富有机质泥页岩有机质孔隙研究进展

Study advances on organic pores in organic matter-rich mud shale

泥页岩有机质孔隙是页岩气储层的主要孔隙类型,是页岩气的富集关键因素之一。近年来对有机质孔隙成因、控制因素及页岩气储层的储渗性能研究取得了较大的进展,研究表明：有机质孔隙的成因包括干酪根生烃形成的孔隙与沥青裂解形成的孔隙2种类型。根据有机质孔隙大小,可分为大孔、中孔（介孔）与微孔。页岩气以吸附态赋存在微孔、介孔中,以游离态保存在大孔中。吸附态主要发生在孔径〈10nm的孔隙中,大孔中游离态烃以非达西渗流方式流动。有机质的成熟度处于0.9%~3.6%、腐泥组与镜质组显微组分、有机碳质量分数〉2.0%是有机质孔隙发育的有利条件;压实程度较高、较高的流体压力、脆性矿物含量高的泥页岩是有机质孔隙保存的有利条件。

The organic pore is the main kind of pore type in the mud shale reservoir and one of the key factors influencing the enrichment of shale gas.In recent years,the genesis and the influencing factors of the organic pore as well as properties of the reservoir and permeability of the shale gas reservoir have achieved great progress.These researches show that the types of the organic pore include the pores formed by the generation of hydrocarbon in kerogen and that formed by tar cracking.According to the sizes,the organic pores can classified into macropore,mesopore and micropore.The shale gas is restored in mesopores and micropores as an absorbed phase,and in macropores as a free phase.The free gas in the organic macropores flows in non-Darcian way.The organic maturity（Ro）of the organic matter is 0.9%~3.6%,the organic type with sapropelic and vitrinite type,and the high TOC content（〉2.0%）are the favorable factors for the development of organic pores.The mud shale with high compaction degree,high fluid pressure and high content of brittle minerals are the advantageousconditions for the preservation of the organic pores.