Distribution and controlled geological factors of oil-rich coal in shaanxi province

Abstract

The green, clean and efficient utilization of coal is an important way for the sustainable development of coal industry. Shaanxi province is rich in coal resources, which are mainly distributed in the five coal fields in the north of Shaanxi province, and the oil-rich coal resources rank first in China. In this paper, the distribution characteristics of oil-rich coal in Shaanxi Province and the geological factors affecting the tar yield of coal are discussed by collecting the previous geological exploration data and the coal core of a coal mine in Yushen mining area of northern Shaanxi Province. The results show that the Jurassic coal field in northern Shaanxi is the best oil-rich coal in Shaanxi Province, and the tar yield is distributed in the range of 7.6%-15.3%. Material composition, oil generation potential, thermal evolution degree and coal-forming environment control the size and distribution of tar yield in coal. The desmocollinite content, volatile matter content, H element content and H/C atomic ratio were positively correlated with the tar yield of coal, and the correlation coefficient was high. There is a high correlation between the hydrocarbon index and tar yield in rock pyrolysis parameters, which can be used as an index to quickly identify tar yield in coal. The tar yield of coal increases first and then decreases with the increase of thermal evolution degree, and reaches the maximum value when Ro is about 0.9%. The higher the coal tar yield value is in the peat swamp facies with micro-flow, strong reduction and shallow overlying water-micro-flow in sedimentary environment. The research results provide reference for geological prediction of oil-rich coal.

Keywords

• oil-rich coal
• coal tar
• shanbei jurassic coalfield
• sedimentary environment
• geological prediction