bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery amid Destruction: Manoel da Maya and the Lisbon Earthquake of 1755
Authors: Rodrigues Lúcia Lima , Craig Russell
Published: November 2008

Amid the losses of library and archival records that were sustained in the Lisbon earthquake of 1755, the director-general of the national archive of Portugal, Manoel da Maya, played an inspirational role in salvage and preservation efforts. Maya’s determination, dedication, and resourcefulness in the aftermath of the earthquake were exemplary and in the best traditions of practice as an archivist.
A Library for Engineering Education: Frank O. Marvin and the University of Kansas, 1875–1915
Authors: Neeley James D.
Published: November 2008

This article investigates the influence of developments in engineering education on the establishment of departmental libraries for engineering in late-nineteenth-and early-twentieth-century American universities. A case study is made of the University of Kansas and Frank O. Marvin, a former president of the Society for the Promotion of Engineering Education and dean of the university’s School of Engineering when its library opened in 1909. While national forces spanning the profession supplied the necessary preconditions for Kansas’s library, Marvin was the local catalyst. His beliefs about what attributes the successful engineer should possess and how a liberal education could produce those attributes made the library inevitable.
Reminiscences of Mexico: A Conversation with Richard Greenleaf
Authors: Schwaller John F.
Published: November 2008

Dr. Richard Greenleaf has been one of the most influential historians of colonial Latin America in general, and of the Inquisition in particular. He received his university and graduate education in his home state at the University of New Mexico. His professional career took him to Mexico City during the exciting period of the 1950s and 1960s. From there he went on to be one of the guiding forces in the consolidation of the Latin American Studies program at Tulane University. This interview was conducted in the summer of 2007 at Dr. Greenleaf's residence in Albuquerque.
Importing Freud and Lamarck to the Tropics: Arthur Ramos and the Transformation of Brazilian Racial Thought, 1926-1939
Authors: Lange Brad
Published: November 2008

If, in the work of Nina Rodrigues, we substitute the terms culture for race, and acculturation formestiçamento, for example, his concepts acquire complete and perfect modernity.

—Arthur Ramos, 1939

Popular legend suggests that a mysterious curse fated Nina Rodrigues’ death in 1906. Though a pioneer of Afro-Brazilian studies, he posited that Afro-descendants possessed a genetic atavism predisposing them to crime and argued that widespread racial miscegenation had contributed to the fin-de-siècle “negro problem” in Brazil. Almost four decades following his death, the curse was reborn, striking Arthur Ramos shortly after he had revived the stagnant field of Afro-Brazilian studies using a modified version of Rodrigues’ methodology. Both Brazilian men died in Paris in their midforties, just as they were reaching the summit of their respective careers.
“A Stalwart Motor of Revolutions”: An American Merchant in Pernambuco, 1817-1825
Authors: Fitz Caitlin A.
Published: November 2008

A new order for the New World was unfolding in the early nineteenth century, or so many in the United States believed. Between 1808 and 1825, all of Portuguese America and nearly all of Spanish America broke away from Europe, casting off Old World monarchs and inaugurating home-grown governments instead. People throughout the United States looked on with excitement, as the new order seemed at once to vindicate their own revolution as well as offer new possibilities for future progress. Free from obsolete European alliances, they hoped, the entire hemisphere could now rally together around republican government and commercial reciprocity. Statesmen and politicians were no exception, as men from Thomas Jefferson and James Monroe to John Quincy Adams and Henry Clay tried to exclude European influence from the hemisphere while securing new markets for American manufactures and agricultural surplus.
2008 CLAH Luncheon Address: Dos Palabras on Mexican Shrines and Contagiousness of the Sacred
Authors: Taylor William B.
Published: November 2008

I am touched and surprised by this recognition, from colleagues who don’t know me personally, as well as from friends in the profession who must have written on my behalf. I like Bill Russell’s idea that a good way of leading is to serve. I have looked for ways to serve, but they have mostly been out of public view. In that spirit I want to acknowledge especially John TePaske who died a few weeks ago—a colleague I’ve looked up to from the beginning as a wonderful example of integrity, generosity, and wisdom.
Navigating Identities: The Case of a Morisco Slave in Seventeenth-Century New Spain
Authors: Cook Karoline P.
Published: November 2008

In 1660 Cristóbal de la Cruz presented himself before the commissioner of the Holy Office of the Inquisition in Veracruz, Mexico, claiming to be afflicted by doubts about the Catholic faith. Born in Algiers and captured at the age of nine or ten by a Spanish galley force, he was taken to Spain, where he was quickly sold into slavery and baptized. Thirty years later, De la Cruz denounced himself to the Mexican inquisitorial tribunal and proceeded to recount to the inquisitors a detailed and fascinating story of his life as he crossed Iberian and Mediterranean landscapes: escaping from his masters and being re-enslaved, encountering Muslims and renouncing Christianity, denouncing his guilt remorsefully before the Inquisitions of Barcelona and Seville, and moving between belief in Catholicism and Islam. His case provides important insights into the relationship between religious identity and the regulatory efforts of powerful institutions in the early modern Spanish world.
Preparing Test Specimens Using Undercompaction
Authors: Ladd RS
Published: November 2008

A specimen preparation procedure is presented that offers an improved method of preparing reconstituted sand specimens for cyclic triaxial testing. The method leads to more consistent and repeatable test results. This procedure (1) minimizes particle segregation, (2) can be used for compacting most types of sands having a wide range in relative densities, and (3) permits determination of the optimum cyclic strength of a given sand at a given dry unit weight.
Railroad Ballast Density Measurement
Authors: Yoo TS , Chen HM , Selig ET
Published: November 2008

Because existing methods were unsuitable for measuring the in-situ density of railroad ballast, studies were conducted to develop a new technique. A laboratory investigation was made of the various factors affecting the measurement of density in railroad ballast, which typically is composed of open-graded and coarse-grained aggregates. An approach employing water replacement in a lined hole was selected for extensive evaluation. Based on the laboratory results, a new apparatus has been devised and test procedures have been developed which subsequently have been successfully applied in the field at various railroad sites. This paper summarizes the research involved in the development of the density-measurement method. The details of the apparatus and procedures are provided in appendixes to the paper. The field tests confirmed the suitability of the method and provided new information on the physical state of ballast. The proposed new method is not limited to use with ballast but is also applicable to most other soil and aggregate materials.
Self‐Esteem and Suicide Ideation in Psychiatric Outpatients
Authors: Bhar Sunil , Ghahramanlou‐Holloway Marjan , Brown Gregory , Beck Aaron T.
Published: November 2008

Depression, hopelessness, and low self‐esteem are implicated as vulnerability factors for suicide ideation. The association of self‐esteem with suicide ideation after controlling for depressed mood and hopelessness was examined. Adult psychiatric outpatients (N = 338) completed measures of self‐esteem, suicide ideation, hopelessness, and depression. Self‐esteem was operationalized as beliefs about oneself (self‐based self‐esteem) and beliefs about how other people regard oneself (other‐based self‐esteem). Each dimension of self‐esteem was negatively associated with suicide ideation after controlling for depression and hopelessness. Of the two dimensions of self‐esteem, other‐based self‐esteem was the more robust predictor of suicide ideation. These findings suggest that even in the context of depression and hopelessness, low self‐esteem may add to the risk for suicide ideation.
A Systematic Review of the Relationship Between Rumination and Suicidality
Authors: Morrison Rebecca , O'Connor Rory C.
Published: November 2008

Rumination has been persistently implicated in the etiology of hopelessness and depression, which are proximal predictors of suicidality. As a result, researchers have started to examine the role of rumination in suicidality. This systematic review provides a concise synopsis of the current progress in examining the relationship between rumination and suicidality, and highlights areas for future research. A search of the international literature was conducted using the three main psychological and medical databases. Eleven studies were identified providing evidence, with one exception, of a relationship between rumination and suicidality. This review also highlights the considerable dearth of studies on this area of concern, specifically of case‐control and prospective, clinical studies, in the worldwide literature.
Changes in Reporting of Suicide News After the Promotion of the WHO Media Recommendations
Authors: Fu K. W. , Yip P.S.F.
Published: November 2008

Media recommendations on suicide reporting are available in many countries and in different languages. Hong Kong newspapers have been found to be noncompliant with WHO recommendations. A booklet containing WHO media guidelines Preventing Suicide: A Resource for Media Professionals, and an awareness campaign were launched in November 2004 in Hong Kong. Content analysis was then conducted to compare the reporting of suicide news before and after the launch. Results indicate that certain reporting styles were changed in accordance with the recommendations; namely, lessened use of pictorial presentations and headlines mentioning suicides. Most of the changes were attributed to the tabloid‐style newspapers. This study suggests that programs to promote media recommendations tailored for journalists appear to be efficacious in altering their way of reporting.
The Activity-Regulated Cytoskeletal-Associated Protein (Arc/Arg3.1) Is Required for Memory Consolidation of Pavlovian Fear Conditioning in the Lateral Amygdala
Authors: Ploski Jonathan E. , Pierre Vicki J. , Smucny Jason , Park Kevin , Monsey Melissa S. , Overeem Kathie A. , Schafe Glenn E.
Published: November 2008

The activity-regulated cytoskeletal-associated protein (Arc/Arg3.1) is an immediate early gene that has been widely implicated in hippocampal-dependent learning and memory and is believed to play an integral role in synapse-specific plasticity. Here, we examined the role of Arc/Arg3.1 in amygdala-dependent Pavlovian fear conditioning. We first examined the regulation of Arc/Arg3.1 mRNA and protein after fear conditioning and LTP-inducing stimulation of thalamic inputs to the lateral amygdala (LA). Quantitative real-time PCR,in situhybridization, Western blotting and immunohistochemistry revealed a significant upregulation of Arc/Arg3.1 mRNA and protein in the LA relative to controls. In behavioral experiments, intra-LA infusion of an Arc/Arg3.1 antisense oligodeoxynucleotide (ODN) was observed to be anatomically restricted to the LA, taken up by LA cells, and to promote significant knockdown of Arc/Arg3.1 protein. Rats given intra-LA infusions of multiple doses of the Arc/Arg3.1 ODN showed an impairment of LTM (tested ∼24 later), but no deficit in STM (tested 3 h later) relative to controls infused with scrambled ODN. Finally, to determine whether upregulation of Arc/Arg3.1 occurs downstream of ERK/MAPK activation, we examined Arc/Arg3.1 expression in rats given intra-LA infusion of the MEK inhibitor U0126. Relative to vehicle controls, infusion of U0126 impaired training-induced increases in Arc/Arg3.1 expression. These findings suggest that Arc/Arg3.1 expression in the amygdala is required for fear memory consolidation, and further suggest that Arc/Arg3.1 regulation in the LA is downstream of the ERK/MAPK signaling pathway.
Transplanted Mouse Embryonic Stem-Cell-Derived Motoneurons Form Functional Motor Units and Reduce Muscle Atrophy
Authors: Yohn Damien C. , Miles Gareth B. , Rafuse Victor F. , Brownstone Robert M.
Published: November 2008

Prolonged muscle denervation resulting from motor neuron (MN) damage leads to atrophy and degeneration of neuromuscular junctions (NMJs), which can impart irreversible damage. In this study, we ask whether transplanted embryonic stem (ES) cells differentiated into MNs can form functional synapses with host muscle, and if so what effects do they have on the muscle. After transplantation into transected tibial nerves of adult mice, ES-cell-derived MNs formed functional synapses with denervated host muscle, which resulted in the ability to produce average tetanic forces of 44% of nonlesioned controls. ES-cell-derived motor units (MUs) had mean force values and ranges similar to control muscles. The number of type I fibers and fatigue resistance of the MUs were increased, and denervation-associated muscle atrophy was significantly reduced. These results demonstrate the capacity for ES-cell-derived MNs not only to incorporate into the adult host tissue, but also to exert changes in the target tissue. By providing the signals normally active during embryonic development and placing the cells in an environment with their target tissue, ES cells differentiate into MNs that give rise to functional MU output which resembles the MU output of endogenous MNs. This suggests that these signals combined with those present in the graft environment, lead to the activation of a program intended to produce a normal range of MU forces.
Tonic GABAergic Inhibition of Sympathetic Preganglionic Neurons: A Novel Substrate for Sympathetic Control
Authors: Wang LiHua , Spary Emma , Deuchars Jim , Deuchars Susan A.
Published: November 2008

The sympathetic tone is primarily defined by the level of activity of the sympathetic preganglionic neurons. We report a novel inhibitory influence on sympathetic activity, that of tonic GABAergic inhibition which could have a profound global effect on sympathetic outflow. Recording from identified SPNs in the intermediolateral cell column (IML) of rat spinal cord slices, application of the GABA receptor antagonist bicuculline, but not gabazine, elicited a change in voltage that lasted for the duration of application. This response was mediated by a direct effect on SPNs since it persisted in tetrodotoxin and low Ca2+/high Mg2+and the amplitude of responses were related to Cl−concentration in patch solutions. Such tonic inhibitory responses were not observed in interneurons, the other neuronal type in the IML, although ongoing IPSPs were antagonized in these neurons. The effects of bicuculline were enhanced by diazepam but not zolpidem or the GABA modulators THIP and THDOC suggesting a role for α5 subunits. PCR using primers for the α5 and δ subunits indicated the presence of α5, but not δ subunits in the IML. Firing rates of SPNs were enhanced by bicuculline and decreased by diazepam indicating that this tonic inhibition has a profound effect on the excitability of SPNs. These data indicate a novel influence for controlling the activity of SPNs regardless of their function.
Rats Harboring S284LChrna4Mutation Show Attenuation of Synaptic and Extrasynaptic GABAergic Transmission and Exhibit the Nocturnal Frontal Lobe Epilepsy Phenotype
Authors: Zhu Gang , Okada Motohiro , Yoshida Shukuko , Ueno Shinya , Mori Fumiaki , Takahara Tomoko , Saito Ryo , Miura Yoshiki , Kishi Akihiro , Tomiyama Masahiko , Sato Akira , Kojima Toshio , Fukuma Goryu , Wakabayashi Koichi , Hase Koji , Ohno Hiroshi , Kijima Hiroshi , Takano Yukio , Mitsudome Akihisa , Kaneko Sunao , Hirose Shinichi
Published: November 2008

Mutations of genes encoding α4, β2, or α2 subunits (CHRNA4,CHRNB2, orCHRNA2, respectively) of nAChR [neuronal nicotinic ACh (acetylcholine) receptor] cause nocturnal frontal lobe epilepsy (NFLE) in human. NFLE-related seizures are seen exclusively during sleep and are characterized by three distinct seizure phenotypes: “paroxysmal arousals,” “paroxysmal dystonia,” and “episodic wandering.” We generated transgenic rat strains that harbor a missense mutation S284L, which had been identified inCHRNA4in NFLE. The transgenic rats were free of biological abnormalities, such as dysmorphology in the CNS, and behavioral abnormalities. The mRNA level of the transgene (mutantChrna4) was similar to the wild type, and no distorted expression was detected in the brain. However, the transgenic rats showed epileptic seizure phenotypes during slow-wave sleep (SWS) similar to those in NFLE exhibiting three characteristic seizure phenotypes and thus fulfilled the diagnostic criteria of human NFLE. The therapeutic response of these rats to conventional antiepileptic drugs also resembled that of NFLE patients with the S284L mutation. The rats exhibited two major abnormalities in neurotransmission: (1) attenuation of synaptic and extrasynaptic GABAergic transmission and (2) abnormal glutamate release during SWS. The currently available genetically engineered animal models of epilepsy are limited to mice; thus, our transgenic rats offer another dimension to the epilepsy research field.
Behavioral Detectability of Single-Cell Stimulation in the Ventral Posterior Medial Nucleus of the Thalamus
Authors: Voigt Birgit C. , Brecht Michael , Houweling Arthur R.
Published: November 2008

In mammals, most sensory information passes through the thalamus before reaching cortex. In the rat whisker system, each macrovibrissa is represented by ∼250 neurons in the ventral posterior medial nucleus (VPM) of the thalamus and ∼10,000 neurons in a cortical barrel column. Here we quantify the sensory impact of individual thalamic neurons in the rat VPM. We first trained animals to report microstimulation of VPM. All animals learned to report microstimulation currents of 2–5 μA. We then evoked action potentials (APs) in single thalamic neurons close to the microstimulation site using juxtacellular stimulation, adding on average 17.8 APs to 2.6 spontaneous APs during 200 ms current applications. A population analysis revealed that animals responded equally often in single-cell stimulation trials as in catch trials without stimulation, suggesting that APs of single thalamic cells in VPM lead to either no or only a very weak perceptual effect. These results are surprising given the relatively small number of VPM neurons and our previous observations that single neurons in other parts of the vibrissal system do have an impact on perception or motor output. Our findings therefore suggest that neural representations in whisker thalamus are more distributed than in other whisker-related structures.
Neural Analog of Arousal: Persistent Conditional Activation of a Feeding Modulator by Serotonergic Initiators of Locomotion
Authors: Jing Jian , Vilim Ferdinand S. , Cropper Elizabeth C. , Weiss Klaudiusz R.
Published: November 2008

We investigated how a neural analog of a form of arousal induced by a mildly noxious stimulus can promote two antagonistic responses, locomotion and feeding. Two pairs of cerebral serotonergic interneurons inAplysia, CC9 and CC10, were persistently activated by transient noxious stimuli. Direct stimulation of CC9–10 activated locomotor activity that outlasted the stimulation and enhanced subsequent nerve-evoked locomotor programs. Thus, CC9–10 function both as initiators and as modulators of the locomotor network. CC9–10 also interacted with the feeding circuit but in a fundamentally different manner. CC9–10 did not directly trigger feeding activity or activate feeding command or pattern generating interneurons. CC9–10 did, however, elicit slow EPSPs in serotonergic cells that modulate feeding responses, the metacerebral cells (MCCs). CC9–10 persistently enhanced MCC excitability, but did not activate the MCCs directly. Previous work has demonstrated that the MCCs are activated during food ingestion via a sensory neuron C2. Interestingly, we found that CC9–10 stimulation converted subthreshold C2 mediated excitation of the MCC into suprathreshold excitation. Transient noxious stimuli also enhanced MCC excitability, and this was largely mediated by CC9–10. To summarize, CC9–10 exert actions on the feeding network, but their functional effects appear to be conditional on the presence of food-related inputs to the MCCs. A potential advantage of this arrangement is that it may prevent conflicting responses from being directly evoked by noxious stimuli while also facilitating the ability of food-related stimuli to generate feeding responses in the aftermath of noxious stimulation.
La racaille
Authors: Tetreault Chantal
Published: November 2008

Dominant French discourses stigmatize la racaille (‘male street toughs’) in a national moral panic about cités (‘subsidized housing projects’). This paper examines how these discourses influence everyday talk and experiences of public space in Chemin de l’Ile, a cité west of Paris. In both national and local discourses, la racaille symbolizes stigmatized public spaces, particularly la rue (‘the street’). However, inhabitants in Chemin de l’Ile mobilize the symbol of la racaille to evoke a set of moralizing discourses that are inflected with cultural, gendered, and generational prescriptions. Specifically, la racaille is constructed as morally threatening to culturally respectful spaces, such as Muslim weddings, and the respect of certain persons including adolescent girls. Adolescent girls’ own perspectives are analyzed to show that through narratives about la racaille they elaborate and resist normative prescriptions for gendered uses of public space in their cité.
Complement C5a receptors in the pituitary gland: expression and function
Authors: Francis Karen , Lewis B Mary , Monk Peter N , Ham Jack
Published: November 2008

Communication between the immune and endocrine system is important for the control of inflammation that is primarily mediated through the hypothalamic–pituitary–adrenal axis. The innate immune system rapidly responds to pathogens by releasing complement proteins that include the anaphylatoxins C3a and C5a. We previously reported the existence of C3a receptors in the anterior pituitary gland and now describe the presence of C5a receptors in the gland. C5a and its less active derivative (C5adR) can bind to its own receptor and to another receptor called C5L2. Using RT-PCR and immunocytochemistry, C5a receptors and C5L2 were demonstrated in the rat anterior pituitary gland and in several rodent anterior pituitary cell lines. Western blotting analysis showed that C5a stimulated the phosphorylation of MAPK and AKT but not p38; C5adR on the other hand, had no effect on any of the signal molecules investigated. The effects of C5a and C5adR on the secretion of the inflammatory molecule, macrophage migration inhibitory factor (MIF) were investigated by ELISA. Both compounds showed a dose-dependent inhibition of MIF release, 30–40% inhibition at around 35–70 nM agonist with IC50 values of around 20 nM. C5a and C5adR also stimulated ACTH secretion (up to 25%) from AtT-20DV16 cells. These data show that functional C5a receptors (C5a and C5L2) are present in the anterior pituitary gland and they may play a role in dampening down inflammation by inhibiting the release of MIF and stimulating the release of ACTH.
Air Injection and Waterflood Performance Comparison of Two Adjacent Units in the Buffalo Field
Authors: Kumar V. K. , Gutiérrez D. , Moore R. G. , Mehta S. A.
Published: November 2008

Buffalo field covers a large area on the southwestern flank of the Williston basin, in the northwest corner of South Dakota. In 1987, 8,000 acres of the field were divided into two units to initiate improved-oil-recovery (IOR) operations with two different methods: air injection and waterflooding. After collecting 19 years of production history, a technical and economic comparison has been made between the two projects to determine the relative success of both units.

The technical performance was evaluated in terms of incremental oil recovery, ultimate recovery, and incremental recovery per volumes of fluid injected. Ultimate primary recovery was estimated using conventional decline-curve analysis on individual wells. Ultimate recovery was estimated by extrapolation of the current performance of the units, assuming the same actual development scheme and operating strategies.

The economic comparison was performed in terms of net present value (NPV), incremental rate of return, and payout time. A sensitivity analysis on some of the key drivers of the project economics—specifically, oil price, operating cost, and capital investment—was also performed.

Throughout the years, the west Buffalo Red River unit (WBRRU) under high-pressure air injection (HPAI) has technically outperformed its "twin," west Buffalo "B" Red River unit (WBBRRU), which is under waterflooding. Nevertheless, the waterflood project has shown greater economic benefit, which results primarily from the low oil prices (less than USD 20/bbl) experienced during most of their operating lives.

This case study shows that for an air-injection project to be successful not only technically but also economically, a sufficiently high oil price (i.e., greater than USD 25/bbl) is needed, mainly because of the high operating costs and capital investment.
Computation of Sand Production in Water Injectors
Authors: Vaziri Hans H. , Nouri Alireza , Hovem Knut Arne , Wang Xiuli
Published: November 2008

A significant proportion of future oil production is expected to be driven by water injectors in reservoirs that are sand prone. Achieving sweep efficiency and sand control in such formations is challenging. In many cases, the ideal sand control is no sand control [e.g., a cased-and-perforated (C&P) completion] that requires rigorous sanding assessment. Sand production in injectors often goes unnoticed until it is too late (sand covering the pay), making it difficult to ascertain the specific set of conditions resulting in sanding and the severity of the individual sanding episodes. On the basis of physics and mechanisms governing sanding, general non-quantitative factors can be postulated on the causes of sanding. To provide a deeper insight into this matter, a numerical study has been undertaken to model sanding in injectors, accounting for several intercoupled factors, including, among others, injection pressure, crossflow, water hammer (WH) pressure pulses, and degradation of the formation matrix resulting from repeated shutdowns.

This paper describes the concepts used for sand-production modeling and shows application of the model to a field problem involving a C&P completion in a sand-prone reservoir. The results show that the mode and magnitude of sanding are influenced by the rock properties, injection operations, and the equipment type and installation. The cases analyzed indicate a correspondence between the rate of shut-in and the onset of sanding. In cases involving unconsolidated sands, the WH effects have a pronounced impact on sanding. Sand control can be omitted in even extremely weak rocks if the injection pressure is optimized, frequency of hard shutdowns is controlled, and hardware is positioned in a manner that reduces the WH-pressure-pulse magnitude. The proposed modeling can be used when determining the sand-sump capacity required over the projected life of the well.
Productivity and Drainage Area of Fractured Horizontal Wells in Tight Gas Reservoirs
Authors: Medeiros F. , Ozkan E. , Kazemi H.
Published: November 2008

This paper discusses the performance and productivity of fractured horizontal wells in heterogeneous, tight-gas formations. Production characteristics and flow regimes of unfractured and fractured horizontal wells are documented. The results show that if hydraulic fracturing affects stress distribution to create or rejuvenate natural fractures around the well, the productivity of the system is significantly increased. Unless there is significant contrast between the conductivities of the hydraulic and natural fractures, hydraulic fractures may not significantly contribute to the productivity. For extremely tight formations, the effective drainage area may be limited to the naturally fractured region around the well and the hydraulic fractures. It is also shown that very long transient flow periods govern the productivity and economics of fractured horizontal wells in tight formations. The results of this study are also applicable to oil production from fractured shale.
Stabilized Well Productivity in Double-Porosity Reservoirs
Authors: Hagoort Jacques
Published: November 2008

In this work, we present a simple1 analytical formula for the stabilized productivity index (PI) of an arbitrary well in an arbitrary closed, naturally fractured reservoir that can be modeled as a double-porosity reservoir. The formula relates the PI to the PI of a well in a single-porosity reservoir with permeability equal to the effective fracture permeability of the double-porosity reservoir. We have elaborated this formula for a vertical and a horizontal well in a rectangular reservoir made up of orthogonal matrix blocks. It appears that the double-porosity characteristics, along with reservoir flow capacity and reservoir volume, combine into a single factor, which plays the same role as the familiar skin factor. For small values of this double-porosity skin, well productivity is dominated by fracture permeability; for large values, the controlling parameter is matrix permeability. Inflow-performance relationship (IPR) curves of wells in double-porosity gas reservoirs can be created readily with the help of the new PI formula. An example is included showing the production profiles of a vertical and a horizontal well in a double-porosity gas reservoir with cubes and square pillars as matrix blocks. The results of this work are particularly relevant for the reservoir engineering of naturally fractured gas reservoirs.
What is Stimulated Reservoir Volume (SRV)?
Authors: Mayerhofer M. J. , Lolon E. P. , Warpinski N. R. , Cipolla C. L. , Walser D. , Rightmire C. M.
Published: November 2008

Ultra-low permeability shale reservoirs require a large fracture network to maximize well performance. Microseismic fracture mapping has shown that large fracture networks can be generated in many shale reservoirs. In conventional reservoirs and tight gas sands, single-plane fracture half-length and conductivity are the key drivers for stimulation performance. In shale reservoirs, where complex network structures in multiple planes are created, the concept of a single fracture half-length and conductivity are insufficient to describe stimulation performance. This is the reason for the concept of using stimulated reservoir volume as a correlation parameter for well performance. The size of the created fracture network can be approximated as the 3-D volume (Stimulated Reservoir Volume or SRV) of the microseismic event cloud. This paper briefly illustrates how the Stimulated Reservoir Volume (SRV) can be estimated from microseismic mapping data and is then related to total injected fluid volume and well performance. While the effectively producing network could be smaller by some proportion, it is assumed that created and effective network are directly related. However, SRV is not the only driver of well performance. Fracture spacing and conductivity within a given SRV are just as important and this paper illustrates how both SRV and fracture spacing for a given conductivity can affect production acceleration and ultimate recovery. The effect of fracture conductivity is discussed separately in a series of companion papers. Simulated production data is then compared with actual field results to demonstrate variability in well performance and how this concept can be used to improve completion design, and well spacing and placement strategies.
Workflow for Stratigraphic Characterization of Unconventional Gas Shales
Authors: Slatt Roger M. , Singh Prerna , Philp R. Paul , Marfurt K. J. , Abousleiman Y. , O'Brien N. R.
Published: November 2008

Because of their fine-grained nature, shales exhibit substantially different reservoir properties than more conventional sandstone and carbonate reservoirs. New ideas and modified methods of reservoir characterization are required to reduce uncertainty in measuring volumetrics, drilling and stimulating a well, and gaining efficient production.

Over the past few years, our studies of unconventional gas shales in the U.S. mid-continent have led to establishing a workflow for stratigraphic characterization that addresses key issues in these unusual reservoirs. Proper characterization is multidisciplinary in nature. It includes (1) characterization of multi-scale sedimentology, litho- and sequence-stratigraphy, biostratigraphy, and geochemistry from cores, (2) relating stratigraphy to log response (including borehole image logs), (3) seismic response, (4) petrophysical and geomechanical properties, and (5) organic geochemistry. In addition, educational opportunities are being provided to university students who can then apply knowledge to petroleum industry careers. The result of this integration has led to better understanding of the evolution of shales and their contained gas, and regional to local mapping of key lithologic or stratigraphic intervals for improved drilling and production.
Impact of Shale Properties on Pore Structure and Storage Characteristics
Authors: Bustin R. M. , Bustin A. M. M. , Cui X. , Ross D. J. K. , Pathi V. S. Murthy
Published: November 2008

Characterising the pore structure of gas shales is of critical importance to establish the original gas in place and flow characteristics of the rock matrix. Methods of measuring pore volume, pore size distribution, and sorptive capacity of shales, inherited from the coalbed methane and conventional reservoir rock analyses, although widely applied, are of limited value in characterising many shales Helium which is routinely used to measure shale skeletal and grain density, permeability and diffusivity, has greater access to the fine pore structure of shale than larger molecules such as methane. Utilizing gases other than He to measure porosity or flux requires corrections for sorption to be incorporated in the analyses. Since the permeability of shales vary by several orders of magnitude with effective stress, methods that do not consider effective stress such as crushed permeability, permeability from Hg porosimetry, and from desorption are of limited utility and may be at best instructional.

For shales investigated to date, clay-rich rocks have higher porosity and permeability than biogenic silica-rich shales or carbonate-rich shales. Shales rich in detrital quartz have higher porosity and permeability than shales rich in biogenic quartz and hence simply knowing the mineralogy of a shale may not be diagnostic. The porosity of most shales is mainly dependent on the degree of pore volume development in pores less than 10 um.

Quantifying total gas in place in shales by much of the industry using coal desorption methods and porosity and water saturation determinations, developed for conventional reservoir rocks, may lead to substantial errors. Canister ‘desorption' methods applied to gas shales routinely captures free and solution gas as well as sorbed gas which, if considered as only sorbed gas, results in a significant overestimation of gas in place. A proprietary method of analyses, referred to as MARIO, results in rigorous total gas in place determinations that avoids errors including those associated with molecular sieving and provides a maximum value of the sorbed gas contribution to total gas.
Modeling Flowback Behavior or Flowback Equals "Slowback"
Authors: Crafton James W.
Published: November 2008

Clear evidence is becoming available that shows that ultimate gas well performance is extremely sensitive to the early time well production management, during the time often referred to as the "flowback". Early time production management in shale gas wells is even more critical than in so-called traditional tight gas reservoirs. This production management problem is exacerbated by the plasticity of shale reservoirs, the need for extensive natural fracture swarms and the now common practice of multiple fracture stimulations of the long-reach laterals. This paper examines three data sets from actual wells that show the adverse impact of excessive early time flow rates, shut-ins during the early time production and the orientation of the laterals. Through numerical simulation and physical experiments, it becomes clear that the traditional performance metrics are at best misleading.
Using Microseismic Events to Constrain Fracture Network Models and Implications for Generating Fracture Flow Properties for Reservoir Simulation
Authors: Williams-Stroud Sherilyn
Published: November 2008

Microseismic monitoring of hydraulic fracture stimulation treatments has done much to diminish the expectation of engineers and geoscientists that symmetrical bi-wing fractures extending away from the well bore from as a result of the treatment. Mapping of microseismic event locations indicates that more often, zones of high complexity form which suggest multiple rock failure mechanisms could be in play during the stimulation treatment. The complexity of the failure is further complicated, or perhaps explained, by the interaction of the perturbed stresses with existing fractures in the reservoir relative to the unperturbed stress state of the reservoir. Existing fracture planes favorably oriented for shear will fail at lower stresses than are required to create new fractures. Geologic mapping and regional to local in-situ stress information will allow informed interpretation of the resulting microseismicity patterns as well as providing predictive capability for fracturing patterns of treatments in subsequent area wells and production planning. Correlative to the improved fracture mapping is the use of the fracture interpretation as input to fractured reservoir modeling and fractured reservoir simulation. Utilizing microseismicity data not only to constrain location of fractures, but also fracture size, shape and orientation allows creation of improved fractured reservoir models based on geologic concepts and supported by the real time data.

In this paper two examples are presented from a hydraulic stimulation of North American mid-continent wells that were monitored with a surface-based geophone array. The resulting microseismicity patterns in both wells show that the fracture development was strongly influenced by pre-existing discontinuities (fractures or faults), which are easily explained by geologic and in-situ stress analysis. The fracture interpretation and microseismicity data from one example is used to generate a discrete fracture network from which fracture flow properties are created in a geocellular model. The resulting model provides a quantitative framework for production history mapping and reservoir behavior, with hard constraints for the behavior of the dominant fractures in the fracture network.
Increasing Fracture Path Complexity and Controlling Downward Fracture Growth in the Barnett Shale
Authors: King George E. , Haile Luke , Shuss Jim , Dobkins Terrell A.
Published: November 2008

Creating an optimum hydraulic fracture to produce gas from nano-darcy shale uses much different technology than that commonly used in low permeability sandstone or carbonate reservoirs. Potentially productive natural fracture pathways are often present but thought to be seldom open in most shales. Effective stimulation in shales requires that the fracture creates an extensive, interconnected and stable flowing network of these natural fractures within the shale, without penetrating into water bearing zones below the shale. Shale wells capable of producing gas at several million scf/d, require development of a fracture pathway with shale face contact of an estimated five to ten million square feet (about one million square meters). Use of downhole microseismic during fracturing has defined sound patterns that confirm the "fracture flow path" in these stimulated shale wells is actually linking intersecting natural fractures into a network of fractures with a flow path width of several hundred feet. These flow paths often have patterns of fracture growth at right angles to the primary fracture direction. Examples of these right angle secondary fractures and the growth cloud of microseismic events that define the complex fracture network are shown in the paper. During extensive fracturing, downward fracture growth can penetrate the carbonates that are found beneath nearly all gas shales. Fracturing into water-wet lower reservoirs can reduce fracture efficiency and severely limit production by flooding the well with water. Effective methods of curtailing this downward frac growth are absolutely essential. This paper reviews some of the prior work on network or complex fracture work in shale and discusses some of the science behind creating the complex fracture network development. The paper also describes the follow-up work using both RA and chemical tracers that helped optimize the flow paths.

Taken together, the development of a very large contact area in the gas-bearing shale (increased shale complexity) and the control of downward growth of the fractures can lead the effort to economically develop and extend the present edges of the Barnett Shale play.
Production Analysis and Forecasting of Shale Gas Reservoirs: Case History-Based Approach
Authors: Mattar L. , Gault B. , Morad K. , Clarkson C. R. , Freeman C. M. , Ilk D. , Blasingame T. A.
Published: November 2008

In this work we present the current status of production evaluation and prediction for shale gas reservoirs. We focus primarily on the effect of wellbore geometry (vertical vs. horizontal) and fracture stimulation, and consider only relatively simple shale reservoir characteristics. Theoretical production responses from hydraulically-fractured vertical and horizontal wells are first described. Analytical and empirical methods for production data analysis and forecasting of shale reservoirs are then described and demonstrated. The empirical approach used is the recently developed "power-law exponential" rate relation [Ilk, et al (2008b and 2008b)] in addition to the more traditional "hyperbolic" rate relation [Johnson and Bollens (1927)], Arps (1945)]. The analytical methods utilized include production type-curves developed for vertical wells completed in single-porosity, single-phase reservoirs. Finally, numerical approaches for forecasting complex, multifractured horizontal wells are also presented. Two approaches for simulating these complex wells, one simple and the other more rigorous, are provided. In the more rigorous approach, the "compound linear flow regime" concept introduced by van Kruysdijk and Dullaert (1989) is verified.

The production analysis methods are applied to field and simulated cases to demonstrate their accuracy and practicality. The empirical power-law exponential method, when applied to both simulated and field cases, is shown to be a reliable method for forecasting shale wells. The analytical (type-curve) methods developed for vertical wells can be useful for analyzing vertical shale wells; when applied to horizontal wells, the resulting estimates of reservoir and fracture properties may be inaccurate. A special case of analysis of a 2-phase shale reservoir is also presented; in this case, the analytical tools developed recently for 2-phase CBM reservoirs [Clarkson, et al (2008)], including 2-phase flowing material balance and type-curves, prove useful.
Marcellus Shale Water Management Challenges in Pennsylvania
Authors: Gaudlip A. W. , Paugh L. O. , Hayes T. D.
Published: November 2008

The management of water resources poses considerable challenges to the Pennsylvania Oil and Gas Industry as it begins to expand the development of the Marcellus Shale. Although the play overlies a seemingly water-rich region the sourcing of fresh water for drilling and completions operations are far from straight forward due to regulatory restrictions. Development companies planning to operate in the state must seek to understand an evolving regulatory landscape that is struggling to create a framework specific to shale gas development. The current regulatory status limits conventional methods of surface water withdrawals from streams and rivers and forces industry to search out alternative water sources from groundwater wells, municipalities, private sources and recycled waters. In addition to the challenge of fresh water sourcing, operators are also limited in the options for disposing waste-waters generated during drilling, flowback and production. The current methodology of pre-treatment and discharge via NPDES permit has a finite capacity which is projected to be insufficient in a short time as the level of drilling activity increases. There is very limited potential for underground injection of fluids into permitted disposal wells and virtually no need for weighted brines for well control. Alternative disposal and recycling options which could potentially process the waste-waters into recycled fresh water and concentrated brine or salt cake are being actively studied by individual operating companies and the industry as a whole.
Economic Evaluation of Shale Gas Reservoirs
Authors: Wright John D.
Published: November 2008

Three 9-square mile areas in the Newark East Field were studied to investigate the economic viability of the Barnett shale gas play. The areas chosen corresponded to the 25th, 50th, and 75th percentiles based on average estimated ultimate recovery per well in the areas. The actual drilling and refrac schedule was used for each area along with actual and forecasted production and today's costs and prices to calculate economics on the 329 wells in the areas. Most of the individual wells are not economic under the assumptions of this study. Of the three areas, only the 75th percentile area was economic when considered as a whole. The results are most sensitive to capital costs and gas prices.
Stimulation and Production Analysis of Underpressured (Marcellus) Shale
Authors: Myers Roger R.
Published: November 2008

EXCO-North Coast's has conducted pilot tests to add incremental reserves in a thin Marcellus through a contrarian approach toward stimulating that shale. In these underpressured Jackson County, West Virginia shale wells, slickwater fracture stimulations were used instead of the more common nitrogen gas or nitrogen foam fluids. The premise for this departure from the standard nitrogen gas or foam treatment was that water, being non-compressible, drives net pressure better in shale stimulations, improving chances of opening other planes of weakness or natural fractures with high pump rates and fluid volumes. Further, there was a sense that the Marcellus shale may not be as sensitive to fresh water as previously thought, at least not in the sense that there are swelling or migrating clays to detrimentally impact production. There still may be concerns about relative permeability effects of water on the shale, water imbibition by the shale, and short and long-term liquids management. Recovering as much stimulation water as fast as possible without damaging the induced fracture's conductivity and keeping the shale perforations dry should be best for gas production. Two wells were drilled to the Marcellus shale. Uphole zones commonly stimulated in a multi-zone same day completion were skipped to allow for a Marcellus only production test. The Reciprocal Productivity Index was used to gauge stimulation effectiveness in one of the wells.