石臼坨凸起西部陡坡带古物源差异演化模式及其对储层的控制作用

Difference of provenance evolution mode and its impact on reservoir in the western steep slope zone of Shijiutuo uplift,Bohai sea

渤海海域属于典型的陆相断陷盆地,储层预测一直是中深层勘探的难点。利用钻井、三维地震以及岩矿测试等资料,改变以现今残留基岩面貌作为源-汇分析的思路,以动态源-汇分析思路为指导,对渤海石臼坨凸起西部陡坡带进行了古物源恢复,重塑了不同时期的古地理格局,并建立了物源差异演化模式。分析了物源差异演化对储层的控制作用,结果表明:在东三段沉积时期,石臼坨凸起西部陡坡带不同位置由于提供物源的母岩类型不同,对沉积区扇体的规模和储层物性具有重要的控制作用。西部以碳酸盐岩为主要物源,储层灰质胶结普遍,物性较差;中部为变质花岗岩、碳酸盐岩和碎屑岩混合提供物源,储层物性中等;东部以火成岩持续提供物源,剥蚀后形成大量碎屑颗粒,砂体规模和储层物性明显优于中西部地区。

Bohai sea area is a typical continental rift basin and reservoir prediction is always a difficulty for the Paleogene exploration. Based on drilling, 3D seismic and rock testing data, changing the thought of source-to-sink analysis by taking dynamic analysis for guidance rather than by the current residual bedrock, the provenance is recovered, the paleogeographic patterns in different periods are restored and the modes of differential evolution of provenances are set up in the western steep slope zone of Shijiutuo uplift. The control of the mode on reservoir is analyzed and results show that different rock types of source rock along the steep slope zone in the same sedimentary period significantly control the scale of fans and reservoir property. The reservoirs in the west have poor property characterized by strong calcareous cementation due to the carbonate provenance; the reservoirs in the center are influenced by metamorphosed granite, carbonate and clastic rocks, and have moderate property; the sand scale and properties in the east are significantly superior to that of the center and west because the provenances come from igneous rocks which can provide more clastic particles after denudation.