bluuebunny/crossref_metadata_2025_split huggingface dataset:
Outsourcing a Two-Level Service Process
Authors: Lee Hsiao-Hui , Pinker Edieal J. , Shumsky Robert A. 
Published: April 2012

This paper studies outsourcing decisions for a two-level service process in which the first level serves as a gatekeeper for a second level of experts. The objective of the system operator (the client) is to minimize the sum of staffing costs, customer waiting costs, and mistreatment costs due to unsuccessful attempts by a gatekeeper to solve the customer's problem. The client may outsource all or part of the process to a vendor, and first-best contracts exist when the client outsources only gatekeepers or experts. When the client outsources the entire system as a two-level process, a client-optimal contract may not exist unless the exogenous system parameters satisfy a particular (and unlikely) coordination condition. In addition, optimal incentive-compatible contracts exist when the vendor's structure choice (one level or two levels) can deviate from the client's preference. Finally, we numerically examine how vendor structure choice and labor cost advantages influence the client's optimal outsourcing option. This paper was accepted by Martin Lariviere, operations management.
Firm Survival and Industry Evolution in Vertically Related Populations
Authors: de Figueiredo John M. , Silverman Brian S. 
Published: April 2012

This paper examines how the density and governance of vertically related populations affect the life chances of organizations. We integrate the literatures on organizational ecology and vertical integration to develop a theory of how (1) specialized upstream industries affect downstream survival rates, (2) the prevalence of different governance forms among upstream and downstream organizations moderates this relationship, and (3) different forms of governance exert differential competitive pressures on focal organizations. We find evidence supporting our hypotheses in an empirical examination of the downstream laser printer industry and upstream laser engine industry.This paper was accepted by Jesper Sørensen, organizations.
Exploring metal-driven stereoselectivity of glycopeptides by free-energy calculations
Authors: Pietropaolo Adriana 
Published: April 2012

A formalism to quantify the chemical stereoselectivity, based on free energy of binding calculations, is here discussed. It is used to explain the stereoselectivity of two diastereoisomeric frameworks, comprising the dimer of a copper(II)-peptide core of L- and D-carnosine, respectively, each bound to two chains of D-trehalose, in which copper(II) adopts a type-II coordination geometry. The stereocenter of carnosine is varied both L and D, giving rise to two diastereoisomers. A thermodynamic cycle crossing the formation of the two enantiomeric copper(II) peptide cores was devised. A harmonic restraining potential that depends only on the bond distance was added to ensure reversibility in bond formation and dissociation, for an accurate estimate of the free energy. The calculation of the free energy of binding between D-trehalose and the two enantiomeric copper(II) peptide cores reproduces the free-energy quantities observed from stability constants and isothermal titration calorimetry (ITC) measurements. This is an example of chirality selection based on free-energy difference.
CO2 Injection into Oil Reservoir Associated with Structural Deformation
Authors: El-Amin M. F. , Negara A. , Salama A. , Bao K. , Sun S. 
Published: April 2012

Abstract
In this work, the problem of structural deformation with two-phase flow of carbon sequestration is presented. A model to simulate miscible CO2 injection with structural deformation in the aqueous phase is established. In the first part of this paper, we developed analytical solution for the problem under consideration with certain types of boundary conditions, namely, Dirichlet and Neumann boundary conditions. The second part concerns to numerical simulation using IMPDES scheme. A simulator based on cell-centered finite difference method is used to solve this equations system. Distributions of CO2 saturation, and horizontal and vertical displacements have been introduced.
Upstream Data Standards at Saudi Aramco
Authors: AlShehry M. A. , Al-Khudiri M. M. , Al-Sanie F. S. , Miyajan R. A. , AlTaiban A. A. , Al-Zawawi A. S. , Khakwani M. S. 
Published: April 2012

Abstract
This paper describes the upstream data standards that Saudi Aramco has recently implemented for Drilling and is in progress to implement them for other areas such as Production and Reservoir Characterization. These standards enable us to make wider use of our monitoring and collaboration centers through a common approach. It also allows us to leverage the evolving WITSML, PRODML and RESQML standards more effectively in our upstream operations.
Saudi Aramco relies on many service organizations to deliver the generated data which requires common and standard data classification when exporting data from source A then importing to destination B. Applying a common approach to information access on a global basis has enabled us to streamline our operations and make wider use of emerging analysis, monitoring and collaboration technologies.
Real-time technologies have been utilized to capture, monitor and analyze operational data from well sites so that critical decisions can be made in real-time to reduce and eliminate operational and safety problems, thus reducing non-productive time. That includes high-tech rigs, smart wells, monitoring & collaboration tools and real-time data visualization systems.
Our aim has been to implement standard upstream information architecture. Our full implementation of WITSML was the vehicle which allowed this to happen in Drilling & Workover operations. We still believe that over the next years with the advancements of technologies there will be more challenges to support open connectivity between different vendors and services supporting the increasing upstream functions.
Coiled Tubing Best Practices in Conjunction with Multistage Completions in the Tight Gas Fields of Saudi Arabia
Authors: Al-Ghazal Mohammed , Abel Justin Tate , Al-Buali Muhammad , Al-Ruwaished Azmi , Al-Saqr Abdulaziz , Al-Driweesh Saad , Wilson Stuart 
Published: April 2012

Abstract
Open hole multistage fracturing (MSF) completions are becoming standard practice in the south gas fields development in Saudi Arabia with more than 25 wells completed to date using open hole packers and selective port technology.
Overall, the production results from the use of MSF completions have been very positive and the forecast is that MSF technology usage will grow considerably over the next several years. In general, MSF completions provide an excellent advantage in that they are intervention-less in their standard mode of operation. An aspect that is evolving is the secondary use of coiled tubing (CT) to handle the planned and unplanned (contingency) operations occasionally required to reach well production objectives. Without optimum operational planning and the selection of correct CT downhole tools, completion problems can be encountered and this ultimately can result in the job objective not being reached at all or only at increased costs.
This paper presents MSF case studies where CT has been deployed and investigates the operational impact and productivity enhancement. Correlations taken from the key hardware variables, such as fracturing port size and type, motor type, mill bit type, and CT size, are also considered and analyzed.
Following the lessons learned and best practices from these experiences, with correct implementation, the findings from this paper should increase the potential for successful multistage completion operations and ultimate improvements in productivity.
Inversion in the Transient Temperature Behavior in the Intervals of Oil and Water Inflow: Theory and Technique for Application
Authors: Ramazanov Ayrat , Valiullin Rim 
Published: April 2012

Abstract
In this paper we discuss on forward modeling of the transient temperature responses during the well testing.
Well thermometry is conducted at all stages in the life of a reservoir: exploration, development, production and injection. Temperature measurements are especially informative ones when we use a transient processes in the well and formations.
The transient temperature variations in saturated porous medium are connected with fluid expansion/compression, heat convection, viscous dissipation and heat conduction. The combined viscous dissipation (frictional heating) and fluid expansion/compression terms comprise the barothermal effect. The barothermal effect is the same as the classical throttling (Joule-Thomson) one in the particular case of steady state flow. The value of the Joule-Thomson coefficient for oil is about (0.04–0.06) K/bar and for water is about 0.02 K/bar. Therefore the steady temperature variation in the oil inflow intervals (under the same pressure drop) is always more than in the water inflow intervals.
The temperature profile in well changes with time and depends on many other factors, including flow rate, fluid and formation properties and completion configuration. As the result the situation is possible, when specific flow rate of water is more than for oil and the inversion of the throttling temperature anomalies is observed. In this case during the time t less than inversion time tinv the water is heated more than oil. And it is observed the "normal" ratio of throttling anomalies for oil and water for time t&gt;tinv.
Analytical and numerical models of barothermal effect in the saturated porous medium are developed. It was received the formulas for estimation of inversion time. It is suggested the technique of application of temperature anomalies inversion for the determination of water inflow intervals to well by thermal logs.
The field cases corroborate the real practical application of this phenomenon.
Using Histogram Equalization and Edge Detection to Enhance Stratigraphic
Authors: Al Garni Khalid , Al Ghamdi Ahmed 
Published: April 2012

Abstract
In this paper we introduce a workflow to improve stratigraphie and lithologie interpretations. In particular, we demonstrate the use of histogram equalization followed by edge detection to enhance geological features such as faults, fractures, and channels. Post-stack and migrated seismic data is often subjected to automatic gain control (AGC) to increase the visibility of low-strength reflections. Unfortunately, AGC can mask stratigraphic details by drastically changing relative amplitude levels and by producing low-amplitude "shadow-zones" near strong reflectors and near unconformity terminations.
Histogram equalization was originally developed for image processing but serves a useful purpose for seismic analysis. Unlike AGC, histogram equalization preserves subtle stratigraphic features and does not create "shadow-zones" beneath strong reflectors. Histogram equalization enhances the sharpness of stratigraphic features thereby allowing edge detection algorithms to more effectively highlight discontinuities in the amplitude level even if the change is small.
The effect of histogram equalization followed by edge detection is demonstrated using 128-fold 3D seismic land data (Figure 1). Using this data we analyze the ability to map a fluvial channel of noticeable thickness. The channel is the result of Hirnantain (Late Ordovician) glaciations subjected to a local tectonic uplift. A time slice of histogram equalized data shows the channel boundary more clearly than the AGC-processed version.
Figure 1 E-W line extracted from 3D seismic data shows the channel system.
Coil Tubing Fill Cleanout Implemented on Plugged Stand Alone Screens: Highly Successful Campaign in Saudi Arabian Gas Producers
Authors: AlTammar Murtadha J. , Asiri Khalid S. , Al-Driweesh Saad M. , Asiri Mohammed A. 
Published: April 2012

Abstract
Gas wells in Field X, south of the giant Ghawar Field, are completed with stand alone screens across a Pre-Khuff sandstone formation as a sand control measure. Although prolific producers, some suffer a severe decline in performance after a period of production, triggering diagnostic work to be performed. Consequently, screen plugging is confirmed and collected samples of present fill are analyzed. Results called for a coil tubing cleanout campaign in order to restore lost productivity. The objective of this paper is to detail the whole operation journey of the fill cleanout jobs that includes fill diagnostic process, assessment of cleanout methods, initial job design, choice of fluids, CT bottomhole assembly tools, execution and field experience, and post-cleanout performance evaluation.
A CT wiper trip method has been implemented with either milling or jetting tools. A newly developed rate-activated circulation valve is deployed to aid in lifting solids at high pumping rates as well as jetting acid across the screen interval after fill removal. The fill cleanout campaign has been very successful in restoring well productivity as compared to pre-cleanout and initial post-drilling well performance. A total of 340 MMSCFD of incremental gas rate were restored to-date from 16 cleanout operations. Unprecedentedly, interesting and valuable findings are shared regarding the nature of fill formed inside and/or above the stand alone screens, recommended milling practices to protect CT bottomhole assembly and minimize CT fatigue, the experience of incorporating acid jetting and squeeze in the CT wiper trip method to stimulate damaged formation pack behind the screens, and the preventive measures taken to cope with the fill accumulation issue.
Aqueous Foams Stabilized with Particles and Surfactants
Authors: Li Zhaomin , Liu Zupeng , Li Binfei , Li Songyan , Sun Qian , Wang Shuhua 
Published: April 2012

Abstract
Foam is a proven method for decreasing gas mobility in both homogeneous and heterogeneous reservoirs. A new foam system, called multi-phase foam system composed of gas, liquid, and particles has been studied in China recently since it has better performance than general gas-liquid foam system in profile control.
The aqueous foams prepared by mixtures of pre-performed particles and surfactants were studied in detail. In this article a new method focusing on liquid drainage velocity was used to estimate the stability of multi-phase foam system compared with classical foam stability studies that record foam height variation versus time. A synergistic effect on foam stability occurs and becomes more obvious with increasing surfactant concentration. The synergistic effect mainly comes from the adsorption of particles on the bubble surface and the formation of a three-dimensional network in the coherent phase. In addition, particle size is a significant factor affecting foam formation and stability. Foam prepared by 3 different size particles indicates that foam formability and stability decrease with increasing of particle size. It is hypothesized that the decrease in the foam formation and stability is related to the particle gravity. Finally, experiments about reservoir conditions like high temperature and salinity were also conducted. It shows that increasing temperature will accelerate the velocity of foam decay and the increase of calcium chloride concentration help to stabilize foam while sodium chloride has an optimum concentration for foam stability.
Innovative Technique to Liven Dead Wells with a Rigless Gas Lift System
Authors: Sunbul Ahmed , Barlow Steve , Khalifa Mohammed , Hernandez Jeremias , Zamka Saleh 
Published: April 2012

Abstract
An innovative gas lift technique was used to restore production of a high water cut oil producer, by using gas directly from a gas well without compression or treatment. The system included a 2" gas line from the gas well to the oil producer (2 km), and a gas measurement and flow control skid located at the producer. A chemical corrosion inhibitor was injected into the gas line at the gas well site to protect downstream piping and casing. Downhole gas lift equipment in the producer was installed using a wireline; a rigless installation resulted in a low cost installation.
Benefits of this gas lift system include:
No requirement to install and operate expensive compressors. No requirement for gas separation and treatment prior to well injection. Simple low cost wireline installation of downhole equipment. Several producers could potentially be gas lifted by a single gas well. No well site high capacity electrical power is needed.
In September 2011, the system was successfully commissioned, production stabilized at 2,500 barrels of fluid per day (BFPD) at 80% water cut and gas injection rate of 1 million standard cubic feet per day (MMscfd).
This gas lift system is potentially an economical alternative to the electrical submersible pump (ESP) artificial lift where suitable high-pressure gas wells are located near oil producers. The performance of this gas lift system will be closely monitored and evaluated as an artificial lift option for other similar fields.
Technologies for Monitoring Matrix Oil Saturation for TA-GOGD
Authors: Edwards John , Hammami Ahmed , Bachman Nate , Fordham Edmund , Flaum Mark , Bakker Gossen , Bettembourg Solenn , Putra Pristiwanto , Rawnsley Keith 
Published: April 2012

Abstract
TA-GOGD is thermally assisted gas-oil gravity drainage suited for heavy oil in highly fractured formations. Steam is injected into the fractures to serve two purposes: to apply a gas gradient across the matrix blocks so that the oil in the matrix drops down by gravity and to heat the carbonate matrix blocks so that the reduced viscosity oil drips out faster. The reservoir has two fluid systems, which are gas/oil/water levels in the fractures and gas/oil/water contacts in the matrix blocks that are separated by the fractures. Reservoir surveillance requires logs of the remaining oil saturation to confirm the recovery, which is dependent upon the heterogeneities of fracture intensity and vertical permeability. The changing fluid saturations in the matrix are primarily oil replaced by hydrocarbon gas, but six fluids could be present and change: methane and steam, hot low-viscosity and cold high-viscosity oil, formation water, and condensed steam. The important zone is above the fracture gas/oil contact, where drained oil is replaced by the secondary gas cap or steam. Time-lapse pulsed neutron capture logs during the pilot phase did not provide the required matrix fluid saturations due to interference from variable annular fluids in the poorly cemented casing that masked the reservoir response. There is no logging tool available that is capable of measuring the matrix oil saturation change without being influenced by the other fluids in the matrix or the fracture-controlled fluid levels in the casing annulus, or characterized for an open gas-filled borehole, and built to withstand 247°C. The physics of nuclear magnetic resonance (NMR) provides the best chance to fulfill this reservoir surveillance requirement. This paper recounts the decision process that preceded this conclusion, and suggests a method of building a high-temperature non-metallic and non¬magnetic flask to facilitate NMR time-lapse logging in dedicated openhole observation wells in TA-GOGD developments.
Advanced Fluid Technologies for Tight Gas Reservoir Stimulation
Authors: Huang Tianping , Clark David E. 
Published: April 2012

Abstract
Wells drilled in tight sand and shale gas reservoirs require hydraulic fracturing treatments to become economically profitable. The primary objectives for these treatments are twofold: (1) create high-conductivity paths from the wellbore to deep penetration; (2) and/or connect natural microfractures within the reservoirs.
Current fracturing fluid systems generate formation damage and/or fracture damage due to fluid leakoff into natural fractures and matrix or polymer residues. This makes tight gas reservoir stimulation much less effective than expected.
This paper will briefly evaluate the damage mechanisms of current fluid systems and introduce an advanced surfactant micelle fluid technology for tight gas reservoir stimulation. Surfactant micelle fluids structured from very low-molecular-weight surfactants into elongated micelles have been used as stimulation fluids in an attempt to remove the drawback of polymer fluids. The viscoelastic behavior of these surfactant micelle fluids is believed to be rooted in the overlap and entanglement of elongated micelles. This yields both the viscous and elastic characteristics to the fluid.
High fluid leakoff and difficult cleanup associated with traditional surfactant micelle fluids have, however, limited their use in tight gas stimulation applications. Recent work has shown that adding carefully selected inorganic nano-crystals—less than 100 nm in size—to a surfactant micelle fluid formulation can overcome damage limitations. This can be done without negatively affecting the internal breaking mechanisms. Recent results highlight the mechanism of fluid loss control and easy cleanup of this nanoparticle reinforced surfactant micelle fluid system for tight gas stimulation applications.
Improved Model for Predicting the Required Minimum Gas Injection Rate for Removal of Cutting during Underbalanced Drilling
Authors: Samson Fadairo Adesina , Churchill Ako , Emmanuel Nwaokete , Olugbenga Falode 
Published: April 2012

Abstract
It has been widely recognized that maintaining adequate air/gas injection rate is vitally important to achieving hole cleaning both against drilling cutting and liquid accumulations. It is highly imperative to accurately predict the annulus pressure drop for determining the critical air/gas injection rate required for cleaning formation both cutting and liquid influx during underbalanced drilling.
A new numerical model for determining annulus pressure drop model has been developed that is required for accurately predicting minimum air/gas injection rate for simultaneous removal of both cutting and liquid during underbalanced drilling. The new model has incorporated the influence of cutting volume which has been overlooked by most researchers. Since the required minimum flow rate needs to be determined at the surface condition, temperature and pressure dependent variables such as gas formation volume factor, (Bg), Oil formation factor, (Bo), and water formation factor, Bw has been considered in the model. The results generated show that the existing models have underestimated the required minimum air/gas flow rate for continuous lifting of both cutting and liquid during underbalanced drilling. Engineering charts have also been generated for predicting cutting and liquid-carrying capacity of air/gas that is injected into the borehole at various rates. This project provides drilling engineers the necessary knowledge and a useful tool for minimizing complications in air/gas drilling operations