bluuebunny/crossref_metadata_2025_split huggingface dataset:
A pilot study to evaluate the effect of Taeumjowi-tang on obesity in Korean adults: study protocol for a randomised, double-blind, placebo-controlled, multicentre trial
Authors: Park Sunju , Park Jeong-Su , Cheon ChunHoo , Yang Yong Joon , An Changsuk , Jang Bo-Hyoung , Song Yun-Kyung , Go Hoyeon , Lee Ju Ah , Shin Yongcheol , Ko Seong-Gyu 
Published: April 2012

Abstract

Background
Obesity, which is described as excessive or abnormal body fat, increases the risk of diet-related diseases. In Korea and around the world, the prevalence of obesity has grown annually from 1998 to 2008. This growth has continued despite various therapeutic efforts. The discovery of new and alternative treatments for obesity should be considered an important priority. Taeumjowi-tang (TJ001), a traditional Korean medicinal extract consisting of eight herbs, is a widely used herbal remedy for obesity in Korea. However, the efficacy and safety of TJ001 have not been fully investigated in a clinical trial. The purpose of this pilot study is to estimate obesity-related parameters and to assess the efficacy and safety of TJ001.

Methods
Our study is a randomised, double-blind, placebo-controlled, multicentre clinical trial of Taeumjowi-tang (TJ001). For this study, we will recruit obese Korean patients of both sexes, ages 18 to 65 years, from four university hospitals. A total of 104 subjects will be recruited. The participants will receive either 7 g of TJ001 or a placebo three times daily for 12 weeks. The primary end point will be the rate of subjects who lose at least 5% of their baseline body weight. The secondary end points will be changes in body weight, body mass index, waist circumference, hip circumference, waist/hip circumference ratio, lipid profiles, body fat composition, blood pressure, fasting glucose concentration, C-reactive protein and questionnaires related to the quality of life. The outcomes will be measured every 4 weeks. The study period will be 12 weeks and will include a total of five visits with each subject (at screening and at 0, 4, 8 and 12 weeks).

Conclusions
The results of our study will inform various estimates of TJ001 and will serve as the basis for a larger-scale trial. This study will assess the efficacy and safety of TJ001 as an alternative herbal remedy for obesity.

Trial registration
Current Controlled Trials ISRCTN87153759
The Power of Diversity over Large Solution Spaces
Authors: LiCalzi Marco , Surucu Oktay 
Published: April 2012

We consider a team of agents with limited problem-solving ability facing a disjunctive task over a large solution space. We provide sufficient conditions for the following four statements. First, two heads are better than one: a team of two agents will solve the problem even if neither agent alone would be able to. Second, teaming up does not guarantee success: if the agents are not sufficiently creative, even a team of arbitrary size may fail to solve the problem. Third, defendit numerus: when the agent's problem-solving ability is adversely affected by the complexity of the solution space, the solution of the problem requires only a mild increase in the size of the team. Fourth, groupthink impairs the power of diversity: if agents' abilities are positively correlated, a larger team is necessary to solve the problem. This paper was accepted by Teck Ho, decision analysis.
From Wires to Partners: How the Internet Has Fostered R&D Collaborations Within Firms
Authors: Forman Chris , Zeebroeck Nicolas van 
Published: April 2012

How did the diffusion of the Internet influence research collaborations within firms? We examine the relationship between business use of basic Internet technology and the size and geographic composition of industrial research teams between 1992 and 1998. We find robust empirical evidence that basic Internet adoption is associated with an increased likelihood of collaborative patents from geographically dispersed teams. On the contrary, we find no evidence of such a link between Internet adoption and within-location collaborative patents, nor do we find any evidence of a relationship between basic Internet and single-inventor patents. We interpret these results as evidence that adoption of basic Internet significantly reduced the coordination costs of research teams, but find little evidence that a drop in the costs of shared resource access significantly improved research productivity. This paper was accepted by Lee Fleming, entrepreneurship and innovation.
First Successful Deployment of a Cost-Effective Chemical Plug to Stimulate Selectively Using CT in Saudi Arabia Gas Fields – A Case History
Authors: Al-Ghazal Mohammed , Abel Justin T. , Al-Saihati Ali , Buali Muhammad , Al-Ruwaished Azmi , Vielma Jose R. , Bustamante Ernesto 
Published: April 2012

Abstract
As the world's demand for natural gas hits new records, technology developers and researchers work interactively to provide new technologies that support gas production and supply. Among these technologies come isolation plugs: mechanical and chemical. Chemical plugs have two main advantages over mechanical plugs. First, chemical plugs enable more flexible movement for Coiled Tubing (CT). Second, chemical plugs are easier to remove once unneeded using acid.
Fluid systems used as diverters and temporary plugs in stimulation and work-over operations, are mostly polymer-based fluids that generate less damage to the formation and can hold higher differential pressures. The use of this technique has minimized the need for mechanical packers, bridge plugs and mechanical diversion techniques.
One application for chemical plugs is selective zonal stimulation, where a coiled tubing and chemical plug are used in multi¬zone gas wells to selectively stimulate zones of interest. This paper outlines the first, in Saudi Arabia Gas Fields, successful deployment of a chemical plug— using CT — to stimulate the lower interval while isolating the upper producing interval. In addition, the plug's key characteristics, optimum rate and amount are addressed.
Analysis of the post-treatment results, production rate and flowing wellhead pressure, demonstrated a very positive productivity.
Integrating Optimized Casing Exit and Solid Expandable Technologies: Bringing New Life to Dead Wells
Authors: Sanders Tom , Hogg Cliff , York Pat , Tompek Franz 
Published: April 2012

Abstract
Six recent well recompletions in Hassi Messaoud Field, Algeria utilized shallow angle casing exit technology in conjunction with solid expandable liner systems to optimize a workover campaign and revitalize an aging field. The operator in this field faced recompletion challenges such as existing well size constraints, reducing top-down drilling cost, and maximizing completion clearance while creating maximum reservoir contact (MRC) wells. The combination of shallow angle and expandable technology proved to be beneficial by reducing the dogleg severity (DLS) at the window exit, reducing the risk of expandable pipe damage across the window exit, and allowing the solid expandable liners to be run out the window and seal above the window. Once in place, these liners were cemented and expanded successfully in both the openhole and through the casing exit window.
In the past, casing exits resulted in significant size step downs for the resulting production liners. This in turn limited the completion options available, particularly for water shut-off. The development of solid expandable liner systems has significantly reduced such sizing limitations and provides greater size and flexibility, enabling the creation of larger laterals and optimum-sized completions. The ability to run expandable liners through a conventional casing exit window has been of some concern due to much higher DLS and possible damage to expandable pipe due to rugged window (if not properly milled and polished). This paper demonstrates that the integration of optimized casing exit and expandable liner technologies is a proven successful strategy for re-entry workover wells. This well enhancement strategy has successfully increased production in this field and others, facilitating the economical development of remaining oil reserves.
Stuck Pipe Best Practices – A Challenging Approach to Reducing Stuck Pipe Costs
Authors: Muqeem Muhammad A. , Weekse Alexander E. , Al-Hajji Ali A. 
Published: April 2012

Abstract
Stuck pipe incidents are one of the major operational challenges of the E&P industry and events usually lead to significant amount of lost time and associated costs. Various industry estimates claim that stuck pipe costs may exceed several hundred million US dollars per year. In Saudi Aramco, the recent increase in drilling activity, drilling in depleted and higher-risk reservoirs have led to an increased risk of stuck pipe. In 2010 Saudi Aramco formed a task force to focus on lowering its stuck pipe costs. In its campaign to reduce this cost, the task force selected key personnel from each of the Drilling & Workover (D&WO) operating departments.
This paper summarizes the result of the Stuck Pipe Teams’ findings and the best practice documents generated. For 2009, 69.5% of the total stuck pipes were due to mechanical sticking and 30.5% attributed to differential sticking. Furthermore, based on the team's findings, a customized training plan was formulated to certify key D&WO operations personnel every 2 years.
Development of Low Permeability Reservoir Utilizing Multi-stage Fracture Completion in the Minimum Stress Direction
Authors: Ahmed Mahbub , Rahim Zillur , Al-Anazi Hamoud , Al-Kanaan Adnan , Mohiuddin Mohammed 
Published: April 2012

Abstract
Saudi Aramco is developing several gas fields in the Eastern Province of Saudi Arabia by drilling horizontal wells in the Khuff and pre-Khuff tight carbonate and sandstone formations. To date, many wells have been drilled in the maximum horizontal stress direction with virtually no wellbore instability occurring during the drilling operation. When these wells are hydraulically fractured, the fracture grows along the wellbore in the direction of well azimuth. To avoid overlapping of two adjacent induced fractures and thereby communication between stages, only 2–3 multi-stage fracture treatments can be performed. Depending upon the length of wellbore-reservoir contact, reservoir development, and stress barriers, more than four fracture treatments can become redundant or even cause premature screen-out in proppant fracture treatments.
Wells drilled in the direction of minimum horizontal stress are potentially more favorable from the perspective of reservoir development and optimal production. In such a situation, hydraulic fractures grow transverse to the wellbore axis allowing multiple fractures to be placed without the possibility of fracture overlapping. Consequently, few wells that have been drilled in the minimum horizontal stress direction encountered several drilling-related problems, such as stuck pipe, breakouts, and breakdowns. A comprehensive study was conducted to overcome the wellbore stability issues and investigate feasibility of drilling wells in the minimum horizontal stress direction. Correct mud weight (MW) prediction is one key factor during the drilling stage to keep the wellbore stable and deliver good borehole geometry to run multi-stage fracturing assembly without complication. Multiple transverse hydraulic fractures easily created in such wellbore geometry maximize reservoir contact area and increase productivity of the low quality tight reservoir.
The key objectives of the study were to define a safe MW program for the horizontal section of the planned wells by conducting a wellbore stability study, and to determine a real-time strategy to mitigate and/or manage wellbore instability problems as they arise. The scope of work included root cause analysis of drilling events, development of Mechanical Earth Models (MEM) for offset wells, integrating sections of the mechanical earth model from the offset well to the planned well trajectory and a safe MW program for planned well.
Electrical Response of a Vuggy Rock Model at Different Frequencies
Authors: Pairoys F. , Al-Zoukani A. , Keskin A. , Akbar M. 
Published: April 2012

Abstract
In formation evaluation, resistivity logs are used to calculate the reservoir water saturation using the well known Archie's law. When high degree of heterogeneity exists, like when vuggy structures are present, the interpretation of electrical logs can be complex. In order to highlight the effect of a vug on a two-phase oil and water flow displacement, a laboratory apparatus was designed. The system employs the 4-contact electrode method to monitor the resistivity response of a rock slab during primary drainage and imbibition cycles. The effect of frequency on the saturation exponent n was also investigated.
Two rock slab models were cut from a strongly water-wet Indiana limestone block: one slab was left untouched while the other one was drilled at its center to simulate the presence of a cylindrical vug (vuggy model). Two transparent windows were placed at both ends of the vug to allow a direct visualization of the fluids distribution with a video camera. The resistivity change was monitored during primary drainage and imbibition cycles on both homogeneous (without hole) and vuggy models. Petrophysical properties of the rock matrix were measured on the homogeneous model (without hole) from the same block.
The visual cell was helpful in understanding the difference of flow behavior between primary drainage and imbibition on the vuggy model. A comparison between the electrical response of the homogeneous and vuggy rock models showed a difference between the two respective saturation exponents at constant frequency. The experimental setup also helped to study the dependence of Archie's saturation exponent n on frequency for the vuggy sample. Because resistivity tools operate at different frequencies (LWD versus wireline), this observation is crucial for the resistivity logs calibration and interpretation for heterogeneous oil reservoirs.
Well Optimization Strategies in Conventional Reservoirs
Authors: AlQahtani Ghazi , Vadapalli Ravi , Siddiqui Shameem , Bhattacharya Srimoyee 
Published: April 2012

Abstract
Well optimization is an important factor in field development strategies targeted to maximizing the hydrocarbon recovery, and economic feasibility of new field development projects. Particularly, in view of shortage in new oil field discoveries, maximizing oil production and net present value (NPV) have become critical factors (hereinafter called the "critical factors") in reservoir engineering. As a result, well optimization research has become a separate field in its own merit. Recent attempts by academic and industrial researchers converged on the goal to create efficient well optimization models that can predict strategies for managing the existing oil and gas fields and developing new fields with potential for maximizing the critical factors.
Important elements in field development optimization include well type, well placement and scheduling. In the last decade, significant amount of work has been done in the area of well optimization for which both gradient based and gradient-free optimization methods were used. In gradient-based well optimization methods, the derivative of the objective function with respect to the decision variables is sought. In gradient-free optimization, a family of algorithms classified as global or "stochastic" algorithms - such as the genetic algorithm, simulated annealing, and particle swarm optimization - can be employed. Other algorithms such as local or "deterministic" algorithms (e.g. Generalized Pattern Search, and Hook Jeeves Direct Search,) are also useful in these studies. These optimization strategies can be applied individually or as an ensemble of optimization methods to maximize the critical factors in reservoir simulation.
In this paper, we review several of the current optimization techniques, and their application to maximize the critical factors. In the process, we address the significance of different methods and highlight their limitations. We discuss as well the challenges associated in extending these methods, and their potential in the future.
Stuck-Pipe Prevention Solutions in Deep Gas Drilling; New Approaches
Authors: Guzman Julio M. , Khalil Mohamed E. , Orban Nicolas , Mohiuddin Mohammed Ahmed , Verma Jaywant , Ganda Sukesh 
Published: April 2012

Abstract
The primary cause of nonproductive time (NPT) incurred by Saudi Aramco in the deep gas drilling environment is stuck-pipe incidents. These incidents are mostly caused by hole cleaning, differential sticking, and wellbore stability issues.
To address the stuck-pipe incidents, the Saudi Aramco drilling engineering division and a service company together developed new procedures and techniques that proved to be efficient in stuck-pipe reduction.
Poor hole cleaning was identified as the main reason for stuck-pipe incidents. Procedures with compilation of best practices having reference to planning, drilling, tripping, and working tight spots were introduced. Torque & drag (T&D) simulation, along with equivalent circulating density (ECD) monitoring, was introduced as a road map to give a bigger picture and to give warning signs along the way.
In addition, past experiences showed that mud weight could significantly be reduced without gas flow occurring. This highlighted that, due to the complex nature of the reservoir, uncertainty existed in reservoir pressure estimation. Hence, it was recommended to run a formation-pressure-while-drilling service to better understand the formation pressure distribution. The idea was to measure, while drilling, the formation pressure of different layers, which would allow an optimal overbalance adjustment to mitigate the differential sticking risk.
Even though drilling in the direction of minimum horizontal stress leads to maximizing the propagation of fractures during the stimulation phase hence increasing production rates, it has also been observed that it leads to wellbore instability, which in turn causes stuck-pipe incidents. To address the stuck pipes in such situations, a technique was developed based on creation of mechanical earth models (MEM). This practice has helped to interpret the response of the wellbore by identifying hazards and to raise awareness of wellbore stability.
The services have been an innovative approach to mitigation of stuck-pipe incidents in deep gas drilling. The techniques are a way forward to reduce stuck-pipe incidents and hence lost-in-hole situations.
Environmentally Acceptable Emulsion System: An Effective Approach for Removal of Asphaltene Deposits
Authors: Salgaonkar Lalit , Danait Achala 
Published: April 2012

Abstract
Precipitation of asphaltene is a serious and common challenge faced by the oil industry during production of heavy oil. Regular treatments are often required to reinstate lost productivity by removal of such deposits from tubing or within the reservoir.
Hydrocarbon-based solvents, like xylene or xylene mixtures, are the most commonly used recipes for dissolution of deposited asphaltenes. While such treatments are effective, they sometimes present problems with respect to health, safety, and environmental (HSE) characteristics (lower flash points and the presence of benzene, ethyl benzene, toluene, or xylene (BETX) components), which can limit their use. Recently, water/solvent emulsion systems that offer significant advantages compared to traditional recipes have been used. The solvents used in these emulsions have relatively higher flash points, making them a safer alternative. Further, the redeposition process is delayed because the treated surfaces are left in a water-wet condition.
This paper describes the application of such water/solvent emulsion systems used to treat asphaltene deposits from two distinct regions of the eastern hemisphere. The steps taken to optimize a recipe suitable for dissolution of the asphaltene deposits are highlighted. This is extremely important to the design of a successful treatment because the complexity of the deposits vary regionally. Higher solubility values were obtained with the emulsion system when compared to xylene. Importantly, these emulsion systems could also be designed with acid as an aqueous phase. This increases the solubility values significantly because acid-soluble inorganic minerals were also found in conjunction with asphaltene in the deposits studied. The data presented demonstrates the applicability of the emulsion system for effective removal of asphaltene deposits and recovery of lost productivity. This environmentally acceptable emulsion system can contribute significantly to profitable and sustained production of heavy oil when faced with asphaltene challenges.
A Step Change in Fishing Efficiency: Recovering Stuck Pipe Using the Fishing Agitation Tool
Authors: Mohanna Assaad , Voghell Mark , Alali Aref , Bakir Rami , Al-Mousa Ahmad 
Published: April 2012

Abstract
One of the challenging and costly situations to overcome in modern day directional drilling applications is stuck bottom hole assemblies (BHAs) and other tubulars due to differential and/or mechanical sticking forces. Chances of recovery decay with time and conventional fishing BHAs are frequently unsuccessful. By incorporating axial-oscillation (agitation) technology, fishing reliability and effectiveness improve significantly. The Fishing Agitation Tool (FAT) is an excitation component of the fishing BHA used to deliver low impact high energy oscillation to the engaged fish. The FAT keeps the string in motion while breaking static sticking friction.
A series of pressure pulses are created by a high speed powersection and valve assembly built into the FAT, while pumping through the engaged fish. The pressure pulses act on a shock sub placed above the FAT, which turns the pulsation energy into mechanical oscillation. The axial movement travels down the fishing string to the stuck point in the form of micro-shocks, breaking static friction into dynamic motion.
After successful electric submersible pump (ESP) retrieval in Australia and casing pulling in Brazil, the FAT was used in Saudi Arabia for the first time to recover a differentially stuck BHA from 6 1/8 in (155 mm) hole in a deep high angle well. The initial application involved pipe that was stuck in hole for over 12 days without any movement, during which several conventional fishing BHAs were tried. The FAT was run in the final fishing BHA in conjunction with the stroking tools. The fish was free in less than an hour of axially oscillating and stroking on the stuck BHA.
The FAT offers a new level of fishing technology that maximizes the effect and reliability of fishing BHAs in challenging wellbore environments, where conventional fishing techniques are deemed insufficient. This increased efficiency offers substantial reduction in fishing lost time, and increased potential for fish and well recovery.