摘要
鄂尔多斯盆地西南部长3油层具备良好的勘探前景，但对长3储层特征的差异性因素研究相对薄弱。在运用铸体薄片、扫描电镜、高压压汞等多项测试技术的基础上，通过对长3储层特征的差异性及其形成因素分析认为。镇北、合水地区长3储层物性相对优于华庆地区的原因主要包括3个方面：一是镇北、合水地区主要受西南物源控制，靠近西缘冲断带，属于近源快速堆积的产物，沉积颗粒未经远距离搬运，因此主要以相对粗粒、块状结构为主，且石英含量较高，储层抗压实能力强。华庆地区远离东北物源区，沉积颗粒经过远距离搬运分异，主要以相对细粒为主，储层抗压实能力相对较弱。二是填隙物总量镇北〈合水〈华庆，呈递增趋势，碳酸盐、黏土矿物以及硅质胶结作用表现为镇北〈合水〈华庆。三是部分绿泥石膜胶结，长石溶解以及岩石的破裂作用有效改善了储层物性．表现在面孔率上为镇北〉合水〉华庆。
Chang3 reservoirs in the southwestern Ordos Basin have good prospects for oil exploration, but researches on difference factors of Chang3 reservoir charactefislics are relatively weak. On the basis of the use of multiple testing techniques such as cast thin section, scanning electrun micrographs, high pressure mercury intrusion and so on, differences in Chang3 reservoir characteristics and their forming factor are analyzed in this paper. It is considered that why the properties of Chang3 reservoirs in Zhenbei and Heshui areas are relatively better than those in Huaqing area mainly includes three aspects： First, Zhenbei and Heshui areas are mainly con- trolled by the source rock in the southwest, and close to the western margin thrust belt. They are the product of near-source rapid accumulation. The deposited particles have not been long-distance transported, Therefore, they take relatively coarse-grained and blocky structures as the main, with high quartz content, leading to the reservoirs with strong anti-compaction capability. Huaqing area is far away from the northeast source area （provenance）. The deposited particles are carried long-distance and differentiated, taking relatively fine grains as the main. Therefore the reservoirs are relatively weak in anti-compaction. Second, the total amount of fillings, and carbonate, clay mineral and siliceous cementation assume increasing tendencies in Zhenbei-Heshui-Huaqing areas. Third, some chlorite film cementation, feldspar dissolution and the rock fracturing effectively improve the reservoir properties, manifesting a decreasing trend of pore-section area ratio accordingly in Zhenbei-Heshui -Huaqing areas.
关键词
鄂尔多斯盆地
长3油层
储层特征
Ordos basin
Chang3 reservoirs
reservoir characteristics
