bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two-Stage De-Oiling Testing for Qualification with MEG Presence
Authors: Riesenberg J. M. , Biega Brandon , Tienhaara Mika , Lammers Bart , van Deurzen Bente 
Published: April 2017

Abstract
Chevron Energy Technology Company performed a flow loop qualification under realistic conditions for a two-stage de-oiling unit in order to test the performance and robustness, especially for subsea developments. The objectives of this qualification were to investigate the effects of both high pressure and the presence of mono-ethylene glycol (MEG), under as realistic conditions as possible, on the system performance using crude oil and water. MEG is a gas hydrate inhibitor which will likely be injected in long subsea tie-backs.
The tested compact produced water treatment system consisted of a two-stage de-oiling arrangement in which the first stage was a bulk de-oiler hydrocyclone, and the second stage was a polishing hydrocyclone. Each stage consisted of a pressure vessel which was filled with multiple hydrocyclone liners. For this qualification, Sulzer's MixedFlow De-Oiling Liquid-Liquid Hydrocyclone technology was used. Sulzer hydrocyclones utilize a design with multiple openings in the inlet as well as a swirl generation element, resulting in a stabilizing and coalescing effect on the oil-water flow. The system was tested at a high pressure test loop with crude and methane to provide the most realistic testing conditions. Tests were also performed with MEG in the feed. MEG is required for gas hydrate inhibition, and under some operating conditions MEG can influence de-oiling efficiency during produced water treatment. For this reason, test points with and without MEG present in the feed were included in the test matrix.
The impact of the inlet conditions (temperature, pressure, oil in water (OIW) concentration, e.g.) on the de-oiling system performance was investigated. The system was tested with temperatures as high as 70°C and pressures as high as 51 bar(g). System efficiencies approaching 99% were found for many cases and pressure drop was measured to be significantly less than that which is expected of similar de-oiling systems. The performance and robustness of this design resulted in a successful qualification of all parts of the system.
Fluid-Front Tracking in a Mature Jurassic Carbonate Reservoir using Innovative Pulsed Neutron Solutions for the First Time Offshore Abu Dhabi
Authors: Serry Amr Mohamed , Espinassous Marianne , Bilbeisi Jawdat , Saldungaray Pablo , Zhou Tong , Rose David , Dasgupta Suvodip 
Published: April 2017

Managing mature fields effectively and efficiently requires monitoring changes in formation fluid saturations as well as production from individual wells. Reservoir saturation monitoring is usually performed using slim pulsed neutron logging (PNL) tools because they can be deployed through tubing and operate in different modes, thus providing a wealth of information. However, several environmental factors can complicate the analysis, including complex completions and unknown or variable borehole fluids (gas in particular), which affect the PNL raw measurements and computed outputs. Factors related to the nature of the reservoir, such as complex lithology and multiple fluid phases, further complicate the analysis, making accurate fluid saturation evaluation and reservoir fluid-front mapping very challenging.
An innovative pulsed neutron technology, recently introduced in the UAE, can help in reducing the evaluation uncertainty. The new device is fitted with multiple detectors and is used with newly developed algorithms to provide self-compensated formation sigma and hydrogen index (HI) measurements, overcoming many of the limitations of previous devices in complex environments. Additionally, the new tool provides a new formation property sensitive to gas-filled porosity, called the fast neutron cross section (FNXS), which, in adequate conditions, can be used to complement the analysis or highlight gas in the absence of openhole logs.
The new PNL tool was run for the first time in an offshore UAE mature field targeting Jurassic formations. The production in the field started in the 1960s, followed in the 1970s by down-flank injection of water with much lower salinity than the connate water, and in the 1990s by crestal gas injection. The Jurassic reservoir mineralogy is a complex mixture of calcite, dolomite, and anhydrite. Completions consist of multiple combinations of tubing, casing, and hole sizes along with packers and other hardware components; often the borehole is filled with gas across the zones of interest, which has proven an obstacle to PNL interpretation. The new PNL device was tested in several wells in which it operated in inelastic gas, sigma, and HI (GSH) mode and carbon/oxygen (C/O) mode. Integration of all the recorded information made possible to reliably track the three-phase fluid saturation changes even in the gas-filled wellbores with complex completions. An additional benefit with the new tool was that because the C/O data were recorded at a speed twice as fast as that of the previous-generation PNL tool, it was possible to acquire the logs in the limited allocated time to help resolve the oil saturation in reservoir zones with variable salinity. The saturation analysis was compared to production logs and well production data where available.
Assessment of the Combined Hurricane and Loop Current/Loop Current Eddy Risk on Existing Mooring System
Authors: Zhu J. , Driver D. , Petruska D. , Xia D. 
Published: April 2017

A strong Loop Current or an Eddy (LCE) persisted in the Gulf of Mexico through the peak hurricane season of 2015 and impacted several BP floating facilities. It was a concern that if a hurricane passed near one of the floating facilities in the presence of LCE, the combined loading may increase the probability of exceeding the mooring system design capacity. As a result, this type of combined event could be more severe than the original hurricane or LCE only design case. Therefore, a long term combined hurricane and LCE risk was evaluated. Since metocean criteria for this type of combined event is not readily available, two approaches were compared: 1) combining observed average LCE speed at the site with the N-year return period hurricane only metocean; 2) reconstructing a long time series of combined LCE and hurricane data and developing N-year return period criteria from this.
The first approach is straightforward; however, it proved to be too conservative, while the second approach reflects a more realistic scenario. Both approaches were applied to evaluate the long term mooring line risk. The critical environmental direction and tension levels were identified to determine minimum factors of safety on mooring components breaking strengths. The results indicated that the mooring line risk of a 1000-year return period combined event is equivalent to the risk of a 100-year hurricane only event.
The other aspect of Loop Current risk is the potential inability of the platform to get back to the nominal position if it is at an unfavorable position during a LCE event. It is possible that the mooring tension could be above the chain jack operational limit due to increase loading from the LCE while also offset from the neutral position, thus increasing the risk of mooring or riser overloading. Different mooring operational options were compared to select the proper strategy to reduce the operational risks. The final operational recommendations were tested in the field to confirm fitness for operation.
Evaluation of the Intrinsic Conservatism in the Design Codes for Subsea Mudmats
Authors: Riet B. A. M van de , Yenigul N. B. , Burgers R. , Pisanò F. 
Published: April 2017

Abstract
Rectangular mudmat foundations for subsea structures are commonly designed according to ISO and API guidelines. However, the modern trend towards deeper waters and heavier structures is currently challenging traditional approaches to foundation design, especially in presence of particularly poor soil conditions. The intrinsic conservatism carried by design codes may not only lead to higher fabrication/installation costs, but also conflict with the operational limits of existing installation vessels.
Based on the analysis of four design cases, it is argued that ISO/API safety factors may be from 1.5 to 2.3 times as low as the predictions of elastoplastic finite element (FE) simulations. Such a conservatism is also found to considerably increase with the embedment depth, whereas the influence of the foundation aspect ratio is nearly negligible. A simple calculation example shows that the systematic use of numerical analysis in design may result in a 47% reduction of the total foundation area, and an overall decrease in fabrication costs of approximately 16%.
Batch Completion Operations Cost Reduction in a Segregated Drilling Campaign: Surface Equipment Requirements
Authors: Canny Steven A 
Published: April 2017

In an effort to reduce project construction and start-up costs, novel and alternative well construction models have been developed and adopted globally. One such approach is to adopt a segregated drilling campaign, the well construction and completions operations can be segregated into two distinct phases. A drilling and casing phase leaving a cased well in a Temporary Abandonment (TA) status, followed by a phase consisting of WBC (wellbore clean-up), completion and stimulation operations resulting in the handover of the well to production to bring hydrocarbon production online. As such this provides an opportunity to reduce surface equipment specification and costs, in comparison to that which is required for drilling activities. A potential solution exists by utilising alternative technology with the capability to perform perforation, multi-zone completion installation, stimulation, WBC operations and well testing, at comparatively lower cost than conventional drilling technology.
This paper describes the collaborative development of such technology, and focuses on the definition of the surface equipment requirements and specification phase, pertaining to the typical downhole operations required to be executed during the multi-zone completion installation, stimulation, WBC operations and well testing. Each operation is assessed to give a base required capability, with further operations that are deemed to have a critical effect on the efficiency and duration, identified.
A typical anticipated operations program is presented and the study focuses on the first principle requirements of each of the steps. Further operation considerations are presented and discussed for each operational step, forming the basis of discreet specifications per step. Further, the identification of operations not on the critical path that can be performed simultaneously or as an offline activity, have the potential to make high cost impacts. Collaboration between the Yangon based operator and service provider drives a design which provides a technically pragmatic and capable ICU (Intervention and Completion Unit) and as such attracting project cost savings allied to lower support equipment costs. Further, the deployment flexibility of the ICU allows it to perform operations ranging from well construction activities such as well slot preparation, completions and intervention, to well deconstruction activities such as heavy workover, Permanent Abandonment (PA) phases and slot recovery. The ability to perform multi-phase operations whilst mobilized to a platform brings further cost benefits and operational flexibility.
Top 10 Alternative Technologies for Offshore Power Generation: How Viable are they?
Authors: Srivastava Ashesh , Chin Y. Doreen 
Published: April 2017

This paper screens the existing and emerging alternative energy generation technologies that can be potentially used for offshore power and selects the top 10 for further discussion and analyses. The objective is to provide the industry a clear understanding of the status and future potential of these technologies.The technologies to be evaluated are divided into two categories - existing and emerging. For existing technologies, the evaluation is conducted from a holistic point of view and present conclusion based on key factors such as: cost, efficiency, safety and environmental impacts, reliability, deployment potential and production capacity. Whereas, emerging technologies are evaluated based on Technology Readiness Level (TRL) and potential. Based on the evaluation, the top 10 technologies are selected for further analysis, which range from renewable, nuclear and other alternative energies.The oil and gas industry is gradually moving towards deeper and more distant offshore developments. At the same time, the power requirement on these facilities is increasing rapidly. So far operators have used localized open cycle gas turbine or diesel generators to meet their demand, which produces high levels of CO2 and NOx. The cost, weight, and deck space requirement associated with power generation units have also increased significantly. The power generation requirement has been a critical element for floating structure design (payload) and offshore field development (cost).Driven by the global demands for climate change control, and greenhouse gas emission, the need to find more viable solutions for alternative energy is becoming inevitable. The offshore industry starts to re-visit the potential of powering offshore facility with alternative and renewable energies once were thought was impractical for offshore because of their unsustainability.These new technologies will transform the oil and gas industry and will power our way towards future developments where power requirement will be in the magnitude of 100s of MW. The technologies, which offer great potential but haven't been used in oil and gas industry are considered and evaluated. Small case studies are presented to highlight their practical applications and results.
A Practical and Interdisciplinary Framework to Develop Post-Earthquake Evacuation and Inspection Thresholds for Offshore Platforms
Authors: Chen Jiun-Yih , Chen Ching-Hsiang , Ku Albert , Sheppard Robert 
Published: April 2017

Abstract
After a strong earthquake occurs near an offshore platform, taking timely actions, such as evacuation of personnel and inspection of the platform structure, is important to minimize the potential for loss of lives. The objective of this paper is to present a practical framework for developing post-earthquake inspection and evacuation thresholds based on information that will be available immediately after the earthquake, such as an estimate of earthquake magnitude and epicenter location from the United States Geological Survey (USGS) website.
Assessing the structural performance of an offshore platform in a strong earthquake is truly an interdisciplinary effort. Seismologists and geologists review the regional seismo-tectonic environment in the vicinity of a platform and characterize the platform's seismic hazard at the bedrock or competent soil level using ground motion prediction equations (GMPEs), commonly known as attenuation relationships, in a process called Probabilistic Seismic Hazard Analysis (PSHA). Geotechnical earthquake engineers then perform a nonlinear site response analysis to capture the local soil effects and develop the seismic ground motion time histories and response spectra that will shake the platform at its foundation. Structural engineers then perform seismic structural analyses to assess the platform response under the earthquake excitations and evaluate its performance for the life safety of the personnel who will need to ride out the earthquake because its timing cannot be predicted in advance. This interdisciplinary effort can be expanded beyond examining structural response to ground motions to develop a tool for post-earthquake response, the seismic action chart.
Seismic action charts showing evacuation and inspection thresholds have been developed for a number of offshore platforms in seismically active regions around the world, such as California, Indonesia, and Trinidad and Tobago. These seismic action charts have been used successfully to date without any known issues. To demonstrate the concept and application, the development of a seismic action chart using the Next Generation Attenuation (NGA) relationships and subduction zone attenuation relationships for an example platform is presented in this paper. The evacuation and inspection thresholds outline three distinct regions on the earthquake magnitude vs. epicentral distance chart. Below the inspection threshold, no action is required. Between the inspection and evacuation thresholds, targeted inspections of critical structural members and joints based on seismic analyses are recommended as soon as practically possible. Above the evacuation threshold, immediate and safe evacuation of platform personnel is advisable.
Concentric Fluid Loss Control Devices Increase Reliability of Subsea Dual-Zone Selective Intelligent Completions in the Deepwater GoM
Authors: Ramnath Lawrence , Gutierrez William , White Christine 
Published: April 2017

This paper discusses the application of Concentric Fluid Loss Control Devices (C-FLCDs) in the sandface sections of dual-zone selective intelligent completions. Specific focus is placed on the need for increased reliability in debris environments over traditional Ball Valve Fluid Loss Control Devices (BV-FLCDs).Historic Non-Planned Time (NPT) events due to debris deposition above BV-FLCDs prompted consideration of alternative FLCD technology that would be more debris tolerant. Technologies considered needed to support features such as: bi-directional pressure integrity for zonal isolation, remote actuation for reservoir communication and integration with intelligent completion hardware.The selected C-FLCD technology allowed debris to pass through the device rather than being deposited above it. In addition, flow erosion and Computational Flow Dynamics (CFD) modelling showed that the C-FLCDs did not limit the flow rate from either the Lower Zone or Upper Zone where installed.To date, after eight dual-zone completion installations in the Deepwater GoM, there has been 100% successful application of the C-FLCDs.
Condition Monitoring Comes of Age for Subsea Production
Authors: Smedstad Eric , Nilsen Geir Werner , Bressand Jean-Yves 
Published: April 2017

With increased focus on integrity management to maximize uptime and output, asset surveillance and integrity management are increasingly becoming core elements of subsea field developments. Condition and Performance Monitoring (CPM) provides critical real-time data to the operator which can prevent unplanned shutdowns saving millions of dollars in lost production and ensuring system integrity. Today, subsea pumps, boosting and compression systems are expected to function properly for 30 years under demanding operating conditions. However, the subsea industry has historically had limited advanced feedback on the mechanical fitness, electrical condition and operating performance of subsea rotating machinery in contrast with the advances made in condition monitoring systems commonplace now in automobiles.
Subsea pumping systems are now available with a comprehensive top down approach to predicting equipment failure from a modal analysis. Advanced instrumentation, such as vibration sensors, are now available and designed specifically to monitor equipment condition and not simply for operational control of the pump system.
Advances in Low Cost, Quantitative Inspection Techniques for Floating Systems
Authors: Guest B. , Carra C. , Wales S. , Potts A. E. , Kilner A. A. , Barrow S. , Pudney S. 
Published: April 2017

Abstract
With the challenges faced by operations in a continuing low oil price environment and the continuing high failure rate of offshore moorings, the value derived from traditional mooring inspection strategies needs to be reassessed. This paper outlines a significantly improved approach to mooring and riser system inspection based on the acquisition of quantitative condition data using low cost/low risk inspection techniques. Specifically, this paper addresses the ability to perform specific, detailed, quantitative inspections using standard inspection tools mobilized to and launched from an offshore facility. By modifying inspection strategies to target specific areas of high risk and known degradation mechanisms, a much-improved understanding of the current condition of the system is gained and appropriate integrity management strategies developed based on the observed and measured rate of component degradation. In addition, the ability to respond rapidly to event-based forms of degradation is significantly improved. This approach will be demonstrated by a case study of the inspection of a known area of risk that is traditionally difficult to inspect and interpret - mooring chain links within a hawse pipe.
High definition imagery of elements within the hawse pipe of an FPSO turret mooring system were acquired and then post processed into highly accurate (±1 mm) 3D chain link data, following which detailed numerical analysis of the remaining link capacity for worn links was performed. Previously acquired diver measured data is compared against 3D scan data and the improvements in the accuracy of the estimate of the remaining strength on the worn links is demonstrated. Based on the understanding of the remaining capacity and rate of degradation, future inspection intervals can be set on an informed basis, such that the rate of volumetric loss can be verified by measurement, thereby confirming the rate of degradation in link capacity. A cost-benefit analysis highlights the improvements in overall lifecycle costs that these quantitative, facility-based, inspection techniques can provide. This paper provides a demonstration of the ability to perform detailed quantitative surveys and utilize the acquired information to assess both current and future condition of safety critical elements. The paper demonstrates improvements in inspection strategy that are consistent with the new approaches to mooring system integrity management that are currently being finalized (e.g. the new API-RP-2MIM).
Experimental Study on the Separator Performance with Various Droplet Distribution in High Watercut
Authors: Kim Sungwoo , Han Junhee , Kim Sunggyu , Im Hyonam , Lee Heesung , Choi Jaewoong 
Published: April 2017

Abstract
Separator's performance with various droplet distributions is experimentally investigated in the pilot scale of facility. The mixture of continuous oil and dispersed water without surfactant is continuously re-circulated in the facility. The droplet distribution is produced by the operation of pumps and mixers through breaking up mechanism. Dispersion band above interface level appears in the condition of high dispersion fraction around 30%. The measured CLD from FBRM is converted into PSD by a peeling method and its converted PSD is changed again into volume-based PSD. Droplet distribution at the inlet reveals that the Sauter mean diameter is proportional to the maximum stable droplet (d95) of volumetric distribution and its value reduces according to increasing watercut. The moments of distribution such as standard deviation, skewness, and kurtosis also show a linear relation with maximum droplet size. The actual cutoff diameter derived from WiO at the oil outlet is estimated around 50μm, which is much smaller than 250μm of cutoff diameter estimated from the Stokes' settling law. It implies the possibility of interaction among droplets inside separator in the condition of large dispersed phase. Actual cutoff diameter and remained water fraction seem to be weakly correlated with the parameter of specific surface area. The measured separator's performance reveals that inlet distribution in high dispersed phase seems to be not valid to estimate separator's performance due to the droplet distribution change in the separator.