渤海湾盆地与鄂尔多斯盆地陆相优质储层形成条件对比分析

Comparison of Control Factors for High Quality Continental Reservoirs Between Bohai Bay Basin and Ordos Basin

渤海湾盆地和鄂尔多斯盆地是我国重要的两类含油气盆地,渤海湾盆地属于拉张性断陷盆地,鄂尔多斯盆地属于克拉通上的坳陷盆地。由于盆地性质的不同,优质储层的主控因素各有差异:渤海湾盆地砂体类型多样,砂体分布具有较强的分割性,有利储层受垂向上次生孔隙发育带和异常压力带的控制;鄂尔多斯盆地砂体类型相对单一,砂体分布连续性强,储层垂向分布分带性不明显,主要受砂体内幕因沉积差异而导致的成岩差异的控制。渤海湾盆地油气勘探可以沉积相为基础,以成岩深度带和层位为线索展开。鄂尔多斯盆地要遵循“砂中找砂”的勘探思路,在普遍低渗背景下寻找相对高渗区。

Baohai Bay basin, a typical extensional rift basin, and Ordos basin, an intracraton downwarped basin, are two important types of basins in China. The main control factors for high quality reservoirs are different because of their respective basin features. In Bohai Bay basin, the sandbody types are abundant and various, the distribution of sandbodies is separated seriously, and the high quality reservoirs are related with secondary pores and abnormal pressure vertically. In Ordos basin, the sandbody types are relatively monotonous, sandbodies have a good continuity, and the reservoirs are mainly controlled by the diagenetic differentiation caused by differential sedimentation inside the sandbodies, so the zonation of reservoir is not obvious vertically. In Bohai Bay basin, the oil and gas exploration should be based on sedimentary facies analysis, and focus on the favorable diagenetic zones and formations. However, in Ordos basin, the focus should be put on the relatively high permeability sandstones in the generally low permeable sandstone backgrounds.