源外斜坡区断裂附近油气聚集有利部位预测方法及其应用

Prediction Method and Application of Oil and Gas Accumulation Favorable Position Near Fault in Slope Area Outside Source

为了明确含油气盆地源外斜坡区断裂附近油气分布规律,先统计研究区已知井点砂体地层砂地比值,将最小比值作为能储集油气砂体的所需最小值,圈闭出能储油砂体分布区;再通过计算得到砂体地层顶面古构造脊分布,将二者叠合部位确定为沿砂体侧向运移向断裂输送油气路径;然后计算圈出断裂侧向封闭部位,将其与能储集油气砂体分布区叠合,该叠合部位即可判定为断砂配置圈闭油气部位。笔者建立了预测源外斜坡区断裂附近油气聚集有利部位的方法,既将输送油气路径和断砂配置圈闭油气耦合部位预测为油气聚集有利部位。将该方法应用于渤海湾盆地歧口凹陷源外歧南斜坡区赵北断裂附近沙一段下部油气聚集有利部位预测中。预测结果显示,源外歧南斜坡区赵北断裂附近沙一段下部油源聚集有利部位主要有2处,均分布在赵北断裂西部,与目前赵北断裂附近沙一段下部已发现油气主要分布在西部相吻合,表明该方法用于预测源外斜坡区赵北断裂附近油气聚集是可行的。

In order to clarify the distribution law of oil and gas near the fault in the slope area outside the source of the petroliferous basin, first, the sand ground ratio of well point sand body formation is known in the statistical study area, and the minimum ratio is taken as the minimum value required for oil and gas reservoir sand body, and the distribution area of oil and gas reservoir sand body is trapped, second, the distribution of paleotectonic ridge on the top of sand body formation is obtained through calculation, the overlapping position of the two is determined as the oil and gas transportation path along the lateral migration of the sand body to the fault, third, by calculating the lateral sealing part of the fault and superimposing it with the distribution area of oil and gas reservoir sand body, the superimposed part can be determined as the oil and gas part of fault sand configuration trap. The authors establish a method to predict the favorable parts of oil and gas accumulation near the faults in the slope area outside the source, which predicts the oil and gas coupling parts of oil and gas transmission path and fault sand configuration trap as the favorable parts of oil and gas accumulation. The method is applied to predict the favorable parts of oil and gas accumulation in the Es;near Zhaobei fault in Qinan slope area outside the source of Qikou sag, Bohai Bay basin. The prediction results show that there are mainly two favorable parts for oil source accumulation in the Es;near Zhaobei fault in Qinan slope area outside the source, which are distributed in the west of Zhaobei fault, which is consistent with the fact that oil and gas in the Es;near Zhaobei fault are mainly distributed in the west, indicating that this method is feasible to predict oil and gas accumulation near Zhaobei fault in the slope area outside the source.