鄂尔多斯盆地华池-庆阳地区延长组长62-63沉积微相研究

为了更精准地研究鄂尔多斯盆地西南部华庆地区上三叠统延长组长6_2-6_3油层组储层特征,运用岩心照片、测井数据、粒度分析、录井数据等资料,对延长组长6_2-6_3油层组的岩性、碎屑颗粒、构造、测井响应、生物标志以及接触关系进行了分析研究。分析了长6油层组沉积微相特征,识别出该沉积时期半深湖-深湖亚相和三角洲前缘亚相两类沉积亚相,半深湖泥、浊积岩、砂质碎屑流砂体、水下分流河道、分流间湾和席状砂6类沉积微相,并分析华庆地区延长组长6_2-6_3期沉积相发育演化过程。沉积微相精细化描述揭示了华庆地区延长组6段油层组沉积环境,为精细化勘探开发提供地质依据。

Sedimentary microfacies in the Chang-62 to Chang-63 oil reservoirs of the Upper Triassic Yanchang Formation in the Huachi-Qingyang region, Ordos Basin

A detailed study is conducted, on the basis of core examination, grain-size analysis and well logs, to the lithology, grain size, sedimentary structure, well logging response, biomarker and contact relation of the Chang-6₂ to Chang-6₃ oil reservoirs of the Yanchang Formation in the Huachi-Qingyang region, Ordos Basin. The sedimentary facies in the study area may be classified into two sedimentary subfacies including the semi-deep lake to deep lake and delta front subfacies, and six sedimentary microfacies including the semi-deep lake mud, turbidite, sandy debris flow, subaqueous distributary channel, interdistributary bay and sheet sand microfacies. During the deposition of the Chang-6₃ oil reservoirs of the Upper Triassic Yanchang Formation, the shallow-lake delta front deposits were well developed in the semi-deep to deep lake sedimentary environments in the northeastern and southwestern parts of the study area, where the sandy debris flow deposits may provide excellent sites for the oil-gas accumulation in the deep lake area. The results of research in this study may be significant to the exploration and development of the Chang-6 oil reservoirs as the key exploration horizons of the Upper Triassic Yanchang Formation in the Huachi-Qingyang region.