准噶尔盆地北三台凸起芦草沟组低渗储层评价

Evaluation on Low-permeability Reservoir in Lucaogou Formation,Beisantai Bulge,Junggar Basin

碎屑岩低渗透储层评价机制包括沉积类型和低渗储层岩石特征评价。在地震资料分析的基础上,应用物源、沉积相和岩石储层特征等对准噶尔盆地北三台凸起二叠系芦草沟组低渗透储层开展了研究。研究表明:芦草沟组发育辫状河三角洲和滨浅湖2种亚相,其物源来自北部北三台凸起、南部博格达山;芦草沟组分为2段,其中芦草沟组一段分布范围有限,属填平补齐,芦草沟组二段分布范围较大,沉积厚度约占据整个芦草沟组的2/3。在沉积相研究的基础上,通过储层岩石学特征、物性特征、空间类型等研究,认为储层孔隙结构复杂,属于中—低孔、低渗储层。根据沉积相类型和低渗透储层岩石特征对芦草沟组作出了综合评价,有利储层的分布与沉积相展布密切相关,优质储层主要发育在辫状河三角洲前缘。

The evaluation mechanism of low- permeability reservoir in clastic rock includes the evaluation on sedimentary types and rock features of low- permeability reservoir. On the basis of analysis on seismic data,provenance,sedimentary facies and reservoir features are used to make research on low- permeability reservoir,Lucaogou Formation of Permian,Beisantai Bulge,Junngar Basin. Research indicates that Lucaogou Formation developed 2 types of sub- facies including braided river delta and shallow shore lake. The provenance is from Beisantai Bulge in the north and Bogda Mountain in the south; Lucaogou Formation can be divided into2 members; the distribution of 1st member is limited,which belongs to filling and levelling up; the distribution range of 2nd member is large and the sedimentary thickness represents 2 /3 of the whole Lucaogou Formation. On the basis of research on sedimentary facies,through research on petrology features,property features,spatial types,it is believed that the pore structures of reservoir are complicated,belonging to medium- low porosity and low permeability reservoir. Based on the sedimentary facies type and low- permeability reservoir features,comprehensive evaluation has been made for Lucaogou Formation. The distribution of favorable reservoir is closely related to the distribution of sedimentary facies. The quality reservoirs are mainly developed at the braided river front.