bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analyses of Wellbore Instability in Drilling Through Chemically Active Fractured-Rock Formations
Authors: Nguyen Vinh X. , Abousleiman Younane N. , Hoang Son K. 
Published: June 2009

Summary
Numerous time-dependent wellbore-instability problems have been reported while drilling through the chemically active fractured-shale formations in the Arabian Gulf. Very often, these shales are characterized by the abundance of not only macroscale bedding planes but also networks of microscale natural fractures. The presence of fractures weakens the shale mechanically and produces higher-permeability fluid-flow paths within the low-permeability rock formation. Because of different fluid-diffusion rates between the fractures and shale matrix, there are two distinct pore-pressure fields in saturated fractured shale. Additionally, in chemically active shale formations, osmotic pressure arises because of the imbalance in mud/shale chemical activity. Practically, it is extremely complex to isolate the fractures from the matrix for analysis or to identify fracture size and fracture density. However, a first-order approach in an attempt to understand the porous fractured-shale behavior is to use dual-porosity and dual-permeability theory of poromechanics in the analytical modeling. In this study, a poromechanical inclined-wellbore solution has been derived that incorporates time dependency, a primary porosity and permeability for the matrix, a secondary porosity and permeability for the fractures, and the chemical effect. The expressions for the stresses and pressure solutions are presented and detailed in Appendix A. These analytical solutions are used to simulate an inclined-wellbore-stability problem in a fractured-shale formation, accounting also for bedding planes in some instances in addition to the microfractures. Additionally, retrieved rock samples of fractured shale were tested by use of an innovative laboratory characterization device, the Inclined Direct Shear Testing Device (IDSTD) (PoroMechanics Institute; Norman, Oklahoma; 2008). This device tests tiny shale specimens (rock volume less than 0.14 in.3) and is capable of measuring cohesion and friction angle while the sample is subjected to in-situ stresses, varying mud pressures, and mud-circulation times.
A General Unstructured-Grid, Equation-of-State-Based, Fully Implicit Thermal Simulator for Complex Reservoir Processes
Authors: Liu K. , Subramanian G. , Dratler D. I. , Lebel J. P. , Yerian J. A. 
Published: June 2009

SummaryThis paper describes a general unstructured-grid, equation-ofstate-(EOS) based, fully implicit thermal simulator for complex reservoir processes. Under the unstructured grid framework, the simulator uses Newton's method to solve component material-balance equations, energy-balance equation, and volume-balance equation for component moles, energy, and pressure, where chemical reactions and external heat sources/sinks are treated in source terms. Because of the similarity among component material-balance equations and the energy-balance equation, energy is treated as a "component" to achieve a uniform formulation with common code for all simulations (black-oil, compositional, and thermal).The thermal simulator was validated using analytical models and other thermal simulators. The thermal simulator is used to study grid-orientation problems and to design and optimize Cold Lake heavy-oil development.
Inevitable Disappointment in Projects Selected on the Basis of Forecasts
Authors: Chen M. , Dyer J. 
Published: June 2009

Summary
Investors often select projects whose estimated performance measures meet or exceed a hurdle value. At the time of decision making, the true performance of a project is unknown but uncertain forecasts are available. Decision makers (DMs) often ignore the prediction errors when they use these forecasts to choose projects. To the disappointment of the DMs, many selected projects result in smaller actual yields than those that were forecasted.
Some have attributed the cause of this to the optimistic bias of the predictions. This paper shows that this disappointment can occur even if the prediction is unbiased. In this case, a bias can be introduced by the selection process that will allow more unattractive (overestimated) projects to be accepted than attractive (underestimated) ones. Although a similar phenomenon has been noted in statistics and finance research, it is not well understood in the context of project selection by DMs.
We present a solution method based on Bayesian updating and demonstrate its effectiveness in eliminating the disappointment in project selection with realistic data from oil exploration and production projects.
Current Mud Practices in Coastal Louisiana
Authors: Gill J.A. , Carnicom W.M. 
Published: June 2009

Abstract
Approximately 70% of the muds in use in coastal Louisiana are calcium treated, and the majority of these are of the recently introduced, more highly inhibited type. The terminology of inhibition is reviewed. Examples of South Louisiana well records and their mud costs are given for the different types of mud. A curve for flow properties vs. mud weight is presented. Centrifuge economics are discussed. Special muds, mud additives and techniques are described.
At the invitation of the Evangeline Section, Society of Petroleum Engineers of AIME, this paper was prepared to present a brief review of recent innovations and current mud practices along the Gulf Coast of Louisiana. The authors feel that the last two years have been significant ones for the drilling mud industry, in that mud costs have been drastically reduced and practical field muds and techniques have been developed which enable the drilling of deeper wells with less trouble than has heretofore been possible.

Mud Types Currently in Use
First in order of interest is a survey of the types of mud currently being used in South Louisiana (Table I).
As indicated statistically in the survey, the low pH red mud is the most economical type for drilling wells which do not require a heavily weighted mud or anticipate salt water contamination. The cost of chemicals for maintaining deflocculation of the mud is very low in the absence of inhibiting ions. The non-inhibited mud has little tolerance for solids, however, and the flow properties become costly to manage at mud densities in excess of 12.0 ppg. The wells which can be drilled in South Louisiana with this type of mud are in the minority.
At the time this survey was taken, 70% of the muds in use were calcium treated — either with lime, calcium chloride, gypsum, or seawater. These more or less inhibited muds have proven themselves very practical for Gulf Coast drilling, where good filtration and flow properties are required at heavy mud weights and in the presence of contaminants.
The Retrievable Valve Testing System Used in Well Evaluation and Completion Operations
Authors: Farley D.L. 
Published: June 2009

Abstract
The retrievable valve testing system has been developed for use with a retrievable multi-purpose packer to provide a means for obtaining a formation test and subsequently performing treating, squeeze cementing, perforating, or further testing operations without removing the tubing from the well. This technique permits the removal or the retrievable valve and pressure recording device from inside the tubing at the completion or the test, leaving an unobstructed opening through the string for further operations. The primary advantage or this system is realized in eliminating many or the usual round trips with the tubing between operations, thereby resulting in considerable saving or costly rig time.
There is a definite demand for this type or service and field results have been successful. On many jobs there have been various combinations or several operations performed on one or more formations with only one trip with the tubing. In some instances the same operations could not be duplicated by conventional means.
There are various techniques which have been developed in the three years or its use which increase the versatility or the system. The system has been successfully used in many areas and will eventually supplement conventional methods in many more areas or the oil industry.

Introduction
In every phase of the oil industry there has been continuous efforts to develop more economical methods for the recovery of oil. Particular attention has been given to reducing the time necessary for a drilling rig or workover rig to remain on the well location for well evaluation and completion operations.
Modern Logging Programs and Interpretation Methods
Authors: Alger R.P. 
Published: June 2009

Recent logging developments have provided more dependable data for reservoir evaluation. These new methods, which include both resistivity and porosity measuring devices, have now been adequately checked against older techniques, core analysis, and production results. Their responses with respect to varied borehole and formation conditions are sufficiently understood to permit the proper selection of logs for most efficient interpretation.
These devices, including the Induction Log (medium and deep), Laterolog, Proximity Log, Sonic Log, and Gamma-Gamma Density, have largely solved the problems of thin-bed resolution and borehole effects. All are essentially focused devices and have improved and predictable response where flushing or invasion is a problem. Their utility is such that any logging program today is likely to include one or several of them. when detailed reservoir information is required, where reservoir conditions are complex, and when wildcats or outposts are drilled the best available logging combination should be used.
The first and most important use of logs is to identify zones for testing or further evaluation. Although the discussion to follow presupposes that logs will provide complete information, it must be remembered that additional data, such as sidewall cores, conventional cores, drill-stem and wire-line formation tests, and cuttings, will assist in the final analysis.
The objectives of this paper are twofold: first, to discuss the new logs, briefly indicating where each fits in the several families of logging devices, and, second, to outline essential logging combinations or programs by mud and formation type.
The basic requirements of any logging program should be:Correlation -the program should include curves that may be reliably correlated with logs(sometimes old logs) from nearby wells. The SP, Short Normal, and Gamma Ray curves are normally used for this purpose. The Laterolog is often used in saltmuds. The Sonic Log can give unique correlations in carbonate reservoirs, evaporite sequences, or in lignite or coal.Depth control - the tops and bottoms of beds should be accurately defined.
Pad devices, such as the Microlog and Microlaterolog, pinpoint bed boundaries. 3. Net pay definition - the net thickness of the productive zones (the sand count) is required for recovery computations. The oldest, and still useful, method involves the SP. The modern combination of the Microlog with a caliper gives maximum efficiency.
Solution of a Typical Reservoir Problem on a Large Scale Computer
Authors: Warren J.E. , Mueller T.D. 
Published: June 2009

Introduction
High speed digital computing machines, in spite of their wide publicity as magic brains, can only add, subtract, multiply, and divide. With this in mind, considerable detailed mathematical analysis and planning work is required on a problem before the machine will perform its job. The purpose of this paper is to show how a typical reservoir problem is put in a form for solution on a high speed digital computer. The problem we have chosen for illustration is prediction of recovery and gas-oil-ratio trend of a solution gas-drive reservoir by the Muskat equation.
The process of obtaining solutions on a high speed computer may be divided into six specific steps:Formulation of the physical behavior to be studied into mathematical terms(construction of the mathematical model);Selection of a suitable mathematical technique for solving the equations governing behavior of the proposed mathematical model;Application of the selected mathematical technique to the model equations(developing a flow diagram which separates the total calculation into particular computing sequences and blocks of computation);Interpretation of the mathematical and logical operations into machine language (done for each computation block and is called coding or programming);Preparation of data needed in the calculation so that the computer can use the data (usually entails entering the data into paper cards or tape);Application of the computer program to a specific problem, listing of results, and verification of the machine program.
In the sections to follow, we plan to discuss each step as it applies to predicting the behavior of a solution gas drive reservoir using the Muskat equation.

Construction of the Mathematical Model
The physical mechanisms by which oil is produced from a reservoir are complex and even today not understood in their entirety. Thus, the engineer or mathematician whose job it is to construct a mathematical model of an oil reservoir is forced to make assumptions regarding the reservoir so as to reduce the problem to one he can formulate in mathematical terms. In addition, he must devise or choose his model so it will retain the particular features of reservoir behavior that he wishes to study.
Involvement of Per-Arnt-Sim Kinase and Extracellular-Regulated Kinases-1/2 in Palmitate Inhibition of Insulin Gene Expression in Pancreatic β-Cells
Authors: Fontés Ghislaine , Semache Meriem , Hagman Derek K. , Tremblay Caroline , Shah Ramila , Rhodes Christopher J. , Rutter Jared , Poitout Vincent 
Published: June 2009

OBJECTIVE
Prolonged exposure of pancreatic β-cells to simultaneously elevated levels of fatty acids and glucose (glucolipotoxicity) impairs insulin gene transcription. However, the intracellular signaling pathways mediating these effects are mostly unknown. This study aimed to ascertain the role of extracellular-regulated kinases (ERKs)1/2, protein kinase B (PKB), and Per-Arnt-Sim kinase (PASK) in palmitate inhibition of insulin gene expression in pancreatic β-cells.

RESEARCH DESIGN AND METHODS
MIN6 cells and isolated rat islets were cultured in the presence of elevated glucose, with or without palmitate or ceramide. ERK1/2 phosphorylation, PKB phosphorylation, and PASK expression were examined by immunoblotting and real-time PCR. The role of these kinases in insulin gene expression was assessed using pharmacological and molecular approaches.

RESULTS
Exposure of MIN6 cells and islets to elevated glucose induced ERK1/2 and PKB phosphorylation, which was further enhanced by palmitate. Inhibition of ERK1/2, but not of PKB, partially prevented the inhibition of insulin gene expression in the presence of palmitate or ceramide. Glucose-induced expression of PASK mRNA and protein levels was reduced in the presence of palmitate. Overexpression of wild-type PASK increased insulin and pancreatic duodenal homeobox-1 gene expression in MIN6 cells and rat islets incubated with glucose and palmitate, whereas overexpression of a kinase-dead PASK mutant in rat islets decreased expression of insulin and pancreatic duodenal homeobox-1 and increased C/EBPβ expression.

CONCLUSIONS
Both the PASK and ERK1/2 signaling pathways mediate palmitate inhibition of insulin gene expression. These findings identify PASK as a novel mediator of glucolipotoxicity on the insulin gene in pancreatic β-cells.
Islet-1 is Required for the Maturation, Proliferation, and Survival of the Endocrine Pancreas
Authors: Du Aiping , Hunter Chad S. , Murray Johanna , Noble Daniel , Cai Chen-Leng , Evans Sylvia M. , Stein Roland , May Catherine Lee 
Published: June 2009

OBJECTIVE
The generation of mature cell types during pancreatic development depends on the expression of many regulatory and signaling proteins. In this study, we tested the hypothesis that the transcriptional regulator Islet-1 (Isl-1), whose expression is first detected in the mesenchyme and epithelium of the developing pancreas and is later restricted to mature islet cells, is involved in the terminal differentiation of islet cells and maintenance of islet mass.

RESEARCH DESIGN AND METHODS
To investigate the role of Isl-1 in the pancreatic epithelium during the secondary transition, Isl-1 was conditionally and specifically deleted from embryonic day 13.5 onward using Cre/LoxP technology.

RESULTS
Isl-1–deficient endocrine precursors failed to mature into functional islet cells. The postnatal expansion of endocrine cell mass was impaired, and consequently Isl-1 deficient mice were diabetic. In addition, MafA, a potent regulator of the Insulin gene and β-cell function, was identified as a direct transcriptional target of Isl-1.

CONCLUSIONS
These results demonstrate the requirement for Isl-1 in the maturation, proliferation, and survival of the second wave of hormone-producing islet cells.
Activation of AMP-Activated Protein Kinase by Interleukin-6 in Rat Skeletal Muscle
Authors: Kelly Meghan , Gauthier Marie-Soleil , Saha Asish K. , Ruderman Neil B. 
Published: June 2009

OBJECTIVE
Interleukin-6 (IL-6) directly activates AMP-activated protein kinase (AMPK) in vivo and in vitro; however, the mechanism by which it does so is unknown.

RESEARCH DESIGN AND METHODS
We examined this question in skeletal muscle using an incubated rat extensor digitorum longus (EDL) muscle preparation as a tool.

RESULTS
AMPK activation by IL-6 coincided temporally with a nearly threefold increase in the AMP:ATP ratio in the EDL. The effects of IL-6 on both AMPK activity and energy state were inhibited by coincubation with propranolol, suggesting involvement of β-adrenergic signaling. In keeping with this notion, IL-6 concurrently induced a transient increase in cAMP, and its ability to activate AMPK was blocked by the adenyl cyclase inhibitor 2′5′-dideoxyadenosine. In addition, like other β-adrenergic stimuli, IL-6 increased glycogen breakdown and lipolysis in the EDL. Similar effects of IL-6 on AMPK, energy state, and cAMP content were observed in C2C12 myotubes and gastrocnemius muscle in vivo, indicating that they were not unique to the incubated EDL.

CONCLUSIONS
These studies demonstrate that IL-6 activates AMPK in skeletal muscle by increasing the concentration of cAMP and, secondarily, the AMP:ATP ratio. They also suggest that substantial increases in IL-6 concentrations, such as those that can result from its synthesis by muscles during exercise, may play a role in the mobilization of fuel stores within skeletal muscle as an added means of restoring energy balance.
Adipose Tissue Expression and Genetic Variants of the Bone Morphogenetic Protein Receptor 1A Gene (BMPR1A) Are Associated With Human Obesity
Authors: Böttcher Yvonne , Unbehauen Hanne , Klöting Nora , Ruschke Karen , Körner Antje , Schleinitz Dorit , Tönjes Anke , Enigk Beate , Wolf Sara , Dietrich Kerstin , Koriath Moritz , Scholz Gerhard Harry , Tseng Yu-Hua , Dietrich Arne , Schön Michael R. , Kiess Wieland , Stumvoll Michael , Blüher Matthias , Kovacs Peter 
Published: June 2009

OBJECTIVE
Members of the family of bone morphogenetic proteins (BMPs) are important regulators of adipogenesis. We examined the role of the BMP receptor 1A gene (BMPR1A) in the pathophysiology of human obesity.

RESEARCH DESIGN AND METHODS
We measured BMPR1A mRNA expression in paired samples of visceral and subcutaneous adipose tissue from 297 subjects and sequenced the BMPR1A in 48 nonrelated white subjects. Twenty-one representative variants including HapMap tagging single nucleotide polymorphisms (SNPs) were then genotyped for association studies in German whites (n = 1,907). For replication analyses, we used a population of Sorbs from Germany (n = 900) and German childhood cohorts (n = 1,029 schoolchildren and 270 obese children).

RESULTS
mRNA expression of the BMPR1A was significantly increased in both visceral and subcutaneous adipose tissue of overweight and obese subjects compared with lean subjects (P &lt; 0.05). In a case-control study, four SNPs (rs7095025, rs11202222, rs10788528, and rs7922846) were nominally associated with obesity (adjusted P &lt; 0.05). For three SNPs (rs7095025, rs11202222, and rs10788528), the association with obesity was confirmed in the independent cohort of Sorbs (adjusted P &lt; 0.005). Consistent with this, BMPR1A SNPs were nominally associated with obesity-related quantitative traits in nondiabetic subjects in both adult cohorts. Furthermore, homozygous carriers of the obesity risk alleles had higher BMPR1A mRNA expression in fat than noncarriers.

CONCLUSIONS
Our data suggest that genetic variation in the BMPR1A may play a role in the pathophysiology of human obesity, possibly mediated through effects on mRNA expression.
Insulin and Metformin Regulate Circulating and Adipose Tissue Chemerin
Authors: Tan Bee K. , Chen Jing , Farhatullah Syed , Adya Raghu , Kaur Jaspreet , Heutling Dennis , Lewandowski Krzysztof C. , O'Hare J. Paul , Lehnert Hendrik , Randeva Harpal S. 
Published: June 2009

OBJECTIVE
To assess chemerin levels and regulation in sera and adipose tissue from women with polycystic ovary syndrome (PCOS) and matched control subjects.

RESEARCH DESIGN AND METHODS
Real-time RT-PCR and Western blotting were used to assess mRNA and protein expression of chemerin. Serum chemerin was measured by enzyme-linked immunosorbent assay. We investigated the in vivo effects of insulin on serum chemerin levels via a prolonged insulin-glucose infusion. Ex vivo effects of insulin, metformin, and steroid hormones on adipose tissue chemerin protein production and secretion into conditioned media were assessed by Western blotting and enzyme-linked immunosorbent assay, respectively.

RESULTS
Serum chemerin, subcutaneous, and omental adipose tissue chemerin were significantly higher in women with PCOS (n = 14; P &lt; 0.05, P &lt; 0.01). Hyperinsulinemic induction in human subjects significantly increased serum chemerin levels (n = 6; P &lt; 0.05, P &lt; 0.01). In adipose tissue explants, insulin significantly increased (n = 6; P &lt; 0.05, P &lt; 0.01) whereas metformin significantly decreased (n = 6; P &lt; 0.05, P &lt; 0.01) chemerin protein production and secretion into conditioned media, respectively. After 6 months of metformin treatment, there was a significant decrease in serum chemerin (n = 21; P &lt; 0.01). Importantly, changes in homeostasis model assessment–insulin resistance were predictive of changes in serum chemerin (P = 0.046).

CONCLUSIONS
Serum and adipose tissue chemerin levels are increased in women with PCOS and are upregulated by insulin. Metformin treatment decreases serum chemerin in these women.