中文摘要：

利用370口钻井试油实测（DST）压力数据分析了临南洼陷异常压力的分布特征和异常低压的成因机制。临南洼陷不仅发育低压,而且存在超压。低压在井深1 300～4 000m区间内普遍发育;超压出现在井深3 200～4 400m区间内。沙三段的低压和超压共存。异常压力的分布与转换伸展型盆地的应力场密切相关。低压主要分布在转换伸展型盆地的最大伸展区域,超压主要沿挤压轴方向展布,且靠近洼陷中央。转换伸展断裂的泵吸作用导致流体低压和低压油气藏的形成。

英文摘要：

Abnormal pressure in transtensional basins are sparsely described in the literature.Based on the data of drill stem test（DST） from 370 drills in Linan Subsag,this paper discusses the distribution and origin of abnormal pressure.It is found that there not only exists prominent underpresure,but also develops overpressure in the transtensional Linnan Subsag.The underpressure ranges from 1 300 to 4 000 m depth,and the overpressure occurs from 3 200 to 4 400 m depth,with the maximum pressure coefficient about 1.6.The underpressure coexists with overpressure in the Sha-3 member.The distribution of abnormal pressure is closely coincident with the stress field of the transtensional basin.The underpressure mainly distributes in the areas of maximum extension located near the ends of the bounding faults whereas the overpressure distributes along the maximum compression stress axis and locates near the centre of the subsag.The fluid pumping of transtensional faults induce the formation of fluid underpressure and underpressured oil reservoirs.