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Remote Sensing Imagery and the derived ancillary products improved the efficiency and safety of upstream oil and gas operations on the North Slope of Alaska. These Arctic regions are remote, very difficult to access in general and sometimes only seasonably accessible. Our prudent and responsible Arctic Operations require regional-reconnaissance exploration, diligent monitoring of environment such as current state of vegetation, temporal changes of terrain, water drainage system and lakes. Finally, we also need very detailed logistical-planning of field operations. Remote sensing imagery and its derived ancillary products demonstrably improved all these aspects of our Arctic Operations.
For Arctic Operations, remote sensing data consisted of optical satellite and aerial imagery at various spectral and spatial resolutions, high resolution LIDAR data for digital elevation and digital surface models and synthetic aperture radar imagery (SAR). A combination of in-house and commercial software was used to ingest and process these data. The optical imagery was processed and enhanced using various spectral combinations and high pass filtering to generate the highest possible spatial-resolution for each sensor. Classic neural networks analysis was used to classify the optical imagery for vegetation. The SAR imagery was calibrated (for all polarizations) and geometrically corrected to remove layover effects. The processed optical and SAR imagery, LIDAR and ancillary products were co-registered and imported into a GIS system for final analysis and applications.
The optical imagery provided information about surface feature such as lake outlines, general drainage, active channels in Colville River, general lake ice conditions, classification of vegetation types etc. The LIDAR data were used to generate slope maps (for arctic vehicles), general topographic conditions and field operations. The SAR imagery was used to monitor surface conditions when optical imagery was not available during the Arctic night conditions. SAR imagery was also used to calculate the ice thickness proxy maps for eventual field operations. All of these products contributed directly to our environmental baseline studies, improved our field operation efficiency and general safety of our Arctic Operations.
For a practicing engineer (individual or team) The remote sensing data and derived products for Arctic Operations were made available via GIS system. This allowed easy integration with other data layers as well as a common background for all different disciplines to monitor progress and to contribute their learnings and ideas to the entire team.
Jo, Y. (Daewoo Shipbuilding and Marine Engineering) | Choi, J. (Daewoo Shipbuilding and Marine Engineering) | Park, S. (Daewoo Shipbuilding and Marine Engineering) | Lee, J. (Daewoo Shipbuilding and Marine Engineering) | Ki, H. (Daewoo Shipbuilding and Marine Engineering) | Han, S. (Daewoo Shipbuilding and Marine Engineering)
The activities related to exploitation for oil and gas in the Arctic areas increase significantly. In order to transport increased resources in the Arctic areas, large Arctic commercial vessels such as gas carriers, oil tankers, bulk carriers, etc. are needed for mass transportation. In Arctic area, the ice load is the main factor of environmental load acting on Arctic vessel. The ice load is increased with the enlargement of vessel.
The largest Arctic commercial vessel was built by DSME in 2016. The vessel was delivered after completion of ice trial in March 2017. The size of Arctic LNG carrier is larger than any other Arctic vessels have been constructed so far. The ice load monitoring system was installed for ice load measurement and structural safety of ice navigation of this large LNG carrier.
This paper is concerned with comparison between estimated ice load for structural design and measured ice load for vessel navigation in Arctic area. Design ice load was calculated according to prescriptive rules of the Classification societies. Actual ice load during ice navigation was measured from ice load monitoring system. The arrangement of sensors in the monitoring system was determined for the precise measurement of ice induced loads acting on the hull. FE analyses were also carried out to compare between estimated ice load and measured ice load considering complex structural details in the Arctic LNG carrier.
Cheng, Yaoze (University of Alaska Fairbanks) | Czyzewski, William (University of Alaska Fairbanks) | Zhang, Yin (University of Alaska Fairbanks) | Dandekar, Abhijit (University of Alaska Fairbanks) | Ning, Samson (Reservoir Experts, LLC) | Barnes, John (Hilcorp Alaska LLC)
Alaska North Slope (ANS) contains vast resources of heavy oil which have not been developed efficiently using conventional waterflooding. Recently, low salinity waterflooding (LSWF) has been considered to enhance oil recovery by reducing residual oil saturation in the Schrader Bluff heavy oil reservoir.
In this study, lab experiments have been conducted to investigate the performance of LSWF in heavy oil reservoirs on ANS. Fresh-state core plugs cut from preserved core samples with original oil saturations have been flooded sequentially with high salinity produced water, low salinity water, and softened low salinity water. The cumulative oil production and pressure drop across the core plugs have been recorded by the AFS-300 coreflooding system. The oil recovery factors and residual oil saturation after each flooding have been determined based on material balance. In addition, restored-state core plugs saturated with heavy oil have been employed to conduct unsteady-state displacement experiments to measure the oil-water relative permeabilities using high salinity produced water and low salinity water, respectively.
It has been found that the core plugs are very unconsolidated, with porosity and absolute permeability in the range of 33 – 36% and 155 – 330 mD respectively. Produced crude oil sample having a viscosity of 63 cP at ambient conditions was used in the experiments. The total dissolved solids (TDS) of the high salinity produced water and the low salinity water are 28,000 mg/L and 2,940 mg/L, respectively. After softening, the TDS of softened low salinity water has little change, but the concentration of Ca2+ has been reduced significantly. The residual oil saturations are reduced gradually by applying LSWF and softened LSWF successively after high salinity water flooding. On the average, LSWF can improve heavy oil recovery by 6.3% of original oil in place (OOIP) over high salinity water flooding, while the softened LSWF further enhances the oil recovery by 1.3% OOIP. The pressure drops observed in the LSWF and softened LSWF demonstrates more fluctuations than that in the high salinity water flooding, which indicates potential particle migration in LSWF. Furthermore, it was found that regardless of the salinity the calculated water relative permeabilities are much lower than the typical values in conventional rock-fluid systems, implying more complex interactions between the reservoir rock, heavy oil, and injected water. This study provides fundamental lab data for evaluating the technical and economic benefits of LSWF in heavy oil reservoirs on ANS.
A new real-time model was developed, based on a deep recurrent neural network (DRNN), to predict response variables, such as surface pressure response, during the hydraulic fracturing process. During the stimulation process stage, fluids are inserted at the top of the wellhead, and the flow is driven by the difference between the hydrostatic pressure and reservoir pressure. The major physics and engineering aspects in this process are very complex; quite often, the measured data includes a large amount of uncertainty related to the accuracy of the measured data, as well as intrinsic noise. Consequently, the best approach uses a machine learning-based technique that can resolve both temporal and spatial non-linear variations.
The approach followed in this paper provides a long short-term memory (LSTM) network-based method to predict surface pressure in a fracturing job, considering all commonly known surface variables. The surface pumping data consists of real-time data captured within each stage, including surface treating pressure, fluid pumping rate, and proppant rate. The prediction of a response variable, such as the surface pressure response, is important because it provides the basis for decisions made in several oil and gas applications to ensure success, including hydraulic fracturing and matrix acidizing.
Currently available modeling methods are limited in that the estimates are not high resolution and cannot address a high level of non-linearity in the treatment pressure time series relationship with other variables, such as flow rate and proppant rate. In addition, these methods cannot predict subsurface variable responses based only on surface variable measurements. The method described in this paper is extended to accommodate the prediction of diverter pressure response.
The model presented in this paper uses a deep learning neural network model to predict the surface pressure based on flow rate and proppant rate. This work represents the first attempt to predict (in real time) a response variable, such as surface pressure, during a pumping stage using a memory-preserving recurrent neural network (RNN) variant (for example, LSTM and gated recurrent unit (GRU)). The results show that the LSTM is capable of modeling the surface pressure in a hydraulic fracturing process well. The surface pressure predictions obtained were within 10% of the actual values. The current effort to model surface pressure can be used to simulate response variables in real time, providing engineers with an accurate representation of the conditions in the wellbore and in the reservoir. The current method can overcome the handling of complex physics to provide a reliable, stable, and accurate numerical solution throughout the pumping stages.
The IMO's International Code for Ships Operating in Polar Waters (Polar Code) entered in to force on 1 January 2017 and provides, for the first time, an international regulatory framework for ships operating in Polar waters. In addition to technical regulations, the Polar Code requires that the Polar Ship Certificate should reference a methodology to assess operational capabilities and limitations in ice: essentially setting operational limitations for the specific ship navigating in Polar waters. The Polar Operational Limit Assessment Risk Indexing System (POLARIS) has been developed as an acceptable methodology for providing guidance on the operational limitations in ice of ships assigned different ice classes and has been directly referenced by the IMO in the Polar Code. The system was developed as a collaborative effort, drawing on operational and regulatory experience from industry and national administrations with experience in setting navigational limitations for ice covered waters. This paper presents the technical background behind the system and supporting information on its practical use both as a voyage planning tool and as real-time guidance on assessing ice regimes ahead of the ship. Validation of the system in the context of other existing regulatory requirements is discussed. The limitations of the system are explored and commentary and proposals are provided on recommended future enhancements.
Pipelines and roads represent the arteries of the oil and gas, and mining and transportation industries, respectively. They move product from remote locations to more centralized locations, either for processing or for shipping to refineries and mills for subsequent processing. Proper infrastructure development is critical to the successful development of the sensitive Arctic environment especially true in light of ongoing climate change where the melting of permafrost poses significant issues for development in the Arctic. The harsh Arctic environment presents unique challenges that are not found in more southern latitudes for the oil and gas and transportation sectors, including permafrost and permafrost degradation. It is well acknowledged that the extent of permafrost in northern environments is poorly known and mapped.
New tools are being used to help determine the extent of permafrost and to identify areas that are more susceptible to permafrost degradation in light of on-going and future development. One such tool is the use of softcopy mapping to help map terrain and geological modifying processes such as permafrost. Softcopy uses traditional stereo aerial photographs in a digital environment to allow scientists the ability to view the landscape at scales of 1:1,000 from traditional aerial photography that were captured at scales of 1:24,000 to 1:40,000. The advantage of softcopy is that by being able to zoom down to such large scales allows terrain scientists the ability to better determine the soil types (sand, silt or clay), drainage conditions (rapid to very poor) and on-going geological processes such as permafrost as evidenced by frost boils and permafrost degradation as evidenced by presence of thermokarst and thaw slides. Another method often utilized where stereo aerial photography is not available is use of remote sensing datasets such high resolution digital elevation models and satellite imagery which are becoming general available in Arctic regions. These elevation models are used to create hillshade images of varying aspects and photorealistic 3D models to help map terrains.
This paper will present a number of examples of where such mapping has been used to assist in pipeline and infrastructure planning in Alaska and Canada's north.
The ‘Frontier Arctic’ offshore has been explored on and off since the 1970s, driven by oil price and areas open for leasing or licensing. While a widespread, future return is questionable, operators contemplating a return can benefit from past experience. Insight and perspective are provided on the technical and non-technical challenges and impact on the business challenge. Actions and opportunities to change the overall cost and non-technical business risk dynamic are discussed.
‘Frontier Arctic’ oil and gas resources have characteristics of 1) being located outboard of established offshore regions of oil and gas exploration and development, 2) having physical attributes of water depth and ice conditions that require the use of specialized equipment or measures to safely and cost effectively drill, and 3) having non-technical business risks with the potential for high business consequences. This loose definition includes much of the Alaskan Arctic, the Canadian Beaufort Sea, Greenland, the far northern Barents Sea, and much of the Russian shelf. The technical and non-technical issues associated with exploration drilling in these regions are well-established, but not necessarily well-integrated.
Interest in ‘Frontier Arctic’ exploration may be rekindled in the future depending upon commodity prices; however, the ability to make material cost changes are limited due to the nature of the technical challenge; and the "Frontier Arctic’ will likely remain a target for environmental activism. Furthermore, exploration drilling would need to take place now or in the reasonably near future if ‘Frontier Arctic’ resources are to have a chance of contributing to a future oil or gas supply shortfall. Notwithstanding, Arctic offshore exploration can be expected to continue in regions where cost and business risk can be managed such as the southern Barents Sea and nearshore Alaska Beaufort Sea region.
The Arctic Response Technology Joint Industry Programme (ART JIP) was completed in 2017. The research program focused on priority areas where new research and technology development had the best chance of significantly advancing in the near future, the capability to respond to spills in the presence of ice as well as in open water. Research topics were chosen to encompass all the key elements of an integrated offshore response system: In Situ Burning, Dispersants, Remote Sensing, Environmental Effects, Trajectory Modelling, and Mechanical Recovery. The ART JIP was initiated by nine oil and gas companies and the work executed by leading scientific, engineering, and consulting firms across the globe.
The research consolidated a vast amount of existing knowledge in these six key areas to provide a robust and more accessible baseline for future regulators, users and industry representatives concerned with assessing, approving, planning, executing and providing oversight to ensure safe Arctic drilling and production programmes in the future.
The scientific research added a significant new knowledge base to the existing peer-reviewed literature on oil spill impacts, herders and burning, dispersants, remote sensing and trajectory modelling. With this new information, these tools can more confidently take their place as response strategies alongside traditional methods such as mechanical recovery.
As a result of past efforts and now the ART JIP, a range of operationally proven tools is available to suit specific regional environments, seasons, drilling and production programmes. A fundamental objective of the ART JIP was to make all results from the research effort publicly available. The results, findings, and strategic implications have been extensively documented and the results can be found on the ART JIP's legacy website, conference proceedings, and journals.
The cruise industry is seeking new markets and products to trigger a growing customer base around the world. As the more traditional cruise ships have become bigger and more geared towards mass tourism in typical locations like the Mediterranean and the Caribbean, there has also emerged a need for smaller niche type of cruises, typically higher end and more exclusive. Exploration of the Arctic and Antarctic is exotic and is seen as the next step after the popular cruises to places like Alaska has become mainstream.
To enable the cruise industry to conquer Polar region a new generation of cruise ships is entering the market. A common feature for all of these is that they are smaller ships with more luxurious accommodation. Strong focus on safety, customer comfort along with sustainability and low environmental footprint are also all key drivers in this market. To achieve these objectives some of latest technology in terms of propulsion, power generation and distribution, navigation and digital solutions is critical. As per today more than 25 such expedition cruise ships are on order, most of which have been contracted in 2017.
Ensuring the safety, comfort and satisfaction of 100s if not 1000s of passengers and crew in such inhospitable regions is no mean feat. Through the experience and innovation in hip power management and propulsion systems some companies have become the leader in providing these type of solutions to the cruise industry. The past 25 years the leading companies have worked closely with ship owners, operators, designers and shipyards to develop the technical that is now setting the standard in the cruise industry.
Historically, naval architects have tackled these issues independently, working within rules developed by individual classification societies. However, the exhaustive harmonization work done in developing the IMO's new Polar Code has delivered a type of equivalence in structural and machinery specifications, as set out in the International Association of Class Societies Unified Requirements for Polar Class (PC) ships, which come into force on 1 January 2017.
Podded propulsion systems offer major safety benefits for ice-going vessels and has built a strong track-record across the sector, as demonstrated by the fact that it already satisfies IMO's Polar Code requirements and is available with PC notations suitable for a range of ice conditions. This level of confidence stems from past performance, with more than 60 vessels now in operation or ordered working in icy waters, including Pechora Sea, Kara Sea, Ob Bay, and Yenisei River.
In addition to ice-going ships, today, around 100 cruise ships are fitted with podded propulsion, including the world's largest such vessels - Royal Caribbean's Oasis class. In fact, due to better vessel maneuverability, improved passenger and crew safety, greater fuel efficiency and lower total cost of ownership, podded propulsion have largely superseded conventional shaftline propulsion in combination with rudder steering across the cruise market.
Given the strength demonstrated by podded propulsion in these distinct markets, it came as little surprise that PC6 classed Podded propulsion was selected for polar discovery yacht Scenic Eclipse-the world's first passenger vessel to be constructed explicitly to Polar Code standards-and for three Endeavor class ships which will be the world's largest expedition yachts with ice class. Before the end of 2017 Lindblad Expeditions Holdings, Inc. signed an agreement with Norwegian shipbuilder and ship designer Ulstein to build a new ice class expedition ship relying on podded propulsion system. According to recent news VARD Holdings Ltd. will build unique state-of-the-art LNG dual fuel electric hybrid icebreaker expedition vessel with the second highest icebreaking class Polar Class 2. When delivered, this ship equipped with pod propulsion will be revolutionary in its class. Taking all this into account, it is fair to consider the modern propulsion technology as the natural starting point for new generation cruise ships crossing polar and sub polar waters.
Offshore Newfoundland and Labrador, Canada, development costs associated with iceberg protection pose significant challenges in terms of project execution and economics for marginal field subsea tie-backs. The current standard practice is to assume that if an iceberg makes contact with a subsea flowline, the flowline is dragged indefinitely imparting significant load to the connections at each end. To isolate flowlines from downstream and upstream assets, weak links are installed in the flowline that are designed to separate once a specified level of tension is reached. This prevents damage to wellheads and other subsea equipment and eliminates the possibility of uncontrolled hydrocarbon release. However, the weak links are very costly and possess inherent risk of failure, which can lead to an uncontrolled release of hydrocarbons. This paper addresses the requirement of weak links by analyzing the flowline tensions transmitted due to iceberg-flowline-soil interaction events.
The assumption that an iceberg drags a flowline indefinetly imparting significant tension on the end connections can be challenged. This paper seeks to estimate the tension loads developed in an untrenched flexible flowline due to interaction with free-floating and gouging icebergs. Large deformation finite element analysis is utilized to simulate the iceberg-flowline-soil interaction scenario. The iceberg keel is idealized with shape and dimensions based on analysis of recent iceberg profiles. A sensitivity study is conducted to assess the influence of keel size, gouge width and depth on flowline tension developed throughout the flowline resting on very dense sand. The sand constitutive behavior is modelled using a user subroutine accounting for the effects of mean effective stress and relative density on the soil strength and volumetric response.
The ice-flowline-soil interaction mechanisms are detailed for free-floating and gouging interaction events. During interaction with free-floating icebergs, the flowline is typically depressed into the seabed, and the keel rides over the flowline. The gouging interaction scenario simulates the complex interaction between the frontal soil mound developed during the gouging process and the untrenched flowline.
This paper provides new insight into the iceberg-flowline-soil interaction scenario that has not been examined previously. Based on the analysis results presented, an alternative strategy to mitigate tension transfer to downstream and upstream assets is discussed.