摘要
三叠纪延长期长7沉积期是鄂尔多斯盆地中生代湖盆发育的鼎盛时期,沉陷幅度大,湖盆范围广。通过研究明确了长7沉积期物源来自盆地周边五个方向,其中东北部、西南部为主要物源方向,西部、南部、西北部为次要物源方向;长7主要发育三角洲相和湖泊相,进一步划分出5种亚相10种微相,其中长73期湖盆面积最大,半深湖—深湖相浊积砂体不发育,暗色泥岩及高阻泥岩发育,为中生界主要优质烃源岩;长72期,半深湖—深湖相沉积面积明显减少,浊积砂体较发育;长71期,湖盆面积及半深湖-深湖相沉积面积继续减少,浊积砂体最为发育,是长7油藏的主力储层。
The depositional stage of member 7 of Yanchang Formation in Triassic was the maximum of Mesozoic lake basin in Ordos basin,the subsidence of lake basin was the largest and the lake basin scope was extensive.it has been clarified that the source sediments were from five directions of basin circumference,the mainly source was located in the northeast and southwest area.In addition,there are three secondary source areas that was located in the west,south and northwest.The sedimentary facies of member 7 of Yanchang Formation are the delta and lacustrine facies,which can be further sub-divided into five sub-facies and ten microfacies.During the deposition of Member 73 of the Yanchang Formation,the lacustrine area was maximum,the turbidite of half-deep lake and deep lake facies were not developed,but the dark and high resistance mudstone were developed,which were main high quality source rock of Mesozoic,the depositional area of half-deep lake and deep lake facies were clearly reduced during the deposition of Member 72 of the Yanchang Formation,the turbidite were relatively developed;the lacustrine area and the depositional area of half-deep lake and deep lake facies continually reduced during the deposition of Member 71 of the Yanchang Formation,the turbidite was extensively developed,which was the main reservoir of Member 7.
出处
《沉积学报》
CAS
CSCD
北大核心
2010年第2期254-263,共10页
Acta Sedimentologica Sinica
关键词
沉积相
三角洲相
湖泊相
长7油层组
鄂尔多斯盆地
sedimentary facies
delta facies
lake facies
Chang-7 oil reservoir set
Ordos basin
