CAJ | 학술논문

贝尔凹陷是海拉尔盆地富油凹陷之一，其中SQ2层序湖侵体系域发育的暗色泥岩、泥灰岩、油页岩和含钙泥岩沉积组合是优质烃源岩，但此前一直被忽视。依据实测有机碳含量（ TOC）、氯仿沥青“A”含量、生烃潜量（ S1＋S2）、镜质体反射率（ Ro ）以及测井曲线预测的有机碳含量，运用层序地层地球化学分析方法，在层序格架内对贝尔凹陷烃源岩进行了精细研究，明确了主力烃源岩和优质烃源岩的发育层序（体系域）和规模，并计算了主力源岩和优质源岩的生烃与排烃量。研究认为，贝尔凹陷SQ2和SQ3层序烃源岩TOC、氯仿沥青“A”与S1＋S2多数达到好源岩级别以上，偏油性有机质所占比重较大，是研究区的主力烃源岩；主力烃源岩内部非均质性较强，优质烃源岩主要发育在湖侵体系域和高位域的早期，SQ2层序的湖侵体系域优质烃源岩最为发育。生烃与排烃量计算结果表明，SQ2层序生油与排油量占绝对优势，并且其内部的优质烃源岩对生油、排油量的贡献比例分别高达84％和93％。结合油源对比研究，认为SQ2层序的优质烃源岩是凹陷内主力的烃源岩。运用层序地层地球化学方法对烃源岩评价，可以指导勘探程度较高的区块油气勘探，同时对勘探程度低、钻井少、源岩取样少的含油气盆地的烃源岩评价工作更为有效。
패이요함시해랍이분지부유요함지일，기중SQ2층서호침체계역발육적암색니암、니회암、유혈암화함개니암침적조합시우질경원암，단차전일직피홀시。의거실측유궤탄함량（ TOC）、록방력청“A”함량、생경잠량（ S1＋S2）、경질체반사솔（ Ro ）이급측정곡선예측적유궤탄함량，운용층서지층지구화학분석방법，재층서격가내대패이요함경원암진행료정세연구，명학료주력경원암화우질경원암적발육층서（체계역）화규모，병계산료주력원암화우질원암적생경여배경량。연구인위，패이요함SQ2화SQ3층서경원암TOC、록방력청“A”여S1＋S2다수체도호원암급별이상，편유성유궤질소점비중교대，시연구구적주력경원암；주력경원암내부비균질성교강，우질경원암주요발육재호침체계역화고위역적조기，SQ2층서적호침체계역우질경원암최위발육。생경여배경량계산결과표명，SQ2층서생유여배유량점절대우세，병차기내부적우질경원암대생유、배유량적공헌비례분별고체84％화93％。결합유원대비연구，인위SQ2층서적우질경원암시요함내주력적경원암。운용층서지층지구화학방법대경원암평개，가이지도감탐정도교고적구괴유기감탐，동시대감탐정도저、찬정소、원암취양소적함유기분지적경원암평개공작경위유효。
Beier sag is one of the prolific sags in Hailar Basin.However,the significance of high quality source rocks con-sisting of dark mudstone,marl,oil shale and calcareous mudstone,developed in the SQ2 sequence of the transgressive sys-tem tract in the sag,had been overlooked in previous studies.Based on various data including the measured TOC,content of the chloroform asphalt “A”,hydrocarbon generation potential(S1 +S2 ),vitrinite reflectance,as well as TOC from log interpretation,a detailed study of the source rocks was carried out in the context of sequence stratigraphic framework by using the geochemical-sequence analysis method to identify and evaluate the system tracts in which the major and quality source rocks had dwelled and calculate the amount of hydrocarbon generation and expulsion of the source rocks.The re-sults show that most indexes including TOC,chloroform bitumen“A”,S1 +S2 ,and etc.,indicate that the source rocks in SQ2 and SQ3 are good to excellent in quality and dominated by oil-prone organic matter,meaning the two sequences are the major source rocks in the sag.The major source rocks are strongly heterogeneous and the high-quality source rocks were mainly developed in transgressive system tracts and early stage high stand system tracts(especially in SQ2).Calcu-lation of hydrocarbon generation and expulsion from the source rocks shows that the source rocks in SQ2 contributed the most with hydrocarbon generation amount accounting up to 84%of the total and hydrocarbon expulsion amount account-ing up to 93%of the total.The SQ2 was therefore considered the most promising home for source rocks in the sag.Evalu-ation of source rocks wiith geochemistry method can be used not only to guide exploration in brown blocks but also to im-prove working efficiency of source rock evaluation of green blocks with rare wells and samples.