bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Play-Based Evaluation of a Deepwater Sabah Exploration Area: Prospect Maturation and Implications for Remaining Prospectivity
Authors: Abdullah Siti Aishah , Barker Steven M. , Jong John , Watanabe Yoshiaki , Bakar Dayang Aimi Nuraini Awang , Khamis Mohd. Asraf 
Published: March 2018

Abstract
This study presents a play-based evaluation of the southern part of the deepwater NW Sabah fold-thrust belt, a key exploration area in Malaysia. The key objective was adding value to the existing database through an integrated approach. This goal was achieved by analysing four critical geological risk elements: reservoir presence, structural evolution, top seal integrity, and timing of hydrocarbon charge and migration, to identify prospective areas for future exploration by integrating all available geological, geophysical and geochemical information into a consistent petroleum system framework. Using the basin-play-prospect maturation workflow, data spanning the geophysical domain (with inputs such as seismic evaluation, structural mapping and attribute analysis) to the geological realm (such as well correlations, fairway mapping, sedimentological studies, biostratigraphic investigations and source rock maturation modelling), are combined with structural kinematic evolution to generate detailed play-based element maps. The application of the tried and tested play-based evaluation methodology from basin evaluation through to prospect maturation has been carried out. This has led to a comprehensive play element analysis yielding a composite risk segment map within a consistent petroleum system framework. In addition, the study has provided sensible explanations for dry hole analysis, an important reality check, but most importantly it has generated a fresh insight into the overall prospectivity of the study area. This enhanced multi-discipline analysis is beneficial for reducing exploration risk for future expenditure in a time of depressed oil prices that calls for a more innovative approach for deepwater exploration. In summary, integration of available data and the application of new in-house ideas and solid geoscientific knowledge has added value through the generation of increased prospectivity, however for further ground-truthing the real litmus test has to come from future drilling.
Estimating Storm Surge And Reservoir Subsidence Of Offshore Platforms Using WaveRadar REX SAAB Sensors
Authors: Anokhin Vadim , Ewans Kevin 
Published: March 2018

Abstract
WaveRadar REX (SAAB) instruments are widely used in the offshore oil and gas industry for wave, tide and air gap observations. This study extends the application of WaveRadar REX to the estimation of storm surge and reservoir subsidence from long-term water level measurements. AirGap data from several offshore fixed steel platforms offshore Borneo island (South China Sea) were analysed, yielding waves, astronomical tides, Sea Surface Anomalies (SLAs), which included storm surge and changes to water level due to long-term climate variability. Vertical platform movements, which can be attributed to reservoir subsidence and Vertical Land movements, were also derived. The storm surge estimates were consistent with values reported for the region, with positive storm surge (+0.3m) peaking in November and December, at the onset of winter western North Pacific Monsoon and northeasterly winds; negative storm surges (-0.2m) were recorded from March to July, coinciding with the boreal summer East Asian Summer Monsoon and southwesterly winds. Locations further offshore showed marginally lower storm surge compared to the coastal stations. Along the coast of Borneo, there was a shift in the timing of the positive storm surge arrival offshore Sabah, with establishment of positive storm surge shifted forward by about a month. Lastly, trends of SLAs derived from WaveRadar REX AirGap can be used to monitor long-term Vertical Land Movements and offshore platform subsidence. The comparison of AirGap subsidence estimates against independent dGPS measurements of vertical platform movement showed excellent agreement for several offshore platforms, all results within 0.05m accuracy. The new technique offers a cheap and reliable method of continuous vertical subsidence monitoring of fixed offshore platforms using instrumentation routinely installed offshore, thus offering an alternative to dGPS subsidence monitoring.
Using Play-Based Pore Pressure Prediction to Avoid Geohazards and Discover Successful New Play Concepts
Authors: Tingay Mark 
Published: March 2018

Abstract‘Play-based Pore Pressure Prediction’ is a new concept that considers overpressures and pore pressure prediction as being a fundamentally similar process to the ‘play-based exploration’ approach commonly used to search for hydrocarbons. For overpressures to exist, the right set of conditions needs to occur in the right order and timeframe. Just like a hydrocarbon play, overpressures need a source (generation mechanism), reservoir (the overpressured formation) and seal (ability to maintain overpressures over geological time). Current pore prediction methods do not consider overpressure over the geological timespan of a basin, and commonly result in overpressures being encountered in unexpected formations and depths, or at greater magnitude than anticipated, and has resulted in many drilling incidents.Play-based pore pressure prediction involves undertaking pore pressure analysis in a similar holistic manner to how prospects are generated during hydrocarbon exploration. The process involves using basinscale geology to establish likely overpressure mechanisms and formations (akin to identifying sources, reservoirs and seals); determining timing of overpressure generation throughout burial history, and; identifying major events causing overpressure transfer or dissipation (akin to hydrocarbon generation, charge analysis and trap development). Regional concepts are used to develop models to determine the likely locations and magnitude of overpressure (akin to hydrocarbon fairways and plays). Finally, regional learning's are applied at the prospect scale to select the best methods to predict pressures for planned wells. The innovation, and added benefit, of this new and novel approach is that ‘play-based pore pressure prediction’ can also be used to identify successful new exploration plays. Herein, I present an example of ‘play based pore pressure prediction’ from the Malay Basin that was used to improve drilling safety, and developed a new play concept that has subsequently resulted in 3 successful discoveries.
Design and Installation of Coupled Mooring System for Tender-Assisted Drilling at a Deepwater TLP
Authors: Kota Ravikiran , Yip Kenneth , Jamal S Amurol 
Published: March 2018

Abstract
The first Tension Leg Platform (TLP) in Malaysian waters was installed in 2016 at a water depth of about 500 m. It is notable in being the 2nd deep water platform in Malaysia with tender-assisted drilling (TAD) feature. The semisubmersible TAD vessel was connected to the platform using nylon hawser ropes which together with chain-polyester-wire moorings on the TAD and TLP allow for station-keeping during drilling operations. This paper describes the planning and execution of the mooring installation campaign. The paper also brings up key learnings from the campaign that may be useful to consider for risk reduction in future projects of similar nature.
Mooring system was purpose-designed for the TAD vessel with ground chain and polyester segments connecting to rig wire for each of its 8 mooring lines. Installation plan was based on pre-installing suction piles and pre-laying ground-chain and polyester. These pre-laid moorings were then retrieved for hook up to the TAD at site. One of the major challenges was identifying suitable pre-lay routes for the lines due to widely prevalent geo-hazards and exclusion zones on the seafloor. Close attention was also given to installation methods of hawsers between the TLP and TAD with emphasis on minimizing personnel exposure to risks of working under tensioned lines and over water. The installation campaign involved several vessels in the field simultaneously operating in the field and was closely coordinated with efficient SIMOPS plan and execution.
Early engagement with various disciplines and stakeholders is crucial in minimizing risks. Interfaces with engineering contractors, geomatics and geotechnical teams, component suppliers and installation contractors were instrumental in safe and injury-free installation and hook-up campaign of the TLP-TAD system currently under operation.
One question that is brought up is to do with risks versus values of load-testing synthetic mooring lines in field. While the need for such tests is well known, operational and safety risks require close attention.
Mitigating Wellbore Stability Challenges of Extended-Reach Drilling in Overpressure and Naturally Fractured Formations
Authors: Asadi M. S. , Rahman K. , Ta Q. D. , Ha V. , Phuong H. 
Published: March 2018

Abstract
When building a 1D geomechanical model for the Rang Dong field in Cuulong basin, offshore Vietnam, the rock structure was found to be very complex. In addition to inter-bedded shale and sand sequences in the overburden, there is an overpressured stratum immediately below and above the normally-pressured and highly fractured sandstones and volcanic rocks at the target depth. During the drilling of offset wells, multiple tight spots were experienced in the overburden. An inflow was detected in the volcanic rocks, and consequently the mud weight was increased in the deeper section of overpressured zone. Further, severe mud losses occurred in the underlying normally-pressured and highly fractured sandstones, and eventually stuck pipe was experienced. This study shows the development of a field-wide geomechanical model that is able to match all the drilling experiences in the offset wells.
A geomechanical model was developed for the field in which in-situ stresses and rock mechanical properties were calibrated with field data and lab measurements. The model predicted different types of borehole failures such as breakouts and drilling-induced fractures that contributed to different types of wellbore instability events in existing wells. Analysis showed that drilling with a significantly high overbalance pressure in the fractured zone increased the risk of tool string differential sticking and stuck pipe. To investigate the root causes of dynamic mud losses in the fractured intervals with major intersecting faults, a Mohr-Coulomb friction sliding criterion was applied. The analysis showed that the majority of natural fractures and faults, which are oriented in the north-east and south-west (NE-SW) direction, are critically stressed and may become conduits for drilling fluid and cause mud losses.
The geomechanical model was used to design a mud weight program for an upcoming well. This program was optimized to mitigate the issues experienced during drilling of the offset wells. The results of this study led to an optimized mud program to minimize shale breakouts in the overburden, control the risk of kicks in the overpressured zone, and reduce the risk of mud losses in the fractured formation. Additionally, an optimized casing program and the use of lower mud weight were recommended, with the addition of loss circulation material (LCM), to drill a highly deviated wellbore within the fractured formation. The drilling campaign of the planned well was successful with good drilling practices such as equivalent circulating density (ECD) control, good hole cleaning and use of the recommended mud weight programs and optimised drilling fluids suggested by this study.
Antinode Fairings: An Optimum Solution for Reduction of Vortex Induced Vibration
Authors: Ramadasan S. , Tao L. , Dev A. 
Published: March 2018

Abstract
An excellent vortex suppression device, in the form of an antinode fairing is presented towards reducing the Vortex Induced Vibration of structural members exposed to flow. An analytical procedure is also developed to optimise the depth and location of the fairings along the members. Two newly developed fairing sections are tested on cylindrical legs of a Jackup model and the results are qualitatively compared with the expected behaviour, particularly the effect of selected fairlead depth and location. A simplified mathematical model is developed based on the principle of conservation of energy, which could be used to decide the optimum location and depth of the vortex suppression devices for the cylinders undergoing Vortex Induced Vibration in a uniform flow. Based on the mathematical studies, modal antinodes are found as the optimum locations for the installation of the fairings and accordingly two compact leg fairing designs have been developed for practical applications. Those are based on NACA0018 profiles but with reduced L/B ratios of around 2.40 and 3.00. The tests with scaled down Jackup models with cylindrical legs demonstrated that both the fairing designs could reduce Vortex Induced Vibration amplitudes significantly, by around 80%. The weathervaning stability of both the fairing designs were also found to be satisfactory. From the mathematical studies and test results, it is inferred that fairings contribute to the reduction of Vortex Induced Vibration in three ways; reduction of excitation force, disruption of vortex synchronisation and the increase in fluid damping. Fairings are also found not to have significant bearing on the drag coefficient of the structure. The fairing design with the lesser L/B ratio of 2.40 is found to be an optimal solution for vortex suppression, when the structure is not sensitive to drag forces. However, fairings are found to initiate galloping responses at higher flow speeds above the lock-in range and hence it is recommended that the same shall be of the detachable type for cylinders exposed to large flow speed variations. The mathematical approach presented will enable practicing engineers to design and optimise antinode fairings for structures experiencing Vortex Induced Vibration. The two fairing section offsets presented may be readily used by Industry for practical applications.
History Matching and Uncertainty Assessment by Using the Ensemble Kalman Filter
Authors: Xu Zhongyi , Cheng Linsong , Wu Yonghui , Huang Pin JiaandShijun , Fang Sidong , Hao Junlan , Gao Yinshan 
Published: March 2018

Abstract
Accurate assessment of uncertainty of production performance is critical for successful planning and assets development. Particularly in deepwater scenarios, where the uncertainty in the fluid and reservoir characterization is of high level for the difficulties for well testing, fluid and core sampling. Therefore, specific methods are needed for efficient uncertainty quantification of production for deepwater reservoirs with limited information.
In this paper, we introduce a history matching method to assimilate static geological data and production data base on the ensemble Kalman filter (EnKF). The EnKF is independent of simulators, and is suitable for uncertainty assessment, reservoir monitoring and performance prediction. We tested this method with a deepwater case. We analyzed the effects of initial ensembles and production history. After that, the uncertainty of production prediction is quantified and the posterior distribution of cumulative production can be estimated.
The EnKF is shown to be efficient in updating fluid and reservoir heterogeneity. By sequentially assimilating observed data, the EnKF is suitable for reservoir monitoring and performance prediction. The results indicate that history match with plausible geology can be improved with the improvement in the generation of the initial ensemble. History matching with longer history can narrow the range of ultimate recovery distribution, thus the uncertainty can be decreased. And the results also show that the updated amounts of parameters in the ensemble is larger in the first iteration, and it will get smaller gradually with more data been assimilated. After the history matching, the ultimate recovery can be obtained with each set of parameters in the ensemble, the uncertainty can be quantified with the statistical frequency distribution of recovery.
The proposed methodology provides a practical means to assess uncertainty in history matching for deepwater fields. This method can also be used to project and risk management.
Returning to Play-Based Exploration; Exploring the Fundamentals
Authors: Shoup R. C. 
Published: March 2018

Abstract
Many companies are now re-focusing on play-based exploration, representing a return to our pre-1990s geoscience roots. Play-based exploration involves understanding all elements of the petroleum system for a given basin or play and then examining how, and more importantly where, those elements come together. This paper will examine the fundamental methods using examples across Asia and review step by step procedures of the play-based exploration process.
Validation Process of IWEX 3D Ultrasonic Imaging for Girth Weld Inspection
Authors: Pörtzgen Niels , Ent Jan van der , Brisac Gaspard , Solem Ola , Pinier Ludovic , Steinskog Bjarne 
Published: March 2018

Abstract
IWEX is an innovative ultrasonic testing inspection methodology which went through a complete qualification program for Carbon Steel pipeline girth weld inspection, from DNV OS F101 certification to implementation on a pilot project, with the aim to be widely implemented into the market as the repair rate and schedule of a project could be drastically reduced. The qualification process will be detailed, with particular focus on feedback from the first production project.
IWEX is a novel inspection philosophy based on ultrasonic imaging of full matrix capture data. Indications in girth welds are imaged real time in 2D and 3D. The images reveal the presence of indications whereby the orientation, position, height, etc., are displayed in true context to the weld geometry. Identification and sizing of indication can be done accurately and unambiguously, leading to a reduced repair rate. Because the IWEX images are independent of the weld bevel design, a standardized sensitivity block can be used, whereby the work preparation and the number of calibration blocks are reduced significantly.
In order to benefit from the full potential of the IWEX technology, industry acceptance is required. Therefore, IWEX was subjected to an extensive qualification program according to DNV OS F101 for carbon steel applications. When the DNV qualification program was completed successfully, the IWEX technology was applied in parallel to a standard AUT inspection on an actual project production line, where a significant number of welds are fabricated every day. This was to ensure the robustness of the system (software and hardware) in a production environment details of which have been published already [1]. The final step in this technology qualification process was the standalone use of the IWEX system on a full scale pipeline project, consisting of two carbon steel pipelines of 16" and 10" diameter. Direct feedback from the Contractor spool base fabrication team on the IWEX performance has been gathered in detail and used to identify required improvements on software and hardware for full project fitness. Feedback from the pipeline owner is also included. This will be detailed in the paper.
This paper describes the IWEX qualification process and details the validation approach and feedback obtained during the use of the IWEX system on its first commercial pipeline girth weld project. It also details all advantages of IWEX technology compared to the standard AUT inspection technique which has been in use until now.
Holistic Approach for the Design of Drill-In Fluid
Authors: Rincon Marco , Phillips David , Gupta Sanjeev , Jacobs Stephen 
Published: March 2018

Abstract
Drilling wells in mature fields normally entails the integration of multidisciplinary teams to increase the likelihood of a successful drilling and completion program. Maximizing wellbore productivity requires thoughtful planning involving analysis, studies, and risk assessment of the best alternative solutions for well drilling and completion.
Selecting reservoir drilling and completion fluid to minimize rock formation damage requires a high level of consideration. Selecting an appropriate fluid strategy becomes more significant when the reservoir section involves horizontal drilling and an openhole completion design. This paper details the design criteria and final application of a nondamaging drill-in fluid to drill a horizontal well completed as open hole in a mature field (first of its kind in the field).
The fluid design strategy was driven based on analysis of reservoir rock samples, reservoir fluid chemistry analysis, and the natural permeability of selected core samples. The fluid selected was a monovalent brine system using highly clarified and acid-soluble biopolymers as filtrate reducer and viscosity control, respectively, and an engineered and tested bridging package based on sized calcium carbonate. The fluid also contained an amphoteric amine to control clay swelling and dispersion. The nature of the well completion used an in-situ acid-generating filter-cake breaker system for removal of filter cake and damage encountered during reservoir drilling or completion. The filter-cake breaker system also affected fluid design (e.g., compatibility between the two systems), which was incorporated into the design strategy. Additionally, the nature of certain details of the completion architecture affected the breaker system application and was necessary to redesign the filter-cake breaker system to achieve optimal wellbore cleanup while accommodating constraints in the completion design and operation.
Finally, application of the fluid program used with the drilling and completion design and architecture rendered a successful project resulting in higher than expected hydrocarbon output.