be acquired to evaluate the area including 3D CSEM which is being considered as a complementary exploration method to seismic data. The controlled-source electromagnetic (CSEM) method has been applied to oil and gas exploration and production for more than 10 years. EM data are used to indicate the presence of hydrocarbons, since hydrocarbon saturated rocks display higher electric resistivity compared to water-filled reservoirs. CSEM is an excellent technique to define the lateral extent of hydrocarbon accumulations and is particularly useful in determining the existence and extent of stratigraphic accumulations. 3D modelling indicates CSEM is sensitive to the Shwe Field reservoirs and can define the lateral extent of the pay zones. 3D CSEM forward modelling has been performed over a range of target sizes within the economic limitations of deepwater drilling, and the modelling shows that CSEM would be sensitive to those targets. Based on these results, it is concluded that CSEM 3D data will detect the presence of hydrocarbon accumulations and thus, high-grade exploration areas in the greater Bengal Basin. Introduction In this paper we describe how the deepwater reservoir sediments in the Bay of Bengal, dominated by a deepwater turbidite depositional process, is the ideal geologic setting for detecting resistive anomalies related to hydrocarbon accumulations. Turbidites, by nature, are anomalous deposits of sand encased in shale. When saturated with hydrocarbons, they are more resistive than the surrounding shales, allowing them to be detected using the marine controlled source electromagnetic (CSEM) method. CSEM is sensitive to the large Shwe field accumulation on the shelf, offshore Myanmar and is used in this study to illustrate the ranges of detectability in the adjacent deepwater areas (Fig. 1).
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Electromagnetic Surveying (1.00)
- Asia > Myanmar > Rakhine State > Bay of Bengal > Andaman Sea > Rakhine Basin > Central Lowland Province > Block A-6 > Shwe Field (0.99)
- Asia > Myanmar > Rakhine State > Bay of Bengal > Andaman Sea > Rakhine Basin > Central Lowland Province > Block A-3 > Shwe Field (0.99)
- Asia > Myanmar > Rakhine State > Bay of Bengal > Andaman Sea > Rakhine Basin > Central Lowland Province > Block A-1 > Shwe Field (0.99)
- (15 more...)
Summary The measured Towed Streamer EM data from a survey in the Barents Sea, undertaken in the Norwegian sector are inverted as a series of unconstrained 2.5D inversion. We show that unconstrained anisotropic 2.5D inversion of the EM data in complex geological settings can produce resistivity models that are consistent with both interpreted log and seismic data, and known discoveries. We consider three cases from the surveys acquired over Skrugard, Caurus and Norvarg areas of Barents Sea. We have compared the results of unconstrained inversion to publically available log data at Skrugard discovery. Not only is the overall depth trend recovered, but the main variation of the resistivity is captured as well as, in some intervals, comparable average interval resistivity. We also show example resistivity and apparent anisotropy sections, while the resistivity section highlights that the sub-surface resistivity is complex, the somewhat simpler anisotropy section reveals an anisotropy anomaly that is co-incident with both the lateral, and depth, extent of Skrugard. The apparent anisotropy corresponds fairly well with Caurus and Norvarg anomalies. However, finding structural outline from the vertical resistivity alone is challenging by unconstrained inversion.
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.98)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Stø Formation (0.98)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Nordmela Formation (0.98)
- (9 more...)
- Asia > Middle East > Yemen (0.98)
- Asia > Middle East > Saudi Arabia (0.98)
- Africa > Sudan (0.98)
- (3 more...)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > PL 054 > Block 31/6 > Troll Field > Sognefjord Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > PL 054 > Block 31/6 > Troll Field > Heather Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > PL 054 > Block 31/6 > Troll Field > Fensfjord Formation (0.99)
- (21 more...)
Abstract The discovery of Skrugard in 2011 was a significant milestone for hydrocarbon exploration in the Barents Sea. The result was a positive confirmation of the play model, prospect evaluation, and the seismic hydrocarbon indicators in the area. In addition, the well result was encouraging for the CSEM interpretation and analysis that had been performed. Prior to drilling the 7220/8-1 well, EM resistivity images of the subsurface across the prospect had been obtained along with estimates of hydrocarbon saturation at the well position. The resistivity distribution was derived from extensive analysis of the multiclient CSEM data from 2008. The analysis was based on joint interpretation of seismic structures and optimal resistivity models from the CSEM data. The seismic structure was furthermore used to constrain the resistivity anomaly to the Skrugard reservoir. Scenario testing was then done to assess potential alternative models that could explain the CSEM data in addition to extract the most likely reservoir resistivity. Estimates of hydrocarbon saturation followed from using petrophysical parameters from nearby wells and knowledge of the area, combined with the most likely resistivity model from CSEM. Our results from the prewell study were compared to the postwell resistivity logs, for horizontal and vertical resistivity. We found a very good match between the estimated CSEM resistivities at the well location and the corresponding well resistivities. Thus, our results confirmed the ability of CSEM to predict hydrocarbon saturation. In addition, the work demonstrated limitations in the CSEM data analysis tools as well as sensitivity to acquisition parameters and measurement accuracy. The work has led to more CSEM data acquisition in the area and continued effort in development of our tools for data acquisition and analysis.
- Geophysics > Electromagnetic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.68)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.98)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Stø Formation (0.98)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Nordmela Formation (0.98)
- (12 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
Improving the Accuracy and Reliability of MWD Magnetic Wellbore Directional Surveying in the Barents Sea
Edvardsen, I.. (University of Tromso and Baker Hughes) | Nyrnes, E.. (Statoil ASA) | Johnsen, M. G. (University of Tromsø) | Hansen, T. L. (University of Tromsø) | Løvhaug, U. P. (University of Tromsø) | Matzka, J.. (Technical University of Denmark)
Abstract The years ahead will see increased petroleum-related activity in the Barents Sea with operations far off the coast of Norway. The region is at high geomagnetic latitude in the auroral zone, and therefore, directional drilling using magnetic reference will experience enlarged azimuth uncertainty compared to operations in the Norwegian and North Seas. Two main contributors to azimuth uncertainty are magnetic disturbances from electric currents in the ionosphere and axial magnetic interference from the drillstring. The former is more frequent in the Barents Sea than further south and the effect of the latter is increased because of diminished value of the magnetic horizontal component. Directional wellbore surveying for operations on the continental shelf in the North Sea and the Norwegian Sea rely on well-established procedures for near real-time magnetic monitoring using onshore magnetic reference stations. The different land and sea configuration, distant offshore oil and gas fields, higher geomagnetic latitude and different behavior of the magnetic field require the procedures to be reassessed before applied to the Barents Sea. To reduce drilling delays, procedures must be implemented to enable efficient management of magnetic disturbances. In some areas of the Barents Sea, the management requires new equipment to be developed and tested prior to drilling, such as sea-bed magnetometer stations. One simple way to reduce drillstring interference is increasing the amount of non-magnetic steel in the bottomhole assembly (BHA). To maintain azimuth uncertainty at an acceptable level in northern areas, it is crucial that directional wellbore surveying requirements are given high priority and considered early during well planning. During the development phase of an oil and gas field, the planned wells must be assigned adequate positional uncertainty models and if possible, be designed in a direction that minimizes the wellbore directional uncertainty.
- Europe > United Kingdom > North Sea (0.46)
- Europe > Norway > North Sea (0.46)
- Europe > Netherlands > North Sea (0.46)
- (2 more...)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Tubåen Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Stø Formation (0.99)
- Europe > Norway > Barents Sea > PL 532 > Block 7220/8 > Johan Castberg Field > Nordmela Formation (0.99)
- (15 more...)
- Well Drilling > Well Planning > Trajectory design (1.00)
- Well Drilling > Drillstring Design (1.00)
- Well Drilling > Drilling Operations > Directional drilling (1.00)