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Carbon Capture and Sequestration (CCS) is a geologic and engineering enterprise designed to reduce atmospheric emissions of greenhouse gases (GHGs). Extensive research links the GHG concentration in the atmosphere to the observed change in global temperature patterns (IPCC, 2013; Cox et al., 2000; Parmesean and Yohe, 2003). CCS technology could play an important role in efforts to limit the global average temperature rise to below 2°C, by removing carbon dioxide originating from fossil fuel use in power generation and industrial plants.
At its core, the intent of Acorn is to develop a hub for carbon capture and storage (CCS), enabling a more sustainable energy system. The project will be focused at St. Fergus in northeast Scotland and includes installation of a new advanced hydrogen reformation process, carbon dioxide (CO2) compression, and the use of redundant pipelines and infrastructure to transport and permanently store CO2 in aquifers and depleted hydrocarbon reservoirs located in the Outer Moray Firth. Hydrogen as a product will initially be blended into the National Transmission System (NTS) at 2% by volume, thereby reducing natural-gas-derived emissions across the UK.
Floating offshore wind turbine technology, much of it developed domestically, is rapidly advancing and is in the early implementation phase, while floating substation technology is still at an early development stage. This study presents novel floating wind power substation platform designs for deepwater wind farm applications. Two types of floating substations configurations are considered to compare technical and cost performance: a semi-type "X-WindStation" and a TLP-type "TX-WindStation". The floating substation platforms are considered for a 200 MW wind farm located in 100 m (328 ft) water depth off the Northeast coast of the United States. The floating substation supports a two-deck electrical power facility that provides sufficient electrical power equipment layout area and includes temporary quarters. Both floating substation platforms are evaluated for global performance and mooring systems (catenary for semi-type and tendon for TLP-type) with the site design metocean conditions for the extreme and survival storm seas. The results are assessed in accordance with industry standards ABS and API, and offshore engineering practices. Capital expenditure (CAPEX) of both substation platforms for a 200 MW farm is estimated by including the electrical substation, platform hull, mooring lines, anchors, integration, installation and commissioning costs. Installed CAPEX costs of the platforms show that the semi-type substation platform cost is lower than the TLP-type cost for the case where each tendon has a dedicated anchor, whereas the cost for the TLPtype with two tendons sharing an anchor is highly comparable to, if not less than, the semi-type platform.
High Modulus Polyethylene (HMPE) fiber ropes have been widely employed in a large variety of marine and onshore load bearing applications, but not yet in permanent offshore mooring systems due to their well-known high creep behavior. The Lankhorst Gama98® HMPE mooring ropes based on low creep Dyneema® DM20 fiber were recently introduced and certified by ABS for the offshore WindFloat Atlantic project's mooring system at a depth of around 100m, which is the first time such HMPE fiber ropes have been used for permanent mooring. Compared with the conventional application of fiber ropes, usually employed as middle segments of mooring lines, the application of HMPE ropes as top segments directly connected with the platform in shallow water creates more challenges from the impact of temperature, UV and marine growth.
For the permanent mooring of WindFloat Atlantic, the HMPE mooring rope was incorporated in the catenary mooring system by Principle Power to transfer the restoring force generated by the bottom chain weight in an efficient and direct manner to the floating platform. This lightweight mooring line enables lower pre-tensions while maintaining the same station keeping performance and excellent fatigue life. This ultimately drives down the pulling capacity requirements for installation of the mooring system and hook-up of the platform. Lessons learned from this application could result in a more efficient approach to HMPE mooring line installation. With such groundbreaking application, the HMPE rope is being demonstrated as a permanent mooring component and its performance assessed in this wind energy project, which may benefit the offshore wind industry. It may also be useful to oil and gas in a permanent use application context.
This paper presents (i) the ABS process details in assessing the proposed HMPE ropes with DM20 low creep fiber for meeting class requirements and WindFloat Atlantic project specific needs, and (ii) address the offshore industry concerns with HMPE ropes such as creep, creep rupture, UV effect, and marine growth.
As data computing and big data driven analytics become more prevalent in a number of spatial industries, there is increasing need to quantify and communicate uncertainty with those data and resulting spatial analytical products. This has direct implication in oil & gas exploration and development where big data and data analytics continue to expand uses and applications of spatial and spatio-temporal data in the industry without providing for effective communication of spatial uncertainty. The result is that communications and inferences made using spatial data visuals lack crucial information about uncertainty and thus present a barrier to accurate and efficient decision making. With increasing cost awareness in oil & gas exploration and development, there is urgent need for methods and tools that help to objectively define and integrate uncertainty into business decisions.
To address this need, the Variable Grid Method (VGM) has been developed for simultaneous communication of both spatial patterns and trends and the uncertainty associated with data or their analyses. The VGM utilizes varying grid cell sizes to visually communicate and constrain the uncertainty, creating an integrated layer that can be used to visualize uncertainty associated with spatial, spatio-temporal data or data-driven products.
In this paper, we detail the VGM approach and demonstrate the utility of the VGM to intuitively quantify and provide cost-effective information about the relationship between uncertainty and spatial data. This allows trends of interest to be objectively investigated and target uncertainty criteria defined to drive optimal investment in improved subsurface definition. Examples are presented to show how the VGM can thus be used for efficient decision making in multiple applications including geological risk evaluation, as well as to optimize data acquisition in exploration and development.
Today, uncertainty, if it is provided at all, is generally communicated using multiple independent visuals, aggregated in final displays, or omitted altogether. The VGM provides a robust method for quantifying and representing uncertainty in spatial data analyses, offering key information about the analysis, but also associated risks, both of which are vital for making prudent business decisions in oil & gas exploration and development.
ABSTRACT: To obtain a full characterization of subsurface stress, both principal stress magnitudes and orientations are necessary. Knowledge of principal stress orientations is particularly important to wellbore stability analysis during drilling of inclined wellbores, hydraulic fracturing operations, and completion design. The assumption of leaving one principal direction vertical while the other two are in the horizontal plane is very often well justified geologically. Under this assumption, by estimating the orientation of maximum horizontal stress, one would characterize the orientation of the other two principal directions as well, hence all three principal directions. Investigation has been performed of well break out, drilling-induced fractures, and natural fractures from image logs in sites of Ordovician and Cambrian aged tight sands in North Africa which have had a complex tectonic history. Separation and collision of Laurasia and Gondwana continents in the Devonian age, followed by the early Cretaceous Austrian deformation and tertiary collision of the Africa/Arabia and Eurasian plates are tectonic events shaping the geology and structure of the area. Drilling-induced fractures and borehole breakout justified by solutions derived from Kirsch's equations around the wellbore are traditionally considered hard data used to estimate the orientation of current day maximum horizontal stress. This work describes the use of natural fracture geometry (dip and dip azimuth) gathered from the same image logs, combined with Mohr Coulomb shear failure (Modes II and III) considerations, to infer local paleo stress orientations and stress regime. The results are further compared to the current day stress orientation inferred from drilling-induced fractures and wellbore breakout. The results exhibit a good match for sites evaluated, indicating that natural fractures under assumption of different modes of failure can be used to infer stress orientation. The claim that natural fractures are created during the whole geologic history of the area and might not be a reflection of current day stresses can be challenged by the fact that the stress states seem to be observed until present day in the sites investigated. Further, by considerations of several modes of natural fractures creation in combination with tectonic local history knowledge, one can infer the geological events which created these fractures aiding reservoir characterization especially in the modeling of a natural fracture network.
Sediment is a fragmented material, primarily formed by the physical and chemical disintegration of rocks from the earth’s crust. These particles range in size from large boulders to colloidal size fragments and vary in shape from rounded to angular and vary in specific gravity, and mineral composition (Rijn, L. C. V. 1993). Sediment materials are classified and named based on their grain sizes. In a tropical peat coast, the sediment consists of sand, mud, and peat debris. The distribution of these grain size becomes very important because it connects to the sediment depository behind detached breakwater which leads to the recovery process of coastal erosion (mangrove replanting activity).
This paper discusses the sediment grain size distribution behind detached breakwaters from the assessment of the field activity and numerical approach. The existing detached breakwater that was installed at the northern part of Bengkalis Island is called the Selatbaru coast. The measurements are based on geo-informatics composed of both terrestrial surveys and photogrammetry. For grain size measurement, we used image analysis and laser analysis methods.
A 1D cross-shore profile model of Xbeach was chosen. The model used the option to define spatially varying sediment grain size. With this feature, it becomes possible to simulate the beach profile response to wave and tidal action in a variety of grain sizes. Analyzing the relationship between the field activity and numerical calculation of sediment grain size distribution will help determine recovery process to coastal erosion especially in the tropical coast of Bengkalis Island, Indonesia.
Bengkalis Island is located 8 kilometers off the coast the main island Sumatra which lies along the west side of Malacca strait. The total land area is roughly 900 km2, of which more than 70% of its area is covered by peat soil with the thickness more than 1 m. The island has relatively flat terrain with a maximum surface elevation of approximately 10-15 meters above mean sea level. Low-lying, swampy, and of peat formation, the island has heavy precipitation (Haidar, 2015). Problems began to arise when the island of Bengkalis experienced erosion which causing coastal retreat, specifically on the coastline which is directly adjacent to Malaysia. This severe coastal erosion has been an issue since 1955 when Bengkalis Island was protected by a mangrove forest (US Army Service, 1955). Typically, it has a function as a natural barrier against coastal erosion, due to deforestation carried by plantation company and local communities that change land functions to various other forms of land use, including agriculture, palm oil plantation, urban and industrial development. Currently, the condition of this area has been severely eroded. The local government of Bengkalis regency has taken several steps to reduce the erosion rate by constructing detached breakwaters in 2015. One of which has built at Selatbaru Beach. From the aerial images taken in July 2017 and March 2018, we see that there has been an increase in mangrove growth behind the detached breakwater of more than 222 percent (see figure 2). The largest growth occurred near the coastline. These results indicate that sedimentation occurs due to detached breakwater construction thus making the areas around breakwaters viable for planting mangroves to reduce the erosion occurring on the island of Bengkalis. As mention above, it is crucial role of the detached breakwater in holding the speed of the sediment transport rates and the sediment deposition rates to create a good environment for mangroves tree to grow.
Gusick, Amy E (Natural History Museum of Los Angeles County) | Maloney, Jillian (San Diego State University) | King, Roslynn B (SCRIPPS Institution of Oceanography) | Braje, Todd J (California Academy of Sciences)
As applications for offshore renewable energy projects increase, state and federal land managers have become concerned over potential impacts to cultural heritage resources along submerged landscapes. Identification, documentation, and management of historical shipwrecks have been relatively common, but methods for identifying submerged pre-contact archaeological deposits are developing in many coastal regions of the continental United States. Permitting agencies in certain regions along the Gulf of Mexico and the Atlantic Ocean typically require management plans that include mitigation measures for submerged archaeological sites. Over the last decade, resource managers along Pacific Coast regions have become increasingly aware of the need for submerged archaeological site protection. This is especially important since the eastern Pacific continental shelf has become a focal point in the search for late Pleistocene migrations into the Americas and other evidence of pre-contact habitation in coastal regions since the Last Glacial Maximum (LGM). Integral to this search is the identification of submerged Pleistocene landforms that may favor preservation of pre-contact archaeological sites.
Stemming from this, our multidisciplinary and multi-institutional effort includes marine geologists, marine biologists, and archaeologists synthesizing existing data using GIS models, and collecting new side scan sonar, CHIRP, and multibeam bathymetry data ground truthed with marine sediment cores. This methodology for the identification of submerged archaeological deposits is not new; however, the landscape approach that defines our research, and our focus on understanding paleolandscapes using modeling, sonar survey, and marine coring is the first of its kind on the eastern Pacific continental shelf.
The goal of our project is to develop an archaeological sensitivity model, which the Bureau of Ocean Energy Management can consult in the offshore energy permitting process. As such, we are building our model using data from California’s Northern Channel Islands and testing the model along Oregon’s central coast. Results suggest that with the right technologies, sensitive landscape features such as paleochannels, paleoestuaries, and offshore tar seeps – all features used by Native American communities during the late Pleistocene and Holocene along the Pacific Coast – can be identified and used to model sensitive archaeological landscapes. We also are testing the efficacy of controlled-source marine electromagnetic methods in conjunction with sonar survey data for the identification of tar seeps, paleochannels, and buried archaeological shell midden deposits. This combined methodological approach is unique to North America’s Pacific Coast and represents a pioneering effort in the search for submerged archaeological deposits, which will help identify, document, and preserve underwater cultural heritage resources.
Pre-contact period submerged landscape archaeology in the United States has been driven and improved by the efforts of cultural resource managers (CRM). While academic organizations in the US have conducted submerged landscapes archaeology, the objective of this paper is to show how CRM projects on the Atlantic outer continental shelf (OCS) and in the Gulf of Mexico have expanded our understanding of principles and methods for mapping and evaluating submerged pre-contact period archaeological sites.
Basically, there are two distinct kinds of submerged cultural resources that are considered by US legislation. These are historic shipwrecks or downed aircraft and pre-contact period archaeological sites. The Secretary of the Interior's qualifications for archaeologists conducting required surveys distinguish between these two kinds of archaeologists - historic and pre-contact. Methods and principles for shipwreck archaeology have been developed and practiced since the 1960s. Survey and analysis for drowned pre-contact sites on the other hand, are recent subjects for marine-focused geoarchaeologists. Geoarchaeologists are uniquely qualified to understand details of local antecedent (pre-transgression) geology, local pre-contact archaeology, and dynamic local sea level rise details necessary for predictive modeling of any particular submerged paleolandscape.
This paper will discuss how a survey for submerged pre-contact sites involves acoustic data and paleolandscape reconstruction techniques, determination of what culture group may have occupied those landscapes, and how details of sea-level rise affected that paleolandscape setting. In addition Phase II operations are necessary to test sub-bottom targets. These include coring and diver dredging operations. These methods and novel techniques for perceiving sites and reconstructing past landscapes will be described. We will show the benefits of following Bureau of Ocean and Energy Management (BOEM) guidelines within state waters as well as federal, and in the process of working offshore to reconstruct culture histories, it may come to pass that offshore industries will be a major contributor.
Khan, Muhammad Hanif (Independent) | Maqsood, Tahir (Tullow Pakistan) | Jaswal, Tariq Majeed (Pakistan Oilfield Ltd) | Mujahid, Muhammad (Spec energy DMCC) | Malik, M. Suleman (Qatar Petroleum) | Jadoon, Ehtisham Faisal (UEP Pakistan) | Hakeem, Uray Lukman (Qatar Petroleum)
This article investigates the seismic reflection geometries (possible reservoir) of Paleogene of Offshore Indus Basin Pakistan (shelf area) from 2D seismic and make an analogue with the proven carbonate reservoir geometries found in countries such as Canada and Middle East. The 2D seismic data are used to interpret the possible carbonate features and methods to identify them and define its depositional setting on the carbonate platform. The offshore Indus Basin is tectonically a rift and a passive continental margin basin, located in Offshore Pakistan and Northwest India where carbonates were deposited on the shelf and the deep offshore area during early post-rift phase. In the deep offshore area, carbonates were set on volcanic seamounts during the Paleogene age. In Paleogene, the Indian Plate was passing through the equator in the conditions of warmer water with appropriate water salinity, where those conditions were suitable for the growth of organisms responsible to develop reefs in the Offshore Indus area. The available seismic data analysis has indicated the possible presence of different carbonate reefs on the shelf. The seismic data enabled to define the possible carbonate Rimmed shelf depositional model in the area. The aim of this article is to highlight and analogue carbonate seismic geometries, their internal architecture in the Paleogene interval of the Offshore Indus Basin (shelf area) and how to identify them, which may help for further exploration in Offshore Indus Basin.