低含油饱和度油藏储层特征及其成藏控制——以准噶尔盆地玛西斜坡中浅层八道湾组为例

Reservoir characteristics of low oil saturation reservoirs and its control on hydrocarbon accumulation: a case study of the middle-shallow Badaowan Formation in Maxi slope, Junggar Basin

王林生 赵晓东 李亮 周伯玉 徐倩茹 赵文苹 纪雪冰

中国石油新疆油田分公司，新疆 克拉玛依 834000 中国石油大学（北京）克拉玛依校区石油学院，新疆 克拉玛依 834000 中国石油新疆油田分公司勘探开发研究院，新疆 克拉玛依 834000

Xinjiang Oilfield Company, PetroChina, Karamay 834000, China School of Petroleum, China University of Petroleum (Beijing) at Karamay, Karamay 834000, China Exploration and Development Research Institute, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China

通过岩心观察和铸体薄片、扫描电镜等分析测试手段，开展了准噶尔盆地玛湖凹陷西斜坡中浅层低含油饱和度油藏的储层特征研究，探讨了强非均质储层对低含油饱和度油藏成藏的影响。研究认为：1）玛西斜坡中浅层侏罗系八道湾组为低含油饱和度油藏，产出品质较好的轻质油，油藏具有低含油、高含水特征；2）储层普遍含砾，以砾岩、砂砾岩等粗岩性为主，储集空间主要为次生粒内溶孔，储层孔隙发育差，连通性差，属于低孔低渗储层，储层非均质强，低含油饱和度油藏主要聚集在较强非均质储层中；3）八道湾组储层主要经历了早期充注与晚期调整的油气成藏过程，油气早期运移形成了百口泉组、八道湾组古油藏，晚期发生构造掀斜，八道湾组古油藏遭受破坏，百口泉组古油藏沿次级断裂调整至八道湾组，强非均质储层对低含油饱和度油藏成藏起到控制作用，强非均质性厚层砂砾岩储层与次级断裂匹配形成低含油饱和度油藏。玛西斜坡中浅层八道湾组低含油饱和度油藏的发现拓展了玛湖凹陷的油气勘探空间，同时增加了在厚层砂砾岩低渗储层中寻找低含油饱和度油藏的勘探实例。

By means of core observation, cast thin section, scanning electron microscope and other analytical tests, the reservoir characteristics study of middle?鄄shallow low oil saturation reservoirs in west slope of Mahu Sag, Junggar Basin was carried out, and the influence of strong heterogeneous reservoir on low oil saturation reservoir forming was discussed. The research shows that: (1)  oil reservoirs of Badaowan Formation in the middle?鄄shallow Jurassic of the Maxi slope are low oil saturation reservoirs with good quality light oil, and the reservoirs are characterised by low oil content and high water cut. (2) The reservoirs are generally conglomeratic, with coarse lithologies such as conglomerate and sandy conglomerate dominating, and the reservoir space is mainly secondary intragranular dissolved pores. The reservoir has poorly developed pores and poor connectivity, belonging to low?鄄porosity and low?鄄permeability reservoir with strong heterogeneity, and the low oil saturation reservoirs are mainly gathered in the stronger heterogeneous reservoirs. (3) The hydrocarbon accumulation of Badaowan Formation mainly underwent a process of early filling and late adjustment. The oil and gas was transported to form the Baikouquan and Badaowan Formation paleo?鄄reservoirs in the early stage, and the Badaowan Formation paleo?鄄reservoirs were damaged by the tectonic lift?鄄off in the late stage. The paleo?鄄reservoir of Baikouquan Formation is adjusted to Badaowan Formation along the secondary faults. The strong heterogeneous reservoirs control the accumulation of low oil saturation reservoirs, and the strong heterogeneous thick sandy conglomerate reservoir matches with the secondary faults to form the low oil saturation reservoirs. The discovery of low oil saturation reservoirs in the middle?鄄shallow Badaowan Formation in Maxi slope expands the scope of oil and gas exploration in Mahu Sag and increases the exploration examples for finding low oil saturation reservoirs in thick sandy conglomerate low?鄄permeability reservoirs.

10.6056/dkyqt202305009