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- Comparative study of the influence of minerals in gas sorption isotherms of three coals of similar rankPublication . Rodrigues, Cristina; Pinheiro, H. J.; Lemos de Sousa, M. J.; yesThis investigation compares the gas adsorption behaviour and capacity of three bituminous coals from South Africa, of similar rank, by assessing the characteristics of the raw coal, as well as the resulting float and sink fractions (at 1.80 cm3/g) obtained by density separation of crushed coal samples. Calculations were also made to obtain the raw coal gas storage capacity from the weighted contribution of both float and sink fractions results, thereby permitting comparison with the analysed results of the raw coal. The study demonstrated that the clean fraction of a coal has the highest capacity to retain gas in the sorbed state, followed by raw coal, and lastly the sink fraction, and re–confirmed previous investigations that showed minerals to be inhibitors of gas adsorption and retention.
- Detection and evaluation of hydrocarbons in source rocks by fluorescence microscopyPublication . Alpern, B.; Lemos de Sousa, M. J.; Pinheiro, H. J.; Zhu, X.In pursing the detection of hydrocarbons in sedimentary rocks by conventional petrological methods, an attempt has been made to correlate standard fluorescence parameters with the quality and quantity of hydrocarbons present in crushed rocks embedded in epoxy resin. The capacity of the embedding resin, commonly used in the preparation of petrographic samples, to extract and physically fix hydrocarbons is recognized. This phenomenon permits one to measure monochromatic fluorescence parameters, I and
- Interlaboratory comparisons of petrography of liquefaction residues from three Argonne Premium coalsPublication . Hower, J. C.; Anderson, K. B.; Mackay, G.; Pinheiro, H. J.; Flores, Deolinda; Lemos de Sousa, M. J.Three Argonne Premium coal samples, the Beulah-Zap lignite (North Dakota), the high volatile A bituminous Stockton (West Virginia), and the low volatile Pocahontas No. 3 (Virginia), were ground to three initial sizes: -20 mesh, -100 mesh, and "micronized". The samples were each subjected to liquefaction at 673 K for 30 min at a 2:1 tetralin :coal ratio and in an H 2 atmosphere at 13.79 MPa (~ 2000 psi). Polished pellets of the unconverted residues were circulated to three laboratories for a study designed to determine, albeit on a limited scale, the interlaboratory consistency in constituent identification and the problem areas in maceral/neo-maceral/mineral recognition. Within broad categories, the agreement for the Beulah-Zap and Pocahontas No. 3 residues is good. The high volatile A bituminous Stockton coal was the most plastic and most altered, resulting in a residue lending itself to more subjective interpretations. The biggest discrepancy between the laboratories is in the distinction of granular residue and mineral matter and in the transitions between "partially reacted macerals" and "vitroplast" and between "vitroplast" and "granular residue". The initial size of the feed coal appears to influence the recognition of material in the residue.
- Prospecting for coalbed methane: preliminary investigation into the possibilities in SpainPublication . Lemos de Sousa, M. J.; Pinheiro, H. J.The fundamental objetive of this study resides in investigating the potential suitability of spanish coalfields to prospecting natural gas from coal in-situ (Coalbed Methane-CBM). The study was based not only on a literature survey and supplemented by onsite visits and investigations, but also on inhouse research activities. Tree selecting criteria have been defined: 1.1. Existing resources: a figure of 20MT of coal was estrablished as the minimum in-situ tonnage worth considering. This limit is comprised of the sum of "very probable" and " probable" resources. 1.2. Coal rank: in agreement with the generally accepted principle that the most significant amount of gas produced by coal corresponds to a coalification level of Rr> 1.2% (ca VM (daf) < 30&), only coalfields reporting such values were selected. 1.3 Geological and Structural considerations such as: 1.3.1 Identification of stratigraphic units, their sedimentary conditions including the presence of coal-bearing units with sufficient seams (frequency) with thickness that will potentially permit their in-situ exploration and exploitation for natural gas. 1.3.2 Structural regime compatible with the retention of gas by the coal beds and adjacent host rocks. 2. On the basis of currently available information, and on applying the abovementioned criteria to spanish coalfields, the following ones have been identified as potentially the most suitable for coalbed methane prospecting (in decreasing order of importance): • Ciñera-Matallana and Cerredo-Villablino, considered to have equivalent potential • La Pernía-Barruelo • Central Asturian Coalfield, South region • El Bierzo.
- Presentation of the Methodology Elaborated for Optical Analyses of Borehole Samples for Oil ProspectionPublication . Alpern, B.; Lemos de Sousa, M. J.; Pinheiro, H. J.; Marques, M. M.; Zhu, X.
- Prerequisites, general criteria and primary studies required in the CoalbedMethane prospecting and exploring: A reviewPublication . Lemos de Sousa, M. J.; Pinheiro, H. J.; Rodrigues, CristinaThe main objectives of this paper are: (i) to review and summarize current concepts of Coalbed Methane (CBM) genesis and storage, (ii) to highlight and present the principal procedures and methodologies concerned with prospecting/exploring of CBM leading to a sequence of basic criteria to be followed at an early stage and, subsequently, during research and exploration, and (iii) to present a list of the most important analytical requirements during the investigations.
- Source rock/dispersed organic matter characterization-TSOP research subcommitee resultsPublication . Teerman, S. C.; Cardott, B. J.; Harding, R. W.; Lemos de Sousa, M. J.; Logan, D. R.; Pinheiro, H. J.; Reinhardt, M.; Thompson-Rizer, C. L.; Woods, R. A.Because sedimentary organic matter consists of a diverse mixture of organic components with different properties, a combination of chemical and petrographic results offers the most complete assessment of source rock properties. The primary purpose of this Society for Organic Petrology (TSOP) subcommittee is to contribute to the standardization of kerogen characterization methods. Specific objectives include: (1) evaluation of the applications of different organic matter (petrographic) classifications and terminology, and (2) integration of petrographic and geochemical results. These objectives were met by completing questionnaires, and petrographic, geochemical and photomicrograph round-robin exercises. Samples that were selected for this study represent different petrographic and geochemical properties, and geologic settings to help identify issues related to the utilization of different classifications and techniques. Petrographic analysis of the organic matter was completed using both a prescribed classification and the individual classification normally used by each participant. Total organic carbon (TOC), Rock-Eval pyrolysis and elemental analysis were also completed for each sample. Significant differences exist in the petrographic results from both the prescribed and individual classifications. Although there is general agreement about the oil- vs gas-prone nature of the samples, comparison of results from individual classifications is difficult due to the variety of nomenclature and methods used to describe an organic matter assemblage. Results from the photomicrograph exercise document that different terminology is being used to describe the same component. Although variation in TOC and Rock-Eval data exists, geochemical results define kerogen type and generative potential. Recommendations from this study include: (1) A uniform organic matter classification must be employed, which eliminates complex terminology and is capable of direct correlation with geochemical parameters. (2) A standardized definition and nomenclature must be used for the unstructured (amorphous) organic matter category. Subdivisions of this generalized amorphous category are needed to define its chemical and environmental properties. (3) Standardized techniques including multimode illumination, types of sample preparations and data reporting will help eliminate variability in the type and amount of organic components reported.
- Optical Morphology of Hydrocarbons and Oil Progenitors in Sedimentary Rocks- Relations with Geochemical ParametersPublication . Alpern, B.; Lemos de Sousa, M. J.; Pinheiro, H. J.The objective of the present research...