Quantitative Research on History of Adsorption Capacity on High Rank Coal Reservoirs: A Case Study From Hancheng area in Ordos Basin, China

Abstract

In China, high rank coal-bearing basins have undergone multiple subsidence and uplift events. Research on the adsorption capacity evolution of high rank coal reservoirs in geological history has implications for better understanding of coalbed methane enrichment and accumulation. In accordance with the data of high-temperature and high-pressure methane isotherm adsorption experiments, a mathematical method was established for predicting adsorption evolution of coal reservoirs and then the adsorption evolution process reconstructed for main coal reservoirs in Hancheng area, Ordos basin. Results show that the adsorption capacity of high rank coal reservoirs is influenced by multiple factors. It is positively correlated with pressure and thermal evolutionary degree of coals, and negatively correlated with temperature, moisture content, ash content and volatile matter content. Based on mathematical analysis, an extended Langmuir model considering temperature, pressure and thermal evolutionary degree was built to predict the adsorption capacity of high rank coals. Combined with the analysis of burial history and thermal history, the adsorption evolution process of the main coal reservoirs in Hancheng area was divided into three stages, including the stable low-adsorption stage, increasing adsorption stage, and stable high-adsorption stage.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015