Recovery of highly viscous oil from some of the deeper oil sand deposits of northern Alberta, Canada, is made possible through injection of heat by steam or hot water flooding of the reservoirs. The rise in temperature lowers the viscosity of the bitumen allowing it to be produced. The increase in temperature accelerates the reactions between the matrix and pore minerals of the formation and can produce reaction products which can significantly alter the permeability of the reservoir. If carbonate minerals are present in the reservoir, inorganic CO2 may also be a reaction product.
The Grand Rapids reservoir consists of relatively clean quartz sand containing 7 wt.% kaolinite, 1 wt.% calcite and a trace of smectite. Core floods of this sand by a neutral NaCl brine at 265°C, 8.2-MPa overburden pressure, 6.0-MPa fluid pressure and a flow velocity of 0.4 pore volumes per hour were used to determine the potential for hydrothermal reactions between clays and carbonate minerals in a natural reservoir sand. Reaction progress was followed by continuous sampling of the production fluids. The produced water was analyzed and the phase chemistry was calculated back to the run conditions using the computer code SOLMNEQF.
Mass-balance considerations on produced total inorganic carbon (TIC) show that calcite broke down very quickly, the maximum in CO2 production occurring after only one pore volume of fluid had passed through the core. The Ca released from the breakdown of calcite was incorporated in the formation of smectite as was shown by post-run clay mineral analysis by the following unbalanced chemical reaction:
calcite+kaolinite+H4Si04Ca-smectite+H20+CO2
Silica was supplied by the dissolution of quartz. Silica concentrations analyzed in the production fluid were depressed from those predicted by previously published quartz rate equations because of the rapid rate of smectite synthesis.
These observations were used to formulate the following model for the passage of the first pore volume of NaCl brine through the core. Initially calcite is present throughout the core. As the brine enters the inlet of the core, it equilibrates with calcite. The brine remains in equilibrium with calcite throughout the core as quartz and kaolinite react to form smectite. This model was tested with the computer code PATH.UBC using CO2 production as a measure of the progress variable ξ. A best fit was achieved to the produced fluid chemistry by varying relative dissolution rates of kaolinite and quatz and varying the suppression of precipitation of certain minerals. 相似文献
A simple modification was made to the reaction vessel designed by Shaw (1963) in order to use it as a hydrogen sensor instead of a hydrogen source, thereby allowing a continuous record of
to be made during an experiment. The advantage of this arrangement is that (reversed)
curves for minerals can be generated from a single experimental run. Other applications are possible.This method was successfully used in the determination of the Ni-NiO-H2O equilibrium between 580 ° and 830 °C at 2 kbar fluid pressure. The corrected 1 atm values are in agreement with electrochemical measurements. An Ag70Pd30 hydrogen permeable membrane was used for the experiment and flow rates of hydrogen through the membrane were calculated by monitoring the rate of increase or decrease in pressure with an induction pressure transducer. These flow rates range up to two times greater than those calculated for a pure platinum membrane. 相似文献
This article explores the globalization of U.S. Major League Baseball (MLB), measured by the participation of foreign-born players in the sport from 1876 to 2005. Data show that the number of non-native athletes has been increasing since the end of World War II, suggesting that MLB is becoming a more globalized organization. An investigation at regional and country levels reveals that most foreign participants in the 1990s and early 21st century are from Latin America, especially the Dominican Republic. In contrast, most African, European, and Asian countries have shown little sign of participation. This implies that the global reach of MLB is limited. An empirical study of 2005 data suggests that prosperous countries, neighboring countries, or countries having a close political relationship with the U.S. tend to provide more athletes to MLB. In other words, the globalization of MLB is reliant on America’s economic, cultural, and geographic proximity to the rest of the world. 相似文献
Fine-scale sampling with alvin and by dredging of the axial ridge in the Mariana Trough between 17°40′N and 18°30°N recovered basalts with isotopic compositions that span the range between N-type MORB and Mariana island arc basalts. There is a local tectonic-morphological control on basalt compositions; MORB-like basalts are found on the deeper ridge segment bounded by the Pagan transform and the ridge offset at 17°56′N, while basalts from the shallower ridge to the north are typical Mariana Trough basalts (MTB) having compositions intermediate between the two endmember rock types. Arc-like basalts were recovered from one site on the axial ridge.The discovery of basalts with such diverse isotopic characteristics from a short (100 km) section of this backarc spreading center constrains the chemical characteristics and distribution of mantle source variability in the Mariana Trough. SrNdPb isotopic variability suggests that the MTB source is heterogeneous on the scale of individual melt batches. The principal component in the MTB mantle source region is depleted peridotite similar to the source of MORB. The enriched component, most evident in the arc-like basalts and intimately mixed in MTB, has isotopic characteristics similar to those observed in the Mariana arc basalts. The isotopic data suggest that source variability for Mariana axial ridge basalts can be explained by mixed arc-like and MORB-like mantle. We hypothesize that there are fragments of old oceanic lithosphere in the backarc source region. This lithospheric component may reflect remnants of subducted seafloor or forearc-volcanic arc mantle that predate rifting in the backarc basin. 相似文献
Biological distributions and fish migrations during the spring and summer in the mid-latitude N Pacific are believed to be
affected by the large-scale wind systems during the preceding winter. These wind systems are related to the field of atmospheric
pressure which, on a monthly or quarterly time scale, show pronounced interannual variations. This exploratory investigation
is concerned with measures of the large-scale wind systems that are indicative of their intensity, location, and size, and
that can be derived from monthly or quarterly sea-level pressure distributions. Of interest are the NW, W, and SW wind systems
which are related to the pressure gradients between the Siberian High and Aleutian Low, the Aleutian Low and the N Pacific
Subtropical High, and the Aleutian Low and the N American High, respectively. Interannual changes in the winter sea-level
pressure distribution pattern are primarily the result of changes in the pressure and zonal displacements of the Aleutian
Low near 50°N. This property permitted simple derivation of wind indices from grid values of N hemisphere mean winter pressures
distributions for the years 1947 to 1985. Indices, presented as normalized anomalies, are for the meridional component of
the wind system at 50°N over the ocean W and E of the Aleutian Low, for the westerlies S of the Aleutian Low and for the longitude
of this Low. The paper concludes with a discussion of the limitations of the indices in terms of reflecting characteristic
atmospheric pressure distribution patterns, an examination of the relationship between wind anomalies and El Nino events,
and a discussion of the results in terms of oceanographic, climate, and biological implications. 相似文献
Geochemical and isotopic analyses have been performed on a suite of samples from a Jurassic quartz tholeiite sill of the Ferrar Group at Portal Peak, Queen Alexandra Range, near the Beardmore Glacier in Antarctica. The data include major and trace element (XRF and INAA) concentrations, as well as Sr and Nd isotopic compositions, and are combined with the results of other studies on samples from Antarctica. It is demonstrated that despite differences in the pre-intrusion (or eruption) evolution of the Ferrar Group magmas, the similarity in isotopic and chemical compositions for these rocks supports the existence of a remarkably uniform mantle source with unusual signature over a distance of thousands of kilometres. The favoured origin of this source involves the subduction of terrestrial sedimentary material into a depleted mantle reservoir. 相似文献
Gaseous nitrogen compounds (NOx, NOy, NH3, N2O) were measured at ground level in smoke plumes of prescribed savanna fires in Lamto, in the southern Ivory Coast, during the FOS/DECAFE experiment in January 1991. During the flaming phase, the linear regression between [NOx] and [CO2] (differences in concentration between smoke plumes and atmosheric background) results volumic emission ratio [NOx]/[CO2]=1.37×10–3 with only slight differences between heading and backing fires. Nearly 90% of the nitrogen oxides are emitted as NO. Average emission ratios of other compounds are: 1.91, 0.047, and 0.145×10–3 for NOy, NH3 and N2O, respectively. The emission ratios obtained during this field experiment are compred with corresponding values measured during former experiments with the same plant species in combustion chambers. An accurate determination of both the biomass actually burned and of the plant nitrogen content, allows an assessment of emission fluxes of N-compounds from Guinean savanna burns. Preliminary results dealing with the influence of fire on biogenic emissions from soils are also reported. 相似文献