基于裂解色谱质谱技术的琼东南盆地渐新统源岩生烃潜力评价  

Pyrolysis-gas chromatography-mass spectrography as a method to evaluate hydrocarbon generation potential of Oligocene source rocks from Qiongdongnan Basin,offshore South China Sea

作　　者：孙永革[1] 杨中威[2] 谢柳娟[1] 张永东[2] 柴平霞[2] 

机构地区：[1]浙江大学地球科学系,浙江杭州310027 [2]中国科学院广州地球化学研究所有机地球化学国家重点实验室,广东广州510640

出　　处：《石油学报》2010年第4期579-585,共7页Acta Petrolei Sinica

基　　金：国家重点基础研究发展规划(973)项目(2009CB219400);国土资源部全国油气资源战略调查与评价项目(XQ-2004-05);(XQ-2007-05);国家科技重大专项(2008ZX05025);国家自然科学基金项目(No.40672084)联合资助

摘　　要：琼东南盆地渐新统崖城组和陵水组发育泥岩、碳质泥岩和煤3类潜在油气源岩,但由于岩屑样品大多受到泥浆添加剂污染,利用经典的热解技术(Rock-Eval)和元素分析法都无法客观评价有机质的生烃特性。针对这种情况,采用干酪根裂解色谱质谱技术(PY-GC-MS)研究了琼东南盆地渐新统崖城组和陵水组烃源岩有机质的生烃特性。研究表明,该两套地层沉积有机质以Ⅱ偏Ⅲ型为主,生烃潜力属中—差水平。但相比之下,崖城组源岩生烃潜力普遍较好,而陵水组仅局部层位(主要是陵三段)可发育好的烃源岩。由于该区潜在烃源岩主要发育于滨海—沼泽和浅海环境,受区域性海侵影响大,相变快,因此,优质烃源岩不可能成片成带展布,其发育主要受控于沉积所处空间位置是否近岸和近岸区域生态系统是否具有高的生产率两个因素。这一研究结论与中海油研究中心对该两套烃源岩所作生烃潜力统计结果相一致。There are three types of potential source rocks in the Oligocene Yacheng Formation and Lingshui Formation of Qiongdongnan Basin,offshore South China Sea,including mudstone,carbonaceous mudstone and coal respectively.Due to severe contamination of mudding additives during drilling,hydrocarbon generation potential of source rocks is usually difficult to be authentically evaluated using cutting samples by traditional Rock-Eval and elemental analyses.In this study,pyrolysis-gas chromatography-mass spectrography（PY-GC-MS） technique was introduced to determine the hydrocarbon generation potential of source rocks from the Yacheng Formation and Lingshui Formation.The results show that both of the source rocks from the Yacheng and Lingshui Formations have a type II-III of organic matter with a medium or poor potential of hydrocarbon generation.By comparison,the hydrocarbon generation potential of source rocks from the Yacheng Formation is better than that of source rocks from the Lingshui Formation.However,the occurrence of good source rocks in the third section of the Lingshui Formation is also possible.Because the development of possible source rocks in this region was strongly influenced by local marine transgression events and they were mainly deposited in shore-swamp and shallow-sea environments with variable facies,excellent source rocks were strictly constrained by two factors： whether the spatial distribution of source rocks is near shoreline and whether there is a high productivity of terrestrial ecosystem near shoreline.This is in agreement with the exploration observation by China National Offshore Oil Corporation（CNOOC）in this region.

关 键 词：裂解色谱质谱 干酪根 优质烃源岩 生烃潜力 渐新统 海相沉积 琼东南盆地 

分 类 号：TE112.115[石油与天然气工程—油气勘探]