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Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mining Science & Technology is the property of Journal of Mining Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Soochow University Philosophy & Social Sciences Edition is the property of Soochow University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to screen synthetically the dispersants of pulverized coal in CBM well-washing technology, the experiments of the dispersion stability of pulverized coal, the wetting characteristics and the coal reservoir damage evaluation have been carried out by using the No. 11 coal of Taiyuan formation in Hancheng mining area and different anionic dispersants, based on the influences of dispersant solution on pulverized coal, coal surface properties and coal reservoir. The effects of different dispersants on coal rock have been investigated. The results show that the pulverized coal with a particle size of less than 300 μm has a poor dispersion stability in water. Adding a dispersant can help to improve the dispersion stability of the pulverized coal. Combined the surface tension of the different dispersant solutions, the contact angle, spreading coefficient and the adhesion work, different pispersants have different wetting degrees to pulverized coal, the best one is the 2 g/ L SDS solution. The coal permeability varies due to the invasion of dispersant solution and the effect of water lock of coal. The damage degree of permeability shows a relationship of SDS>CMN> SN. And with the changes of capillary force, the permeability damage rate by the invasion of dispersant solution increases. For the Hancheng block, the SDS dispersant can make the pulverized coal easier to disperse, and it can cause some damage to coal permeability. Therefore, in the well-washing process, the bottom-hole flowing pressure should be kept stable and the dispersant solution should be avoided entering into the coal reservoir in the near-well bore region. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pulverized coal is one of the important problems during the CBM well drainage.Aimed at pulverized coal with different diameters,the No.11 coal of Taiyuan formation in Hancheng block was studied.Using different anionic dispersants,the experiment on screening dispersants was carried out.Dispersion stability of pulverized coal with different particle sizes was analyzed according to dispersing characters,suspension concentration and viscosity.The optimal dispersant in CBM well-washing technology was screened.The results showed that the dispersion stability changed in different degrees with the increase of the pulverized coal particle size,and the concentration of pulverized coal in each dispersant suspension was reduced with the growth of time.On the comprehensive analysis,the SDS dispersant performed the best for pulverized coal with size less than 200 μm,the CMN dispersant dispersed the best for pulverized coal in 200-300 μm.For the characteristics of pulverized coal in Hancheng block,the SDS dispersant had the best dispersion effect on pulverized coal and the SDS dispersant dispersion of pulverized coal was the most stable. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Selected areas evaluation of coalbed methane has always been an important link in the process of coalbed methane (CBM) exploration，in which the evaluation method is the key to favorable area. The methods gradually developed from the qualitative evaluation to quantitative evaluation in recent years. This paper uses southern Junggar Basin as an appraisal area. Firstly，five typical kinds of evaluation methods are discussed，in which the merits and demerits are systematically expounded. It is founded that qualitative evaluations are still practical，although quantitative evaluations have improved the veracity of evaluation，subjectivism and empirical judgments are still existed in the process of quantitative evaluations to some extent. Based on the differences and similarities of the five evaluation methods，principal component analysis (PCA) has been proposed for the purpose that avoids the subjectivism and empirical judgments. The Sigonghe to Dahuangshan area has been selected as a favorable area by PCA method，the same result is generated by the five evaluation methods，which proves that the PCA method is feasible in selecting the favorable CBM areas，and its greatest advantage is to avoid the subjectivism. The authors advocate that the thought of “first qualitative judgment，second quantitative analysis，and final qualitative verification” should be used to select favorable CBM areas. [ABSTRACT FROM AUTHOR]

Coal fines generation can cause downhole failures during coalbed methane development, which include poor drainage, pump leakage and stuck pump. In order to prevent and control these failures, the research on the forecast of damage on production equipment caused by coal fines through monitoring dynamometer card was conducted. Based on the coalbed methane production in Hancheng, Ordos Basin, the load analysis and shape comparison of typical dynamometer cards of coal fines-related downhole failures were performed. Two quantitative parameters for indicating downhole failures by monitoring dynamometer card were proposed, which were R, unload line lag range and θ, load line deviation angle. According to the variation range of R and θ, the intensity of failures was divided into four grades respectively. The example analysis of poor drainage and stuck pump showed that the shape feature of dynamometer card could be indicative for the severity of coal fines aggregation and related downhole failures. The comprehensive analysis of the production data, such as the shape and load ratio of dynamometer card, the current fluctuation of inverter, and daily water yield change, can accurately identify the functional state of downhole equipment and the damage degree of coal fines. Adopting reinjection drainage, well washing and other control measures to the wells with failure symptom can effectively dilute coal fines concentration, disrupt coal fines aggregation, accelerate coal fines migration, and then mitigate coal fines damage and related downhole failures. [ABSTRACT FROM AUTHOR]