Seismic studies of coal bed methane content in the west coal mining area of Qinshui Basin

The coal bed methane content(CBMC)in the west mining area of Jincheng coalfield,southeastern Qjnshui Basin,is studied based on seismic data and well-logs together with laboratory measurements.The results show that the Shuey approximation has better adaptability according to the Zoeppritz equation result;the designed fold number for an ordinary seismic data is sufficient for post-stack data but insufficient for pre-stack data regarding the signal to noise ratio(SNR).Therefore a larger grid analysis was created in order to improve the SNR.The velocity field created by logging is better than that created by stack velocity in both accuracy and effectiveness.A reasonable distribution of the amplitude versus offset(AVO)attributes can be facilitated by taking the AVO response from logging as a standard for calibrating the amplitude distribution.Some AVO attributes have a close relationship with CBMC.The worst attribute is polarization magnitude,for which the correlation coefficient is 0.308;and the best attribute is the polarization product from intercept,of which the correlation coefficient is-0.8136.CBMC predicted by AVO attributes is better overall than that predicted by direct interpolation of CBMC;the validation error of the former is 14.47%,which is lower than that of the latter 23.30%.CBMC of this area ranges from2.5 m^3/t to 22 m^3/t.Most CBMC in the syncline is over 10m^3/t,but it is below 10m^3/t in the anticline;on the whole,CBMC in the syncline is higher than that in anticline.

Thermodynamic Analysis and Optimization of the C3/MRC Liquefaction Process

In the natural gas liquefaction process,the mixed refrigerant natural gas liquefaction process is widely used in LNG liquefaction plants because of its advantages of low energy consumption.This paper focuses on the influences of important parameters in the C3/MRC liquefaction process,that is,the comparison between propane precooling temperature and the number of moles of methane in mixed refrigerant,power consumption and loss.In addition,the total process was optimized with the optimizer and manual adjustment in HYSYS software to minimize the total power consumption.The results show that with increasing propane precooling temperature,the propane flow rate is almost unchanged,while the mixed refrigerant flow rate decreases significantly,and the loss of the heat exchanger increases significantly.The power consumption of the propane precooling cycle and hybrid refrigeration cycle increases with increasing methane content in the refrigerant,so the power consumption of the whole process increases accordingly.The effect of the methane content in the mixed refrigerant on the process evaluation index is more significant than that of the propane precooling temperature.