bluuebunny/crossref_metadata_2025_split huggingface dataset:
Periodically ordered nanohetero inorganic structures of nanoparticles, nanorods and layers in a matrix from self-assembled block copolymers
Authors: Wakayama Hiroaki , Yonekura Hirotaka , Kawai Yasuaki 
Published: September 2014

ABSTRACTPeriodically ordered nanohetero inorganic structures offer great promise due to their unique electric, ionic, magnetic, and photonic properties. Many studies have focused on the formation of periodically ordered nano-hetero inorganic structures through layer-by-layer adsorption, sputtering, and self-assembly methods. However, the construction of three-dimensional periodically ordered nanohetero inorganic structures with desired sizes and morphologies remains a great challenge. We present a simple method for producing three-dimensional periodically ordered inorganic nanoheterostructures with controlled shape and size by replicating self-assembled block copolymers (BCPs) containing precursors of metals and metal oxides. Precursors were dissolved with BCPs in a solvent. Upon evaporation of the solvent, each precursor was selectively introduced into a separate polymer block. Application of an external magnetic field (10 T) to the BCP-precursor composites resulted in a phase transition of from spheres to hexagonal cylinders. Subsequent pyrolytic removal of the BCPs produced periodically ordered nanoheterostructures that were structural replicates of the precursor–BCP composites. Self-assembled nano-hetero inorganic structures of nanoparticles, nanorods and layers in a matrix were produced. The morphology and domain size can be tailored by controlling the molecular weight and relative block length of block copolymers. The controlled size and morphology of the inorganic nanoheterostructures demonstrate the method’s utility for producing highly functional materials.
Crossover between Ferroelectric and Quantum Paraelectric in SrTiO3 both by Isotopic Substitution and Hydrostatic Pressure
Authors: Wang Ruiping , Itoh Mitsuru 
Published: September 2014

AbstractQuantum paraelectric SrTiO3 undergoes a transition to ferroelectric by the substitution of 18O for 16O. The Tc vs. x in SrTi(16O1-x18Ox)3 follows Tc = 30.4(x - 0.33)1/2. Application of the hydrostatic pressure on the SrTiO3 and SrTi(16O0.0718O0.93)3 have the effects of decreasing ε and depressing Tc, respectively. Above the critical pressure pc, ferroelectricity of SrTi(16O0.0718O0.93)3 disappears. Fitting the data to the Barrett's formula, ε , elucidated that T0 and T1 for both compounds changes linearly with pressure.
Successful Use of Mixed Aluminum-Steel Drill Pipe String in Complex Horizontal Wells: Case Study
Authors: Menand S.. , Lehner Jeffry K. , Evans Nigel , Palmer Aaron , Arthur Metcalfe 
Published: September 2014

AbstractHigh strength-to-weight aluminum alloy drill pipe is a powerful torque and drag reduction tool for deviated wells. The aluminum alloy drill pipe enables to achieve strength to weigh ratios equivalent to 160 ksi yield strength steels and is typical 30-50% lighter than similar steel drill pipe. An operator has recently tested aluminum alloy drill pipe in a complex and highly deviated well profile.This paper presents the key findings regarding the benefits of drilling using aluminum drill pipes in a mixed aluminum-steel string compared to a string using steel pipes only. Firstly, the innovative drill pipe design is presented, followed by lessons learned during rig operations regarding pipe handling practices, rig compatibility and pipe inspection. Then, the paper presents results of an advanced torque, drag and buckling simulations taking into account the rigorous mechanical characteristics of aluminum drill pipe. In well planning phase, sensitivity analysis enabled to optimize the placement of aluminum drill pipe along the mixed aluminum-steel drill string according to the well profile and to predict anticipated torque, drag and loads on pipes while drilling. Through extensive modeling and field data interpretation, the paper presents a comparison of the overall drilling performances between steel only and aluminum-steel drill pipe string, and provides metrics in terms of torque and drag reduction. These results were then used to challenge horizontal and extended reach drilling well profiles where the utilization of steel drill pipes only has shown its limitation.
Ultra-Deepwater Blowout Well Control Analysis under Worst Case Blowout Scenario
Authors: Yuan Zhaoguang , Hashemian Yahya , Morrell Daniel 
Published: September 2014

AbstractFor offshore wells, the regulatory agency requires the submission of a worst discharge analysis and relief well planning report. The ability to control the blow out under worst case blowout scenario shall be documented and is a requirement for the operators to successfully apply for a permit to drill in the US offshore fields.As the water depths of offshore drilling operations are getting deeper and deeper, due to the increased frictional pressure losses in kill lines and formation fracture strength, bringing the blow out well under control with worst case discharge becomes more challenging. Operational parameters need to be carefully controlled to avoid exceeding the operational limitations such as breaking the formation or exceeding available pump capacity.In this study, dynamic simulations of multiphase flow are carried out to evaluate the operational parameters during the kill process. The simulations account for transient changes including frictional pressure losses, U-tube effect and fluid density variations. By optimizing the operational sequence with regards to, kill mud density, pump flow rate, pump down staging, relief well drillstring and trajectory, blowout can be controlled without exceeding the operational window.The paper shows the required volumes of the kill mud, required pump capacity, optimal flow rate arrangement, and minimum time required to get full kill mud return to the sea floor during the well kill operation. Through the aid of advanced transient software models, assessment of the required capacity to kill a blowout enables development of realistic contingency plans to ensure that well control can be re-established in case of an ultra-deep water worst blowout scenario.
Shaped Charge Selection and Underbalance Optimization Using the Perforation Flow Laboratory for Deepwater Subsea Wells in Offshore Africa
Authors: Osarumwense Osarennomase , Satti Rajani Prakash , White Ryan , Ochsner Darren , Sampson Tim , Gilliat Jim , Fraser Graham 
Published: September 2014

In recent years, the oil and gas perforating industry has seen the growth of perforating flow laboratories to develop shaped charges for reservoir-specific conditions. Flow laboratories can help measure perforation tunnel characteristics, flow features, productivity and the performance of shaped charges. Such information is critical to perforating job design, particularly in challenging deepwater wells.
In this study, we are focused on a deepwater subsea sandstone field (1000-1700m water depth) in offshore Africa. The fields typically consist of sinuous turbidite sandstone channel systems of Turonian age. The wells are completed as cased and perforated completions with no active sand control. Typically, deepwater cased and cemented completions are frac-packed, which reduces reliance on perforating performance for efficient flow path from the reservoir into the wellbore. The completion design in this case relies heavily on effective perforations for an efficient flow path, including perforating past drilling damage and minimizing the risk of sand production through selective perforating and reduced shot density.
The formation properties were evaluated to select an analogous rock for implementing a comprehensive testing program. In the first phase, a series of API RP19-B Section IV tests were conducted using various shaped charges to obtain a baseline understanding of shaped charge performance. The rock was stressed to simulate reservoir conditions of overburden, reservoir and wellbore pressures. The testing program aimed at selecting an optimal shaped charge and ensuring the maximum clean up/productivity that can be achieved based on the underbalance method. In addition, the test results provided insight into tunnel geometry, inflow performance and dynamic pressure data to develop an informed perforating strategy. Subsequently, the second phase of the program evaluated the effects of mud invasion on perforation geometry and the higher magnitude of static underbalance on perforation cleanup. This study demonstrates how the perforating flow laboratory can be utilized to design perforating jobs in a deepwater environment. The flow laboratory serves as a unique tool to measure and optimize shaped charge performance in a wide variety of downhole scenarios.
Wellbore Strengthening in Sandstones by Means of Nanoparticle-Based Drilling Fluids
Authors: Contreras Oscar , Hareland Geir , Husein Maen , Nygaard Runar , Alsaba Mortadha 
Published: September 2014

Abstract
Drilling operations of both conventional and unconventional oil and gas accumulations are becoming more challenging especially in deep-water operations. Due to the narrow mud weight window in offshore wells, a proper wellbore stability analysis is required for a cost-effective execution. Wellbore strengthening is an approach used to increase the fracture pressure of the rock, widen the mud window and consequently enhance the well integrity and mitigate mud losses. This paper demonstrates the feasibility of wellbore strengthening in permeable formations using oil-based mud (OBM) containing in-house prepared nanoparticles (NPs) combined with graphite. A significant increase in the fracture pressure was achieved and the predominant wellbore strengthening mechanism was identified.
Fracture pressure increase was quantified by carrying out hydraulic fracturing tests on 5 3/4″×9″ Roubidoux sandstone cores. A 9/16″ wellbore was drilled, cased and cemented to simulate well conditions. Overburden and confining pressure were applied on the cores while testing to simulate a normal-faulting regime. Two injection cycles were applied allowing 10 minutes of fracture healing between the cycles. The fracture pressure was increased by 65% when calcium-based NPs (NP2) blends were used, whereas it increased by 39% in the presence of iron-based NPs (NP1). Optimum NPs concentrations were established after a comprehensive experimental screening. A strong relationship between wellbore strengthening and mud filtration at high-pressure high-temperature (HPHT) using a filter press on ceramic discs was found. Optical microscopy, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) analyses were conducted on the hydraulically fractured cores. The fractures were seen to be completely sealed from tip to wellbore. Therefore, tip isolation by the development of an immobile mass was identified as the predominant wellbore strengthening mechanism. A 40 micron-seal containing homogeneously dispersed NPs and graphite was observed. In addition, a 300 micron-filter cake was developed around the wellbore also containing homogeneously dispersed NPs.
Using High-Strength Dissolvable Metals to Increase Flow Assurance in High-Temperature and High-Pressure Environments
Authors: Carrejo N.. , Kellogg B. R. , Gaudette S. L. , Barnard J. J. 
Published: September 2014

AbstractIncreased completion of ultra-deep, high-pressure, and high-temperature wells has been driven by the growing demand for hydrocarbons. Extreme pressure frac screens (XPFS) have been developed to handle the higher loads and conditions. An XPFS is a high-pressure-rated sand control screen, capable of withstanding up to 15 ksi burst and collapse. The XPFS utilizes engineered, high-strength disintegrating materials (HSDM) to operate as a fluid-loss barrier that can be run-in on the liner. This new technology combines ease of use with a controlled delay in the activation that opens the screen to flow. The HSDM covers and seals over a bonded bead matrix that, when the HSDM dissolves, acts as a screen equal in filtration performance but better than current sand control alternatives in its erosion resistance. The beaded matrix can be customized to ensure filtration through a wide range of particulate sizes and currently prevents passage of 85 to 90% of all particulates larger than 53μm. The HSDM covering the beaded matrix is formulated to corrode in the presence of brine and/or acid and provide access to the sand control media, enabling normal well production. The system increases the efficiency of hydraulic fracturing treatments, and can be installed in a steerable drilling liner. Alternatively, the beaded matrix can be replaced with a solid HSDM plug, thus acting as a fluid-loss friendly, solid-base pipe during run-in and leaving a pre-drilled liner after the HSDM dissolves, eliminating the expensive need to later perforate the pipe. This paper studies the pressure rating dependability and sand control capabilities of a liner that provides operators with an intervention-less ability to complete ultra-deep, high-pressure, high-temperature wells.
Managing Suspension Characteristics of Lost-Circulation Materials in a Drilling Fluid
Authors: Kulkarni Sandeep D. , Jamison Dale E. , Teke Kushabhau D. 
Published: September 2014

Abstract
Lost-circulation materials (LCMs) are often used to mitigate the loss of drilling fluids into subterranean formations. Well-known LCMs include ground marble, graphitic carbon, and cellulosic particulates. The carrier fluid's ability to suspend the LCM material is critical in high-pressure/high-temperature (HP/HT) or inclined wells. This paper provides methods to help determine and manage suspension characteristics of LCMs in the fluid with the aid of certain suspending agents (e.g., fibers).
A detailed experimental study was conducted to evaluate the suspension of a range of LCMs in various drilling fluids and investigate the effects of suspending agents (e.g., fibers) on LCM suspension. Based on experimental data, semiempirical models were developed to help predict the influence of fibers on LCM suspension. The design parameters used in these models included fiber concentration, fiber density, number of fibers per unit volume, and average fiber length and diameter. The modeling work discussed in this paper also provides methods for tailoring the suspending agent properties necessary for achieving effective LCM suspension in the fluid.
The uniform suspension of LCM in the carrier treatment or drilling fluid is necessary during LCM pill preparation and during wellbore applications, such as a hesitation squeeze operation. Thus, using fibers to manage the suspension characteristics of LCM in carrier fluids can help ensure efficient use of LCMs for lost-circulation control. This method is particularly important in severe-loss zones where large sized LCMs are used as well as in HP/HT or inclined wells where maintaining LCM in suspension can be challenging.
Flow Rate and Total Discharge Estimations in Gas-Well Blowouts
Authors: Liu R.. , Hasan A. R. , Mannan S.. 
Published: September 2014

AbstractDespite multitier safeguards in any drilling operation, blowouts occur. When such accidents take place, the total discharge of hydrocarbons becomes the focal point for all concerned, including the operator, the service provider, and the regulatory body. Rate estimation becomes a daunting task with scant information about the formation and fluids at the time of the accident. Given that new regulatory guidelines require such estimates for any offshore drilling, systematic investigation is imperative.This study presents an analytical model coupling the flow in a reservoir/wellbore system of a gas well. The model considers flow in the tubing, annulus and riser, and the attendant heat transfer in this formulation. To gauge safety concerns, plume dispersion is modeled under various wind speed scenarios when ignition sources were not present. In the event of gas ignition, the energy of the explosion of the flammable gas is estimated with an empirical method in terms of trinitrotoluene (TNT) equivalency. The energy released by the jet fire associated with flammable gas is also evaluated.Two published field cases provided insight into the model's applicability in actual situations and some perspective on solution quality. However, given the large number of unknowns in any setting, we adopted the statistical design of experiments to understand the impact of independent variables. These variables include formation permeability, connected reservoir pore-volume, and restrictions in flow path, among others. Overall, the model results are in agreement with the previous findings. Specifically, we observed that reservoir permeability controls the flow rate; hence, the cumulative production for a given flow cross-sectional area in the well. In addition, the reservoir pore-volume connected to the well has a large impact on the rate of production decline; therefore, the total discharge volume.
Combined Rate of Penetration and Pressure Regulation for Drilling Optimization Using High Speed Telemetry
Authors: Shishavan Reza Asgharzadeh , Hubbell Casey , Perez Hector D. , Hedengren John D. , Pixton David S. 
Published: September 2014

Abstract
Low latency feedback, high bandwidth, and improved sensor placement are key benefits provided by wired drill pipe (WDP) technology. Improved WDP reliability, based on over 100 wells of field experience, enables more aggressive application of the technology, including closed-loop control of drilling processes. Often, there is a requirement to consider multiple variables when attempting to control complex processes such as drilling in deepwater wells. Such is the case when dynamically optimizing rate of penetration in a pressure-critical wellbore environment.
Formerly, rate of penetration (ROP) and borehole pressure (BHP) have been considered separate optimization and automation tasks, respectively. This study combines ROP and BHP into a single comprehensive controller for a managed pressure drilling (MPD) application. The controller adjusts mud pump flow rate, choke valve position, drill string rotation rate, and weight-on-bit (WOB) simultaneously and with coordinated actions. The automated operations are guided by an objective function that includes factors relevant to both BHP stabilization and ROP maximization. A preliminary MPD case study is used to assess the performance during different drilling events, including transition into varying formations causing an unexpected gas influx. For the unwanted gas influx case, the controller better stabilizes the pressure when there are low latency communications by simultaneously adjusting ROP. With WDP and the optimizing controller, there is substantial decrease in time required to control influx events as compared to earlier controllers or manual methods. The high speed data availability affects both the pressure control reaction time and the resulting severity of the kick. When encountering different formations, there is also noticeable benefit by allowing pressure to fluctuate within an acceptable range to optimize ROP.
Combining ROP and BHP control minimizes risk, decreases drilling costs, and reduces operator workload. Improvements in drilling performance include higher ROP, lower risk of uncontrolled kick events, and more uniform cuttings loading. Another benefit of this combined ROP / BHP controller is that the reaction to gas influx is made more consistent and predictable relative to manual operations, reducing the demand for time-consuming remedial efforts.
Reverse Cement Placement Technique: A Case Study from Deepwater Gulf of Mexico
Authors: Bogaerts M.. , Gubanov E.. , Dooply M.. , Pringuey T.. , Sutama C.. 
Published: September 2014

Abstract
Reverse cement placement is an existing technology that is being used infrequently, mainly during land cement operations. During reverse cement placement, the cement travels down the casing – open hole annulus and up the casing. Although reverse cement placement is not very common in deepwater cementing, it has many potential benefits compared to the conventional placement.
Simulation of reverse placement is not possible with existing commercial software. Therefore, jobs were designed using specialized prototype software that enabled the design engineer to accurately reconstruct field conditions. Reverse cement placement will result in lower bottom hole circulating pressures as the direction of the flow follows gravity for the majority of the job. The reverse flow path also has an effect on the temperature the cement will see during placement, which needs to be accurately identified for proper laboratory testing. Proper mud removal is very important to achieve the cement job objectives. Careful attention needs to be given to fluid design as the fluid density and rheological hierarchy are reversed during the placement compared to conventional placement.
A deepwater well in the Gulf of Mexico was identified for permanent plug and abandonment. Based on certain design limitations in the well, the operator requested that several cement plugs be set using the reverse placement technique. In total, seven cement plugs in four wells were set successfully using the reverse placement technique.
Successful Placement of an Advancing Sand and Fines Control Chemical as a Remedial Sand Control, using Subsea Flow Lines from an FPSO
Authors: Piemontese Michele , Colombo Marco , Ripa Giuseppe , Dario Pellicanò , Singh Pratyush , Murphy John 
Published: September 2014

Abstract
The ENI Nigerian subsidiary operates a subsea field located in the north western sector of the Nigerian offshore deep-water, is an oil and gas producing field. The production is from subsea wells which are directed to a Floating Production, Storage and Offloading vessel (FPSO). All the wells in this field require sand control measures in the reservoir section from the onset to prevent sand production. Sand control in the field is challenging and various methods (gravel pack, frac pack and expandable sand screens) have been used. Conventional sand control integrity has failed in one of the wells, compromising production rate and exposing subsea asset to risks related to sand production. Compared to heavy workover required for primary sand control application, an advancing chemical treatment bullheaded through the subsea flowline and the production tubing provided a unique, highly economical, and effective solution to this challenging problem. The product effect creates an ionic attraction between the sand grains and fines, using non-damaging water-based fluid. The chemistry mitigates sand production, reduces or stops fines migration and increases the Maximum Sand Free Rate (MSFR). After pumping chemical treatment through a 4.2 km flow line in the failed frac packed completion, well returned to production with minimal sand presence, less than 24 hours NPT and eliminating the need for re-completion. This was the first time the chemical had been pumped from an FPSO and through subsea flow line. This paper discusses the planning, execution, post job analysis and lessons learned.