大情字井地区青山口组二段IV砂组和V砂组沉积微相研究

Sedimentary microfacies for Ⅳ and Ⅴ sand groups of the second member of Qingshankou formation in Daqingzijing area

（1.大庆石油学院地球科学学院,黑龙江大庆 163318;2.中国石油天然气股份有限公司吉林油田分公司勘探开发研究院,吉林松原 138000）

Faculty of Earth Science,Daqing Petroleum Institute,Daqing 163318,China

从区域地质背景出发,通过岩心观察、粒度分析、重矿物和测井曲线等资料的综合分析,对吉林大情字井地区青山口组二段IV砂组和V砂组的沉积背景、物源方向和沉积特征进行了研究,确定其主要为三角洲前缘—前三角洲沉积体系,主要发育了水下分支河道、河口坝、远砂坝和重力流等沉积微相,储油砂体以水下分支河道、河口坝微相为主。编制了IV砂组和V砂组10个小层的沉积微相平面分布图,对砂体的演化规律进行了分析,认为沉积环境为以西南保康水系为主的三角洲前缘相沉积,砂体以水下分支河道和河口坝为主,其中水下分支河道砂体呈南西—北东向展布,向东逐渐减薄,河道的侧向摆动造成了砂体的叠置或切割,形成了条带状和断续分布特征。

Based on regional geologic background,core observation,particle size analysis,and comprehensive analysis of heavy mineral and logging curve were carried out to study the sedimentary background,provenance direction and sedimentary characteristics of Ⅳ and Ⅴ sand groups of the second member of Qingshankou formation in Daqingzijing area,which indicates that the depositional system is mainly of delta-front and pre-delta,it develops sedimentary microfacies such as underwater distributary channels,debouch bars,distal bars and gravity flow.The sedimentary facies of oilbearing sand bodies are mainly underwater distributary channels and debouch bars.We mapped sedimentary microfacies plane distribution of ten sublayers from Ⅳ and Ⅴ sand groups,and analyzed the sand evolution rule.The result shows that sedimentary environment is mainly of delta front from southwest Baokang water system,and the sedimentary microfacies of sand bodies is underwater distributary channels and debouch bars.The sandbodies from underwater distributary channels are in the direction of southwest to northeast,and are gradually thinner to the east.The lateral swings of channels lead to superposition or cutting of sandbodies, and form banded and discontinuous distribution characteristics of sandbodies.