苏北盆地辉绿岩、蚀变带特征及其与油气的关系

Characteristics of the Diabase and Altered Zone in BXP Area of Subei Basin and Relationship Between the Diabase and the Formation of Hydrocarbon Reservoir

认识到苏北盆地 BXP地区中段辉绿岩分布广 ,厚度变化大 ,呈多期、多通道侵入特征 ,对下伏地震反射层 T3 1、T3 3 具有很强的屏蔽作用 ,影响其资料品质及构造落实程度 .为了解决这一困扰多年的问题 ,从辉绿岩的形成机理入手 ,结合钻井资料 ,运用各种地质物探等方法 ,对本区辉绿岩的分布、侵入时期与断层组合关系等进行深入研究 ,进而探索辉绿岩与油气形成的复杂关系 .研究表明 :本区辉绿岩的侵入时期晚 ,在加速 E1f2 、E1f4 段生油岩有机质向烃类转化的同时 ,也破坏了早期原生油气藏 ,影响了次生油气藏的形成 ;另外辉绿岩的侵入优化了围岩渗透性 ,导致蚀变带的产生 。

The diabase in BXP area, Subei Basin is characterized by wide distribution, great variation in thickness, invasion of multiperiod and multipassage. It has strong shielding action to the seismic reflection horizons of T 3 1 and T 3 3, and it influences the accuracy of the obtained seismic data and finding structures. Based on the formation mechanism of the diabase and drilling data, the distribution and invasion periods of the diabase and the combination relation of it with faults are studied by various geological and geophysical methods. The complicated relationship is discussed between the diabase and the formation of hydrocarbon reservoir. The results show that the diabase penetrating into E 1f 2 and E 1f 4 accelerates the inversion of organic matter to hydrocarbons, but it destroys original oil and gas reservoir, and influences the formation of secondary oil and gas reservoir. The diabase optimizes the permeability of host rock, leads to the production of altered zone and supplies the carrier and storage body for oil and gas.