断裂对沿砂体侧向运移油气聚集的控制作用

CONTROLLING ACTION OF THE FAULTS ON THE LATERAL MIGRATION AND ACCUMULATION OF THE HYDROCARBON ALONG THE SANDBODIES

在砂体输导油气条件及能力特征研究的基础上，通过分析油气沿砂体侧向运移所形成的油气藏与断裂之间的关系，研究断裂产状和封闭性对油气聚集及富集程度的控制作用。结果表明：只有油气运移期停止活动，且位于油气运移上倾方向、岩性致密的断裂，才能对侧向运移的油气聚集形成有效遮挡；断裂产状控制着沿砂体侧向运移油气的聚集程度，反向断裂封闭形成的油气藏明显多于顺向断裂封闭形成的油气藏，且反向断裂的上、下盘断距越大，油富集程度越高；断层圈闭所能封闭油气数量除了受到断圈幅度和面积制约外，更重要的是受到断层封闭性强弱的影响，断层侧向封闭性越强，断层圈闭所能封闭住的油气数量越多。

Abstract ： On the basis of the studies of the transporting conditions and ability characteristics of the hydrocarbon in the sandbodies, the controlling action of the fault occurrences and its sealing ability on the petroleum accumulation and enriched degree are studied by the help of the relation between the faults and oil-gas reservoirs accumulated by the lateral migration. The results show that only for the faults stopped their activities in the period of the oil-gas mi- gration and moreover the hydrocarbon upper-wards migrating and the lithology is dense, the effective barrier and screen of the faults can be formed for the laterally-migrating hydrocarbon accumulation; the fault occurrences con- trol the accumulated degree of the lateral migration along the sandbodies, the petroleum reservoirs enriched and sealed by the antithetic faults are obviously more than those by the consequent faults and furthermore more the big- ger the downdip fault throws of the former faults are, the higher the oil enrichment will be; besides constrained by the faulted and trapped amplitude and area, the amount of the sealed petroleum by the fault traps are critically influenced by the sealing ability of the faults i. e. the stronger the lateral sealing ability is, the more hydrocarbon will be sealed and enriched by the fault traps.