Heavy oil is characterized by its high viscosity, which is a major obstacle to both logging and recovery. Due to the loss of T 2 information shorter than the echo spacing ( TE ), estimation of heavy oil properties from NMR T 2 measurements is usually problematic. In this work, a new method has been developed to overcome the echo spacing restriction of NMR spectrometer during the measurement of heavy oil. A FID measurement supplemented the CPMG in an effort to recover the lost T 2 data. Constrained by the initial magnetization ( M 0 ) estimated from the FID and Curie's law and assuming lognormal distribution for bitumen, the corrected T 2 of bitumen can be obtained. This new method successfully overcomes the TE restriction of the NMR spectrometer and is nearly independent on the TE applied in the measurement. This method was applied in the measurement of systems at elevated temperatures (8 ∼ 90 °C) and some important petrophysical properties of Athabasca bitumen, such as hydrogen index ( HI ), fluid content and viscosity were evaluated by using the corrected T 2 . Well log NMR T 2 measurements of bitumen appear to be significantly longer than the laboratory results. This is likely due to the dissolved gas in bitumen. The T 2 distribution depends on oil viscosity and dissolved gas concentration, which can vary throughout the field. In this work, the viscosity and laboratory NMR measurements were made on the recombined live bitumen sample and the synthetic Brookfield oil as a function of dissolved gas concentrations. The effects of CH 4 , CO 2 , and C 2 H 6 on the viscosity and T 2 response of these two heavy oils at different saturation pressures were investigated. The investigations on live oil viscosity show that, regardless of the gas type used for saturation, the live oil T 2 correlates with viscosity/temperature ratio on a log-log scale. More importantly, the changes of T 2 and viscosity/temperature ratio caused by solution gas follows the same trend of those caused by temperature variations on the dead oil. This conclusion holds for both the bitumen and the synthetic Brookfield oil. This finding on the relationship between the oil T 2 and its corresponding viscosity/temperature ratio creates a way for in-situ viscosity evaluation of heavy oil through NMR well logging.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains viii, 92 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 85-88).

Sophisticated electromagnetic pulse sequences that control spin dynamics have been developed in Nuclear Magnetic Resonance (NMR) over the last few decades. However, due to more and more demanding criteria, such as unknown parameters, larger bandwidths, higher signal to noise ratio (SNR), less power consumption, etc., new pulse sequences are constantly needed. This thesis presents new pulse sequences for several important applications of NMR. / Engineering and Applied Sciences

Bibliography: leaves 299-320. / xv, 320 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this thesis is to determine the amount of exhumation in the Cooper-Eromanga Basins. The compaction method is applied in order to achieve this aim. The study expands the traditional use of the sonic log as the main 'tool' in compaction-based analysis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1997?

Thesis (M.S.)--Brigham Young University. Dept. of Geological Sciences, 2007. / Includes bibliographical references (p. 63-68).

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xii, 82 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 80-82).

Thesis (M.S.)--Baylor University, 2009. / Superscript: 6 and 3 in "106m3". Includes bibliographical references (p. 170-175).

Due to the usefulness of sonic logs in formation evaluation, efforts have been made to develop a method for calculating pseudosonic logs for wells in which sonic logs were not originally obtained. These efforts attempt to use electrical resistivity data in the calculation of pseudosonic logs by means of empirical scale functions. The purpose of this study is to examine ways of applying these relationships in relatively shallow wells where the principal formation fluid is fresh or brackish water. Data from four wells situated in Brunswick, Georgia were used in this study. Conventional focused resistivity logs are sensitive to beds as thin as one foot and can provide detail similar to that seen on sonic logs. Focused resistivity logs should be best for conversion to pseudosonic logs in shallow wells, where invasion is minimal and the water used for drilling fluid has electrical resistivity close to that of formation water. Sonic and resistivity logs from a representative well are needed in the procedure for finding an empirical relationship between sonic transit time and resistivity. Values of transit time plotted versus resistivity are read from corresponding depths on both types of logs. The graphs obtained in this study reveal significantly more scatter than previously published graphs based upon deep well data. An important feature clearly evident in the graphs is the presence of groups of points which me offset from each other. A separate scale function relating transit time and resistivity can be obtained from each group of points. It is noted that the different groups correspond to differences ir1 the chlorinity of the formation water. The results of this study indicate that it is necessary to consider the salinity of the formation water as well as electrical resistivity for purposes of calculating pseudosonic logs. In previous studies three constant coefficients were deterrnined experimentally in order to obtain an empirical scale function. The present study suggests that it may be possible to replace these constants with chlorinity dependent coefficients. The final results of this study indicate that reasonably reliable pseudosonic logs can be obtained only by using high quality focused resistivity logs from wells where information about the salinity of the formation water is also available. / Master of Science

O principal objetivo deste trabalho foi avaliar um procedimento de campo para testar o comprimento mínimo que fraturas devem ter para construir uma rede de fluxo em escala de dezenas de metros ao longo de maciços cristalinos. O comprimento mínimo é determinado a partir do limite de percolação, definido por modelos baseados na Teoria da Percolação e a densidade de fraturas no poço, determinada pela perfilagem ótica. Para testar o valor de 3,9 metros que foi encontrado, foram realizados bombeamentos em dois poços próximos enquanto o nível estático era registrado no poço de observação. O método apresenta facilidades em termos de operação e para obter-se o número de fraturas que interceptam o poço, no entanto o registro do nível estático é afetado por fatores externos, como presença de efeitos de maré e variação da pressão atmosférica, e correções são necessárias para permitir identificar a interferência proveniente somente do bombeamento. / The objective of this work is to develop a field procedure to determine a minimum characteristic length forming a connected fracture network in crystalline rocks. This minimum length is determined as a percolation threshold defined by models based on Percolation Theory and fracture density data determined from borehole imaging with well-logging probes. The characteristic length (3.9 meters) once estimated for a testing well was evaluated by monitoring its water head meanwhile nearby wells at different distances were pumped. The water head variation recorded in the testing well was disturbed by interfering effects associated to earth tides and atmospheric pressure, requiring further corrections to isolate effects induced by pumping. The results of these tests validate the percolation limit determined from logging data suggesting a rock mass with very low connectivity. The proposed test can be regarded as simple and easy to apply in many practical situations, for example when evaluating groundwater resources or geotechnical properties in fractured crystalline rocks.

O principal objetivo deste trabalho foi avaliar um procedimento de campo para testar o comprimento mínimo que fraturas devem ter para construir uma rede de fluxo em escala de dezenas de metros ao longo de maciços cristalinos. O comprimento mínimo é determinado a partir do limite de percolação, definido por modelos baseados na Teoria da Percolação e a densidade de fraturas no poço, determinada pela perfilagem ótica. Para testar o valor de 3,9 metros que foi encontrado, foram realizados bombeamentos em dois poços próximos enquanto o nível estático era registrado no poço de observação. O método apresenta facilidades em termos de operação e para obter-se o número de fraturas que interceptam o poço, no entanto o registro do nível estático é afetado por fatores externos, como presença de efeitos de maré e variação da pressão atmosférica, e correções são necessárias para permitir identificar a interferência proveniente somente do bombeamento. / The objective of this work is to develop a field procedure to determine a minimum characteristic length forming a connected fracture network in crystalline rocks. This minimum length is determined as a percolation threshold defined by models based on Percolation Theory and fracture density data determined from borehole imaging with well-logging probes. The characteristic length (3.9 meters) once estimated for a testing well was evaluated by monitoring its water head meanwhile nearby wells at different distances were pumped. The water head variation recorded in the testing well was disturbed by interfering effects associated to earth tides and atmospheric pressure, requiring further corrections to isolate effects induced by pumping. The results of these tests validate the percolation limit determined from logging data suggesting a rock mass with very low connectivity. The proposed test can be regarded as simple and easy to apply in many practical situations, for example when evaluating groundwater resources or geotechnical properties in fractured crystalline rocks.