bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Well Placement Under Time-Dependent Uncertainty
Authors: Ozdogan Umut , Horne Roland N. 
Published: April 2006

Summary
Well-placement decisions made during the early stages of exploration and development activities have the capability to improve later placement decisions by providing more information (greater certainty). Therefore, recovery and efficient use of information may add value beyond the amount of oil recovered. This study proposes an approach that emphasizes the value of time-dependent information to achieve better decisions in terms of reduced uncertainty and increased probable net present value (NPV). Unlike previous approaches, well-placement optimization is coupled with recursive probabilistic history-matching steps through the use of the pseudohistory concept. The pseudohistory is defined as the probable (future) response of the reservoir that is generated by a probabilistic forecasting model. To test the results of the proposed approach, an example reservoir was investigated with multiple realizations, all of which match the same production history. The results of this study showed that subsequent well-placement decisions can be improved when probabilistic production profiles obtained from the wells, as they are drilled, are incorporated in the optimization scheme.
Secondary Porosity and Permeability of Coal vs. Gas Composition and Pressure
Authors: Mavor Matthew J. , Gunter William D. 
Published: April 2006

Summary
We have been investigating the sequestration of atmospheric pollutants by injection into coal seams while at the same time enhancing hydrocarbon productivity by displacement of methane with pollutants. Our effort is one of several field-based research efforts into CO2 storage in coal seams that are currently operating in Canada (Mavor et al. 2004), China (Robinson et al. 2004), Japan (Nago and Komaki 2004), and Poland (Van Bergen et al. 2004). During the course of our field measurements, we have been using single-well injection, soak, and production tests to collect data required to understand and predict enhanced coalbed methane (ECBM) recovery potential and sequestration capacity. We found that changing the composition of the gas sorbed into the coal changes the porosity and permeability of the coal natural-fracture system owing to gas-content changes, which cause matrix swelling or shrinkage due to relative adsorption of different gases.
We collected sufficient information to develop a method for predicting the permeability and porosity of a coalbed as a function of the secondary porosity system (SPS) pressure and the gas content and composition of the primary porosity system (PPS). The method uses data from injection/falloff tests with water and/or a weaker adsorbing gas (WAG) than CH4 and a stronger adsorbing gas (SAG) than CH4. Estimates of effective permeability to gas and water obtained from these tests are used with an iterative computation procedure subject to constraints to solve for equivalent SPS porosity and absolute permeability at atmospheric pressure.
Once calibrated, the model can be used to predict a coalbed's permeability and porosity as a function of injection pressure and injected-fluid composition, which in turn are used to predict injection performance. The model is applicable to production forecasts to account for SPS permeability and porosity changes as reservoir pressure declines with changes in gas composition.
This paper describes the new model and discusses well-test procedures to obtain the data required for model calibration. Also included are coal property estimates resulting from Alberta Medicine River (Manville) coal core and test data and an example model calibration.
Wettability-Index Determination by Nuclear Magnetic Resonance
Authors: Looyestijn Wim , Hofman Jan 
Published: April 2006

Summary
Knowing the wetting condition of a reservoir at an early stage is crucial for selecting optimum field-development options. Paying insufficient attention to the wetting condition (e.g., assuming water-wet behavior) may result in incorrect oil-in-place estimates and in unexpected dynamic behavior (e.g., under-waterflooding).
A novel method is presented to determine the wettability of rocks from nuclear-magnetic-resonance (NMR) data. The method is based on the additional nuclear relaxation that fluids experience when in direct contact with the rock surface. Reduction of oil relaxation time away from its bulk value is generally known as a qualitative wettability indicator, assuming external factors to be negligible and/or invariant from one experiment to another. Through detailed modeling of the NMR response, this concept has been developed further to provide a quantitative wettability index. It is based on a model for the microscopic distribution of the crude oil and the wetting state of the rock at any given overall saturation. The method requires an NMR measurement on a sample containing two reservoir fluids (i.e., brine and crude oil). Multiacquisition schemes including diffusion effects make the interpretation more robust, but a normal NMR acquisition suffices as can be made with all available NMR tools (wireline and while-drilling).
The new NMR-based method has been verified extensively on core data against standard wettability tests. Application to NMR logs is in progress.
‘Science in Africa’ By E. B. Worthington
Authors: Ogilvie Alan G. 
Published: April 2006

Opening ParagraphReaders of the accounts by the great naturalist explorers of the later eighteenth and early nineteenth centuries are often impressed by the acuteness of observation displayed, and even more often by the variety of the phenomena described. Since the day of these pioneers every one of the aspects of Nature and of Man about which they wrote has become the field of a separate branch of science, and each decade sees new shoots emerge with the accelerated specialization of science and its researches. With the rapidly increasing means of publication all these extensions of knowledge contribute to a literature so vast that no individual can follow it over the domain of even one of the major divisions, whether of Earth lore or the social sciences. The appearance, then, of any form of authoritative book which provides a conspectus of existing knowledge in a given field is welcome. When the field is a continent, or any geographical unit, we are generally better off than usual in this respect, since the function of geography is both analytic and synthetic and above all is correlative; for Africa, indeed, excellent general geographical treatises exist in at least three languages.
Malangali School
Authors: Mumford W. Bryant 
Published: April 2006

Opening ParagraphLast year I wrote a paper on ‘Education and the Social Adjustment of Primitive Peoples to European Culture’. It was an attempt to analyse the problem of the downfall of native races brought into contact with Europe, and to suggest an educational policy which might obviate some of the evils resulting from such contact. The educational policy suggested was based upon two principles, firstly that the school should be built on native tradition and continuous with any system of training youths which existed prior to the advent of the European, and secondly that these institutions should be developed and enriched to meet the needs of the changing environment and to train the pupils to be leaders in social and economic progress. The principles have thus a dual aspect, that of trying to ensure continuity of development from the past by basing the school on native tradition, and that of developing these traditions to meet the demands of improved standards of living and of improved methods of production.
The Present State of Studies in Culture Contact: Some Comments on an American Approach
Authors: Malinowski B. 
Published: April 2006

Opening ParagraphAnthropology is an aggressive science. It has infected the study of contemporary social conditions with its outlook and methods. Witness the work done in Middletown, on the Irish countryman, and at Newburyport; the gradual pervasion of European folk-lore research with the methods of exotic field-work; and such a movement as Mass-Observation in England. Anthropology is now turning to the full sociological study of the great oriental cultures in China, India, and Japan. Nor is the reason for its effective aggressiveness difficult to find. The anthropologist among all other students of humanism was forced to obtain his material at first-hand through the direct observation of primitive races. For in his subjectmatter, there is no relying on written documents. Thus the strongest asset and the most inspiring force of the anthropological point of view is its thorough-going empiricism. Ethnography is the laboratory of social science.
Das Geschichtliche Fundament der Hamitischen Sprachen
Authors: Zyhlarz Ernst 
Published: April 2006

Opening ParagraphDer. Begriff ‘hamitisch’ gehört mit zu den bisher am schwersten zu fassenden Problemen der Afrikanistik. Die Gründe dafür liegen einerseits in der phänotypen Verschiedenheit innerhalb der als ‘hamitisch’ geltenden Volksstämme, andererseits aber in dem sichtlichen Mangel einer einheitlichen Linie des geschichtlichen Werdegangs der Sprachen solcher Völker, soweit man einen solchen nach den Methoden der modernen Linguistik theoretisch festzustellen versucht hatte. Hier versagen solche Methoden, wenn auch nicht innerhalb des Einzelidioms, so doch im Hinblick auf einen historischen Sprachstamm. Während sich demgegenüber die rassisch auch nicht einheitlichen sogenannten Bantu schon durch den linguistisch einwandfrei und exakt festzustellenden historischen Bantu-Sprachstamm als eine geschichtliche Schicksalsgemeinschaft denkassimilierter afrikanischer Völker erweisen, so fehlt es auf dem Gebiete des ‘hamitisch’ genannten Volkstums durchaus an auch nur einigermassen systemfähigen allgemeinen Sprachkriterien. Während nämlich der moderne Afrikanist heute an der Hand von Meinhofs Vergleichsmethodik jederzeit imstande ist, schon bei erster Durchsicht eines in einem bislang noch unbekannt gewesenen afrikanischen Eingeborenenidiom abgefassten Textes eindeutig festzustellen, ob das Bantu ist oder nicht, und wenn ja, welche Stellung dieser Sprache im Rahmen des Gesammtsprachstammes zukommt, so war man bezüglich der Kriterien der Hamitensprachen bis vor Kurzem in der Hauptsache genötigt, ein mehr oder minder irrational formuliertes Allgemeinbekenntnis zum Glauben an eine sprachliche Einheit des Hamitischen abzulegen. Wer dann der gehörten Botschaft gegenüber seinen fehlenden Glauben betonen zu müssen meinte, den konnte man auch nicht widerlegen, selbst wenn er den ganzen Fragenkomplex rundweg negativ abzutun bereit war.
Co-Operation in Health Education
Authors: Blacklock Mary 
Published: April 2006

Opening ParagraphThe Public-Health Problem In Tropical Africa. A Survey of medical reports from all parts of tropical Africa shows us a remarkable similarity in the nature of the paramount diseases. True, certain diseases such as yellow fever, plague, and relapsing fever occur in some districts and are rare or unknown in others, but the conditions necessary for their occurrence and the danger of their spread are generally present in the so far unaffected countries.
Études sur la Cosmologie des Dogon et des Bambara du Soudan Français
Authors: Zahan D. 
Published: April 2006

Opening ParagraphDans un article intitule ‘Un Gnomon soudanais’ nous avons relevé l'existence et l'emploi du gnomon chez les Bambara du Soudan Français. Il n'est pas sans intérêt de présenter également la notion que ce peuple a de l'écliptique. Des idées similaires se retrouvent à ce sujet chez les Dogon; sans essayer de faire du comparatisme qui peut être fallacieux, nous mettrons en regard, cependant, cette notion astronomique commune aux deux peuples qui, démographiquement et spirituellement, témoignent d'une même origine.
The Study of ‘Social Change’ in British West Africa
Authors: Little Kenneth 
Published: April 2006

Opening ParagraphA visitor to West Africa today will find most of the conventional trappings of a western civilization. He can travel on trains and in motor-cars and airplanes, and stay at rest-houses equipped with electric light and a flushed toilet. He can visit African homes furnished in the latest western style in which there is refrigeration and cooking is done by electricity. He will see Africans working in shops, offices, and factories, growing crops for foreign consumption, and leasing and renting land. He will visit churches and schools, play outdoor games, attend dances, performances of amateur dramatics, baby shows, and buy a flag for charity—all these activities being organized by Africans. On the other hand, he will also see a majority of Africans living in huts of wattle and daub and of grass, herding cattle, and cultivating their farms and plots with home-made implements, pounding their food in mortars, crossing rivers in dug-out canoes, dancing to the music of wooden drums, and worshipping ancient gods and spirits.
Swahili Borrowings from English
Authors: Gower R. H. 
Published: April 2006

Opening ParagraphSwahili is, by origin, a Bantu language which was strongly influenced by Arabic. In the course of time Swahili has borrowed words from a variety of languages. During the last thirty or forty years it is not surprising to find that Swahili has continued to enrich its vocabulary, more particularly from English.
Positional Succession Among the Wambugwe
Authors: Gray Robert F. 
Published: April 2006

Opening ParagraphAmong the Wambugwe of Tanganyika, when a person dies a member of the same lineage is designated to take his place in the kinship structure. The substitute assumes most of the kinship relations of the dead person and also, in the case of a married person, his affinal relations. This well-integrated institution has the function of restoring to surviving relatives the loss that attends death: parents have a lost child replaced, children a lost parent, and a married person a lost spouse. So far as I know, this institution has not been previously reported in such organized form for an African society or from elsewhere in the world; though most of its features, taken separately, are found in other societies. These include rules for the inheritance of property, for succession to social position, and for preferential marriage of widows; principles of guardianship for orphans; and adoption customs. All of these are organized in the single institution described in this paper.
The Social Functions and Meaning of Hausa Praise-Singing
Authors: Smith M. G. 
Published: April 2006

Opening ParagraphIn this paper I illustrate an objective method for the determination of the meaning and values of social institutions, using data on the custom of praise-singing (roko) among the Hausa of Northern Nigeria. To direct attention to the method of analysis clearly, I shall present the field-data and their examination separately. I concluding, I shall indicate certain problems which seem to arise from this paper.
Clan, Chieftainship, and Slavery in Luvale Political Organization
Authors: White C. M. N. 
Published: April 2006

Opening ParagraphThe Luvale in Northern Rhodesia came under British administration in the early years of the present century, the first Government headquarters in Balovale district having been established in 1907. Some time previously, about 1892, they had already come under pressure from the Lozi to the south as a result of Lozi intervention in the war between the Luvale and the Lunda. When, therefore, the Barotseland protectorate was established at the beginning of the century, the Balovale district was included within it. Relations with the Lozi authorities were slight in the early years of British administration; later, about 1930, when the Lozi sought to introduce a greater degree of political control in Balovale district, their relations with the Luvale (and Lunda) became strained. The Luvale chiefs acquired a special role as the focal point of Luvale opposition to Lozi interference, and thereby enhanced their status and prestige in the eyes of their people. The Balovale district was finally excised from Barotseland in 1941 after a Royal Commission had inquired into the dispute. Thereafter certain of the Luvale chiefs were gazetted with de jure recognition under the Native Authorities Ordinance.
Ibo Land Tenure
Authors: Jones G. I. 
Published: April 2006

Opening ParagraphThe Ibo-speaking people of Eastern Nigeria can be regarded as a single culture area which may provisionally be subdivided into five main divisions: Northern or Onitsha, Southern or Owerri, Western or Ika, Eastern or Cross River, and North-eastern or Abakaliki. The first two divisions, whose boundaries correspond very roughly to those of the Administrative Provinces of Onitsha and Owerri, contain the bulk of the population; the Western occupies the Niger riverain region and the forest country beyond, and their culture has been influenced by that of the Edospeaking tribes farther west, and by Benin; the Cross River Ibo are another marginal group whose affinities with the ‘Semi-Bantu’-speaking tribes on the eastern bank of that river have yet to be studied; while the North-eastern Ibo are a specialized group that has developed, in comparative isolation, a culture and a social structure better adapted to the savannah country in which they live. The remarks which follow refer mainly to the Northern, Southern, and Cross River Ibo; the North-eastern Ibo system differs in many important respects; the Western has not been studied. The terms used in defining Ibo social groupings have been explained in Africa, vol. xix, No. 2, p. 151, and in places where this may cause confusion the ‘official’ or alternative term is given in brackets.
Anuak Village Headmen
Authors: Lienhardt Godfrey 
Published: April 2006

Opening ParagraphThe specific form and function of many Anuak customs connected with competition and prestige, some of which I briefly described in the first part of this study, are to be interpreted in relation to the political structure of Anuak villages; and this I now describe, first in general outline, and later in more detail with reference to a particular village
N!ow
Authors: Marshall Lorna 
Published: April 2006

Opening ParagraphN!ow is a belief concerning rain and cold which is held by the !Kung Bushmen in the region around Nyae Nyae in South West Africa.About ten inches of rain falls in an average year in this part of the Kalahari Desert and sinks into the deep sands. There is no run-off in streams and there are few water holes. The rain is sufficient to support a covering vegetation of grass, shrubs, and scrubby trees. The vegetation includes numerous edible roots, tubers, leaves, fruits, and nuts, for which the Afrikaans language provides the convenient word veldkos.
Migratory Labour from North-Wester Nigeria
Authors: Prothero R. Mansell 
Published: April 2006

Opening ParagraphReaders of Africa will be well aware of population migration as a characteristic feature of a continent where movement between one part and another is largely unrestricted as compared with the more settled parts of the world. There is much evidence of large-scale tribal migrations in the past, of the age-old seasonal wanderings of herders, and of recent labour migration to centres of mineral and industrial production, the last particularly in Central and South Africa. Information is more limited concerning the features of labour migration in West Africa at the present day. In general it is thought that migrants leave their home areas, after the harvest at the commencement of the dry season, to seek work elsewhere for a period of from three to six months and then return to take up farming with the commencement of the next rains. The major source area for these migrants is to the north of the tenth parallel where the wet season is concentrated into a period of about four months, thus severely restricting agricultural activity. Cultivation during the dry season is possible only on a very limited scale. There is thus a considerable period of the year when the primary economic activity of the people is not possible. It is logical that they should seek work elsewhere.
The Migration and Expansion of the Tiv
Authors: Bohannan Paul 
Published: April 2006

Opening ParagraphOne of the most obvious social situations in the middle Benue Valley is the expansion in all directions of the Tiv, who number some 800,000 and are the largest pagan tribe in Northern Nigeria. One of the most puzzling aspects of Tiv expansion has been that, although it is obviously connected in many areas with land shortage and accompanying economic factors, it is precisely in those areas in which land shortage is least severe that the rate of migration appears to be most rapid.Centrifugal expansion is intimately associated with the social and political structure of the Tiv people—is, in fact, a facet of it. In order to analyse this association, and incidentally to explain the paradox of the rate of expansion, it is necessary to divide the movement into two sorts: expansion and disjunction. Expansion refers to that type of movement which leads to the enlargement in area of a lineage's territory. It may eventually lead to a change in geographical location of the lineage territory; it does not affect the over-all juxtaposition of lineage areas. Disjunction, on the other hand, characteristically brings about a separation of groups in space and affects not only the geographical position of a lineage territory, but also the juxtaposition of lineage territories.The first section of this article will set forth briefly the relationship between movements of lineages, territorial organization, and the structure of political lineages. The second section will examine expansion; the third, disjunction. The fourth will show that the two types of migration are both present in all parts of the country, and that it is the primacy of one or the other which gives rise to an apparent difference in rate of migration.
The Social Context of Cewa Witch Beliefs
Authors: Marwick M. G. 
Published: April 2006

Opening ParagraphMost Cewa believe that certain persons are witches (mfiti, sing, and pl.) who impoverish, harm, or kill their fellow beings by using destructive magic and by performing supernatural feats of various kinds. That they are greatly preoccupied with this belief and its various implications is shown by the frequency with which they attribute death and misfortune to witchcraft, and by their related tendency to take precautions against possible attacks by ‘witches’, e.g. by having their bodies and huts magically protected.
Marriage Customs among the Barolong
Authors: Matthews Z. K. 
Published: April 2006

Opening ParagraphThe Barolong belong to the Western cluster of the Sotho group of the Bantu-speaking tribes of South Africa. The Western Sotho, who are commonly called the Tswana, are scattered over a considerable portion of South Africa, including the whole of Bechuanaland Protectorate, the portion of the Cape Province known as British Bechuanaland, the western Transvaal and a portion of the Orange Free State. Although the Barolong are to be found mainly in British Bechuanaland, they are in the peculiar position of being strongly represented in all the political divisions of Southern Africa referred to above, for they have important settlements in the Lobatsi district of Bechuanaland Protectorate; in the Lichtenburg district of the Transvaal, and in the Thaba Nchu district of the Orange Free State as well as in the Vryburg and Mafeking districts of British Bechuanaland (Cape Province).