CONTROLLING FACTORS OF THE SHALE GAS ENRICHMENT IN TAIYUAN AND SHANXI FORMATIONS OF ZHONGMU BLOCK, HENAN PROVINCE

The MY-1 well in Zhongmu block of Henan Province is the first shale gas exploratory well with marine-continental transition facies in southern North China. A total natural gas production of 1256m³ per day is obtained through test fracturing in Taiyuan and Shanxi formations. Based on the comprehensive researches on MY-1 well and seismic data, it is believed that the enrichment and productivity of shale gas in both formations depend on the original deposition and later preservation conditions. The peat bog and lagoon subfacies are most favorable for the development of shale gas. Large thickness and high content of TOC are important evaluation indexes for target selecting. Many of faults in the block thrust up to the surface, with caprock of mudstone rather than better sealed gypsum salt rock, indicating the overall preservation conditions are ordinary. Therefore, under the similar conditions of geochemical indexes, thickness, burial depth, sedimentary facies and caprock of shale gas layers, the key to further exploration is to search for areas with relatively stable structures.