松辽盆地梨树断陷下白垩统泥岩盖层特征及封闭能力定量评价  

Characteristics and quantitative evaluation of sealing capability of Lower Cretaceous mudstone caprock in Lishu Rift of Songliao Basin

作　　者：岳刚 蒋有录[1] 苏圣民 董秀伟 侯帅 YUE Gang;JIANG Youlu;SU Shengmin;DONG Xiuwei;HOU Shuai(School of Geosciences,China University of Petroleum,Qingdao 266580,China;Research Institute of Petroleum Exploration and Development,Sinopec Northeast Oilfield Company,Changchun 130062,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中国石化东北油气分公司勘探开发研究院,吉林长春130062

出　　处：《大庆石油地质与开发》2023年第5期18-26,共9页Petroleum Geology & Oilfield Development in Daqing

摘　　要：盖层封闭性直接影响了油气的保存及富集程度,研究盖层封闭能力有助于油气勘探和评价。综合应用钻井、测井和地震等资料,对松辽盆地梨树断陷下白垩统泉头组和营城组盖层宏观及微观特征进行研究,并选取盖层单层厚度、累计厚度、断接厚度和排替压力等参数,运用层次分析法和模糊数学评价法对其封闭能力进行定量评价。结果表明:梨树断陷泉头组泥岩盖层厚度普遍大于300 m,盖层排替压力较大,普遍大于20 MPa;营城组盖层呈现由北向南逐渐减薄的趋势,盖层排替压力最大可达50 MPa。油气分布受控于泉头组和营城组2套盖层;营城组盖层断接厚度大时,油气于营城组盖层之下深层富集;营城组盖层被错断时,油气于泉头组盖层之下多层系富集。自上而下,封闭能力好―较好的Ⅰ类和Ⅱ类盖层分布范围逐渐减少;泉头组沉积期,Ⅰ、Ⅱ类盖层主要发育于研究区中部;营城组沉积期,封闭能力好―差的Ⅰ—Ⅳ类盖层均有不同程度发育。勘探实践表明,油气分布范围与Ⅰ、Ⅱ类盖层范围基本一致,证实评价方法具有较高的可行性。研究成果可为梨树断陷下一步油气勘探提供借鉴。Sealing capability of caprock directly affects hydrocarbon preservation and enrichment in reservoirs,and study of caprock sealing capability is helpful for oil and gas exploration and evaluation.Comprehensive application of drilling,logging and seismic data to study the macroscopic and microscopic characteristics of the lower Creta⁃ceous Quantou Formation and Yingcheng Formation caprocks in Lishu Rift of Songliao Basin.Parameters of single layer thickness,cumulative thickness,faults juxtaposition thickness and caprock discharge pressure are selected to quantitatively evaluate sealing capability by analytic hierarchy process and fuzzy mathematics rating method.The re⁃sults show that the mudstone caprock of Quantou Formation in Lishu Rift has thickness generally higher than 300 m,and the caprock has high discharge pressure,generally higher than 20 MPa.The caprock of Yingcheng Formation shows a trend of thinning from north to south,and the maximum discharge pressure of caprock may reach 50 MPa.Oil and gas distribution is controlled by 2 sets of caprocks of Quantou Formation and Yingcheng Formation.When the fault juxtaposition thickness of Yingcheng Formation caprock is large,oil and gas are enriched in deep layer below Yingcheng Formation caprock.When the caprock of Yingcheng Formation is broken,oil and gas are en⁃riched in several layers below the caprock of Quantou Formation.From top to bottom,the distribution range of ClassⅠand ClassⅡcaprocks with good-better sealing capability gradually reduces.During sedimentary period of Quan⁃tou Formation,ClassⅡand ClassⅡcaprocks were mainly developed in middle part of studied area.During sedi⁃mentary period of Yingcheng Formation,ClassⅠ-Ⅳcaprocks with good-poor sealing capability were developed with varying degrees.Exploration shows that oil and gas distribution range is generally consistent with the range of ClassⅠand ClassⅡcaprocks,confirming the feasibility of the evaluation method.The research can provide refer⁃ence for further oil and gas exp

关 键 词：泥岩盖层 排替压力 断接厚度 封闭能力 定量评价 梨树断陷 松辽盆地 

分 类 号：TE121[石油与天然气工程—油气勘探]