徐家围子断陷徐深31井地质条件研究及失利分析

徐家围子断陷徐深31井位于徐家围子断陷徐东地区兴城鼻状构造东翼、徐中断裂东侧下降盘向东南倾没的斜坡带上，部署目的是探索该区营城组火山岩的含气性，进一步向东扩大兴城鼻状构造的含气规模。从钻探的显示效果来看，徐深31井营城组火山岩储层物性较差，且自身沙河子组暗色泥岩较薄，烃源岩不发育，虽紧邻徐东生烃中心，但生烃中心埋藏较深，其上有致密的火山岩，且徐深31井与生烃中心之阃的断裂也可能起到了遮挡的作用，具有较好的封闭能力，故天然气没有好的运移通道到达徐深31井物性较差的储层中，综合分析认为：储层物性差、自身烃源岩不发育、断层阻挡侧向天然气运移是该井失利的主要原因。

Study on Geological Conditions and Analyse Defeat of Well Xushen31 in Xujiaweizi Fault Depression

In order to confirm the volcanic rocks gas reservoir in east wing of Xingcheng nosing structure of Xudong area in Xujiaweizi fault depression, xushen31 well in Xujiaweizi fault depression was drilled in the upper wall slope of Xuzhong fault. According to the result of the drilling, We can get a Conclusion that the Reservoir properties are Unfavorable in Yingcheng group volcanic rocks. And there is no thick dark mudstone in Shahezi group, no thick source rocks have been found in this area. In spite of nearing the hydrocarbon--generating center, hydrocarbon can＇t migrated to this area due to the shelter of fault in the migration path and hardly migrated in the dense volcanic rocks. Analysis of the Accumulation factors, un- favorable reservoir properties, lack source rocks and shelter of fault are main reasons of the failure of drilling.