bluuebunny/crossref_metadata_2025_split huggingface dataset:
CO2-Soluble, Nonionic, Water-Soluble Surfactants That Stabilize CO2-in-Brine Foams
Authors: Xing D. , Wei B. , McLendon W. , Enick R. , McNulty S. , Trickett K. , Mohamed A. , Cummings S. , Eastoe J. , Rogers S. , Crandall D. , Tennant B. , McLendon T. , Romanov V. , Soong Y. 
Published: January 2013

Summary
Several commercially available and a few experimental, nonionic surfactants were identified that are capable of dissolving in carbon dioxide (CO2) in dilute concentration at typical minimum- miscibility-pressure (MMP) conditions and, upon mixing with brine in a high-pressure windowed cell, stabilizing CO2-in-brine foams. These slightly CO2-soluble, water-soluble surfactants include branched alkylphenol ethoxylates, branched alkyl ethoxylates, a fatty-acid-based surfactant, and a predominantly linear ethoxylated alcohol. Many of the surfactants were between 0.02 to 0.06 wt% soluble in CO2 at 1,500 psia and 25°C, and most demonstrated some capacity to stabilize foam. The most- stable foams observed in a high-pressure windowed cell were attained with branched alkylphenol ethoxylates, several of which were studied in high-pressure small-angle-neutron-scattering (HP SANS) tests, transient mobility tests using Berea sandstone cores, and high-pressure computed-tomography (CT)-imaging tests using polystyrene cores. HP SANS analysis of foams residing in a small windowed cell demonstrated that the nonylphenol ethoxylate SURFONIC® N-150 [15 ethylene oxide (EO) groups] generated emulsions with a greater concentration of droplets and a broader distribution of droplet sizes than the shorter-chain analogs with 9–12 ethoxylates. The in-situ formation of weak foams was verified during transient mobility tests by measuring the pressure drop across a Berea sandstone core as a CO2/surfactant solution was injected into a Berea sandstone core initially saturated with brine; the pressure-drop values when surfactant was dissolved in the CO2 were at least twice those attained when pure CO2 was injected into the same brine-saturated core. The greatest mobility reduction was achieved when surfactant was added both to the brine initially in the core and to the injected CO2. CT imaging of CO2 invading a polystyrene core initially saturated with 5 wt% KI brine indicated that despite the oil-wet nature of this medium, a sharp foam front propagated through the core, and CO2 fingers that formed in the absence of a surfactant were completely suppressed by foams formed because of the addition of nonylphenol ethoxylate surfactant to the CO2 or the brine.
Casing Burst Stresses in Particulate-Filled Annuli: Where Is the Cement?
Authors: Kalil Issa A. , McSpadden Albert R. 
Published: January 2013

Summary
For burst design, engineers routinely assume that the casing annular space is filled by a fluid equivalent. This assumption ignores mechanical resistance provided by solid cement. Some studies addressed this shortcoming by modeling the cement sheath as a solid with elastic failure criteria. Prior work used cement elastic modulus and Poisson's ratio to classify cement as "ductile" (soft) or "brittle" (hard).
In the current study, numerical results from finite-element analysis (FEA) indicate that casing burst resistance is increased by the presence of the cement sheath. This study focuses solely on improvement offered by the cement sheath to casing burst resistance and ignores consequences of cement failure on overall well integrity.
Comparisons are provided for casing burst resistance, assuming various backup profiles. These include fluid hydrostatics, solid cement matrix (both elastic and plastic response), and cement as "loose" particles. The fluid hydrostatics include mud weight in hole, cement-slurry density, mixed-water density; normal pressure (saltwater column), and actual pore pressure. Calculations show that these fluid profiles are conservative when used as burst-resistance backup. Original cement-slurry density is least conservative.
Because well designers are familiar with fluid profile backup assumptions in casing burst design, recommendations are provided to approximate cement behavior as particles with a fluid profile. This allows ease of calculation and is consistent with current practice. Guidelines are provided to explicitly calculate the enhanced casing burst resistance caused by the particulate cement.
Comparison of Skin Factors for Perforated Completions Calculated With Computational-Fluid-Dynamics Software and the Karakas-Tariq Semianalytical Model
Authors: Sun Datong , Li Baoyan , Gladkikh Mikhail , Satti Rajani , Evans Randy 
Published: January 2013

Summary
Many factors affect flow performance of perforated completions, including perforation-tunnel geometry, drilling and perforation damage, and formation-permeability anisotropy. The combined effect of these factors is usually accounted for by means of a single parameter: total-skin factor, which is an important input parameter for inflow-performance-relationship prediction and reservoir simulation. The Karakas and Tariq (1991) semianalytical skin-factor model is the most commonly used in the industry (Bell et al. 1995; Kabir and Salmachi 2009; Zhan et al. 2012). It assumes that the total-skin factor can be expressed as a linear combination of horizontal skin, vertical skin considering permeability anisotropy, perforation-damaged-zone skin, and other skins. The purpose of this study is to investigate the validity of the Karakas-Tariq semianalytical model in a realistic operational range of perforating-parameter values.
For this purpose, we use computational-fluid-dynamics (CFD) software to simulate the production flow of a vertical cased-and-perforated well in a representative 3D geometric formation. We consider three effects: drilling damage, perforation damage (crushed zone around the perforation tunnel), and permeability anisotropy, assuming no pressure drop along the interior of perforation tunnels. All combinations of the three effects are considered. Computed skins are compared with the semianalytical skin model of Karakas and Tariq (1991).
Computed results show good comparisons between skin factors calculated by use of CFD software and the Karakas and Tariq model (1991) for most cases. However, significant deviations in skin-factor comparisons are observed when both perforation damage and formation anisotropy exist if considering permeability anisotropy in the crushed zone. We also conclude that an additional skin-factor term, related to the ratio of the modified wellbore radius to the original wellbore radius, should be explicitly listed in the Karakas and Tariq model (1991) for perforation tunnels extending beyond the drilling-damage zone.
Calculated CFD skin factors can be used as a database for predictive prejob analysis. Deviation between skin factors calculated by use of CFD and the Karakas and Tariq (1991) model highlights the need for improving industry methods to estimate skin factor in vertical perforated completions if considering crushed-zone anisotropy.
Experiments and Analysis of Multiscale Viscous Fingering During Forced Imbibition
Authors: Sharma Jyotsna , Inwood S.B.. B. , Kovscek A.R.. R. 
Published: January 2013

Summary
Immiscible displacement of one fluid by another in porous media has practical applications when viscous oil is produced by water injection. A greater understanding of the flow patterns that evolve during such unstable displacements yields insights into improving predictive capability and increasing oil recovery. Immiscible multiphase displacement exhibits a wide range of behaviors depending on the relative magnitude of viscous, capillary, and gravity forces. Using flow-visualization images from forced-imbibition experiments carried out in etched-silicon micromodels, we show that the conventional Darcy-type modeling of fluid flux is not predictive under unstable, immiscible, forced-imbibition conditions at the scale of interest. When a less viscous fluid displaces a more viscous fluid at low capillary numbers, the displacement patterns show viscous instabilities in the form of fingers and local capillary control of interface movement. We show that such complex displacement patterns are well modeled using statistical theories. We derive a scaling model to describe quantitatively the functional forms for saturation, fractional flow, and capillary dispersion profiles using the self-similar characteristics inherent in the displacement patterns. For the specific range of flow rates (Nc ~ 10−7) and oil/water viscosity ratios (M ~ 8–400) considered in our experiments, both capillary and viscous forces are important, and the displacement pattern indicates fractal features. Results show that functional relations of the scaling model are in considerable agreement with our experimental data.
North Sea World Record Installation–Deepest Sealed Multilateral System
Authors: Eck-Olsen Johan , Solheim Ove Andre , Morten Falnes 
Published: January 2013

Summary
In October 2010, the deepest-set sealed multilateral (ML) junction in the industry was installed at 6900-m measured depth (MD) in Oseberg South Well 30/9-F-9 AY1/Y2. The differential pressure across the junction in the well was expected to be in the range of 250 bar. To meet this pressure requirement, a junction system rated to 370 bar was identified. The high-pressure junction components and entire multilateral system have undergone an extensive testing and qualification program, including several component tests and a full-scale system interface and integration test.
A 10¾-in. precut window was installed as an integral part of the 10¾-in. liner. The plan was to perform the milling operation through this window. A stuck-string incident during the 10¾-in. liner installation accidentally caused the liner to drop in the hole. The liner ended up at the wrong orientation, and the window could consequently not be used.
The main bore was drilled to total depth (TD) at 8583-m MD, and the 7-in. liner was run and cemented. After the liner perforation, the BL operations started with the installation of an anchor packer and a latch interface assembly (LIA). The milling operation was performed in a two-step operation with milling of a first-pass window by use of a downhole milling machine before installing a whipstock and performing the second-pass milling operation.
The lateral branch was drilled to TD at 8258-m MD, and a 5½-in. screen completion was run and dropped off into the 8½-in. open hole. The junction was finally stung into a completion deflector, simultaneously with an openhole seal stinger entering the top of the screen liner in the open hole, tying the branches together. A 6900-m upper completion string with inflow control valves was finally installed to allow for surface control of the two branches.
Despite severe drilling problems in the transport sections of the well, the ML operations were deemed successful. Major risk and challenges with this well design involved orientation of the 10¾-in. liner (to position the premilled window) at this depth, debris management after milling operations, and general depth control during junction construction. Debris management in particular became essential as the backup ML solution meant milling steel rather than aluminum.
Although the two different reservoirs could be drained by two conventional extended-reach-drilling (ERD) wells, this would be a less cost-efficient solution. Furthermore, the construction of an ML well means that the aforementioned challenges drilling the transport sections had to be handled only once. The successful installation at this depth has proved that ML technology is feasible for use in ERD wells, either to improve the total reservoir exposure or to reach multiple targets from one well.
Qualitative and Quantitative Analyses of the Three-Phase Distribution of Oil, Water, and Gas in Bentheimer Sandstone by Use of Micro-CT Imaging
Authors: Feali M.. , Pinczewski W.V.. V. , Cinar Y.. , Arns C.H.. H. , Arns J.-Y.. -Y. , Turner M.. , Senden T.. , Francois N.. , Knackstedt M.. 
Published: January 2013

Summary
It is now widely acknowledged that continuous oil-spreading films observed in 2D glass-micromodel studies for strongly water-wet three-phase oil, water, and gas systems are also present in real porous media, and they result in lower tertiary-gasflood residual oil saturations than for corresponding negative spreading systems that do not display oil-spreading behavior. However, it has not yet been possible to directly confirm the presence of continuous spreading films in real porous media in three dimensions, and little is understood of the distribution of the phases within the complex geometry and topology of actual porous media for different spreading conditions. This paper describes a study with high-resolution X-ray microtomography to image the distribution of oil, water, and gas after tertiary gasflooding to recover waterflood residual oil for two sets of fluids, one positive spreading and the other negative spreading, in strongly water-wet Bentheimer sandstone.
We show that, for the positive spreading system, oil-spreading films maintain the connectivity of the oil phase down to low oil saturation. At similar oil saturation, no oil films are observed for the negative spreading system, and the oil phase is disconnected. The spatial continuity of the oil-spreading films over the imaged volume is confirmed by the computed Euler characteristic for the oil phase.
Automatic Isotherm Derivation From Field Data for Oilfield Scale-Inhibitor Squeeze Treatments
Authors: Vazquez Oscar , Corne David , Mackay Eric James , Jordan Myles Martin 
Published: January 2013

SummaryOilfield scale formation represents a significant flow-assurance challenge to the oil and gas industry, because of increasing water production worldwide and higher oil prices. Scale-inhibitor (SI) squeeze treatment is the most widespread method to combat downhole scaling. To predict SI squeeze treatments accurately for further optimization, it is necessary to simulate the SI retention in the formation, which may be described by a pseudoadsorption isotherm. Although these are often derived from coreflood experiments, sometimes they are not appropriate for modeling well treatments because the core tests on which they are based cannot fully represent field-scale processes. In practice, the parameters of an analytic form of the isotherm equation are modified by trial and error by an experienced practitioner until a match is obtained between the prediction and the return profile of the first treatment in the field.The main purpose of this paper is to present a stochastic hill-climbing algorithm for automatic isotherm derivation. The performance of the algorithm was evaluated by use of data from three field cases. Two success criteria were defined: the ability to match a single historical treatment and the ability to predict subsequent successive treatments. To test for the second criterion, a candidate isotherm was derived from the first treatment in a well that was treated with the same chemical package on consecutive occasions, and then the predictions by use of the suggested solution were compared with the observed SI concentration-return profiles from the subsequent treatments. In all the calculations, the performances of both the isotherms suggested by the hill-climbing algorithm and the isotherms derived by trial and error were compared. The results demonstrate that the hill-climbing algorithm is an effective technique for deriving an isotherm for a single treatment, although predictions for successive treatments worsened slightly with each treatment.
Explicitly Coupled Thermal Flow Mechanical Formulation for Gas-Hydrate Sediments
Authors: Klar Assaf , Uchida Shun , Soga Kenichi , Yamamoto Koji 
Published: January 2013

Summary
This paper presents an explicit time-marching formulation for the solution of the coupled thermal flow mechanical behavior of gas-hydrate sediment. The formulation considers the soil skeleton as a deformable elastoplastic continuum, with an emphasis on the effect of hydrate (and its dissociation) on the stress-strain behavior of the soil. In the formulation, the hydrate is assumed to deform with the soil and may dissociate into gas and water. The formulation is explicitly coupled, such that the changes in temperature because of energy flow and hydrate dissociation affect the skeleton stresses and fluid (water and gas) pressures. This, in return, affects the mechanical behavior. A simulation of a vertical well within a layered soil is presented. It is shown that the heterogeneity of hydrate saturation causes different rates of dissociation in the layers. The difference alters the overall gas production and also the mechanical-deformation pattern, which leads to loading/unloading shearing along the interfaces between the layers.
Environmental Safety Assessment of Drilling Operations in the Marcellus-Shale Gas Development
Authors: Olawoyin Richard , Wang John Y. , Oyewole Samuel A. 
Published: January 2013

Summary
The process of gas development is intensive and involves risk to theenvironment. Statistics confirm that 0.5 to 1% of wells drilled result in ablowout. Causes of these exploration risks are identified as violations ofenvironmental laws enforced by the Pennsylvania Department of EnvironmentalProtections (DEP), operational pollution (accidental spills and leaks), andoperator's policy. In addressing this concern, a risk-assessment methodologywas used to evaluate all violations by operators in the State of Pennsylvaniafrom January 2008 to November 2010, by use of Statistical Analysis Software(SAS). The most significant causes of environmental damage and risk weredetermined by use of the doubly repeated measure analysis of covariance(ANCOVA). The category effect and interaction effect were used to prove theusefulness of the developed model, which helps explain the safety level of thelocality. There were a total of 2,601 violations between 2008 and 2010committed by 65 different operators in the Marcellus Shale, out of which only27 of the operators showed significance difference based on environmentallydamaging violations (ranked 5 to 10). A statistical comparison was made tounderstand the difference between the operators based on the 2,601 totalviolations. The most significant incidents are ranked [on the basis of Bordacount (Saari 1985)] 3, 5, 9, 10, which accounts for 67% of all the violations.These data reflect several environmental concerns that are currently prevalentin the Marcellus-shale area. This research identifies environmental incidents,causes and effects of exploration risk, and safety impediments in the Marcellusgas play. It also presents guidelines for feasible options to minimizeenvironmental risks and consequently increase the degree of safety in the area.Recommendations on how to mitigate these impending problems are presented.
The Optimal Range of the Nitrogen-Injection Rate in Shale-Gas Well Drilling
Authors: Li Jun , Guo Boyun , Liu Gonghui , Liu Wei 
Published: January 2013

Summary
Given the downturn of natural-gas prices in North America, it is vitally important to reduce the cost of drilling shale-gas wells. Gas-percussion drilling with nitrogen gas recently has been used in shale-gas field development. It has increased footage capacity by approximately 60%. Because the rate of penetration (ROP) is fast in gas-percussion drilling, it requires injection of an adequate quantity of nitrogen gas to clean the hole. However, a high rate of gas injection often causes wellbore erosion and deviation problems. It is imperative to determine the optimal range of the nitrogen-gas-injection rate that can mitigate the problem.
This paper presents an analytical method for predicting the optimal range of the nitrogen-gas-injection rate required to balance the borehole-cleaning and -integrity issues. The optimal gas-injection rate was sought between the minimal value required for hole cleaning and the maximal permissible value to avoid hole erosion. The minimal value was determined on the basis of Angel's kinetic-energy theory for cuttings removal modified with Charles' theory of particle-grinding energy. The maximum required value was estimated by use of the sonic flow criterion at the bit. Good consistency was observed between the predicted optimal range of gas-injection rate and field problem-free nitrogen-gas-injection rates. This paper provides drilling engineers a practical tool for designing the optimal range of nitrogen-gas-injection rate to cut shale-gas drilling cost.
Influence of malocclusion on the development of masticatory function and mandibular growth
Authors: Nakamura Aya , Zeredo Jorge L. , Utsumi Dai , Fujishita Ayumi , Koga Yoshiyuki , Yoshida Noriaki 
Published: January 2013

ABSTRACT

Objective
To verify the hypothesis that appropriate acquisition of masticatory function and normal growth of the mandible are modified by malocclusion.

Materials and Methods
Eighteen Jcl:ICR mice were divided into two groups. In one group we shifted the mandible laterally using an occlusal guidance appliance, creating a posterior crossbite at 5 weeks of age. The other group served as control. After 10 weeks, three-dimensional jaw movements and muscle activities were recorded simultaneously during mastication. Microcomputed tomography scans were obtained in vivo to evaluate morphometric changes in the mandible.

Results
(1) The jaw movement pattern in the sagittal plane showed significantly less anteroposterior excursion in the malocclusion group during the late-closing phase (power phase). (2) Electromyography showed significantly less masseter activity in the malocclusion group. (3) The condylar width and mandibular bone mineral density (BMD) were significantly reduced in the malocclusion mice compared to the normal mice.

Conclusions
These findings suggest that optimization of the chewing pattern and acquisition of appropriate masticatory function is impeded by malocclusion. Altered mechanical loading to the mandible may cause significant reduction of condylar width and mandibular BMD.
Current Practice Patterns and Identified Educational Needs of Health Care Providers in Managing Patients With Type 2 Diabetes
Authors: Williamson J. Chad , Glauser Terry A. , Nevins P. Holder , Schneider Doron , Kruger Davida F. , Urquhart B. Scott , Whitfield Suzanne F. , Dubois Anne Marie 
Published: January 2013

IN BRIEF
This article describes the results of surveys distributed to a national audience of specialty, primary care, and allied health care providers (HCPs) who manage patients with type 2 diabetes on a daily basis. The results provide insights into current educational needs and can inform the design and development of education programs for these HCPs.