Total organic carbon (TOC) estimation is very important for shale gas reservoir characterization. There are many introduced methods for TOC prediction in organic-rich shales. However, there are still some weaknesses with the most of the methods. This paper proposes a new method using machine learning, Gaussian Process Regression, which is expert in processing high-dimension, small samples, and non-linear problems. Compare to the Neural Network, and Support Vector Machine, Gaussian Process Regression has adaptation and generalization ability. This paper takes Zhangjiatan shale of the Yanchang Formation of the Triassic period in the south-eastern Ordos Basin as an example. A total of 7 kernel functions are applied to build the regression model. As a result, the Cauchy kernel is chosen due to lowest error. Then, feature selection is carried on based on the weights which calculated from 4 weights algorithms. Finally, compared the Gaussian Process Regression results to the traditional methods, (e.g., Passey and Schmoker methods), we found that Gaussian Process Regression works well for TOC estimation.
Sexual dimorphism in limb muscles is widespread among anurans, with males having stronger limbs than females. This phenomenon has been interpreted in the context of intrasexual selection: 1) the robust forelimb muscles in males are associated with amplexus, in which the male tries to grasp the female tightly, and also with rejection of rivals' attempts at taking over, and 2) massive hindlimb muscles favor the ability to kick away rivals during scramble competition. However, in a few species, fertilization occurs without any form of amplexus and in these species the hmb muscle dimorphism is expected to be absent. We tested this prediction in Feirana taihangnicus: a species without amplexus. As expected, we detected non-significant sexual differences in the mass of both forelimb and hindlimb muscles after accounting for body size and age. Our findings represent an interesting example of coevolution of form and function.
With further progress of Steam-Assisted Gravity Drainage (SAGD) technology, a growing number of oil sands or heavy oil reservoirs were put into production in an efficient way. However, owing to the existence of muddy laminae within reservoirs, there are challenges associated with the expansion of the steam chamber and oil drainage during the SAGD process. The purpose of this study is to evaluate the adverse impact of muddy laminae on conventional SAGD performance and introduce an improvement strategy with multilateral well patterns to reduce the adverse impact and improve the performance. In the research reported here, the reservoir numerical simulation approach is applied to conduct the research. The analysis conducted on a prototypical reservoir reveals that the steam chamber may expand slowly in some sections due to the poor capacity of heat and mass transfer, and the expansion of the steam chamber is relatively uneven along the wellbore, when the muddy laminae are existing in the formation. The influence level of the muddy laminae on conventional SAGD performance under different distribution modes is different, but the adverse effect is mainly reflected in the delay of peak oil production, the decrease in peak oil production, the decrease in steam chamber volume, and the increase in the cumulative steam oil ratio (mainly in early and middle stages of the SAGD process). On the basis of aforementioned researches, the improvement strategy with two different multilateral well patterns, planar multilateral well and upward multilateral well, is introduced to improve the SAGD performance. The results indicate that the combination of a planar multilateral injector and planar multilateral producer has the best performance. By adopting such kind of combination, the recovery factor can be increased from 31.36% to 47.08%, and the cumulative steam oil ratio can be decreased from 5.29 m3/m3 to 4.64 m3/m3 under the combined distribution mode of muddy laminae. It can be known that the branches of the planar multilateral well are very helpful for the expansion of the steam chamber and oil drainage, once the heat connection between branches of the injector and producer is well established. Overall results show that the multilateral well pattern is promising for SAGD applications at oil sands or heavy oil reservoirs which are rich in muddy laminae.
Factors associated with IPV among immigrant women are not well understood. Using linked immigration and justice data, we compared the incidence of justice-identified IPV (JIIPV) among 58,564 international immigrant women born outside of Canada, 30,098 women born in other Canadian provinces (i.e., interprovincial migrants), and 88,662 long-term Manitoban resident women. International immigrant women had the lowest incidence of JIIPV compared to matched long-term Manitobans (adjusted hazard ratio (aHR) 0.49, 95% CI: 0.43–0.56) and interprovincial migrants (aHR 0.56, 95% CI: 0.43–0.73). Among immigrants, JIIPV varied substantially according to birthplace, increased with length of residence, and was less frequent among secondary immigrants.
Age determination is crucial for a full understanding of population dynamics. In this context, we studied the age structure of the paddy frog, Fejervarya multistriata, in a population from the central east of China, using a skeletochronological method. The lines of arrested growth in the phalanges were distinct, and each line was assumed to represent one year of age. Ages ranged between one and four years for adult males and two and four years for adult females. No significant difference was observed in the mean adult age between the sexes. In addition, a significant relationship between age and body size within each sex was detected. Results of ANCOVA analysis suggested a significant difference in body size between sexes when the effect of age was removed. The von-Bertalanffy model showed that females had a larger asymptotic body size than males, and the growth rate of females was higher than that of males. Therefore, the growth rate is a major factor underlying body size patterns in both sexes of F. multistriata in the study population.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.