【摘要】 准噶尔盆地西北缘中拐凸起东斜坡风城组发育一套遭受风化剥蚀而残留的薄层火山岩地层,该地层内部出现"油水倒置"现象,由于成藏规律认识不清,制约了对该地层的进一步评价。针对该地层岩相、岩性单一,并发育风化壳的地质特征,综合运用岩心、薄片及典型电性识别等方法对风化壳结构进行了识别,识别并划分出土壤层+水解带、淋蚀带、崩解带、母岩4种风化壳结构,根据划分结构建立了风化壳结构组合模式,分析风化壳结构对储、盖组合的控制作用,剖析已发现的油藏。结合岩体发育特征,建立了斜坡薄层火山岩风化壳油藏成藏模式,得到中拐凸起东斜坡薄层火山岩油藏主要发育于构造中低部、风化体结构完整的岩体,有利成藏区环凹陷呈条带状分布的结论。运用该结论指导油藏勘探评价并取得突破,证实了该类地层油气分布规律。研究结果对类似地层的油藏评价具有启示意义。更多还原

【Abstract】 A set of thin volcanic strata resulted from weathering and denudation is developed in Fengcheng Formation on the east slope of Zhongguai salient in the northwest margin of Junggar Basin,and a phenomenon of " oil and water inversion" occurs inside the formation. The further evaluation of the formation is restricted by the unclear understanding of the petroleum accumulation rules. Based on the geological characteristics like single lithofacies and lithology and development of weathered crust,the methods like core,slice and typical electric property identification were used to identify the weathered crust structure,which was then divided into 4 types: soil layer + hydrolytic zone,leached zone,disintegration zone,and parent rock. Based on the division structure,the combined model of weathered crust structure was built to analyze the control effect of weathered crust structure on the reservoir and caprock assemblage,and then analyze the discovered oil reservoirs. Combined with the development characteristic of rock mass,the petroleum accumulation model of thin volcanic weathered crust reservoir on slope was built,and the following conclusions were obtained: the thin volcanic reservoir on the east slope of Zhongguai salient is mainly developed in structural middle and low where the weathered rock mass structure is complete,and the favorable hydrocarbon accumulation zone distributes in banding around the sag. The above conclusions were used to guide the reservoir exploration evaluation,and a breakthrough was made,confirming the oil and gas distribution law of this kind of formation. The study results are instructive for reservoir evaluation of similar formations.更多还原