胶莱盆地东北部白垩系烃源岩特征与评价  

Characteristics and Evaluation of Cretaceous Source Rocks in the Northeastern Jiaolai Basin

作　　者：可行 赵青芳[1,3] 吴飘 杨传胜 廖晶[1,3] 龚建明 KE Xing;ZHAO Qingfang;WU Piao;YANG Chuansheng;LIAO Jing;GONG Jianming(Qingdao Institute of Marine Geology,Qingdao,Shandong 266237,China;School of Earth Sciences and Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266237,China)

机构地区：[1]青岛海洋地质研究所,山东青岛266237 [2]山东科技大学地球科学与工程学院,山东青岛266590 [3]青岛海洋科学与技术试点国家实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266237

出　　处：《现代地质》2023年第5期1358-1368,共11页Geoscience

基　　金：崂山实验室科技创新项目(LSKJ202203401);山东省自然科学基金项目(ZR2020MD071);国家自然科学基金项目(42076220);中国地质调查局地质调查项目(DD20230317)。

摘　　要：胶莱盆地具有页岩气形成条件和勘探潜力,本研究对胶莱盆地莱阳凹陷和海阳凹陷中部、西南部的白垩系莱阳组水南段和逍仙庄段露头泥页岩进行了系统采样与有机地球化学测试,以期为后续盆地内页岩气的研究和勘探提供基础资料。数据分析得出研究区白垩系莱阳组烃源岩总体品质中等-差。莱阳凹陷水南段仅有22%的样品为有机质丰度中等的Ⅱ_(2)型成熟烃源岩,海阳凹陷中部水南段仅有16%的样品为有机质丰度较差的Ⅱ_(2)型成熟烃源岩,海阳凹陷西南部水南段仅有22%的样品为有机质丰度较差的Ⅱ_(2)型低成熟烃源岩,除去以上达到有效烃源岩标准的样品,其余样品均为非烃源岩。通过分析各项有机地球化学参数,认为本次样品遭受了强烈的风化淋漓作用,导致各项参数普遍偏低,在该区烃源岩评价中的作用有限,但可提供一份基础资料作为在胶莱盆地莱阳组研究的参考。露头样品相对于井下样品品质差异较大,部分构造稳定的露头区可能烃源岩保存条件较好。结合大量前人研究成果综合分析认为,莱阳组水南段烃源岩在后期遭受了强烈的风化,使露头样品的测试结果表现为不利于有机质保存的氧化环境,而井下样品的测试结果则表明烃源岩形成于还原环境且生源以藻类为主,所以莱阳组烃源岩的实际品质可能优于本次样品,因此推测莱阳组水南段存在一套较好的烃源岩。Previous research shows that the Jiaolai Basin has shale gas formation conditions and exploration potential.This study encompasses systematic sampling and organic geochemistry analysis on shale outcrops in the Shuinan and Xiaoxianzhuang members of the Cretaceous Laiyang Formation in the middle and southwestern Laiyang Sag and Haiyang Sag in the Jiaolai Basin.The study aims to contribute basic data to future shale gas research and exploration in the basin.Data analysis shows that the overall quality of local Cretaceous Laiyang Formation source rocks is medium to poor.For the Shuinan Member,only 22%of the samples from the Laiyang depression are typeⅡ2 mature source rocks with medium organic matter abundance,only 16%of the samples from the central Haiyang depression are typeⅡ2 mature source rocks with low organic matter abundance,and only 22%of the samples from the southwest Haiyang depression are typeⅡ2 low mature source rocks with low organic matter abundance.Except for certain samples that meet the effective source rock standard,the remaining samples from these three sampling spots are non-source rocks.Through analyzing the various organic geochemical data,we considered that the samples have undergone from strong weathering and dripping,resulting in generally low content,which plays a limited role in the evaluation of local source rocks.However,our study can contribute basic data as a reference for sampling in the Laiyang Formation of the Jiaolai Basin.The quality of outcrop samples differs greatly from that of core samples,and some outcrops with stable structures may have better preservation conditions of source rocks.Combined with the comprehensive analysis of a substantial published data,we considered that the source rocks in the Shuinan Member(Laiyang Formation)underwent strong weathering in the late stage,and thus the samples show an oxidizing environment that is not conducive to organic matter preservation.Meanwhile,our results on core samples show that the source rocks were formed in the original env

关 键 词：胶莱盆地 白垩系莱阳组 水南段烃源岩 有机地球化学 

分 类 号：P618.13[天文地球—矿床学]