Geological controls on the formation of coalbed methane reservoirs and prediction of target areas of Turpan-Hami basin, Northwest China

摘要

To better understand the controls on coalbed methane (CBM), a lot of surveys and experiments (including coal petrology analysis, mercury porosimetry, Brunauer-Emett-Teller (BET) nitrogen adsorption at low temperature and methane adsorption/desorption) are conducted. The structures, coal-bearing strata and coal facies are revealed by geological research and the laboratory tests showed the coal petrologic characteristics, coal types, macerals, vitrinite reflectance (Ro). permeability, pore and cleats characteristics and coal adsorption/desorption ability. Finally, based on above analysis, analytic multi-hierarchy process-fuzzy mathematics (AMP-FM)method is introduced into appraising the CBM resources. The results show that Turpan-Hami basin was divided into five levels for CBM resources, in which Aiweiergou and Yilahu mines are the most favorable CBM development districts. Total CBM resources less than 1 500 m in Turpan-Hami basin are 2.058 7×1012 m3 calculated using cubage method, and the average abundance of CBM resources for Turpan-Hami basin is 1.56×108 m3/km2.