华北地区东部下古生界烃源岩分布特征及其发育模式

华北地区下古生界烃源岩研究对前第三系油气战略资源选区具有重要意义。从沉积学角度出发,通过对研究区有机碳含量、生烃潜力和氯仿沥青"A"等参数的统计分析和平面制图,划分了烃源岩类型,并进行了品质评价,分析了烃源岩的成因,总结了烃源岩发育模式。研究认为:华北东部奥陶系上、下马家沟组及峰峰组为较好的烃源岩,平均有机碳含量分别为0.183%、0.21%和0.181%;下寒武统发育优质烃源岩(TOC平均值为6.46%,最高值为11.2%),但分布范围局限。华北地区东部烃源岩按岩石类型不同可分为两套,即下寒武统泥质烃源岩,中、下奥陶统的碳酸盐岩烃源岩。烃源岩的成因取决于沉积环境,泥质烃源岩发育于陆棚浅海环境,而碳酸盐岩烃源岩则受控于云坪和局限台地环境。对烃源岩空间展布规律研究发现,合肥盆地为潜在的泥质烃源岩发育区,而东濮拗陷、临清拗陷、冀中拗陷为潜在的碳酸盐岩烃源岩发育区。

The Distribution Character and Development Model of Hydrocarbon Source Rocks of Lower Palaeozoic,the Eastern North China

Researching the hydrocarbon source rocks of Lower Palaeozoic in North China is very important to the pre-Tertiary oil-gas strategic precinct.From the point of view of sedimentology,the type,quality evaluation,genesis and development model of hydrocarbon source rocks in the study area were analysed according to the statistics of parameters TOC(%),S1 S2 and bitumen "A".The research shows: there are preferable hydrocarbon source rocks in the Lower-Majiagou Formation,the Upper-Majiagou Formation and the Fengfeng Formation of Ordovician,whose mean TOC values are 0.183%,0.21% and 0.181% respectively;The high quality hydrocarbon source rocks develop in Lower Cambrian and distribute in the limited region,whose mean TOC value is 6.46% and max TOC value is 11.2%.According to the rock types,the hydrocarbon source rocks in North China can be divided into two series,the claystone type source rock in Lower-Cambrian and the carbonatite type source rock in Lower-Middle Ordovician.The genesis of hydrocarbon source rocks lies on sedimentary environment: claystone type source rock develops in the shallow-sea continental shelf and carbonatite type source rock is controlled by the tidal flat and restricted platform.The study of spatial distribution rule of hydrocarbon source rocks finds that Hefei basin is the potential developed region of claystone type source rock and Dongpu depression,Linqing depression and Jizhong depression are the ones of carbonatite type source rock.These results can provide a lot of effective geological information of the pre-Tertiary oil-gas strategic precinct in the eastern North China.