河流相层序地层及岩性油气藏油气富集规律——以准噶尔盆地红29三维工区为例

Sequence Stratigraphy and Discipline of Lithologic Reservoirs for Hydrocarbon Accumulation in Fluvial Facies:A Case Study of Well Hong 29 District of 3D Seismic Exploration in Junggar Basin

以准噶尔盆地红山嘴油田红29三维工区中三叠统克拉玛依下亚组(克下组)为研究对象,根据钻井和测井资料对其进行高分辨率层序地层划分,识别出1个长期基准面旋回和3个中期基准面旋回(MSC1、MSC2、MSC3)。在长期基准面旋回从上升到下降的过程中,河道弯曲指数明显出现低—高—低的分异特征,河道砂体连续性表现为好—差—好的演变。通过分析克下组油藏以及出油气特征,发现油气主要富集于MSC2中期基准面旋回中;该中期旋回内河道弯曲度较高,河道砂体连续性较差。结合岩性油气藏的成藏规律,总结出'富砂中找贫砂'的勘探思路。该思路指出,长期基准面上升到最高位置附近的'贫砂'层系也是岩性油气藏发育的有利层位,并提出断层-岩性型复合圈闭为有利的勘探目标。

Targeting on the Middle-Triassic Lower Karamay Formation in Hong 29 district of 3D seismic exploration of the Hongshanzui oil field in the Junggar basin,combining with the drilling data and logging date,it can identified a long scale cycle and 3 middle scale cycles（MSC1,MSC2,MSC3） by high resolution sequence stratigraphy.During the course of long scale cycle,the river channel bending index apparently presented characteristics as low-high-low,meanwhile the continuity of channel sand also displayed an evaluation as good-bad-good.By analyzing the characteristics of reservoirs and hydrocarbon of Lower Karamay Formation,it found that the oil and gas were mainly assembled in the MSC2,while the river channel bending index during this cycle was relatively high,and the channel sand bodies had a bad continuity.Connecting with the rule of the lithologic reservoir accumulation,it put forward an exploration method that ＂finding the poor sand in the rich sand＂,which presented that the ＂poor＂ sand at the highest location of long base-level was also the advantaged zone for exploration and fault-lithology composite trap was the favorable explorationary target.