The coalbed methane (CBM) resource in the southern Qinshui Basin, North China, is abundant. Proper understanding of the geological control factors on CBM enrichment in Anze Block of southern Qinshui Basin is critical to design efficient CBM development plan in this area. Field and laboratory data including well logging, well testing, hydraulic fracturing, and groundwater chemical analysis of were used to evaluate the characteristics of the hydrodynamic and geostress, and then, the combined effect of hydrodynamic and geostress field on CBM enrichment was analyzed. The results show that the total dissolved solids (TDS) of groundwater in the west is generally lower than that in other areas in the block, and the primary formation water is NaHCO3-type. The geostress field shows a σ H > σ v > σ h dominated geostress type in this area, and the western block has a lower value than the eastern block. The strong hydrodynamic field with low TDS also has a lower gas content while the weak hydrodynamic field with high TDS has a higher gas content. Both the TDS value and the horizontal stress differences are positively related to the gas content, indicating that inactive hydrodynamics and large horizontal stress difference of coal reservoir is favorable for CBM preservation.

Owing to its good tribological and mechanical properties, polyamide material was widely applied to prepare sliding mechanical parts. A lot of studies confirmed that adding different functional materials or surface modifications to polyamide could reduce the friction coefficient, improve wear resistance and reduce water absorption, so as to prolong the service life of polyamide parts. This paper summarized the common reinforcement methods of polyamide materials: blending, surface modification and filler. The reinforcing mechanism of different fillers and polymers, the effects of different methods on the tribological properties, mechanical properties and water absorption of polyamide composites, and the preparation methods of polyamide composites have been systematically discussed.

No abstract