鄂尔多斯盆地石炭-二叠纪海陆过渡相页岩气成藏条件及勘探潜力  

Permo-Carboniferous Marine-terrestrial Transitional Facies Shale Gas Reservoiring Condition and Exploration Potential in Ordos Basin

作　　者：刘亢 Liu Kang(Exploration and Research Institute,CNACG,Beijing 100039)

机构地区：[1]中国煤炭地质总局勘查研究总院,北京100039

出　　处：《中国煤炭地质》2021年第9期1-7,共7页Coal Geology of China

基　　金：中国煤炭地质总局科技专项ZMKJ-2019-J02。

摘　　要：我国页岩气储层类型多样,海相页岩气勘探开发取得的实质性突破对海陆过渡相煤系页岩气勘探潜力的研究有着重要影响。本文基于泥页岩发育特征、地化特征、储层物性等分析,对鄂尔多斯盆地石炭-二叠纪海陆过渡相页岩气勘探潜力进行了研究。研究结果表明,鄂尔多斯盆地石炭-二叠纪海陆过渡相页岩TOC含量一般大于2%,最高可达28%,决定了其较高的页岩气聚集能力;干酪根以Ⅲ型为主,缓慢连续长期地生成气态烃;有机质成熟度一般在1.0%~1.5%,处于成熟—高成熟阶段;盆地南北部脆性矿物含量达40%以上,易于泥页岩后期的压裂开发;孔隙度1.07%~10.08%、渗透率0.001~0.452mD,属于低孔低渗,具备良好的页岩气成藏条件。海陆过渡相泥页岩总体上具有以下特殊性:岩性多旋回发育、与薄煤层互层,有机碳含量高、变化快;热演化程度适中,以生气为主;矿物组成富黏土矿物、贫脆性矿物;多种天然气藏同时发育。Shale gas reservoir types in China are diversified. The acquired substantial breakthroughs in marine facies shale gas exploration and exploitation have significant impacts on marine-terrestrial transitional facies coal measures shale gas exploration potential study. Based on argillutite development features, geochemical features and reservoir physical property etc analyses, the paper has carried out Ordos Basin Permo-Carboniferous marine-terrestrial transitional facies shale gas exploration potential study. The result has shown that the TOC content in the transitional facies shale is generally above 2%, maximum can be 28% as high, thus dictated rather high shale gas accumulation capability. Kerogen is mainly belonged to type Ⅲ, generated gaseous hydrocarbon slowly and steadily over a long period. Organic matter maturity is generally within 1.0%~1.5%, in maturation to high maturation stage. Brittle mineral content in north and south parts of the basin can be above 40%, thus easy to later stage argillutite fracturing and exploitation. Porosity is 1.07%~10.08%, permeability 0.001~0.452 m/d, thus the strata belong to low porosity and low permeability with favorable shale gas reservoiring conditions. As a whole, transitional facies argillutite has following particularities: well developed multi-cyclic strata, alternating with thin coal seams, high organic carbon content with rapid variations;thermal evolution degree moderate for gas generation mainly;mineral composition rich in clay minerals, poor in brittle minerals;simultaneously developed diversified natural gas reservoirs.

关 键 词：页岩气 海陆过渡相 煤系泥页岩 石炭-二叠系 鄂尔多斯盆地 

分 类 号：P618.11[天文地球—矿床学]