摘要
【目的】渤海湾盆地辽河坳陷西部凹陷雷家地区沙四段以黏土、长英质、碳酸盐及方沸石矿物混合的湖相细粒沉积岩,为该区油气赋存的主要载体,但混合细粒岩成分复杂且横向变化快,导致储层非均质性强,为优质储层预测带来一定困难。【方法】以西部凹陷雷家地区雷15井、雷14井和雷61井为例,基于时间序列分析方法、高精度碳酸盐U-Pb定年及自然伽马测井数据对沙四段混合细粒岩进行旋回地层学分析。【结果】(1)以相关系数法估算雷15井、雷14井和雷61井的最佳沉积速率,发现最佳沉积速率依次增大,分别为10.57 cm/kyr、11.40 cm/kyr和13.93 cm/kyr;(2)对古气候替代指标(自然伽马)进行频谱分析,与标准偏心率、斜率、岁差合成曲线(ETP曲线)数据频谱分析结果进行对比,识别雷15井、雷14井和雷61井混合细粒岩中的天文旋回信号,并利用405 kyr长偏心率进行天文调谐,以雷14井2 766.61 m处年龄43.4±1.7 Ma为锚点,建立绝对天文年代标尺;(3)沙四段中识别出6个405 kyr长偏心率周期,~17个~129 kyr短偏心率周期,结合地球轨道周期与高频层序之间的联系,建立偏心率尺度的精细地层划分对比格架。【结论】通过对雷家地区沙四段开展旋回地层学研究,有效识别沙四段中天文旋回信号,以量化方式建立具备时间属性的精细地层划分对比格架,对该区油气进一步勘探具有重要指导作用,并且有望拓宽旋回地层学在渤海湾盆地的适用性。
[Objective]Lacustrine fine-grained sedimentary rock mixed with clay,felsic,carbonate and analcite minerals,developed in the Fourth member of the Shahejie Formation of the Leijia area in the Western Sag of the Liao⁃he Depression in the Bohai Bay Basin,is the main carrier of oil and gas in the region.Owing to the complex composi⁃tion and rapid lateral changes of mixed fine-grained rocks,the reservoirs are highly heterogeneous,which brings cer⁃tain difficulties to the prediction of high-quality reservoirs[.Methods]Taking wells Lei 15,Lei 14,and Lei 61 in the Leijia area of the Western Sag as an example,and based on time series analysis method,high-precision carbonate U-Pb dating,and natural gamma ray(GR)logging data,the mixed fine-grained rocks of the Fourth member of the Shahejie Formation were analyzed using cyclostratigraphy.[Results](1)The optimal sedimentation rates of wells Lei 15,Lei 14,andl Lei 61 were estimated by Correlation Coefficient(COCO),the optimal sedimentation rates increased sequentially and were 10.57,11.4,and 13.93 cm/kyr,respectively.(2)We performed spectrum analysis on the paleoclimate proxy indicator(GR)and compared it with the data spectrum analysis results of the standard eccentricity,slope,and precession(ETP)composite curve,identifying the astronomical cycle signals in mixed fine-grained rocks in wells Lei 15,Lei 14,and Lei 61.Then,we used the 405-kyr long eccentricity cycle for astronomical tuning.We set the age 43.4±1.7 Ma at 2766.61 m in well Lei 14 as the anchor point to establish an abso⁃lute astronomical time scale.(3)6 long eccentricity cycles of 405 kyr and~17 short eccentricity cycles of~129 kyr were identified in the Fourth member of the Shahejie Formation.Combining the connection between the Earth's orbit⁃al period and high-frequency sequences,a fine stratigraphic division and correlation at the eccentricity scale was established.[Conclusions]By conducting cyclostratigraphic research on the Fourth member of the Shahejie Formation in the Leijia area,its astronomical cycle signals can be effectively identified.This method quantitatively establishes a fine stratigraphic division and comparison framework with time attributes,which plays an important role in guiding further oil and gas exploration in the area and broadens the applicability of cyclostratigraphy in the Bohai Bay Basin.
作者
李阳
李晓光
张廷山
邹丙方
陈昌
李金鹏
周晓龙
王高飞
刘洋
戚雪晨
郭美伶
高洋
LI Yang;LI XiaoGuang;ZHANG TingShan;ZOU BingFang;CHEN Chang;LI JinPeng;ZHOU XiaoLong;WANG GaoFei;LIU Yang;QI XueChen;GUO MeiLing;GAO Yang(PetroChina Liaohe Oilfield Company,Panjin,Liaoning 124010,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China)
出处
《沉积学报》
北大核心
2025年第6期2053-2067,共15页
Acta Sedimentologica Sinica
基金
中国石油天然气股份有限公司辽河油田分公司重点科技项目(2023KJXM-11)
辽宁省自然科学基金项目(2024-BS-338)。
关键词
混合细粒岩
天文旋回
沉积速率
精细地层划分
西部凹陷
mixed fine-grained sedimentary rock
astronomical cycle
sedimentation rate
fine stratigraphic division
Western Sag
