Abstract: This study is concentrated on the distribution of fluid pressure in the Mesozoic strata in south of Shanxi-Gansu-Ningxia Basin by means of "equaldepth" technique based on the formation compaction curves. It has been discovered that abnormally high pressure is existed in all wells penetrating Chang-7 oil-group. The distribution of abnormally high pre-ssure in each subgroups of Yanchang Group shows a similar pattern areally. Such pressure is highest nearby Lingwu-Yanchi in the northwest part of the studied area, is moderate nearby Hulu Rever-Luo Rever in the southeast part; and is lowest in the northeast and the southwest parts. A contrast of the distribution of abnormally high pressure and known oil-bearing areas suggests that oil fields and commercially productive wells is located mainly in the regions having lower abnormal pressure in the corresponding oil-bearing formation group; and the oil-bearing formations mainly is located in the normal pressure section, veatically, and relative lower pressure zones within the abnormal pressure zones come to the next. Based on the above analysis, this paper emphatically discusses the migration and accumulation of oil and gas in Chang-7 oil-group, the main source rock in Yanchang Group. It is pointed out, that there are two belts in favour of accumulation of oil and gas; one is Jirigbian-Wuqi-Qingyang and a region sourthwest to it, i. e, an area located between the abnormally high pressure regions: Lingwu-Yanchi and Hulu River-Luo River, being the first, and Ansai-Fuxian and its eastern region being the second.

摘要： 本文在泥岩压实曲线基础上,利用平衡深度法计算得出了陕甘宁盆地南部中生代地层的流体压力分布。研究区各井下部均发育有稳定的过剩压力,其中长7油组的幅度普遍较高。延长组各油组过剩压力平面分布的格局具明显继承性。研究区的西北灵武—盐池—带过剩压力最发育,东南葫芦河—洛河一带次之,而东北与西南则较差。过剩压力分布与已知含油情况分布的关系表明,绝大部分油田与产油井段在平面上均分布在相应油组过剩压力低值带,纵向上主要分布在正常压力段,其次为异常压力段中的相对低值带。据此探讨了延长组主力生油层长7油组油气的运移及聚集条件,并指出研究区内有两个有利聚集地带。一是在灵武—盐池与葫芦河—洛河高压带之间的靖边—吴旗—庆阳及其西南一带;二是研究区东缘安塞—富县一线及其以东地区。