河南中牟区块太原组-山西组页岩气富集控制因素

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

河南中牟区块牟页1井是南华北地区第一口海陆过渡相页岩气探井,对太原组、山西组压裂试气,取得了日产1256 m3天然气的重大发现.基于对牟页1井及地震等资料综合研究,认为太原组和山西组页岩气富集与产能控制因素取决于原始沉积条件和后期保存条件;泥炭沼泽亚相和潟湖亚相为页岩气发育最有利相带,页岩厚度大、有机质含量高是页岩气勘探选区的重要评价指标;区块内通天断层较多,盖层为泥岩而非封闭更好的膏盐岩,显示总体保存条件一般;在页岩气层系地化指标、厚度、埋深、沉积相及盖层条件相似的情况下,寻找构造相对稳定的区域是下一步勘探选区的关键.

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 1256 m3 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.