流体改造及地貌高差:含油气盆地分析和评价的重要内容

云参1井是楚雄盆地云龙凹陷部署的第一口参数井,在钻进过程中发生严重井漏。对其发生条件和周邻环境的综合剖析揭示,云参1井严重井漏是该地区在较广阔范围内发生非封闭性流体运动及交换的表现,与盆地后期强烈而不均匀的改造造成较近距离地貌起伏高差较大有成因联系。这说明,流体改造是盆地后期改造的重要形式。地貌高差是流体改造作用发生所需的必不可少的基本条件,二者共同导致了流体改造型盆地的形成。所以,地貌高差与流体改造是含油气盆地地质研究和评价的重要内容。同时指出,对地表起伏较大、大气降水量多、水系发育和河流切割较深的盆地或地区(如在我国西部和南方诸盆地),在油气评价和勘探部署时,应加强对流体改造在油气聚散、成藏、改造和分布等方面可能产生影响的研究。

Topographic relief and fluid modification: the important content of petroliferous basin analysis and evaluation

The Well Yuncan-1 is the first stratigraphic well in Yunlong depression,Chuxiong Basin.A severe lost circulation happened during the drilling of the well.Comprehensive analysis of the conditions and adjacent environment of the accident reveals that it may be caused by non-sealed extensive fluid motion and exchange in the study area and genetically related to the relatively large topographic relief in a short distance caused by strong and inhomogeneous reformation during the later stage of the basin formation.This indicates that modification of fluid flow is one of the most important effects during the later stage of basin formation and topographic relief is one of the basic conditions for modifications of fluid flow.Both of them contributed to the formation of fluid modification basins.Therefore,this article suggests that both topographic relief and modification of fluid flow are indispensable to analysis and evaluation of petroliferous basins.As to basins or areas featuring in large topographic relief,large amount of atmospheric precipitation,well-developed drainage system,deep fluvial incision(e.g.,basins in western and southern China),the influence of fluid modification on accumulation and dissipation,reservoiring,adjustment and distribution oil and gas shall be strengthened during oil and gas evaluation and exploration deployment.