准噶尔盆地春光油田白垩系吐谷鲁群组储层特征及流体识别

Reservoir characteristics and fluid identification in Cretaceous Tugulu group of Chunguang oilfield,Junggar Basin

春光油田白垩系吐谷鲁群组地层岩性复杂,火山岩、沉积岩交杂,呈条带状分布。结合岩心、岩石薄片、录井等资料,分别从岩石学特征、储层空间类型、储层物性特征及孔隙结构特征4个方面研究吐谷鲁群组有利区带低阻储层,同时对油水层进行了识别。结果发现,白垩系吐谷鲁群低阻储层岩石类型主要为灰色砂砾岩,含砾细砂岩、粉砂岩,岩石成分以石英居多,成分成熟度较高,储集空间主要为粒间孔隙、溶蚀孔缝、微裂缝。根据碎屑岩储层物性分类标准,储层类型属于中孔中渗储层,毛管压力曲线主要为分选比较好的粗歪度类型和分选中等的偏细歪度类型,孔喉分布频率曲线主要为单峰偏粗态型和平峰偏细态型。鉴于春光地区流体的特殊性,应用阵列感应电阻率差异参数DR和综合识别参数RD_R建立春光油田白垩系吐谷鲁群组流体识别交会图版,能较好识别低阻流体。

Lithology of Cretaceous Tugulu group in Chunguang oilfield is complex, and the formation is banding distributed, which vol- canic rock and sedimentary rock mix together. Combining with core, rock slice, mud logging data, the low resistivity reservoir of creta- ceous favorable zones were studied respectively from four aspects, the petrology characteristics, reservoir space types, reservoir physical characteristics and pore structure features, at the same time, the oil and water layer were identified. It was found that, the cretaceous low resistivity reservoir rock types are mainly gray glutenite, conglomeratic fine sandstone and siltstone, rock composition in the majority with quartz, composiliona] maturity is higher ,reservoir space is mainlty inte：cgranu]~ar pore, disst）lutitm pore seam, microfraeture. According to the classification of elastic rock reservoir property standard, the type of reservoir in Chunguang oilfield belongs to the middle porosity and middle permeability, the capillary pressure curve is mainly coarse slanting degrees of better sorted and smaller slanting degrees of moderate sorted, the pore throat distribution frequency curve is mainly unimodal type crude state and fiat peak slant thin state. In view of the particularity of fluid in Chunguang area,applying array induction resistivity difference between De and comprehensive identification parameters RDR to build oil layer intersection chart of fluid identification in Cretaceous Tugulu group in Chunguang oilfield, can better i- dentify low resistance oil layer.