德惠断陷下白垩统碎屑岩储层特征及控制因素分析

Hydrocarbon reservoir and their controlling factors of Lower Cretaceous in Dehui fault depression

德惠断陷下白垩统登娄库组、营城组、沙河子组储层物性差,勘探风险大.利用岩心观察、铸体薄片鉴定、扫描电镜分析、黏土X线衍射分析等方法,分析储层基本特征、储层成岩作用和控制因素.结果表明:德惠断陷下白垩统碎屑岩储层成分成熟度和结构成熟度较低,储层孔隙类型主要有残余原生孔、次生孔和混合孔,储层物性和孔隙结构较差;压实作用是导致储层物性变差的主要原因,溶蚀作用改善储层物性;纵向上发育2个次生孔隙带,主要形成于中成岩期,次生孔隙带的形成与有机质生烃排酸和断裂有关.研究结果为德惠断陷下白垩统进一步油田勘探提供地质依据,对其他地区类似储层研究有一定借鉴意义.

Reservoirs of Denglouku formation,Yingcheng formation and Shahezi formation of lower Cretaceous in Dehui fault depression all present poor physical property,thus bring high risk to oil and gas exploration.Based on methods of core observation,cast thin-sections authentication,scanning electron microscope analysis,and X-ray diffraction of clay minerals analysis,the basic characteristics,diagenesis,and controlling factors of reservoir were investigated.It is indicated that the textural and compositional maturation of the reservoir are both low.There are three kinds of pores,such as:remainder intergranular pore,secondary pore and mixed pore,and both of the physical property and pore structure are very poor.The compaction is responsible for the loss of the primary porosity,and the dissolution improves reservoir property.There exist two secondary pores belts vertically,which formed during middle diagenesis phase.The secondary pores is related with organic acid and fault.The above research results can provide guidance for the further oil and gas exploration of lower Cretaceous in Dehui fault depression,and it is favorable for the reservoir research in other areas with similar characteristics.