bluuebunny/crossref_metadata_2025_split huggingface dataset:
Jack-Up Drilling on Conventional Subsea Wellheads
Authors: Kotrla Johnnie , Cummins Ray 
Published: September 2013

Abstract
Throughout the 1970s, 1980s and 1990s, many relatively shallow-water wells were drilled at water depths less than 600 ft. (183M) utilizing conventional Semi-submersible Rigs, Subsea wellheads and/or subsea templates. A goodly portion of this drilling was done in the North Sea, in both the Norwegian and UK sectors. Now, as those wells age to the point of requiring intervention to maintain, or enhance production, new generations of large Cantilever Jack-up rigs are available that can rework thes wells at a much lower day-rate than conventional semi-submersible rigs, be they anchor moored or dynamically positioned.
Jack-up rigs hav not been, and were never intended to be able to attach to a subsea wellhead assembly. To date, this was the exclusive territory of Semi-submersible rigs or Drillships (but primarily Semi-submersibles). This basic equipment incompatibility needs to be addressed before detailed plans can be formalized.
The most obvious solution to this problem is to install a subsea BOP Stack onto each of these new Jack-up rigs so that the connection to the subsea wellhead can be accomplished in a traditionally acceptable manner with relatively conventional equipment packages.
Secondary Intervention for Blowout Preventers
Authors: Klassen William P. 
Published: September 2013

Abstract
Currently available secondary intervention systems may not successfully operate critical subsea blowout preventer (BOP) safety functions such as closing pipe rams, blind rams, and shear rams. Failure may occur because sufficient hydraulic power (pressure times flow rate) is not available to operate these functions quickly in a flowing well, causing failure of sealing elements. This paper describes current shortcomings and identifies a novel ROV-based intervention.
With numerous combinations of rams, bore pressures, bore flows, pipe sizes, and additional equipment inside the well, it is difficult to determine the right amount of hydraulic power required to meet closure times specified by the subsea industry and regulatory groups. This paper considers well conditions and determines the necessary power.
Neither current ROV hydraulic pumping interventions nor hydraulic accumulator interventions can provide the necessary combination of large amounts of flow and pressure for successful secondary operation of BOP safety functions. Also, because current intervention systems are not integrated with ROV systems, they require significant deployment time. Hydraulic accumulator intervention systems provide maximum power at the wrong time—at the beginning of the ram stroke instead of the end—and also have depth limitations.
Given the limitations of current hydraulic intervention systems, an ROV-based intervention system is being developed to reliably operate BOP safety functions. This intervention system, which is integrated with current work-class ROV electrical and hydraulic power functionality, uses novel power management designs.
Umbilical Communications Condition Monitoring
Authors: Bagley Phil , Gillespie Alisdair , Grant Kevin , Neale Dafydd 
Published: September 2013

Abstract
Umbilical communication utilising optical fibre has increased in recent years, however communication via an electrical umbilical still dominate the industry. When communicating over electrical conductor’s modulation techniques such as Orthogonal Frequency Division Multiplexing (OFDM) and Quadrature Amplitude Modulation (QAM) can be used to improve data rate and reduce transmission errors. These modulation technologies lend themselves to condition monitoring approaches that do not affect the performance of the communication channel. Here we present a condition monitoring system to detect in real time umbilical communications deterioration before failure.
The Aker Solutions electrical communications modem utilise OFDM or QAM techniques to encode digital data such that a particular phase and amplitude represent a binary code. These data can be represented graphically where a particular phase and amplitude are shown as locations on a XY graph (constellation diagram). Noise, communication channel interference, or any other factor reducing communication channel performance will result in a move away (an error vector) from the ideal location on the constellation diagram. The QAM data also contain pilot tones transmitted at know amplitudes and frequencies to enhance modem performance. These pilots can be utilised to produce a frequency response of the umbilical communication channel. For condition monitoring the error vector and channel frequency response can be utilised to determine the end-to-end health of the communication channel.
The communications modem is capable of fault free operation with large error vectors and poor channel frequency response. Therefore, the user may not be aware of deterioration in umbilical performance until the communication channel fails. The ability to monitor the condition of umbilical communications in real time without affecting data throughput presents a significant advantage. Enabling the user to detect and correct umbilical communications problems before failure.
This paper will present results from trials using the umbilical condition monitoring system on QAM16 communications over a Research and Development umbilical simulator.
Positioning Challenges of the Arctic Subsea
Authors: Hanton Sam 
Published: September 2013

Abstract
The location and environment of the arctic region provides a number of additional challenges and considerations to those experienced during operations in the current locations popularly serviced by the majority of the Oil and Gas companies and contracting subsea supply chain.
The paper provides a brief overview of the arctic region and the existing and forecast Oil and Gas investment and developments over the coming years.
The paper then focuses on the positioning and navigation challenges posed by operations in the arctic, both from a technical perspective and also with consideration of equipment design to survive the harsh environment. We aim to describe the challenges posed to the different types of positioning systems by the harsh environment, including the effects of high latitude on DGNSS and heading sensors, the difficulties of using the increasingly commonly encountered Inertial Navigation Systems around the North pole, and the potential effects of intact and melting ice on subsea acoustics. The logistics associated with arctic operations are also introduced.
Potential solutions and alternatives through assessment of system options and combinations of sensors will be discussed, along with recommendations of the basic essentials to be considered when planning positioning in the arctic.
Subsurface Interpretation and Pre-Messinian Deposits Prospectivity of the Algerian Offshore Basin
Authors: Khennaf Nahim , Benabdelmoumen Sadek 
Published: September 2013

Abstract
The Algerian offshore area is located in the western mediterranean sea, East of alboran basin, and south of algero provencal basin.
In geological perspective, it covers the area from the narrow continental shelf to the deep basin, water depth range from 0-2800m.
Prospectivity is primarily associated with pre-messinian deposits, in addition to Pliocene.
The seismic data consists mainly of 2D surveys, with relatively coarse coverage in addition to gravity and magnetic. The 2D seismic coverage acquired in 2011 (5000km) covers the main deep water area. The evaluation of the 2D seismic data has highlighted a number of significant leads with different sizes. They are related to different kind of traps (anticlines, faulted and tilted blocks, …).
Only one deep well (4496.5m) and two core drills have been drilled. The onshore geological map reveals the extension toward the offshore of the Chelif basin. The petroleum potential of this onshore basin is proven since the 1940’s with the discoveries of Ain Zeft and Tliouanet oil fields.
Reservoirs are expected to consist of sandstones related to Miocene, in addition to the Oligocene (Numidian flyshs) that can be found in the eastern part. The hydrocarbon potential interest in the eastern part could be enhanced by the positive discoveries in the Sicilian channel and also by the proven petroleum system of the Numidian in the onshore part of Tunisia and Algeria (Ain Regada).
Compact Processing Solutions : Inline Gas-Liquid Separator on the Santos Wortel Field
Authors: Imaduddin Imaduddin , Tienhaara Mika 
Published: September 2013

Abstract
For the Santos owned and operated Wortel field, shallow waters offshore Indonesia, there was a need to install compact inline gas/liquid separation equipment with high performance. Due to space constraints, an inline gas/liquid separator was selected. Santos implemented the ASCOM Twinline technology on the platform, which has been in operations since February 2012 and is performing very well. This is an example of rapid technology development, initiated in 2010, with performance verified over a longer period under operations.
Shearwater - Securing the Chalk - Effects of Depletion of a HPHT Reservoir on Chalk Overburden
Authors: van Bergen P. F. , De Gennaro S. , Fairhurst F. , Hurry R. , Concho M. , Watson J. , Sturgess L. , Bevaart M. 
Published: September 2013

Abstract
In preparation for a new phase of development of the deep, &gt;8000 psi depleted, high-pressure, high-temperature (HPHT) Shearwater field in the UK Central Graben of the North Sea, the existing well stock had to be prepared to enable slot availability for sidetracking operations. Here techniques and key learnings gained from the slot preparation activities, in particular with respect to the chalk overburden, are described.
During the slot preparation activities new data on fracture gradients and the extent of porosity in the chalk was acquired. This information was then integrated with the results gained from the use of state of the art logging tools and unique data acquisition (including chalk hydrocarbon molecular and isotope compositions). In addition, an analysis of overburden time shifts from re-processed 4D seismic data was completed, along with geomechanical modelling work.
A new understanding was gained of the effects of reservoir depletion on the chalk, from being a solid uniform tight rock with very low permeability to a more heterogeneous permeable formation with differential reactions to reservoir depletion. The key learnings have been integrated into the ongoing slot recovery operations and future well plans. The overall integrated data allowed a greater understanding of the heterogeneity of the entire chalk section, which has been valuable in considering chalk overburden complexity.
Subsea Water Treatment and Injection Station
Authors: Olsen Jon-Erik , Pinchin David 
Published: September 2013

Abstract

Description
Many reservoirs in the UKCS are experiencing rapid pressure drop, reduced production, low recovery rates and high water cuts. More fields are also being developed as subsea fields. Moving the water treatment and injection to the seabed offers opportunity for improved recovery. Such a complete subsea water flooding system is now available as a Subsea Water Treatment and Injection Station with qualified technology for the first time, providing a change in mindset for offshore recovery by enabling treatment and injection subsea.

Application
Treating water at depth, and injecting from the seabed, enables cost-effective developments avoiding expensive flow-lines. 4D-seismic reveals that optimal positioning of water injection wells is not always technical or economical reachable from platform. With maximum flexibility and without the traditional topside restrictions, an improved reservoir drainage strategy enables increased/enhanced recovery. The technology is therefore applicable for all offshore fields at any stage of their production life.
The unique merging of proven technology into a standard template provides operators with a turn-key ready station for subsea water injection of treated water. The Subsea Water Treatment and Injection Station contains water treatment, injection pump(s), and injection trees. The station ties back to host with an umbilical, providing power and controls. Future systems may also include membrane modules.
The subsea water injection and treatment concept is applicable to Subsea Production and Processing Systems. With an added separator, fields with high water cut can be processed subsea to re-inject produced water.

Conclusions
The new subsea seawater treatment system has recently completed successful 24 months of trials on the seabed with the help of two global JIP ̀s. The new water treatment system provides water superior in quality compared to that achieved by a traditional topsides water treatment plant in areas important for water injection for IOR. – I.e. a lower degree of bacterial concentration, good disinfection and solids reduction.
In this paper, system capabilities and experience from testing together with membranes will be presented.
Pull or No-pull: Risk-based Decision Support for Subsea Blowout Preventers (BOPs)
Authors: van Asten Pieter 
Published: September 2013

Abstract

Overview
The tragic Gulf of Mexico accident in April, 2010 can be marked as the defining moment which confirmed the idea for making a subsea Blowout Preventer (BOP) risk model.
The accident showed that society is our biggest stakeholder with its own risk acceptance perception, enabled by the immediacy of social-media, the tenacity of the press, and today’s instantaneous technology for transmitting newsworthy and life-altering events.
When thinking back to that day in April, we can ask: what does the majority of society remember about this tragedy? The most common answer to this question is the graphic photos of massive amounts of oil washing up on once pristine Gulf beaches, killing fish, birds, and other ancillary industries which rely on clean Gulf waters and beaches to survive. Although not pictured with such detail, the casualties will never be forgotten either.
Approximations of Primary, Secondary and Tertiary Recovery Factor in Viscous and Heavy Oil Reservoirs
Authors: Kaczmarczyk Rafael , Herbas Julio , Del Castillo Juan 
Published: September 2013

Abstract
Limitations in the availability of methods to estimate recovery factor at the initial stage of petroleum exploration pushes for investigation new ways of analysing available datasets.
This work investigates empirical and volumetric methods to estimate recovery factors in viscous and heavy oil reservoirs. It also investigates newly available advance screening methodology to determine tertiary/ultimate recovery factor in these reservoirs. Initially, primary recovery factor was estimated based on field analogy. Secondary recovery factor was calculated using empirical equations. In the second, main part of this work, ultimate recovery factor was approximated using data mining/machine learning approach to reveal eventual trends in viscous or heavy oil databases.
Information contained within this project was used to estimate recovery factors in certain viscous oil reservoirs at the initial stage of exploration. However, after reformatting original data base, advance screening methodology would be potentially applicable to any viscous or heavy oil reservoir around the world.
It was found during the project that the primary recovery factor can be successfully estimated based on the field analogy. Empirical methods can be applied in some cases. The quality of the obtained results depends on whether they were derived for conventional or heavy oil reservoirs. Based on advance screening, it was shown that tertiary/ultimate recovery factor can be successfully estimated.
Final product includes development of a methodology on how to approach the recovery factor approximation in viscous or heavy oil reservoirs without production history or at early stage of the field life.
The Return to the North Sea: Looking To Unlock Further Value
Authors: Mayland P. J. , Conley B. , De Boer W. , Robertson L. , Clark R. 
Published: September 2013

Abstract
After a period of nearly 10 years absent from the North Sea oil and gas sector, in 2012 Cairn Energy re-entered the UK Continental Shelf, and for the first time entered the Norwegian North Sea through the combined corporate acquisitions of Agora Oil and Gas AS (a private Norwegian company) and Nautical Petroleum (an AIM-listed E&P company), respectively. Cairn had upstream experience in both the UK and Dutch sectors of the North Sea and was an active non-operating partner in the Gryphon heavy oilfield in Quad 9 and in the P6 and P12 gas fields in the Netherlands.
This paper outlines the method and approach taken to rebalance Cairn’s portfolio after sustained success in South Asia and the sale of Cairn’s majority shareholding in Cairn India and the subsequent need to rebuild a portfolio with a cash flow generating base to underpin exploration and appraisal opportunities, both internationally and in the North Sea itself. It explains Cairn’s rationale and key drivers for entry and (re)-investment in the North Sea versus other possibilities. It also discusses the importance and value of preserving knowledge and expertise within the acquired companies and the process of integration.
The paper will also investigate: (i) the technical aspects of Cairn’s acquired interest in two key oilfields, Kraken and Catcher which, in gross terms, will deliver approximately 10% of the UK's oil production when onstream and (ii) Cairn's remaining exploration portfolio in the North Sea and subsequent plans and opportunities for growth.
Development of Spilled Oil and Gas Tracking and Monitoring Autonomous Buoy System and its Application to Marine Disaster Prevention
Authors: Kato N. , Senga H. , Suzuki H. , Choyekh M. , Kimura R. , Akamatsu T. , Yoshie M. , Tanaka T. , Sakagami N. 
Published: September 2013

Abstract
This paper describes the ongoing project on autonomous spilled oil and gas tracking buoy system and application to marine disaster prevention system for 5 years since FY2011. The objectives of this project are as (1)autonomous tracking and monitoring of spilled plumes of oil and gas from subsea production facilities by an underwater buoy robot(SOATB-I), (2)autonomous tracking of spilled oil on the sea surface and transmission of useful data to a land station through satellites in real time by multiple floating buoy robots(SOTAB-II), (3)improvement of the accuracy of simulations for predicting diffusion and drifting of spilled oil and gas by incorporating the real-time data from these robots.
SOTAB-I is different from normal type underwater gliders in terms of vertical and horizontal movement, because SOTAB-I focuses on almost the same movement in horizontal plane as in vertical movement. It installs an underwater mass spectrometry, CTD and ADCP so that the vehicle can identify the characteristics of oil and gas and the place where they are leaked using data obtained by the vehicle in combination with numerical simulation of blowout of oil and gas from deep water.
SOTAB-II utilizes the control low of a sail so that the buoy drifts along the resultant velocity vector of water current and 2-5 % of wind velocity watching the drifting substances on sea surface by sensors mounted on the mast. Multiple SOTB-IIs are deployed just after an oil spill accident to track patches of spilled oil. SOTAB-II can provide us with real-time measured data on position of spilled oil on sea surface, the meteorological and oceanographic data and characteristics of spilled oil for a long range. The combination of the real-time data and the numerical simulation of the drifting spilled oil on sea surface will enable us to predict the precise drifting of the spilled oil.
Post-fire Structural Integrity of Composite Gratings for Offshore Platforms
Authors: Holliday R. J. , Gibson A. G. , Humphrey J. , Di Modica P. , Christke S. , Kotsikos G. 
Published: September 2013

Abstract
In parallel to studies by the HSE resulting in the issuing of a Safety Alert warning to the offshore industry on possible failure of fire resistant composite gratings (Bulletin No: HID 2-2012), a study was made by MMI Engineering in conjunction with Newcastle University into the post-fire integrity of phenolic and polyester FRP gratings to determine whether such gratings can be safely used following exposure to fire.
Firstly the range of weights of offshore workers was established. The recommended residual strength required for post-fire use should exceed the load generated by a running person, at the upper 5-percentile of the weight spectrum, carrying fire fighting or rescue equipment. This load includes a dynamic amplification factor to allow for the effect of running, additionally a further safety factor is required to account for fatigue effects.
Samples of gratings were tested to determine the stresses resulting from running or walking by applying strain gauge instrumentation to individual beam elements of gratings to measure the strains produced. The strain gauge study was augmented by modelling to quantify the relationship between applied load and local strains. These strains were found to depend on the ‘footprint’ area over which the load was applied.
Fire exposure tests involved using a propane burner to expose individual beam elements to three heat fluxes of 12.5kW/m2, 37.5kW/m2 and 100kW/m2 as well as jet fire testing at ~250kW/m2 representing the full range of fire types considered on oil and gas installations. The duration of the fires were increased in increments up to 16 minutes to establish the rate of deterioration.
This paper presents the results of the testing, provides information to operators on where these materials can be safely used as well as providing grating manufactures with guidance on future product testing and development to produce more fire resistant systems.
Structural Response Monitoring Of Huntington HP Drilling And Completion Riser
Authors: Rimmer A. , Bamra B. , Allan R. M. , Proud G. , Davidson S. , Parker B. 
Published: September 2013

Abstract
Use of full bore high pressure (HP) risers in ever more challenging locations and conditions has increased requirements to collect in-situ response data to confirm that the riser design is acceptable and confirm integrity. Due to the challenging combination of the 91m water depth and harsh environment at Huntington field in the North Sea, considerable analytical work was required to design and configure the proposed 24inch diameter HP drilling riser and well conductor system to allow successful and safe all year operations from the jackup rig. As well as careful strength and fatigue design of the upper and lower most HP riser joints, this potentially required modifications to the rig’s CTU deck to support the high loads expected. Typical conservatisms in analysis methodologies also needed to be removed to allow for a viable theoretical design. In-field measurements were therefore proposed to allow for verification and calibration of the analysis used as a basis for the design decisions and to ensure that the integrity of the riser was maintained during the 12 months of drilling and completion operations. The monitoring system developed to address this, the first type of its kind to be installed on a jackup rig, incorporated a range of accelerometer and strain sensors to record motion, load and fatigue responses of the riser and jackup system in real-time.
This paper describes the background to the monitoring system design, the components that make up the monitoring system and presents the comparisons between the collected data and analytical predictions that allowed the objectives of verifying the analysis and confirming integrity of the riser to be achieved. Recommendations are also given as to how the monitoring system can be improved for future use in similar applications.