松辽盆地梨树断陷致密气储层特征研究

Study on the characteristics of tight gas reservoir inLishu fault depression of Songliao Basin

梨树断陷下白垩统油气资源量大,勘探程度低,储层埋藏深,岩性致密,主要为中-细粒砂岩,孔隙类型以粒间孔、粒内溶孔、晶间微孔为主,铸模孔、粒缘缝和破裂缝次之。本文主要从岩石成分和孔隙类型两个方面分析影响储层储集性的因素,认为长石含量是决定储层物性的主要因素,浊沸石在成岩阶段早期被溶蚀形成有利孔隙,成岩晚期大量高岭石的出现说明生烃过程的排酸作用改变了成岩环境,方解石胶结物的溶蚀改变了储层的渗透性。

The lower Cretaceous in Lishu fault depression has a large amount of oil and gas resources,a low degree of exploration,a deep buried reservoir,and a dense lithology.It is mainly composed of medium to fine-grained sandstone.The pore types are mainly intergranular pore,intragranular dissolution pore and intergranular micropore,followed by mold pore,grain margin fracture and fracture-fissure.In this paper,the factors affecting reservoir property are analyzed from two aspects:rock composition and pore type.It is considered that feldspar content is the main factor determining the reservoir properties.In the early diagenetic stage,the laumontite is dissolved to form favorable pores,while in the late diagenetic stage,a large amount of kaolinite indicates that the acid excretion during hydrocarbon generation process changes the diagenetic environment,and the dissolution of calcite cement changes the permeability of reservoirs.