bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multi-Resolution Probabilistic Ocean Current Forecasting System for Offshore Energy Operations
Authors: Srinivasan Ashwanth , Sharma Neha , Gustafson Drew
Published: April 2018

We present a multi-resolution probabilistic ocean forecasting system designed to support offshore energy operations worldwide. The system is composed of an integrated suite of ocean circulation models including a global model of 25 km resolution, Atlantic and Indian Ocean models of 6 km resolution, and 8 fine scale models (< 3 km resolution) for high-priority regions such as the Gulf of Mexico, offshore Brazil, West Africa, and the Caribbean. It expands on current ocean prediction systems through exclusive access to proprietary data streams, state-of-the-art data assimilation methods and ensemble modeling capabilities. The global and basin scale models incorporate large-scale information from satellite and in-situ observations and provide initial and boundary conditions for the regional models. The regional scale models then dynamically downscale the initial and boundary conditions to produce both deterministic and probabilistic fine-scale forecasts for regions of interest.

The system has been validated for consistency, quality, and accuracy against a suite of publicly available models and field observations (Remotely sensed observations, ARGO float data and Drifting Buoys). Results show that the system compares favorably to other leading ocean current forecasting systems such as HYCOM and the Mercator system. Experiments in the Gulf of Mexico demonstrate that the fine-scale forecasts are further improved by using proprietary data streams and when operated in an ensemble (probabilistic) mode they also provide robust quantification of uncertainty in forecasts.

The system has been operational since the beginning of 2017, providing daily 7-day forecasts of ocean currents. Additionally, 20-year hindcasts for some regions are in progress and outputs will be available for extreme value analysis for planning and structural design. It is expected that Ocean current hindcasts and forecasts through the new system will translate to increased situational awareness, reduced downtime, improved environmental protection, and safety.
Development of New CRA Grade for High Pressure High Temperature Application
Authors: Song S. , Richoux V. , Gomes C. , Decultieux F. , Néel G.
Published: April 2018

In High Pressure High Temperature "HPHT" wells (pressure above 10 000psi/690bar, temperature above 300°F/150°C which contain CO2 (sweet corrosion) and H2S (sour service), the oil & gas operators need to select materials which are resistant in corrosive atmosphere during the well lifetime. At the same time, high strength grades are usually required to meet collapse and burst properties. The aim of the end users is to get the specific grade which can resist to corrosion while minimizing the cost, which involves qualification with corrosion tests.

The API 5CRA standard defines corrosion resistant alloy (CRA) grades for casings and tubings, from group 1 named "Super 13Cr 13-5-2" (suitable up to 356°F/180°C), to group 2 "Duplex" grades 22-5-3 (450°F/232°C) or "Super Duplex" 25-7-4 (482°F/250°C) and higher grades.

Therefore, when the well temperature is above 356°F/180°C, duplex grades or higher are commonly selected as these materials have a larger application domain at higher temperature range.

A new metallurgy was developed with high strength properties demonstrating a superior corrosion resistance at higher temperature compared to the standard Super 13Cr 13-5-2 grade and which is a cost effective solution compared to Duplex grades.
Effect of Seabed Trenching on the Holding Capacity of Suction Anchors in Soft Deepwater Gulf of Guinea Clays
Authors: Sassi Khalida , Zehzouh Slimane , Blanc Matthieu , Thorel Luc , Cathie David , Puech Alain , Colliat-Dangus Jean-Louis
Published: April 2018

Seabed trenching, related to large motions of relatively taut deepwater mooring systems in the long Gulf of Guinea swell, can reach the suction anchor and the chain padeye depth, thus raising serious concerns about the holding capacity of the suction anchors and the safety of the mooring systems. The potential reduction of the anchor capacity, estimated by means of 3D finite element (FE) calculations, needs to be verified by means of testing, and this is the objective of the study presented here. The paper describes the IFSTTAR geotechnical centrifuge test facility and the model soil preparation procedure for obtaining large open trenches with natural deepwater Angola clay in the swinging centrifuge. The scope of the study includes a number of holding capacity tests on suction anchors without trenches (reference cases) and with large trenches reaching the suction anchor and padeye depth. Tests were performed under vertical and inclined loading (actual case of taut deepwater moorings with significant vertical loading component), with the measurement of pore pressures at different levels below the anchor tip for verifying the effect of the trench on the reverse end bearing (passive suction) capacity. The centrifuge test results are compared with Plaxis 3D FE calculations for the purpose of comparison with previously published results. The preliminary results presented show that the REB capacity is mobilized, even with large trenches reaching the anchor and padeye depth. It is also confirmed that Plaxis 3D FE modelling offers a reliable tool for the assessment of the post-trench holding capacity of the suction anchors.
The World's First Successful Implementation of Solid Fluidization Well Testing and Production for Non-Diagenetic Natural Gas Hydrate Buried in Shallow Layer in Deep Water
Authors: Shouwei Zhou , Qingping Li , Wei Chen , Jianliang Zhou , Weixin Pang , Yufa He , Xin Lv , Liangbin Xu , Qiang Fu , Jiang Lin
Published: April 2018

Based on the characteristics of shallow buried, non-trap structure and close cover, non-diagenesis, weak cementation and easy fragmentation of natural gas hydrate deposits in China, a solid fluidization well testing and production scheme to develop these kind of natural gas hydrate is proposed. The main idea is to transfer the non-diagenetic natural gas hydrate sediments buried in shallow layer of deep-water into a closed multi-phase transporting and lifting system through mechanical crushing fluidization, during the lifting riser system from seabed to surface, hydrate will be dissociated gradually based natural rule of sea water temperature rising and the hydrostatic pressure decrease with the change of water depth during the lifting process, to turn the uncontrollable decomposition process of non-diagenetic hydrate into controllable, and to achieve safe field exploitation of natural gas hydrate in the surface and shallow layer of deep-water. After the validity was verified by the laboratory experimental study, CNOOC successfully implemented the world's first solid fluidization well testing and production of marine non-diagenetic hydrate with the water depth of 1310m and the hydrate sediments layers 117~196m depth in May 2017. It means China has found an innovation way about natural gas hydrate exploration and development with self-developed key technology and tools. The implementation relied on the Deepwater Engineering & Survey Vessel "HYSY708" at the station of Li Wan 3 in the South China Sea and it was supported by fully self-developed technology, process and facilities.
Estimation of Wind and Current Load on Offshore Structures Using Wind Tunnels and CFD
Authors: Cho S. , Hwang S. , Jung J. , Sung H. , Park B. , Vazquez-Hernandez A.
Published: April 2018

This paper suggests the improved technology to predict the wind and current loads on offshore structures such as FPSO and Semi-submersible. Wind tunnel tests and CFD analysis are conducted and results and application methods are discussed. The characteristics of flow and extrapolation to real Reynolds number condition are also analyzed with regard to loads. To analyze the load and flow characteristics, the detail conditions of wind tunnel and CFD are investigated such as flow field and model setup and their effects on results are examined. From the comparison of wind tunnel tests and CFD, flow physics are analyzed regarding the characteristics of the flow. This paper shows the parameters which affect the wind tunnel tests and explain the reason of differences between wind tunnel tests and CFD. The flow field such as velocity profiles and turbulence is major parameter and model setup and test condition must be described as accurate as possible. The additional and new consideration for wind tunnel test is suggested based on observed results. The flow around semi-submersible differ from FPSO and different approaches are necessary considering flow characteristics. The extrapolation to real Reynolds number condition is very difficult for the offshore problem. Based on above results, the extrapolation is discussed for the estimation of wind and current loads on FPSO and Semi-submersible. The results show that new suggestions of wind tunnel test give the improved prediction and reduce the uncertainties. CFD analysis considering wind tunnel environment give more reliable results and extrapolation may afford more efficient and conservative estimation of wind and current loads. This may significantly influence the design of mooring system and offshore structure.
BOP Testing and It's Availability on Demand-A Case Study
Authors: Zulqarnain Muhammad
Published: April 2018

Blowout Preventer (BOP) is an integral component of defense in depth approach adopted in deepwater drilling operations. Regulatory bodies require frequent testing of these barriers, to make sure that they will be available to perform their intended functions when demand arrives. As BOP works only in demand mode, therefore the calculation of average probability of failure on demand (PFDavg) is one of the technique that can provide the critical information about the availability of these barriers.

In this study PFDavg formulation is used to carry out s systematic performance evaluation a BOP's barrier elements. A sensitivity analysis is also performed to account for some of the real demand conditions that cannot be tested during routine tests, an example is the testing of shearing capability of blind shear rams. Multilevel test formulations are used that accommodates both of proof test and partial stroke testing concepts. The interdependency of these barrier elements is modeled by using beta factor model, which account for common cause failures.

The results are presented for three flow paths of open wellbore flow, flow through drillpipe-casing annulus and flow through drillpipe. Corresponding BOP's barrier elements are used to estimate the availability of these barriers when they are demanded. The analysis results indicate high common cause failures of BOP's main control system with an average value of 0.25. Which is a significantly high dependency of both of the BOP's control pods on some of the common elements that can fail them simultaneously. The results also show that average availability of drillpipe-casing annular and open-hole barrier channels is dominated by the BOP's main control system, mainly due to its high failure rates. The analysis also revealed that a beta factor contribution significantly impacts the unavailability of drillpipe-casing annular channel barrier elements.

Results for other demand scenarios and combination of working of these barrier elements are also presented. The presented results highlight some of the critical safety measures of BOP's barrier element performance and also highlight some of the deficiency areas that need to be taken care of to improve the system's performance. It is therefore hoped that the presented results will be helpful to gain insight into different modes of operation and in improving the system's performance.
Using Weather Pattern Typology to Identify Calm Weather Windows for Local Marine Operations
Authors: Steele Edward , Neal Robert , Dankers Rutger , Fournier Nicolas , Mylne Kenneth , Newell Paul , Saulter Andrew , Skea Alasdair , Upton Jon
Published: April 2018

The cost and complexity of offshore operations, combined with the vulnerability of equipment to prevailing conditions, requires weather-sensitive decisions to be made to ensure the continued accessibility and availability of marine assets. In the current economic context, this is especially important since the robust (timely) identification of calm weather windows has the potential to save many thousands of dollars per day in unplanned downtime and vessel contracting, allowing large efficiencies in sequencing, mobilisation and demobilisation costs if decisions are taken at the earliest possible opportunity. As forecasts extend weeks to months ahead, it is well known that predictability limits make the direct characterisation of small-scale weather events all but impossible, but there still remains a considerable amount of useful information contained within the large-scale weather circulation types. These circulation types, termed ‘weather patterns’, have a strong influence on the variability of marine wind and wave fields. Here, we present a new method for the tracking of calm weather windows out to several weeks ahead. Using a 34-year hindcast to elicit the daily maximum significant wave height experienced at the location of interest – and an analysis of the associated weather pattern under which they occurred – the circulation types are linked to the viability of offshore operations on a local scale. When subsequently applied in forecast mode, this method can enable earlier decision-making than is typically done at present. As weather patterns are more predictable than the actual weather itself at long lead-times, knowledge of the corresponding historic wave heights can enable identification of expected conditions within a probabilistic weather pattern forecasting system. In addition, the approach facilitates contingency planning; further supporting improved decision-making and reduced operational costs for the offshore oil and gas and marine renewable energy sector.
Derivation of Continuous Irreducible Water Saturation and Pore Throat Aperture Distribution from Well Logs in an Offshore Brownfield
Authors: Li Ting , Zhou Xin , Cui Yunjiang , Xu Jinxiu , Liu Huan
Published: April 2018

In this case study, we propose a new petrophysical workflow to evaluate an offshore mature field. In the field studied, hydrocarbon production mainly comes from sandstone reservoirs with good permeability and low water salinity. The operator typically drills deviated wells and runs Logging While Drilling (LWD) tools to make timely completions decisions. The petrophysical properties critical for these decisions are porosity, permeability, irreducible water saturation (Swi) and total water saturation (Sw). Occasionally, Nuclear Magnetic Resonance (NMR) logs are run to characterize Swi and permeability, but are only available in select wells. The challenge for the petrophysicist is to make the most of the commonly available measurements and compute the petrophysical properties required for decision making.

We propose a technique that derives continuous Swi and pore throat radius distribution from porosity and permeability logs. When the well is cored, continuous permeability can be obtained through core calibration. When only basic well logs are available, permeability is typically estimated from a porosity-to-permeability relationship, which is derived from core data in an offset well. We then usea well established relationship to compute pore throat radii from interpreted porosity and permeability logs for a range of mercury saturations. We can further construct a synthetic Mercury Injection Capillary Pressure (MICP) curve from mercury saturation and capillary pressures (Pc) corresponding to different pore throat radii. Since Swi varies with Pc, we can apply a Pc cutoff on the synthetic MICP curve to obtain Swi. This cutoff can be determined empirically or from height above free water level.

From the level-by-level synthetic MICP curves, we can also construct a histogram of pore throat radius at each depth level. This plot provides valuable visual aid that helps interpreters identify good quality rocks.

To validate this method, we calculated the bound water volume (BFV) from synthetic MICP and compared it to BFV derived from NMR T2 distribution. There is an excellent agreement between the two computed BFV curves. The proposed workflow is only meant to provide a rock quality evaluation when log data is scarce. For accurate characterization of Swi and rock quality in complex reservoirs, more advanced measurements are recommended.
Flexible Riser Remnant Life Assessment Using Artificial Neural Networks and Advanced Inspection Methods
Authors: Francis Kirk , Chaves Victor
Published: April 2018

This paper presents a methodology that is currently being utilized to assess the remnant life of flexible risers. The objective is to accurately determine whether flexible risers can safely continue to operate by determining the current condition of the annulus and armor wires, and determining the remnant life using advanced analysis methods in combination with inspection data.

The inspection part of this method consists of ultrasonic scanning of the flexible riser in key locations to confirm whether the annulus is dry or flooded and, if flooded, determine the remaining tensile wire thickness. The results of the ultrasonic scanning are then used in combination with global and local riser analysis to determine the remnant fatigue life of the riser. In order to have a more refined and realistic numerical model, time-domain irregular wave approach is used. However, the combination of the need for detailed nonlinear models and the demand for long time series simulations makes this type of analysis extremely time consuming. The method proposed to reduce computational costs in this type of numerical model is a hybrid methodology that combines Finite Element Analyses (FEA) and Artificial Neural Networks (ANN). The proposed hybrid methodology aims to predict the loads at a defined section of the flexible riser. Firstly, using short FEA simulations to train the ANN, and then using only the ANN and the prescribed global riser response to get the remainder of the stress time histories.

Results to date have shown that the general assumptions used on corrosion rates and the regular wave dynamic analysis approach are each very conservative, and significant life extensions have been justified based on the results of the combined inspection and analysis method. The use of these methods has the potential to confirm the acceptability of flexible riser life extension beyond the original design life, or to confirm the acceptability to continue to operate with annulus conditions outside the original design specification.

The use of ANN for flexible riser fatigue analysis and the use of ultrasonic scanning to determine the present conditions of the flexible riser annulus and armor wires are each advanced techniques in flexible riser integrity management. When combined together as this paper proposes, these methods provide both a current status of the flexible pipe integrity as well as a forecast of the remaining allowable life, allowing key field decisions to be made quickly and accurately.
Big Data in the Digital Oilfield Requires Data Transfer Standards to Perform
Authors: Neri Philip
Published: April 2018

The digital oilfield is evolving with the number of sensors and measuring devices and the frequency of data sampling both increasing dramatically, which is the onset of what is commonly referred to as Big Data. These increases are needed as the motivation for the collection and transmittal of data has moved from the remote observation of operations to the remote operation of increasingly automated systems, as well as the goal of reliable prediction tools that improve efficiency.

A lot is written and discussed about how to handle Big Data in the context of data management and analytics. However, the task of transferring the digital information from the field to the back office is critical. This is built on advances in standards for data formats, metadata and transmission protocols that have been published to support the digital oilfield of the future. The first advance has been the larger amount of metadata, providing detailed information on the data source's characteristics, eventual transformations to the data (by who, using what tools, etc.) and prior vetting. The second one is to replace transmission protocols based on polling different servers with streaming processes that do away with inefficient interrogation, handshake and packaging overheads.

The implementation of these improved standards allows operators to build solutions that involve different vendors. A test was put in place involving an active North Sea drilling operation, with data being transferred to onshore observers both at the operator's facilities and on the premises of a service provider. Data was streaming on to the screens of both observing parties less than one second after the event took place on the rig. This compares to lag times of 15 to 20 seconds using polling methods. The bandwidth usage was approximately 1/10 compared to previous methods, such that more sensors could be added to the data transmittal.

With more immediate access to a much broader and richer set of data both at the operator's facilities and also at the premises of many contractors, service providers in particular could make more educated assessments of developing situations on the rig, which in several cases avoided the need for a team to go to the offshore rig, thus reducing the number helicopter flights to the offshore installations and accounting for fewer people-on-board (POB), which contributed to lower HSE exposure and lower costs.
Combining DWS Depressurization Method and Heat Injection to Improve the Hydrate Recovery
Authors: Sun Ting , Chen Yuan , Zhao Ying
Published: April 2018

Natural gas hydrate (NGH) is a new kind of clean resource with a large reserve and wide distribution, which is considered as an important alternative energy. While extracting natural gas hydrate using the method of depressurization, the temperature will decrease for the absorption of heat in the process of hydrate decomposition, which may cause the formation of ice or the re-formation of hydrate and further cause the reduction of natural gas recovery; meantime, the decomposition of natural gas hydrate will cause the decrease of formation pressure, as a result, water coning may occur, which will also cause the reduction of natural gas recovery.

The DWS (downhole water sink) method has shown that this technology could increase oil production and control water coning when exploiting oil. This paper adopted this technology and made some improvements to fit in the exploitation of natural gas hydrate. The objective of this paper is to determine the improvement degree of natural gas recovery and whether it can effectively control water coning using the method of combining DWS depressurization method and heat injection method.

In this paper, the mathematical model of natural gas hydrate exploitation is built first, then numerical simulation is used to compare three natural gas hydrate production methods - common depressurization method, DWS depressurization exploitation method and the method of combining DWS depressurization method and heat injection. The simulation results confirm that the combined method has better recovery by showing a big increase of recovery factor comparing to the other methods. The results also give a large reduction of water cut.

The simulation experiments clearly show that the main advantage of using the method of combining DWS depressurization method and heat injection method is that it is easy to control the recovery process and water coning. For this method, production process could be optimized for maximum recovery and minimum water production by seeking a best combination of gas and water production rates.
Evaluation Testing of Completion Tubular Connections for an HPHT Environment in the Gulf of Mexico
Authors: Cole S. , Groh J. , Perkins J. , Dickerson G. , Pattillo D.
Published: April 2018

The industry standard that governs the testing of casing and tubing connections is API Recommended Practice (RP) 5C5. Due to the complexity and variety of load combinations that a connection can experience in the field, especially in deepwater/HPHT applications, a new version of API RP 5C5 was released in January 2017. (The previous version of RP 5C5 was the Third Edition published in 2002.) This latest version requires in-depth collaborative involvement from both the operator and supplier to ensure that the testing fulfills both the industry standard and any operator-specific functional requirements.

In order to assess structural integrity and sealability, an operator requires validation testing of production tubing connections to demonstrate "fit-for-service." Due to the critical nature of production tubing, acting as the primary barrier for produced fluids, the most rigorous testing protocol was selected—API RP 5C5:2017 CAL IV. Of all the connection assessment levels (CALs) outlined in API RP 5C5:2017, CAL IV most accurately captures the sequence and severity of loading that may be experienced by production tubing in an HPHT environment.

This paper outlines the evaluation and testing methods conducted collaboratively between a supplier and an operator, appropriate for a deepwater HPHT project. Three different oil-country tubular goods (OCTG) connection sizes were tested to API RP 5C5:2017 CAL IV. This paper includes a step-by-step overview of the process—initial review of the connection, gap analysis of product-to-testing requirements, modification of testing protocol, physical connection testing, and final reporting of the results.

The operator and supplier wish to share their experience and lessons-learned in testing connections to the latest qualification standard. This experience includes the detailed coordination and communication needed among all parties involved.
Lateral Response of Trenched Pipelines to Large Deformations in Clay
Authors: Kianian M. , Esmaeilzadeh M. , Shiri H.
Published: April 2018

Subsea pipelines are usually buried in shallow waters for physical protection. Buried pipelines may experience large lateral displacement in different occasions such as ice gouging, ground movement, significant thermal gradients, and dragging by anchors, fish traps, etc. Backfilling materials are often heavily remoulded under functional and environmental loads and are considerably softer than trenched native ground. This, in turn, affects the failure mechanisms in the surrounding soil and the lateral load-displacement response of the pipeline, consequently. These important considerations are covered less often in the design codes and standards. In this study, the lateral pipeline-backfill-trench interaction was studied through centrifuge testing of sixteen distinct pipe-soil configurations under drained and partially drained conditions. A transparent observation window combined with digital cameras were used for Particle Image Velocimetry (PIV) analysis. A range of instruments was installed on the pipeline, backfill, and the trench to obtain the key data and the lateral p-y response of the buried pipe. The influence of several key parameters on the lateral pipeline response was also investigated including backfilling properties, trench geometry, interaction rate effect, and burial depth. The results showed that the failure mechanisms, affected by various pipeline-backfill-trench interaction parameters, have a significant impact on the lateral p-y response and the ultimate soil resistance. The study program provided an in-depth insight into this challenging area and prepared the ground for proposing new models and methodologies for incorporating more realistic conditions for pipeline design subjected to large lateral displacements.
Digital Oilfield Implementation Challenges Management in Offshore Environment
Authors: Udofia Emmanuel , Obong Benjamin
Published: April 2018

Digital Oilfield (DOF) is an Intelligent Energy concept that assures continuous optimisation of an asset or group of assets through integration of standard tools, domain experts, defined business processes and appropriate facility or space. Digital oilfield solutions include real-time production optimization and extend to improvements in team integration and asset risk reduction. The objective of this paper is to highlight challenges of digital oil field implementation and provide appropriate mitigations.

Following over two decades of implementation of digital oilfield by several operators globally, digital oilfield concept has undergone series of transformation in implementation strategy and sustainability drive. The fundamental principle and objectives of digital oilfield remains the same that is optimisation of an asset in the short term and to extend the life cycle value of an asset in the long term. However, the difference amonst the operators are the name each operator refers to this concept. Shared business perspective from experiences in several implementations will assist in driving the message of how to effectively manage digital oilfield programme.

Documented evidences has demonstrated that short term solutions from digital oilfield implementations are delivered, but the challenges has been value erosion overtime due to lack of effort or commitment to ensure solid embedment of the process and sustainability of the solutions. The said outcome involves evaluation of the business impact of the DOF implementation in addressing challenges of digital oilfield implementation. The observed challenges includes but not limited to the following:

Poor alignment of the project implementation objectives with the business need of the asset Lack of involvement of the asset at the inception of the project and ensure seamless ownership and sponsorship process. No clear succession plan for the process champions which equally hamper value sustenance Lack of defined training and retraining of personnel remains a big exposure in digital oilfield benefits realisation.

To manage these gaps, a novel sustainability framework is proposed that is developed and built to ensure the digital field solution addresses the asset-specific business need with the right sustainability model. The result from this paper could be applied in similar project elsewhere.
Evaluation of Rock Mass Stability and Rock Fall Hazard for Pipelines in Submarine Environments
Authors: Bertalot D. , Malgesini G. , Parker E. J.
Published: April 2018

Although relatively uncommon, rocky submarine outcrops with high to nearly vertical gradients do occur in various offshore settings, including high latitude fiords and tectonic margins with narrow or absent shelves, or high-gradient aprons constituted by ancient lithified carbonate reefs. Here pipelines and flowlines are subject to the hazard of landslides developed in the instable rock-mass and consequent impact of individual boulders. This paper proposes a methodology for the evaluation of landslide and rock fall hazard for pipelines in submarine rocky slopes. The analysis includes results from several common marine site investigations such as high resolution geophysical surveys, Side Scan Sonar imaging, ROV video transects and conventional geotechnical boreholes, and specific datasets including in-hole structural drilling and data from analogue outcrops into a probabilistic framework, aimed at establishing the risk of pipeline structural damage. The assessment of rock fall hazard for onshore infrastructures such as railways and roads is routinely evaluated based on well-established methodologies. Such analyses, however, either requires a full geomechanical understanding of the rock mass, hardly achievable offshore due to data limitations or a probabilistic evaluation of historical events, not applicable offshore. The methodology we propose overcomes these limitations and allows, after defining the maximum allowable impact energy for the design pipeline, obtaining the overall frequency of offshore pipeline damage and thus quantifying the risk associated to rock fall based on relevant standards and guidelines. The rock slope stability is evaluated using a limit equilibrium approach which includes pseudo-static accelerations. Given the uncertainties associated to key input parameters such as the mechanical properties of the rock mass, as well as to the size and trajectories of the failed rock wedges, a Monte Carlo probabilistic approach is preferred. The main outcome of the proposed methodology is the probability of pipeline failure in environments where rock mass instability and consequent rockfall phenomena represent a potential hazard.
Mapping Benthic Habitat Conditions and Seafloor Deposits Using Sediment Profile Imaging and a Semiautomated Image Processing System
Authors: Revelas Eugene , Sackmann Brandon , Thurlow Aimee , Jones Craig
Published: April 2018

Objectives/Scope

Sediment profile imaging (SPI) technology characterizes in situ physical, geochemical, and biological seafloor features. SPI was required by Mexico’s Agency for Safety, Energy, and Environment in 2017 for environmental baseline surveys (EBS) of oil lease blocks in the southern Gulf of Mexico. Because of its ability to provide information on benthic community health and the distribution of very thin (down to the centimeter scale) layers of deposited materials, SPI technology is highly effective for mapping drill cuttings or drilling muds released around wellheads during exploration or production and documenting their ecological impacts. SPI technology has not been widely used in the oil and gas industry for EBS or other monitoring activities. A primary objective of this work is to improve the transparency and consistency of the SPI data generation and data management process.

Methods, Procedures, Process

The SPI camera works like an inverted periscope and obtains an undisturbed 21x15-cm cross-sectional image of the upper sediment column. The camera is internally powered and can be deployed rapidly from a standard winch in depths to 4,000 m. Many stations can be sampled in a single day by "pogo-sticking" across a survey area. Sediment grain size, penetration depth, surface boundary roughness, natural and anthropogenic depositional layers, depth of the oxidized surface sediment layer, maximum biogenic mixing depth, and infaunal successional stage can be directly measured at sea or immediately following the cruise. Final SPI data sets can be provided within a few weeks of the survey.

Results, Observations, Conclusions

Details on the features measured in SPI images and the underlying interpretive paradigms are presented. To standardize the SPI data generation process, Integral Consulting Inc. has developed 1) a semiautomated image analysis platform, and 2) a SPI data-specific database architecture that allows both numerical and non-numerical metrics to be incorporated into a standard database structure. An integrated, software-based SPI analysis platform has been developed that imports image files and metadata and provides a graphical user interface. The software automatically stores the data, which can then be reviewed for quality assurance, plotted, statistically analyzed, and mapped or exported to other platforms (e.g., Esri ArcGIS©) for further evaluation. Image processing algorithms have been developed using a combination of open-source and commercially available software packages (e.g., MATLAB® and OpenCV) to automatically quantify key parameters.

Novel/Additive Information

SPI technology’s underutilization in the oil and gas industry may be in part due to a lack of standardization in the measurement of basic features in SPI images. A primary objective of this work is to develop a streamlined, standardized, and transparent process for generating and managing SPI data.
FlatFish Resident AUV: Leading the Autonomy Era for Subsea Oil and Gas Operations
Authors: Zagatti R. , Juliano D. Russo , Doak R. , Souza G. Mimoso , de Paula Nardy L. , Lepikson H. A. , Gaudig C. , Kirchner F.
Published: April 2018

Challenged to remain competitive in a low oil price environment whilst navigating the energy transition, the industry is now seeking ways to evolve operations through digitalisation. Robotics has already enabled an evolution of the Oil and Gas industry by enabling deepwater operations through the deployment of ROVs. Now the industry seeks to reduce the unit operating costs of offshore facilities whilst improving safety and environmental performance. Autonomous underwater vehicles (AUVs) such as FlatFish can help the industry achieve this objective by reshaping the concept of operations for subsea surveillance.

Oil and gas operators stand to benefit from robotic technologies which have been successfully adopted in other industries such as aerospace and defence. Technologies that can perform autonomous subsea inspections and interventions: faster, safer, and cheaper than traditional approaches. Robotics and AI (Artificial Inteligence) can play a fundamental role in increasing the competitiveness of the oil and gas industry, the prize for rapid deployment into daily subsea surveillance tasks means not only the unlocking of deep water ventures, but also the safe life extension of offshore assets.

The FlatFish project is a leading example of how technology development in robotics and AI can contribute to the reduction of inspection costs, improve the accessibility of offshore installations and reduce safety risks. The technology development program has shown the capabilities of FlatFish AUV such as: performing autonomous visual inspection, tracking pipelines, hovering around structures such as tree systems and manifolds and returning to the docking station for recharging and data transfer.

The development and pre-production qualification are in the final stage, next steps are the industrialization and commercialization. FlatFish is a leading example of where Robotics and AI can contribute towards a reduction in subsea inspection costs.
Advances in LDHIs and Applications
Authors: Chin Y. D. , Srivastava A.
Published: April 2018

This paper is to represent reviews of low dosage hydrate inhibitor's (LDHI) evolution and advances, and to provide a general guide for LDHI considerations, historically, hydrate risk has been managed by keeping the fluids warm, removing water, and/or by injecting thermodynamic hydrate inhibitors (THI), commonly methanol or glycol. THIs require high dosage rate therefore production systems can reach a treatment limited by supply, storage, and umbilical injection constraints. Besides, high dosage of MeOH can cause crude contamination for downstream refineries, which may result in penalty.

Over last two decades LDHIs have been extensively researched and developed as an alternative hydrate management chemical for oil and gas industry. LDHIs are divided into two main categories; Kinetic Hydrate Inhibitor (KHI) and Anti-Agglomerant (AA), both have been successfully used in field applications, but each comes with their unique challenges for applications, OPEX and CAPEX considerations. LDHIs have proven track records in numerous fields in their performance, either as stand-alone chemical treatment or reducing amounts of methanol/glycol usage, which has directly resulted in CAPEX and OPEX reduction. LDHIs have been instrumental in managing risks of early water breakthrough, high cost of THI storage and transportation, HSSE concerns around THI handling, and undersized pump capacity for required chemical volumes. Switching to LDHIs also offers an economic advantage by reducing umbilical line diameter. Latest advances in the LDHI technology is breaking barriers and pushing limits.

The paper summarizes historical advancements in LDHIs over the last two decades, discusses application advantages and limitations, and the criterions to consider for selecting LDHIs.
Ten Years in the Water: Observation and Detailed Evaluation of a Riser after Extensive Service Life
Authors: Tricarico Mike , O'Neil Chris , Peter Thomas
Published: April 2018

Life extension of existing assets is an important aspect of offshore oil and natural gas operations in the Gulf of Mexico. As part of an effort to evaluate existing riser systems, Anadarko launched an inspection and testing program to investigate risers retrieved following well abandonment after a service life of nearly 10 years in the water. To assess the pipe and connections, 12-3/4′ T95, Anadarko and Vallourec performed visual inspection of the full pipe body length (internal and external), ultrasonic inspection, and wet magnetic particle inspection. The original testing was repeated on the post service pipe and connection. For both sealability and fatigue testing one side of the connection was left in the "in service" condition, while the other side was broken out and made-up again. Sealability testing followed the ISO13679/API 5C5 CALIII protocol. Fatigue testing repeated the original stress level, and was cycled to failure.

The pipe and connection performed very well under the post service testing and evaluation. Overall corrosion and defects in the pipe were very low, and within service parameters. The connection evaluation also showed very good results. The most important evaluation/observation was of the internal and external seal. The field broken connections had signs of galling and rust. However, further evaluation of the damage, as well as review of the connections not broken out during riser pulling, pointed towards handling damage during pulling operations. Review of photographs taken during pulling operations showed no signs of degradation from the environment or galling. Further inspection of connections that were broken out at the testing facility indicated no damage to the connections. The fatigue testing results were also positive, indicating significant remaining life, had the riser been left in service.

This represented a rare opportunity to evaluate the state of the threaded and coupled risers after such a long service life, along with assessing the remaining longevity of the riser system. It was a chance to observe and measure the effects of actual service life as opposed to calculated service conditions on the pipe and connections. The findings provided valuable insights into the future usability of similar riser systems.
Integrating Big Data: Simulation, Predictive Analytics, Real Time Monitoring, and Data Warehousing in a Single Cloud Application
Authors: Mounir N. , Guo Y. , Panchal Y. , Mohamed I. M. , Abou-Sayed A. , Abou-Sayed O.
Published: April 2018

The E&P industry is rich in all types of data. Without proper database and analytics, companies are not able to retrieve and analyze the data they need in an efficient way. The result of the data management problems is that decisions are often made using incomplete or incorrect information. Even when the desired data is accessible, requirements for gathering and formatting it may limit the amount of analysis performed before a timely decision must be made.

Strong data management is required to transform wells-related data into an integrated system of information. The key to successful data management is in the use of sophisticated platform-independent codes that doesn't need any special setup or systems which allows easy transfer of information and data over the internet. This paper describes the data management and accompanying analytics approach taken in support of operations in Egypt to provide a shared knowledge system.

This innovative cloud application provides a common interface to multiple systems in the organization, allowing a richer and more complete source of data to be used for decision making. Moreover, it enables the integration of static data, such as well logs in a particular region, with a real-time system to facilitate integrative real-time analyses using artificial intelligence, cloud-hosted physics-based simulators, or both.

To support deepwater needs such as those in Egypt, the system incorporates productivity optimization analysis, reservoir geomechanics (pore pressure prediction, log interpretation, reservoir collapse, fault activation, subsidence, compaction, etc.), and data mining of key development uncertainty and well performance drivers.
The Design of Subsea Foundations Subject to General Cyclic Loading Using a Massively Scalable Web Based Application
Authors: Doherty James , Krisdani Henry , O'Neill Michael , Erbrich Carl , Bransby Fraser , White David , Randolph Mark
Published: April 2018

Subsea developments require the design of large numbers of shallow skirted foundations to support structures such as manifolds, pipeline and umbilical terminations and in-line tees. Safe and economic design relies on the accurate assessment of foundation capacity against thousands of load-combinations. Performing these design calculations is a significant computational task. The objective of this paper is to demonstrate how new developments in cloud computing can be utilized to optimize foundation design.

Engineering design is no longer limited by computing power thanks to the introduction of low-cost on-demand cloud computing platforms. This paper describes a massively scalable cloud based application for rapidly assessing the vertical-horizontal-moment-torsional capacity of shallow skirted foundations against thousands of cyclic load case combinations that arise from numerous environmental and service conditions. The detrimental effect of cyclic loading and the beneficial effect of consolidation on soil strength are incorporated within a single workflow.

It is shown that cloud technologies can radically improve traditional engineering design procedures, allowing engineers to focus on the innovative and creative aspects of their work, while the tasks of preparing, executing and documenting calculations become near instantaneous and more easily assessed for quality assurance. More critically, the technology allows rapid and rigorous optimization of the foundation dimensions to achieve the most cost-effective solution that satisfies all load cases. The scalability of the application allows multiple users to run large numbers of calculations simultaneously across a virtually unlimited number of computer nodes. The system can be accessed through a standard web browser and can run simulations on any internet-connected device. Results are saved in the cloud and can be accessed anywhere and shared among colleagues, enhancing collaboration and quality assurance. The approach results in demonstrably superior design outcomes, achieved more quickly.

This paper presents what is believed to be the world's first web based application for shallow foundation design that exploits the availability of low cost on-demand cloud computing services. The paper will explain some of the challenges in implementing such a system and provide examples. We believe this type of technology represents the future for geotechnical design work, providing better design in a more efficient manner.