川西南地区上三叠统须家河组砂岩储层综合评价

Reservoir Evaluation of Upper Triassic Xujiahe Formation in Southwest Sichuan Basin

通过大量岩心、薄片观察和钻测井、储集物性资料分析,发现川西南地区须家河组储集体为辫状河三角洲前缘砂体,其分布广泛,物性较差,属于低孔低渗储层;储层岩性主要为长石质、岩屑质石英砂岩,储集空间为残留原生粒间孔、粒间溶孔、粒内溶孔、铸模孔和裂缝,水下分流河道与河口坝是有利储集体;储层在须二段和须四段发育(须二段储层物性好于须四段),以Ⅱ、Ⅲ类储层为主,Ⅰ类储层分布较少,优质储层受控于构造、沉积相带和岩石粒度。

According to core and thin-section observation, drilling, logging and reservoir physical property analysis, the reservoir body in the Xujiahe Formation of the southwest Sichuan basin is braided delta front sandbodyies which have wide distribution, poor physical properties, and low porosity and low permeability. The lithology is mainly feldspar quartz sandstone and lithic quartz sandstone, and the main pore spaces are relict primary intergranular pores, intergranular solution pores, intragranular solution pores, pores in grain films and fractures. Reservoirs of the Xu 2 and Xu 4 are well developed and the Xu 2 reservoir physical properties are better than Xu 4. Favorable reservoirs were underwater distributary channels and mouth bars. High quality reservoirs are controlled by structural conditions, sedimentary facies and particle size of rocks. The types of reservoirs in the Xujiahe Formation are mainly Types Ⅱ and Ⅲ, and the type Ⅰ is less.