bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collapse Behaviour of As-Fabricated; Thermal Aged JCOE Line Pipe - Experimental Study by External Pressure Ring Collapse Testing and FE Analysis
Authors: Kathayat T.S. , Goyal Rajesh K. , Shant J. Raghu 
Published: February 2015

This paper presents the experiments and studies conducted on pipes for the assessment of Middle East to India Deepwater Pipeline (MEIDP) requirement. The MEIDP will be located in water depths up to 3500 m and consequently be subjected to very high external pressures which make the pipe collapse strength a major consideration for the project. The pipes of size 660.4 mm (26") OD × 37.1 mm WT and SAWL485 FDU manufactured by JCOE process were used for external pressure ring collapse testing in as-fabricated (AF) and thermal aged (HT) conditions. The simulation of ring collapse pressure using Finite Element Analysis (FEA) was also studied.
The ring pressure collapse test results consistently demonstrated the advantage of heat soaked treatment at 3LPP coating temperature for enhanced external collapse pressure as compared to the as-fabricated pipes. The strain gauges and deflection sensors were used to measure the external collapse pressure by ring method. The test results were compared with the values predicted by Linear-Elastic Thick Wall theory considering the plain strain behaviour and ABAQUS for Non-Linear Finite Element analysis to simulate the collapse pressure. A comparative study of ring collapse pressure testing, FE analyzed collapse pressure and DNV calculated collapse pressure is also presented along with tensile and compression behaviour of pipe material.
Experience and Lessons Learned from the Jet-In and Drill-Ahead Operation During Malaysia Deepwater Drilling Operations
Authors: Maniam Thanasekaran , Kien Ming Lim , Punniamoorthy Sellathurai 
Published: February 2015

Surface casing jet-in and drill-ahead have become a common practice for deepwater drilling operation around the world. The main objective of the jet-in and drill-ahead operation is to set the surface conductor casing which is typically 36-inch in size and drill ahead the next hole section with the same bottomhole assembly (BHA).
This paper reviewed 25 jet-in and drill-ahead BHA runs for deepwater drilling operations in Malaysia, with the intention to share the experience and findings. It is aimed to highlight the pertinent operating procedures needed for a successful jet-in and drill-ahead operation for future deepwater drilling operations, both in Malaysia and in other parts of the world.
Multiple designs of BHAs in various sizes were imperative to achieve an optimum outcome for the jet-in and drill-ahead operation. The bit size, jet-in procedures, jetting speed, bit extension (stick out), assembly type, flow rate, formation and survey procedures are among other key aspects for a successful deepwater jet-in and drill-ahead operation.
While all the deepwater jet-in and drill-ahead operations in Malaysia were performed with a mud motor BHA, a recent deployment of a rotary steerable system BHA in an ultra deepwater drilling operation had achieved a faster, verticality improvement to ±1°, a value-added outcome.
Modeling and Prediction of Frac-Pack Tool Erosion in Multizone Wells
Authors: Clem N.J. , Silva Z.S. , McGuire A.M. , Imhoff J. 
Published: February 2015

Reservoir conditions in attractive deepwater wells are leading operators to request increasing frac pump rates and proppant volumes in order to achieve effective frac packs. Additionally, a long payzone can be difficult to stimulate and complete in a single interval due to multilayer formations with varying properties. Therefore, the best completion practice is to isolate the payzone into multiple zones of production. As a result, the frac pack service equipment used to treat multiple zones is exposed to an accumulative amount of high rate erosive flow.
The tools which deliver these stimulations must be qualified using testing procedures which replicate actual job conditions, as closely as possible, to ensure the integrity of these tools when deployed in these challenging environments. High stimulation rates and large slurry volumes which must be replicated in a testing environment require an investment in assets and logistics on the order of that required for an actual deployment. Therefore, testing parameters must be selected based on those anticipated in the completion for which the tools are being qualified.
Modeling and analysis techniques have advanced resulting in improved erosion prediction and optimized frac port geometry and materials. Full scale designs have been thoroughly tested following analysis. The results and correlations of analysis and test results will be discussed.
The analysis and testing methods of erosion resistant design and materials leads to more efficient launch of new technology to meet sand control needs in challenging deepwater multizone wells.
Unique Cement and Spacer Design for Setting Horizontal Cement Plugs in SBM Environment: Deepwater Indonesia Case History
Authors: Farahani Hamidreza , Brandl Andreas , Durachman Ridwan 
Published: February 2015

The placement of cement plugs in extended-reach drilling (ERD) wells is a challenging task. Poor hole cleaning, insufficient mud displacement, incomplete centralization, and tight ECD management are some of the more common risks. Mud displacement efficiency and accurate cement placement is notably more complicated in ERD wells due high deviation angles and asymmetrical fluid velocities; problems which are compounded in presence of Synthetic Based Mud (SBM). In fact, the industry standard for setting and successfully testing cement plugs in highly deviated wells is 2.4x per successful attempt. For deepwater projects, these risks must be mitigated to ensure timely operations as the financial implications of failed cement plugs are vast.
Adopting best cementing practices in job planning and execution are beneficial elements to overcome the challenges; however even with excellent operational guidelines cement plug failures are common. A properly designed job should consider appropriate selection of equipment and materials, tailored properties of slurry and spacer systems, accurate down-hole pressure and temperature simulation, extensive laboratory testing, and identification and management of key risks.
This paper will discuss the various operational, engineering, and unique design techniques for setting horizontal cement plugs in a SBM environment on a project in deep waters offshore Indonesia. To date, four kick off plugs have been set successfully in the first attempt on four consecutive ERD wells. Conservative cost savings for achieving first attempt kick-off is 1.2 MM USD, applying 12 hours per well (48 hours total) with a daily rig rate of 600K USD.
The achievement is owing to application of best cementing practices in job design and execution, along with use of a unique cement system and innovative spacer. Techniques used in placing challenging kick off plugs are discussed followed by discussion on how the trouble-free operation has created value for both the client and service provider. Multiple case histories will be presented, along with specifics of the unique slurry and spacer system.
The Effectiveness of Two- versus Three-start Helical Strakes in Suppressing VIV of Flexible Cylinder
Authors: Quen Lee Kee , Abu Aminudin , Muhamad Pauziah , Kato Naomi , Sahekhaini Asnizah , Abdullah Hanida 
Published: February 2015

The proposed paper investigates experimentally the effectiveness of strakes in suppressing the vortex-induced vibration (VIV) of a long flexible cylinder by varying the pitch, height and the number of helix of the strakes, which differ from the previous studies that only focus on short rigid cylinder. The experiment was conducted in towing tank with constant velocity under subcritical Reynolds number () by using a Poly Vinyl Chloride cylinder with aspect ratio of 162. CCD cameras were installed to capture the amplitude vibration and the frequency responses in both in-line (IL) and cross-flow (CF) directions while the fluctuation of tension was measured by using tension load-cell. The theoretical laminar boundary layer thickness around a circular cylinder was calculated and was used as a benchmark in deciding the height of strakes for the experiment.
The purpose of present study is to identify the optimum configuration of helical strakes that can be implemented on a long flexible riser with low mass ratio.
The experimental result shows the helical strakes perform well in mitigating the VIV. Significant VIV mitigation is found for the strakes with a certain height which is larger than the laminar boundary layer thickness. However, its effectiveness in suppressing the vibration amplitude of flexible cylinder is far smaller than the rigid cylinder. Varying the pitch of strakes influents the occurrence of lock-in region and prevent the switch of frequency into higher mode. Previous study stated that pitch of 15D is as effective as 5D for a rigid cylinder. However, it does not work on a flexible cylinder. Changing the height of strakes narrows the lock-in region and contributes most in suppressing the vibration of cylinder. Also, it is surprising to find that two-helical strakes perform slightly better than three-helical strakes in lower velocity range. The hydrodynamic forces of cylinders are still in the process of analysing.
The information presented in this paper will shed some light on the effectiveness of strakes with different configurations and suggest the appropriate dimension of strakes in term of pitch, height and the number of helix of the strakes as currently the available resources are limited.
Wheatstone Development - Challenges and Solutions in Formation Water Treatment and Disposal
Authors: Titley Mark 
Published: February 2015

OTC Asia 2014 conference presentation
Wheatstone Development – Challenges and Solutions in Formation Water Treatment and Disposal (Mark Titley – Chevron's ETC Perth Process Manager: mxhx@chevron.com)

Abstract
The Wheatstone Development is a major integrated LNG development; it is a joint venture development between a number of partners: Chevron, Shell, Apache, KUPFEC and Kyushu. The overall development comprises: subsea gas wells and flowlines, a central processing platform (which includes separation, compression, dehydration, and water treatment) an export trunkline, an onshore receiving facility, an LNG plant, a domestic gas plant and export pipeline, LNG and condensate product storage and export, and marine facilities.
The paper and presentation will provide an overview of the platform and two key issues, which determined the requirement for a platform and its design, including the compression and water handling facilities. The key issues, reservoir pressure and reservoir water production, will discussed and how these influenced the design.
The reservoir water production presented key challenges, particularly due to Australia's stringent oil-in-water limits. These challenges included potential emulsions, sand production, changing water production profiles, and water and condensate slug/surge handling. The presentation will discuss in detail the mitigation measures considered, discuss key learnings and finish with an explanation of those adopted and the final, integrated water treatment solution from the well through to discharge.
This approach is considered best practice within Chevron as a method for reducing or minimizing environmental discharge.
Analytical Predictions and Field Observations in Liwan3-1 CEP Jacket Installation
Authors: Yuan Yujie , Lee James , Yin Hanjun , Liu Yuxi , Huang Huaizhou 
Published: February 2015

A modified HYSY 229 barge was utilized for the loadout, transportation and launch operation of LW3–1 CEP jacket. The barge is modified from a conventional launch barge (225mx52.5mx13.5m) to a "T" shape floatover and launch barge with a beam width of 42m at bow and 65m at stern. In order to verify the calculated results in transportation motion responses with this "T" shape barge, a model test in a model basin was performed and the test results were compared with these calculated results from the transportation motion analysis. From these comparisons, noticeable differences were observed with considerable higher motion responses from these model test results. During the final jacket transportation, a motion monitoring system will be installed at the jacket to further verify the motion behavior of this modified barge.
Based on the same reasons, a motion and trajectory monitoring device will be installed on the jacket during the launch in order to confirm the basic launch characteristics of this modified "T" shape launch barge. These collected data from these monitoring systems under real operational environments should provide a reliable design basis for the use of this large "T" shape barge for future jacket installations.
Control upending process was selected as the based case for LW3–1 CEP jacket upend design because of the large base dimension. This large jacket base dimension also imposes a challenge to maintain a minimum bottom clearance during the upending steps under a maximum crane hookload of 2,000mt. Extensive on-bottom stability analysis were performed to unsure the safety of the on-bottom stability under installation design conditions.
LW3–1 CEP piled foundation is the largest one in the world with 4 – 108" dia. vertical skirt piles at each jacket corner. Each pile is 158 meters in length. The maximum dry weight of one pile is 755mt. A 126m stick-up length in initial self penetration makes the pile design a challenge one in stick-up analysis and in fatigue analysis including both pile driving fatigue analysis and in-place pile fatigue analysis.
Riser Integrity Monitoring System for Offshore Fields
Authors: Blondeau S. , Andre M. , Garnier P. , Benmedakhene S. , Quesnel J.J. 
Published: February 2015

All the structural elements which make up offshore fields are by nature submitted to harsh environmental constraints: seabed to surface liaisons, export lines, mooring systems and all oil & gas operators must keep pace with the technological challenges posed by deeper water depths and increasingly severe weather environments. The top priority is threefold:to mitigate human and technical risks to protect valuable assets and to limit damages to promote safety and sustainable development
A real time surveillance of structural integrity is an absolute necessity in order to keep under control the overall good condition of the field infrastructure. It really allows to improve asset management and to intervene in case of emergency.
The primary objective is to monitor and predict the behavior of the bottom to surface liaison in order to anticipate excessive wear and fatigue as well as overstress, hence the development of original solutions.
Among technologies that are shaping the future of subsea activities, Asset Integrity is a key trend to optimize lifecycle of fields.
This paper focuses on Riser Integrity Monitoring Purpose, and most particularly on reliable and cutting edge technological solution used to measure the static and dynamic loads imposed to the various kind of Risers to anticipate structural degradation but also to detect structural ruptures. The first is known as a Vibrating Wire Gauge (VWG) for the monitoring of SCR's Hybrid Risers and Riser Towers. The second product uses the Acoustic Emission technology to monitor the integrity of tensile armor wires in flexible pipes.
Study of Different Water Alternating Carbon Dioxide Injection Methods in Various Injection Patterns in an Iranian Non Fractured Carbonate Reservoir
Authors: Bagrezaie M. A. , Pourafshary P. , Gerami S. 
Published: February 2015

In the commonly-used EOR methods such as waterflooding and gas injection, high and unsuitable mobility ratio leads to viscose fingering and reduction of sweep efficiency. Early breakthrough of the injected fluid caused in the production wells is the major problem associated with these processes. A solution to this problem is an alternative process called water-alternating-gas (WAG).
WAG injection could increase the recovery by contacting the upswept zones, especially recovery of attic or cellar oil by exploiting the segregation of gas to the top or accumulating of water towards the bottom. The WAG process has been proved beneficial in re-pressurizing the reservoir when compared to a waterflood only process. This higher pressure is caused by the gas slug being injected at an extremely high voidage replacement rate because of its high mobility. WAG injection increases the efficiency of the plain gas injection, too. By alternating the gas injection with water injection, the gas relative mobility in the reservoir is reduced over gas injection only. Therefore, less gas breaks through to producing wells, reducing gas handling requirements. Furthermore, the lower producing GOR associated with WAG injection over straight gas injection results in less erosion of the production equipment.
In this work, scenarios of water alternating carbon dioxide injection such as (WACO2), (HWACO2), (WACO2a.WF),(SWACO2),(SSWACO2) and water and carbon dioxide injection are compared to specify the appropriate injection method. Also these scenarios in four patterns such as 4-spot, Dual 4-spot,5-spot, Dual 5-spot were compared.
Results indicated that, SWACO2 injection has the higher oil production and lowest residual oil saturation. In addition, amoung these scenarios SWACO2 in Dual 5-spot pattern had the highest recovery and lower residual oil saturation. 5-spot pattern had the higher recovery and lower residual oil saturation than Dual 4-spot pattern, so adding the number of wells could not raise the recovery.
Finite Element Studies for Assessment of Collapse Modelling Methodologies for Unbonded Flexible Pipes
Authors: Edmans Ben 
Published: February 2015

Unbonded flexible pipes are a key technology in subsea production systems.
Procedures for the assessment of dents and imperfections in steel pipeline are well established and incorporated into industry codes; however, equivalent methods for the assessment of flexible pipes have not been developed. Considering the trend towards production in greater depths and the introduction of novel designs, it is valuable to develop more powerful tools to evaluate the consequences of the presence of defects in flexible pipe due to clashing, dropped objects and other operational damage.
In this article, a finite element model for the assessment of the residual collapse capacity of dented pipes is demonstrated. In distinction to other collapse models, this model allows the complex shape of the carcass layer to be modelled exactly. Based on previous studies and observations of dent types, the indentation process is simulated with different indenter types. The model also incorporates the effects of ovalisation, pipe axial load and static curvature. A parametric model generator and batch job scheduler is included in the model. Validation of the undented model against other assessment methods for flexible pipes is shown. Studies are carried out investigating indenter shape and load and the effects of axial force and pipe curvature on the limit collapse load. Results showing the sensitivity of flexible pipes to dents and imperfections are presented.
This article describes a validated model suitable for assessing damaged flexible pipes under combinations of damage types and loading conditions of use for defect assessment and life extension and provides a tool for developing future guidelines for flexible pipes.
Lazy Wave SCR versus Conventional and Bottom Wetted SCRs for Tying Back to a Spar Tube
Authors: Yu Alan , Stanton Paul , Caldwell James 
Published: February 2015

Since developed in early 90's for the Shell Auger TLP project in nearly 3,000 ft of water, the number of steel catenary riser (SCR) installations has outnumbered other types of risers for deepwater field development. For water depths over 2,000 ft, the application of SCRs for importing and exporting oil and gas and for water injection on TLPs, Spars, Semis, and FPSOs seems to be unlimited.
This paper illustrates the development of a steel lazy wave riser (SLWR) designed to interface with an existing "I" tube of a Spar hull. It compares the SLWR with a conventional SCR on the basis of their strength and fatigue performance and interference performances with the adjacent vertical risers. The SLWR also was simulated through the installation steps. A successful installation campaign carried out in the Gulf of Mexico in a record 14-month EPCI project provides an example of SLWRs

Application
Import risers for existing Spars

Results, Observations, and Conclusions
SLWRs are viable alternatives to SCRs and flexible pipe risers for tying back subsea wells to Spars that do not have available porches or J-tubes for that purpose.

Significance of Subject Matter
SLWRs can be enabling technology for tying back subsea wells to existing Spars or for outfitting new Spars for future tie backs.

Area of Interest
Riser Systems
Centrifuge and Numerical Modelling of Reaming as a Mitigation Measure for Spudcan-Footprint Interaction
Authors: Hartono Hartono , Tho K.K. , Leung C.F. , Chow Y.K. 
Published: February 2015

Re-installation of jack-up close to footprints created by previous spudcan installations can be problematic. Instead of purely vertical loading during normal installation, the spudcan footing is subjected to eccentric and inclined loading arising from the combined effect of uneven seabed and shear strength variation in the vicinity of the footprint. Several mitigation measures have been proposed to alleviate this problem but so far only limited study has been conducted to investigate the effectiveness of these measures.
Reaming, otherwise known as leg-working or leg reciprocation, is the mitigation measure considered in this paper. Very limited information is available in literature regarding the procedure of reaming. This paper will present the results from centrifuge model tests and large deformation finite element analysis in an attempt to systematically investigate the efficacy of reaming technique for jack-up re-installation close to existing footprint in normally consolidated clay.
Several reaming strategies involving different amplitudes of leg penetration-extraction cycles were investigated. The induced vertical, horizontal and moment forces during reaming were compared with that of a generic spudcan re-installation. It is found that for reaming technique to be effective, reaming should be executed with small amplitude of penetration-extraction cycle. Moreover, the number of cycles for a particular leg penetration-extraction increment does not appear to play an important role in increasing the reaming effectiveness against footprint interaction. Back analysis using three-dimensional large deformation finite element analysis reveals a good agreement with centrifuge test data.
This study using centrifuge model coupled with large deformation finite element analysis provides insightful information pertaining the mechanisms and efficacy of reaming as a mitigation measure for re-installation of jack-up close to existing footprints.