准噶尔盆地侏罗系层序格架中油气藏的分布规律及其主控因素

DISTRIBUTION OF OIL AND GAS POOLS IN SEQUENCE STRATIGRAPHIC FRAMEWORK OF THE JURASSIC IN JUNGGAR BASIN AND ITS MAIN CONTROLLING FACTORS

以 17条统一流程处理的区域地震大剖面为骨架网 ,综合分析地震、钻井和露头资料的结合 ,并经过 6次反复标定 ,建立起准噶尔盆地侏罗系统一的层序地层格架。将 5 8个已发现的侏罗系油气藏归位到层序和体系域中 ,分析其在层序和体系域中的分布规律。研究发现 ,在层序级别上 ,不同地区油气富集的层位不同 ,总体上有从西到东层位变新的趋势 ;在体系域级别上 ,侏罗系油气主要富集在低位域 ,只在腹部有少量的油气藏位于水进域和高位域。层序格架对油气富集的控制作用主要表现为储盖组合条件对油气聚集的控制 ,不同体系域内储集层物性的差异对油气富集也有控制作用。因此 ,在今后对准噶尔盆地侏罗系的油气勘探中 ,应重视低位域和盆地的边缘地带。

By the use of 17 cross-basinal seismic profiles, a sequence stratigraphy framework of the Junggar Basin was established by comprehensive analysis on the data of seismic, drilling and outcrops. For studying the control of sequence stratigraphy for oil and gas distribution, 58 oil and gas pools discovered in the Jurassic were placed in this framework. In the level of sequences, the oil and gas pools in the Jurassic were found more and more in the new sequences from the west to the east of the basin, which is mainly controlled by the distribution of regional cap-rocks of the Jurassic deposition. In the level of system tracts, most of oil and gas pools in the Jurassic were found in the low system tract. Only a small number of pools were found in the transgressive system tract and the high system tracts in the center of the Basin. The distribution of oil and gas pools in the system tracts was mainly controlled by the reservoir-cap rock. The reservoir properties in the different system tracts also have some influences on the distribution of hydrocarbon reservoir. It is suggested that the future exploration of the Jurassic hydrocarbon pools should give emphasis on the low system tracts, especially on the marginal parts of the Junggar Basin.