济阳坳陷地层圈闭成藏特征及地质风险评价

The reservoir characteristics and geologic risk evaluation of the Jiyang downwarp stratigraphic trap

济阳坳陷地层圈闭分为地层超覆不整合、地层削蚀不整合遮挡两种类型,多发育在凹陷与凸起结合的斜坡部位,环绕凹陷呈裙带状分布,其成藏受不整合面控制作用明显。由于距离烃源岩较远,油气运移聚集条件成为地层圈闭成藏的主要控制因素。针对各项评价要素,可分别采用钻探成功率分级法、累计概率曲线法、地质分析法建立其地质风险评价标准。为了反映不同评价条件及评价要素在成藏及圈闭描述识别中的作用,可利用“评价要素加权求和”的方法计算5项评价条件的评价值,在此基础上,利用“5项条件评价值加权求和”的方法求取圈闭地质风险系数。应用表明,所建立的地质风险评价标准,能反映济阳坳陷地层圈闭勘探的实际情况。

The Jiyang downwarp stratigraphic trap was divided into two types, that is, formation overlying unconformability and formation truncation unconformable barrier, most of them developed at the position of the slope where the sag surrounded by the trap was integrated with prominence, which showed in group-belts distribution, the reservoir forming for the formation trap was obviously subjected to the unconformable surface control. Due to far away from the hydrocarbon source rock, oil-gas migration and building-up conditions became the main controlling factor of the formation trap reservoir forming. As to the evaluation factors, geologic risk evaluation criteria can be set up by respectively adopting the methods of drilling success rate grading, cumulative probability curve and geologic analysis. In order to reflect the functions of different evaluation conditions and factors in reservoir forming and trap description and identification, the method of evaluation factors weighting sum could be used to calculate evaluation values, which were coincident with the five evaluation conditions. Based on this, trap geologic risk factor was also worked out to the obtained values. The application results indicated that the established geologic risk evaluation criteria could reflect the real situation of Jiyang downwarp stratigraphic trap exploration.