重磁成果与东海西部凹陷带中生代沉积层展布

Gravity-magnetic result and distribution of Mesozoic Era sedimentary stratum in west depression belt of the East China Sea

生油理论及勘探技术的发展,要求对东海陆架盆地西部凹陷带进行中生代沉积层展布研究。基于中生代沉积层与上、下地层间具有明显的密度差异及中酸性岩浆岩具磁性的特点,采用重磁成果进行中生代沉积层及中酸性岩浆岩的展布研究是可能的。运用2.5维重磁人机交互正反演拟合技术对4条剖面的地质结构进行了研究,以此剖面研究成果作为约束条件,对平面重磁成果运用小波分解及变倾角化极技术进行处理与综合研究,进而对中生代沉积层及中酸性岩浆岩展布进行研究。研究认为中生代沉积层在西部凹陷带基本可以连续分布,但在北纬30°附近被隔断,其厚度大于3km的地区具有含油气远景区的基础条件。

With the development of oil generating theory and exploration technique, studying distribution of Mesozoic Era sedimentary stratum is demanded in west depression belt of the East China Sea shelf basin. On the basis of intermediate-acidity magmatic rock with magnetism and the density difference of Mesozoic Era sedimentary stratum and upper layer and down layer, studying distribution of Mesozoic Era sedimentary stratum and intermediate-acidity magmatic rock is possible. Using 2.5D gravity-magnetic man- computer interactive formal-inversion calculation, geological structures of four profiles are studied. The result is a condition of restriction. Using the technique of wavelet analysis and polarization, plane＇s gravity- magnetic results are processed and comprehensivly studied. Distribution of Mesozoic Era sedimentary stratum and intermediate-acidity magmatic rock are studied. In the text, Mesozoic Era sedimentary stratum is considered as continual distribution in west depression belt of the East China Sea shelf basin, but it is separated at 30°N. Mesozoic sediment thickness is greater than 3km is the basic condition to form oil-gas perspective areas.