上覆优质源岩对上生下储式致密油成藏的控制作用——以松南中央坳陷区青一段泥岩为例  

Controlling function of overlying high-quality source rocks on above-generation and below-storage tight oil reservoir:taking mudstone in Qn_1 formation at central depression in southern Songliao basin as an instance

作　　者：蔡来星[1,2] 卢双舫 黄文彪 李昂[3] 任欢颂 

机构地区：[1]中国石油大学(华东)非常规油气与新能源研究院,山东青岛266580 [2]国土资源部青岛海洋地质研究所,山东青岛266071 [3]东北石油大学地球科学学院,黑龙江大庆163318

出　　处：《中国矿业大学学报》2016年第2期280-292,共13页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2014CB239005);国家重点自然科学基金项目(41330313);国家油气重大专项(2011ZX05007-001)

摘　　要：基于优质源岩在致密油成藏过程中的作用越来越显著,以松南中央坳陷区青一段泥岩为例,综合运用测井、录井及地球化学测试等资料,提出由排烃角度建立源岩评价标准,在此基础上,综合优质源岩的供烃能力、古超压发育特征及封盖能力等因素,详细阐述其对下伏泉四段致密油成藏的控制作用.研究结果表明:青一段暗色泥岩有机质类型以I型和II_1型为主,具有丰度高、类型好、生烃潜力大的特征,其中,TOC>2.0%,Ro>0.9%的泥岩排烃量明显增大,为优质烃源岩;优质烃源岩厚度由湖盆边缘向沉积中心逐渐增加,纵向上主要集中在青一段下段,平面上以长岭凹陷中、北部和红岗阶地东部海坨子地区最为发育;研究区青一段优质源岩的展布范围控制了泉四段致密油藏的分布格局;其累计厚度及生、排烃强度控制油源充足程度,使得石油最大下排深度达160m;青一段古超压是石油下排的充注动力,其与油源断层的配置关系控制了泉四段下部砂组的油气富集程度;此外,青一下亚段的优质源岩为泉四段致密油藏的保存提供有效封盖.Based on the more and more significant function of high-quality source rocks in the process of tight oil reservoir,this paper studied the mudstone in Q（n1） formation at central depression in southern Songliao basin,by using logging data and geochemical analysis data,and proposed the viewpoint of establishing the evaluation standard of source rocks from the angle of hydrocarbon expulsion.On these foundations,this paper elaborated its controlling function ontight oil reservoir in Q4 formation,by colligating the hydrocarbon supplying ability,ancient overpressure characteristics and sealing ability of high-quality source rocks in Q（n1） formation.The results show that the types of dark mudstone＇s organic matter in Q（n1） formation mainly are I and II1 type,which have the characteristics of high abundance,good types and great potential of hydrocarbon generation.Among them,the mudstone whose TOC2.0% and Ro0.9%and has an obvious increase of the hydrocarbon expulsion is high-quality source rocks and its thickness increases gradually from the edge to the sedimentary center of the lake basin.Highquality source rocks mainly distributes in lower Qn1 formation in the vertical and mostly develops in northern and central of Changling depression and Haituozi area in Honggang terrace on the plane.In these study areas,the distribution range of high-quality source rocks in Q（n1） formation controls the distribution pattern of tight oil reservoir in Q4 formation.The high-quality source rocks＇ cumulative thickness,generation and expulsion intensity of hydrocarbon controls the degree of oil source,which prompts the maximum downward-migration depth of oil in Q4 formation reach to 160 m.The ancient overpressure in Q（n1） formation is filling power for oil＇s downward migration,whose match relationship with source faults controls the oiliness of lower sand group in Q4 formation.What＇s more,the high-quality source rocks in lower Q（n1） formation provides effective sealing for tight oil reservoir in Q4 formation.

关 键 词：优质源岩 评价标准 控藏作用 上生下储式致密油藏 青一段泥岩 松南中央坳陷区 

分 类 号：P618.13[天文地球—矿床学]