bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subsea Sand Detection in Digital Oil Age: Case Study of An Innovative Virtual Erosion Probe Technique
Authors: Perrier Sebastien , Martins Licinio 
Published: October 2017

Abstract
The presence in the outflow of sand or minerals coming from the reservoirs is of course undesired, and generates a series of technical challenges and threats to installations.
Sand diagnosis (through conventional acoustic methods) is generally a frustrating process, with frequent false positive and false negative signals, and a large uncertainty on the detection thresholds.
This paper presents two innovative data treatment techniques, adapted to digital oil age:An original data transform to get the best of the conventional acoustic data analysisAn innovative virtual metering technique based on the continuous estimation of the erosion of the choke (‘pseudo erosion probe’).
This pseudo erosion probe technique has four key advantages:Significant reduction of the risks of confusion or indecisions with respect to classic acoustic methods of detection (lower sensitivity threshold than other technique), giving a chance to intervene earlier.Without being fully quantitative, it is possible to use the data obtained to define the grade of severity of sand production (in particular in term of well-to-well comparisons)It is very simple and requires no additional equipment in the case of wells equipped with individual flowmeters.Using a cumulative indicator (erosion) rather than instantaneous indicator (noise), low sand rate production or intermittent damaging sand events can be detected and not ‘overlooked’.
Combining the 2 techniques presented in this paper contributes to significant improvements in sand production diagnosis (production shortfall reduction, protection of assets…) and benchmarks between wells.
However, as learning by trial and error in the domain of offshore completion is very expensive, we found that those two techniques were particularly valuable to improve sand control failure diagnosis and select with good degree of information the appropriate solutions.
Coaching; An Effective Learning Tool to Fill Competency Gaps-A Case Study of an Upstream Oil & Gas Company
Authors: Al-Daihani Eisa , Nandi Arun Kumar , Razaa Syed Mohammad , Usmani Shereen 
Published: October 2017

Abstract
Coaching is an effective learning tool to fill Competency Gaps. This requires an identification of a pool of experts within the organization to act as coach, to equip identified experts with coaching skills and finally to ensure competency gaps are filled through effective coaching.
Coaching has an enormously important role in building and sustaining of great organizations and extraordinary workplaces. People who want to accomplish great things often get stuck along the way. Coaching helps people to deal with challenges to accomplish the objectives. An example of this is that while many leaders, executives, and managers in organizations seems to "know" intuitively what they need to do to move forward, few of them actually follow through because they're stuck in some way. Coaching helps people focus on the things that are considered as barrier or challenges, and then move beyond them.
The present paper emphasizes on the coaching process to be more effectively implemented especially targeting new hires. The improved process has helped us to manage and establish coaching culture through a systematic approach. Several elements have been analyzed for evolving a successful coaching process and experience. An approach has been adopted to identify a pool of experts who can transfer their knowledge to young professionals and more importantly they are willing to contribute in this process effectively. Finally, introduced a systematic coaching process after organizing awareness session for coaches to enhance and refresh their coaching skills.
This new coaching approach adopted has helped more than 400 young professionals towards completion of the program under new hire's roadmap. These young professionals have contributed in the real on-going projects that impacted directly or indirectly on achieving the business need of the group and the company.
Therefore, an effective coaching process has helped in creating competency based organization and building a pool of talent. Besides, it helped to equip these talents with right competencies at right time so that they can contribute in real time production.
Technical experts (SMEs) may be fully equipped with technical knowledge and skills but not necessarily having required skills to transfer their knowledge effectively. Also without having a systematic and robust quality assurance process, the efficiency and outcome will not be as desired.
Therefore, it is vital to first identify the experts to act as a coach with good communication skills and willingness. An effective approach adopted to establish a Discipline Experts Council and equip them with sufficient knowledge and skills related to "Coaching Process". In addition, Quality Assurance at all stages is equally important to measure the effectiveness.
The Effect of Survey Station Interval on Wellbore Position Accuracy
Authors: Codling J. 
Published: October 2017

Abstract
Operational reasons exist for surveying with measurement-while-drilling (MWD) instruments at station intervals greater than the recommended maximum of 100 ft (30 m). The objective of this study is to quantify the degradation of position accuracy with longer station intervals and to enhance the MWD survey error model by adding a survey-station, length-dependent term in a standard format.
The source data for this study include 150 continuous gyroscope surveys run in drillpipe in the open hole. The surveys are calculated to determine the change in bottomhole location from the original complete survey to the same survey calculated with the regular stations removed to simulate longer survey intervals. The resulting displacements are normalized by survey length, analysed statistically, and correlated to various factors, including interval length, hole angle, and overall angle change between stations.
The results of the study show a strong correlation between the length-dependent error and the angle change between survey stations. A minimum angle change per length was observed on each of the surveys, which is presented as a minimum statistical tortuosity. Therefore, vertical or inclined sections of wells that are planned or surveyed with little angle change still have a length-dependent error. The results of the study agree with perceived knowledge that highly curved sections of wells improve their accuracy through extra surveying, and vertical or straight sections do not degrade significantly when surveying with longer intervals. This study provides a simple formula for calculating the additional survey error in terms of units per 1,000 units of drilled depth. The formula is inserted into the MWD error model, sensitizing it to the length between survey stations. The study also contains an analysis of misalignment error at low angles, as it contributes to the interval-dependent error. Survey comparisons in near-vertical wells indicate that over short sections, the misalignment error causes a larger lateral error than is currently estimated using the MWD model, which has an impact on the collision-avoidance separation near the surface for platform wells. It also indicates that for longer survey intervals (&gt;1,500 ft), the misalignment is actually smaller than what is estimated using the current MWD error model. If this revised misalignment error is adopted, the wellheads will need less separation at the surface or less effort to nudge them apart to maintain minimum separation rules on land pads.
The quantification of the survey-position error, which is dependent on the survey interval length, has not been previously presented and provides valuable information for well planning and accounts for collision-avoidance distances compared to wells that were previously drilled with surveys at infrequent intervals.
A Cost/Benefit Review of Completion Choices in the Williston Basin Using a Hybrid Physics-Based Modeling/Multi-Variate Analysis Approach
Authors: Mayerhofer Michael , Oduba Oladapo , Agarwal Karn , Melcher Howard , Lolon Ely , Bartell Jenn , Weijers Leen 
Published: October 2017

Abstract
In the Williston Central Basin the role of a well's completion design has a significant impact on well productivity and ultimate recovery. More than 12,000 horizontals have been drilled and completed while completion practices continue to vary widely across the basin. Several companies have adopted slickwater-only designs while others have dramatically increased proppant mass. Completions strategies have differed depending on the area in the basin. The objective of this paper is to discuss the impact of various completion changes in the Central Basin and determine which particular change delivers the most "bang for the buck" using a $/BO metric.
The approach centered around multi-variate analysis (MVA) from an extensive petrophysical/completion/production database to verify what completion and petrophysical parameters independently drive production in different areas. While MVA has been used by the authors and many others before, statistical models are limited by their ability to provide predictive relationships (mostly simple linear regressions and un-reliable beyond the data range). This paper provides a novel hybrid approach that uses calibrated relationships from physics-based modeling (combination of fracture and numerical reservoir modeling) between completion parameters and production response in combination with statistical MVA results. Specifically, the physics-based model is calibrated or "history matched" to a measured production/completion parameter response as provided by MVA, thus delivering a constrained and more physically realistic production response to suggested completion changes. This model is then coupled with a completion cost model to determine which completion method is the most effective to lower $/BO.
Many common completion parameter changes, such as increasing stage intensity, moving to plug & perf cemented well designs, increasing injection rate, increasing proppant mass per lateral foot and fluid volume per lateral foot, have a positive impact on production and are advantageous to lower $/BO in all areas of the Middle Bakken and Three Forks. The new hybrid MVA approach indicates that pumping slickwater treatments with average proppant concentrations of 1 lb/gal and treatment sizes from 750 to 1,150 lb/ft at pump rates approaching 100 bpm through a stage length of 200 ft (50 stages for a 10,000 ft lateral) may be the economic optimum provided there are no significant well communication issues.
Drilling Mud Loss in Naturally Fractured Reservoirs: Theoretical Modelling and Field Data Analysis
Authors: Razavi Omid , Lee Hunjoo P. , Olson Jon E. , Schultz Richard A. 
Published: October 2017

Abstract
Real-time analysis of drilling mud loss data is an effective tool to characterize the size, distribution and permeability of natural fractures. The estimated properties of natural fractures can then be used to modify the drilling fluid properties and design remedial mud loss treatment to stop further drilling fluid loss. Moreover, characterization of natural fracture provides crucial information for the design and application of reservoir stimulation operations.
In this paper, we present a theoretical model to simulate the invasion of the drilling fluid into natural fractures. Mathematical modelling was performed for two types of rheology constitutive models which are commonly used for drilling fluids, namely Bingham Plastic and Herschel-Bulkley. The fluid leak-off into the formation is modelled using Carter's model. Moreover, a simplified local elasticity equation is used for the fracture width variation due to fluid pressure. A forward finite-difference numerical scheme is used to solve the pressure drop equation. The developed model is then validated against well-known analytical solutions and numerical simulations. Parametric studies were conducted to evaluate the impact of the fracture deformability, formation leak-off properties, drilling fluid rheology, and the pore fluid contribution. Finally, the output of the developed model is compared with the field data of a welldocumented mud loss incident.
The obtained results indicate that the incorporating the effect of the fluid leak-off may significantly increase the rate of mud loss volume. Therefore, for highly permeable formations (such as carbonates), considering the impact of the fluid leak-off effect seems necessary for a realistic characterization of the mud loss problem. Fracture deformability affects the mud loss volume, with higher deformability leading to a larger mud loss volume. Also, the numerical results confirmed that the rate and magnitude of mud loss volume is significantly affected by the rheological properties of the drilling fluid, in particular the yield stress. In contrast, the effect of pore fluid seems relatively negligible for typical formation fluid types. Comparing the results of our simulation with mud loss field data shows that the developed model can accurately predict the rate and total volume of mud loss into the fractures. Moreover, it shows that incorporating the impact of the fluid leak-off and the fracture stiffness may significantly affect the fracture width prediction. Therefore, these factors should be considered to obtain an accurate estimate of the natural fracture aperture.
Dynamic Modeling to Support the Successful Start-Up of a Challenging Well
Authors: Wang J. Y. , Troshko A. A. , Gallo F. G. , Mayer C. S. , Rosenbaum D. F. , Lopez T. H. , Helgestad D. E. , Seitinger P. 
Published: October 2017

Abstract
Effectively managing risks to achieve a safe and reliable start-up is a crucial step before diverting a well to production facilities. This paper describes a successful offshore well start-up in Norway's Sigyn field, assisted and guided by advanced well simulation. The field's low reservoir pressure presented a challenge to offload drilling mud from the well lower completion. Thus, a decision was made to displace the upper completion with lift gas to facilitate unloading. However, start-up of the Sigyn well still presented a challenge due to complex multiphase transient flow during offloading and the possibility of large liquid surges during kick-off. These surges could potentially overwhelm the test separator and force the well to be shut in. To minimize these risks, robust start-up guidelines were needed accounting for a range of completion, flow lines, surface separator and reservoir conditions.
To develop these guidelines, an integrated multiphase dynamic model was developed to evaluate the merits of different completions and start-up strategies. The model was able to simulate 3-phase, 5-species (mud/brine/nitrogen/oil/reservoir gas) multiphase flow in the well and facilities including tubing, annulus, gas lift valve, choke, riser, pipeline and separator. Modeling results provided operators with data about expected flow parameters and timing of events. This information enabled the host platform to anticipate the time and magnitude of liquid surges. Associated well completion erosion risks during mud clean-up from an unconsolidated reservoir were also assessed and managed. Sensitivity studies allowed selection of the fit for purpose equipment and identification of the consumables required to start up the well.
The well was successfully unloaded in July 2016. Good agreement was found between the real-time measurements and model predictions. The results demonstrated that information gained from complex modeling can provide valuable insights leading to development of the informed guidelines for the safe and reliable start-up.
Characterization of Reservoir Flow Units Based on a Power-Law Equation of Permeability Obtained from an Interacting Bundle of Leaky Tubes Model
Authors: Civan Faruk 
Published: October 2017

Abstract
The conventional approach to flow units’ characterization according to Amaefule et al. (1993) is based on the Kozeny-Carman equation. Although, the Kozeny-Carman equation has been used widely for relating permeability to other properties of porous materials, it suffers from the assumption of non-interacting flow tubes. In this paper, the effects of pore connectivity, valve action of pore throats, and cementation factor are considered by an interacting bundle of tortuous leaky capillary-tubes model of porous media to derive an improved equation of permeability. The parameters of the power-law form of this equation are related to pore connectivity measured by the coordination number using the functional relationships derived from the phenomenological rate equations. The validity and accuracy of this approach is established by comparison with directly measured core data. This approach allows for incorporation of various data within a single, compact, and simple power-law equation over the full range of porosity and permeability. The power law exponent of the leaky-tubes model is shown to deviate significantly from the unity assumed in the Kozeny-Carman equation. While the Amaefule et al. (1993) approach characterizes the reservoir flow units solely based on a flow-zone indicator (FZI) parameter, the present improved approach adds a power-law exponent which allows for enhanced flow units’ characterization using two porosity dependent parameters. The analysis of the permeability vs. porosity data demonstrates that the power law flow units’ model alleviates the deficiencies of the classical Kozeny-Carman equation. This model adequately approximates the actual flow patterns in porous media because it allows interactions and cross-flow between the capillary hydraulic paths.
Optimized Grids for Accurately Representing Geology in Geomechanical Simulations
Authors: Gringarten Emmanuel , Lecuyer Jean Daniel , Villarubias Elsa , Cosson Camille , Li Wan-Chiu 
Published: October 2017

Abstract
To reliably quantify changes in the in-situ stresses due to oilfield exploitation, it is necessary to start from a representative description of the subsurface and simulate both fluid movement and geomechanical effects. For this purpose, a new 3D "hybrid" grid is presented. This grid accurately honors geological features, with no unwarranted simplifications, while being ideally suited for geomechanical simulators and the new generation of flow simulators.
The new 3D Hybrid Grid is dominated by hexahedrons arranged in a structured manner except around faults, where it is made up of tetrahedrons. The grid is constructed from the underlying geological model and the sealed fault network. Both structured (hexahedrons) and unstructured (tetrahedrons) parts follow stratigraphic deposition information. For geomechanical simulations, each compartment is considered as an independent mesh part allowing sliding effects along the faults. At the interfaces between the hexahedrons and tetrahedrons in a fault block, shared nodes are used to ensure stress equilibrium and displacement continuity.
Uncertain states of stress and unforeseen changes in the integrity of the subsurface can have grave economic and environmental consequences. Understanding these helps mitigate development risks, and optimally develop the field. Today, geomechanical studies are not routinely performed and are often based on simplified descriptions of the subsurface. With this new Hybrid Grid, we propose to combine a reliable representation of subsurface with state-of-the art rock mechanics to assess how reservoirs respond to drilling, completion and production. Simplifications in either can lead to incorrect assessment of risks or production forecasts. The grid presented in this paper aims at honoring geology accurately while also being optimal for numerical computations. The zones of tetrahedrons enable the inclusions of even the most complex faulting systems, while the structured hexahedrons precisely follow the stratigraphy and are most efficient for geomechanical simulations.
The gridding technology presented enables a coherent representation of the subsurface for constructing geological models for simulating both flow and geomechanics. Although such meshing schemes exist for modeling manufactured objects, these are difficult to apply to geological formations; our approach now enables them by guiding the meshing using the chronostratigraphic parameterization of the subsurface. It will allow engineers to routinely include the effects of stress changes during production and will build confidence in development plans.
An Innovative and Efficient Approach to Deepwater Well Testing for a Challenging Carbonate Reservoir Offshore Malaysia
Authors: Hosatte Pierre , Anderson Ryan N. , Venugopal Shangkar , Marimuthu Suresh , Bidi Firdaus , McBain Ben , Royce Peter 
Published: October 2017

Abstract
This paper reviews an offshore Malaysia deepwater appraisal well drilled and tested Q1 2016 and presents innovative drillstem testing (DST) solutions specifically engineered and developed to enable efficient deployment, safe production, and successful collection of representative downhole hydrocarbon samples from a challenging carbonate gas reservoir.
The following DST solutions and methodologies are presented: An Open-Hole DST design to address downhole fractured conditions with multiple zones prone to total losses and deployed using pressurized mud cap drilling (PMCD) mode, providing high operational efficiency with no requirements for tubing conveyed perforating (TCP).A subsea safety test tree (SSTT) system operating philosophy and fit-for-purpose subsea well controls contingency procedures to ensure safe emergency shutdown (ESD) and emergency quick disconnect (EQD) from a dynamic positioning (DP) rig.A carefully designed wireless acoustic telemetry system to enable real-time collection of multiple downhole samples of reservoir fluids and real-time bottomhole data transmission for critical decision making.A production shutdown (PSD) system using a state-of-the-art programmable logic controller (PLC) for effective ESD in high-H2S environments.
The DST solutions developed enabled appropriate management of the operational risks identified and provided increased levels of contingencies to guarantee successful and efficient delivery of the well objectives. High-quality downhole samples of reservoir fluids were collected, and the overall key objectives of the well test in terms of reservoir characterization were successfully achieved in a cost effective manner with reduced personnel, health, safety, security, environment (HSSE) and process safety (PS) exposure. This paper showcases how innovative DST solutions, engineered to suit well conditions and combined with fit-for-purpose operational procedures, enabled the safe, efficient, and successful delivery of critical well objectives in a challenging and hostile deepwater environment.