Abstract: Capillary pressure of core samples from the Triassic oil reservoirs of Ordos basin was determined by mercury injection, and the data thus obtained were used to determine the thickness of the oil-water transition zone. The results show that the reservoir rocks are highly heterogeneous in lithology and physical properties, with the following characteristics in their oil-water distribution: 1. alternate distribution of oil and water depending on the variations in sandstone properties; 2. considerable thickness of the oil-water transition zone, generally greater than the closure of trap. Most reservoirs have an oil-water transition zone, and almost all wells produce water in oil.

摘要： 鄂尔多斯盆地陕北斜坡三迭系延长统长2、长3油层,在陕北和陇东地区普遍分布,岩性致密,储油物性很差,非均质性严重,为高含水低产油层。本文应用毛细管理论对油水分布特征进行了解释。