渤海湾盆地歧口凹陷歧北斜坡古近系沙二段滨浅湖滩坝沉积模式与勘探实践  

Depositional pattern and exploration practice of shallow shore lake beach bar sand body in the second member of Shahejie Formation in Qibei slope in Qikou Sag,Bohai Bay Basin

作　　者：周立宏[1] 韩国猛[1] 马建英[1] 牟连刚[1] 赵军[1] 周可佳[1] 王昌丽[1] 董越崎[1] 孟立娜[1] 周素彦[1] 陈双清[1] 尹玲玲[1] Zhou Lihong;Han Guomeng;Ma Jianying;Mou Liangang;Zhao Jun;Zhou Kejia;Wang Changli;Dong Yueqi;Meng Lina;Zhou Suyan;Chen Shuangqing;Yin Lingling(PetroChina Dagang Oilfield Company)

机构地区：[1]中国石油大港油田公司,天津市300280

出　　处：《中国石油勘探》2023年第3期64-77,共14页China Petroleum Exploration

基　　金：国家重点研发计划项目“地质资源精准开发风险预测的大数据智能分析技术及平台建设”(2022YFF0801204);中国石油天然气股份有限公司前瞻性基础性科技项目“成熟探区精细勘探关键技术研究”(2021DJ0702)。

摘　　要：近年来,滩坝砂体作为陆相滨浅湖重要的岩性油气藏勘探评价目标,增储作用愈发突出。针对渤海湾盆地歧口凹陷歧北斜坡古近系沙河街组二段(沙二段)分析滩坝砂体的形成机制和空间分布规律,指导油田滩坝砂体勘探。基于沉积古背景分析,认为沙二段滩坝砂体主要发育在基准面上升半旋回早期阶段,滨Ⅳ上、滨Ⅲ下油组沉积时期规模最大;在邻近物源供给充足、往复动荡的水动力及湖盆底形的影响下,水下古隆起控制厚层坝砂的沉积分布。利用地震模型正演技术,明确了厚层坝砂地震响应特征;根据频谱分析法,确定了厚层坝砂低频率—强振幅门槛值,采用低频率—强振幅属性融合技术,预测了厚层坝砂的有利发育区。通过滩坝砂体勘探实践研究,建立了构造宽缓浅水区圈定滩坝范围、水下古隆起锁定厚层坝砂、低频率—强振幅属性融合确定厚层坝砂有利发育区的勘探评价方法。优选出歧北斜坡沙二段3个坝砂有利发育区,钻探4口井获工业油气流,钻井成功率达到100%。勘探实践表明,歧北斜坡滩坝砂体发育,尤其是厚层坝砂产量高、油藏富集,是老油区增储建产的重要接替领域和方向。As the major exploration and evaluation target of lithologic type oil and gas reservoirs of continental shallow shore lake facies,the beach bar sand body shows more and more important position in increasing reserves in recent years.The formation mechanism and spatial distribution law of beach bar sand body in the second member of Shahejie Formation(Sha 2 member)in Qibei slope in Qikou Sag are analyzed to guide the exploration in the oilfield.The analysis of paleo sedimentary settings indicates that beach bar sand body was mainly developed in the early stage of base-level rising half cycle,with the largest scale in BinⅣ^(U)and BinⅢ^(L)oil groups;The distribution of thick bar sand body was controlled by underwater paleo uplift and influenced by the sufficient material supply by the adjacent provenance,repeatedly turbulent hydrodynamic force,and the shape of lake basin floor.The forward seismic modeling technique enables to define the seismic response characteristics of thick bar sand body.The threshold value of low frequency-strong amplitude of thick bar sand is determined by spectrum analysis,and the favorable zone for the development of thick bar sand is predicted by using low frequency-strong amplitude attribute fusion technology.Based on the exploration practice,the exploration and evaluation method of beach bar sand body is established,namely,delineating the range of beach bar in shallow water area with wide and gentle structure,searching for thick bar sand in underwater paleo uplift,and determining the favorable zone for the development of thick bar sand by low frequency-strong amplitude attribute fusion method.The research results guided the selection of three favorable zones with bar sand developed in Sha 2 member in Qibei slope,and commercial oil flows were obtained in all four wells,with a drilling success rate of 100%.The exploration practice shows that the beach bar sand body is well developed in Qibei slope,and the thick bar sand is characterized by oil enrichment and high-yield production,which sh

关 键 词：歧北斜坡 沙二段 滩坝砂体 宽缓构造 岩相组合 地震正演 

分 类 号：TE122.11[石油与天然气工程—油气勘探]