The sequence stratigraphy and sedimentary system analysis suggest that the Bonan sub-sag could be subdivided into 2 tectonic sequences and 7 third rank sequences. The sub-sag was an asymmetry Tertiary fault-step basin, south of which was slow fault-step belts and are mainly delta plains and delta front sediments. But in the north part of the sub-sag, controlled by the syn-sedimentary fault, steep fault-step was developed with mainly deposition of sub-aqueous fan, turbidity fan, and front of fan-delta. The sandstone groups No. 0-9 were developed from the uplift in the SE direction and the sandstone groups No. 0-8 were developed in the fan-delta environment, suggesting a main process of lacustrine filling up and prorogation.

花沟-高青气田是济阳坳陷唯一的纯气田, 存在着多种类型的天然气藏, 以CO2气藏为主.气藏围绕青城凸起分布, 天然气组成呈东西分区特点(烃类气藏分布于东部-北部, 西部以CO2气藏为主), 这与凸起东邻博兴生烃洼陷以及西部火山活动强烈有关.西部气藏中CO2含量高达70%以上, δ13CCO2值范围为-3.4‰～-4.5‰, He气含量大于1%, 3 He/*$4 He比值为3.55×10-6～4.49×10-6, 为岩浆-幔源成因; 花501井馆陶组气藏CO2含量大于30%, 而N2含量大于50%, 系幔源成因为主的CO2-N2气藏.有利于形成CO2气藏的大地构造环境是地幔隆起和超壳断裂-岩浆活动带.花沟-高青气田CO2气藏正处于上新世-中新世玄武岩分布区内, 每一期岩浆的侵入和喷出就是一次成气期和可能的成藏期.上新世是本区最主要的非烃类气体的成藏期.在岩浆活动以前形成并与气源断裂直接连通的构造为CO2气聚集的有利圈闭.与此相比, 莺歌海盆地CO2气不大可能是含钙砂泥岩的热解产物,其形成很可能与中新世岩浆热液活动有关.

The ninth sandbody group of the third section of the Shahejieformation of Paleogene system in the Bonan Oilfield could be divided into two fourth-order sequences and fourteen fifth-order sequences. The clastic supply from abundance, moderate to deficiency and the lacustrine change from quickly falling, slowly falling, slowly rising to quickly rising contribute to the development of each fourth-order sequence. The combination of moderate clastic supply and steady lacustrine level change is the best opportunity for the porous permeable sandstone reservoir to be deposited. As a result, we conclude that the favorable reservoir sandbodies of sequence Ⅰ and sequence Ⅱ should be in the southeast and the south of the study area respectively.