高邮凹陷北斜坡辉绿岩区解释方法研究

Study of seismic interpretation method about diabase in north ramp slope of GY Hollow

中国石化江苏油田分公司地质科学研究院,江苏扬州 225009

Geologic Research Institute of SINOPEC Jiangsu Oilfield Company, YangZhou 225009, China

高邮凹陷北斜坡第三系地层内发育了4套辉绿岩。各套辉绿岩分布地区及侵入地层层位不一,厚度不稳定,且速度高达5500m/s,使其下伏地层成像精度受到影响。分析不同厚度情况下辉绿岩的反射特征,结合测井资料和地质资料的解释,表明研究区辉绿岩层速度变化不大,但厚度变化大,这是影响平均速度的主要因素之一。解释中,分析了辉绿岩通过断层的4种状态,并建立了断层模式,使断层解释结果合理可靠。

There are four layers of diabase in the north slope of GY sag. The distribution and thickness of the diabase layers and their belonging horizons varies and the velocity of the diabase layer is up to 5500 m/s, which impairs to image the underlying structures seriously. It is showed, from the analysis of the reflection characters of the diabase layers with different thickness and the interpretation of logging and geologic data, the interval velocity of the diabase layers is steady and their thickness changes rapidly. Therefore the thickness of the diabase layers is the major factor to affect average velocity. A fault pattern has been established after an analysis of the four different situations when the diabase crosses faults.