苏北地区下寒武统幕府山组页岩气勘探前景

通过野外地质调查、岩心观察、老井复查、分析测试及模拟实验等方法,研究苏北地区下寒武统幕府山组富有机质泥页岩的有机地球化学特征、储层特征及含气性等,并探讨其页岩气勘探前景.幕府山组富有机质泥页岩发育于该组下部,为陆棚-盆地相沉积,厚度一般在50～200m之间,顶界埋深一般为2.5～4.0 km,干酪根类型主要为Ⅰ型和Ⅱ1...

Shale-gas exploration prospect of Lower Cambrian Mufushan Formation in the northern Jiangsu, China

Based on the geological surveys in the field,core observation,historical well re-examination,analysis and testing,simulation experiment etc.,this paper analyses the organic geochemistry characteristics,reservoir characteristics and gas-bearing features of the rich-organic matter shale in Lower Cambrian Mufushan Formation of northern Jiangsu.The rich-in organic matter shale develops in the lower part of Mufushan Formation and is shelf-basin facies with a cumulative thickness generally of 50~200 m.The top depth is generally 2.5~4 km.The main kerogen types are I and II1.The shale has a high organic matter abundance.The an average of TOC is 3.32% and the maximum TOC is 12.1%.In the high heat evolutionary stage,the equivalent vitrinite reflectance is 0.73%~3.01% and averages 2.83%.The shale contains abundant clay minerals and quartz and a small amount of K-feldspar and gypsum.The main compositions of clay minerals are illite and I/S mixed layer,but the clay minerals do not contain smectite.Micropores and microcracks develop well in the shale reservoir.The isothermal adsorption simulating experiment shows that the shale has good gas absorbed capacity.It is estimated that the average shale-gas(free and absorbed gas) content of Mufushan Formation in the northern Jiangsu is 1.4 m3/t,and the shale-gas resources amount is 1.8×108 m3/km2,which indicates a great shale-gas resources potential.According to the preliminary prediction,the favorable areas for shale-gas exploration of Mufushan Formation in northern Jiangsu are mainly distributed from Quanjiao in Anhui Province to Liuhe in Jiangsu Province and over the Yangzhou-Gaoyou-Xinghua area in Jiangsu Province.