南堡凹陷沙一段烃源岩综合识别及分布预测

Comprehensive identification and distribution prediction of source rocks in Es_(1) in Nanpu Sag

目的 针对南堡凹陷烃源岩在不同次凹中具有明显非均质性这一问题,深入开展烃源岩层系识别与分布预测研究。方法 选取对有机质较敏感的测井曲线,对研究区不同沉积相带采用Δlg R法和多元线性回归法分别建立烃源岩TOC定量预测模型,并依据预测结果对比验证,优选预测模型;同时确立工区烃源岩地震反射特征与地化特征的对应关系,建立单井烃源岩-地震相-沉积相关系,并进行横向追踪。结果 结果表明,研究区多元线性回归法预测TOC误差较小,可较好地满足TOC预测精度。优质烃源岩TOC测井曲线以箱形为主,偶夹锯齿状特征曲线,地震反射特征主要呈中-强振幅、中-高频、高连续性,并具亚平行-平行反射结构;中等烃源岩TOC测井曲线以高值尖峰锯齿状为主,地震反射特征为中-弱振幅、中-低频、连续-较连续,并具亚平行反射结构。结论 南堡凹陷沙一段烃源岩主要在3个区域发育,面积最大的地区位于林雀次凹5号和1号构造带之间,其次为高柳断层与西南庄断层接合部的上盘以及3号构造带附近。研究结果可为南堡凹陷非常规油气藏勘探开发提供理论指导。

Objectives Addressing the significant heterogeneity of hydrocarbon source rocks in various subdepressions in the Nanpu Sag,it carried out an in-depth study to identify and forecast the distribution of these hydrocarbon source rock formations.Methods Select logging curves that are more sensitive to organic matter,establish a quantitative prediction model for hydrocarbon source rock TOC using the Δlg R method and multiple linear regression method for different sedimentary facies zones in the study area,and compare and verify the prediction results to select the optimal prediction model.At the same time,establish the correlation between seismic reflection characteristics and geochemical properties of source rocks in the Nanpu Sag,develop a relationship among single-well source rocks,seismic facies,and sedimentary facies,and perform lateral tracing.Results The results indicate that the multiple linear regression method in the research area has a small prediction error for TOC,which can better meet the precision of TOC prediction.The TOC logging curves of high-quality hydrocarbon source rocks are mainly box shaped,occasionally interbedded with serrated characteristic curves.The seismic reflection characteristics mainly show medium to strong amplitude,medium to high frequency,high continuity,and have sub parallel-parallel reflection structures.The TOC logging curve of medium hydrocarbon source rocks is mainly characterized by high-value peak sawtooth shape,with seismic reflection characteristics of medium-weak amplitude,medium-low frequency,continuity-relative continuity,and sub parallel reflection structure.Conclusions The source rocks of the Es_(1) in the Nanpu Sag are mainly developed in three regions.The largest area is located between the 5th and 1st structural belts of the Linque Sag,followed by the hanging wall at the junction of the Gaoliu Fault and the Xinanzhuang Fault,as well as near the 3rd structural belt.The research results can provide theoretical guidance for the subsequent exploration and development of unconventional oil and gas reservoirs in the Nanpu Sag.