摘要
近年来,鄂尔多斯盆地东南部多口致密砂岩气探井获得工业气流,先导试验区实现效益开发,展示出该地区良好的致密砂岩气勘探开发前景。优质烃源岩形成的良好气源条件、较强的生烃增压及成藏动力条件是控制致密砂岩大气田形成的基础,但研究区尚未开展系统的烃源岩研究。基于大量测井、录井、岩心、分析化验资料,详细分析了鄂尔多斯盆地东南部煤系烃源岩的地球化学特征和平面展布特征,建立了煤系烃源岩总有机碳含量(TOC)测井解释模型,并在此基础上定量计算了生烃强度。结果表明:①鄂尔多斯盆地东南部上古生界煤的TOC平均值为56.2%,炭质泥岩TOC平均值为9.6%,暗色泥岩TOC平均值为2.4%;有机质类型为Ⅲ型干酪根,均处于过成熟生干气阶段;②平面上,煤和暗色泥岩在本溪组和山西组广泛发育,呈现由西北向东部逐渐增厚的特征,炭质泥岩在研究区发育厚度薄;③优选出自然伽马(GR)、声波时差(AC)、密度(DEN)等与实测拟合关系最好的测井参数,根据多元回归方法分别建立煤、炭质泥岩、暗色泥岩3种总有机碳含量(TOC)测井解释模型;④鄂尔多斯盆地东南部上古生界生烃强度较高,分布于(17.6~58.3)×10^(8)m^(3)/km^(2)之间,平均值为38.4×10^(8)m^(3)/km^(2),其煤层生烃强度优于暗色泥岩和炭质泥岩,东区生烃强度最大,主要介于(29.2~58.3)×10^(8)m^(3)/km^(2)之间,平均值为42.4×10^(8)m^(3)/km^(2)。
In recent years,dozens of tight sandstone gas exploration wells in the southeast of Ordos Basin has tapped industrial gas flows and a pilot area has been developed efficiently,showing this area has a bright exploration and development prospect for tight sandstone gas.It is well-known that good gas source conditions provided by high-quality source rocks,strong hydrocarbon generation pressurization and dynamic conditions for reservoir formation are the fundamental conditions controlling the formation of large tight sandstone gas field,but source rocks in the study area haven’t been investigated systematically.In this work,based on large amount of well logging,mud logging,core,analysis and assay data,geochemical characteristics and planar distribution of coal measure source rocks in southeast of Ordos Basin have been analyzed in detail,logging interpretation model of the total organic carbon content(TOC)of coal measure source rocks have been established,and hydrocarbon generation intensity of the source rocks have been calculated on this basis.The results show that:(1)In the Upper Paleozoic of southeastern Ordos Basin,coal,carbonaceous mudstone and dark mudstone have average TOC contents of 56.2%,9.6%and 2.4%,respectively.The organic matter type of coal is type Ⅲ,and are all in over-mature dry gas generation stage.(2)On the plane,coal and dark mudstone are widely developed in Benxi Formation and Shanxi Formation and thicken gradually from the northwest to east,while carbonaceous mudstone is thin in the study area.(3)Logging parameters such as GR,AC and DEN matching best with the measured data were picked out to establish TOC logging interpretation models of coal,carbonaceous mudstone and dark mudstone source rocks respectively by using multiple regression method.(4)The Upper Paleozoic source rocks in the southeast of Ordos Basin have higher hydrocarbon generation intensities of(17.6-58.3)×10^(8)m^(3)/km^(2),with an average of 38.4×10^(8)m^(3)/km^(2),in which the coal seams have higher hydrocarbon generation in
作者
师展
赵靖舟
孙雄伟
石石
赵龙梅
李军
SHI Zhan;ZHAO Jingzhou;SUN Xiongwei;SHI Shi;ZHAO Longmei;LI Jun(School of Earth Science and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Shanxi Key Laboratory of Hydrocarbon Accumulation Geology,Xi'an Shiyou University,Xi'an 710065,China;PetroChina Coalbed Methane Company Limited,Beijing 100028,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第9期1612-1626,共15页
Natural Gas Geoscience
基金
国家科技重大专项(编号:2016ZX05050)资助.
关键词
上古生界
煤系烃源岩
多元回归法
生烃潜力
鄂尔多斯盆地东南部
Upper Paleozoic
Coal measures hydrocarbon source rock
Multiple regression method
Hydrocarbon generating potential
Southeastern Ordos Basin
