甘肃酒泉盆地营尔凹陷层序地层特征与岩性勘探目标

甘肃酒泉盆地营尔凹陷发育中生代陆相断陷沉积，沉积构造研究表明下白垩统具备形成岩性油气藏的石油地质条件，但前人对该区岩性油气藏勘探领域的研究较少，目前尚未开展针对岩性油气藏的勘探。借助东部陆相断陷盆地的成功经验，利用钻井、地震等资料，开展了层序地层研究；将区内下白垩统划分为4个三级层序，自下而上依次为赤金堡组下段层序（Ⅰ）、赤金堡组上段层序（Ⅱ）、下沟组下段层序（Ⅲ）和下沟组上段层序（Ⅳ）；重点对区内主要勘探目的层段赤金堡组上段（层序Ⅱ）和下沟组下段（层序Ⅲ）进行了体系域划分。各层序及体系域具有不同的岩性、电性及地震反射波组特征响应，在体系域格架内利用三维属性反演、地震相分析、切片等手段开展了沉积相和岩性圈闭识别研究，发现3个岩性圈闭，综合评价认为1号岩性体是本区岩性勘探的有利目标。

The Characteristics of Sequence Stratigraphy and Lithological Exploration Target in Ying'er Depression of Jiuquan Basin, Gansu Province

Mesozoic continental deposition is developed in Yingr depression of Jiuquan Basin.Depositional and structural research indicates that Lower Cretaceous has the condition of forming lithological oil-gas reservoirs.At present,the research on lithological oil-gas reservoirs is less and the exploration aiming at lithological oil-gas reservoirs is still not developed.In this paper,by the successful exploration experience in faulted depression basins of the eastern China,we attempt to do research on sequence stratigraphy according to drill and seismic data,Lower Cretaceous is divided into four sequences.From bottom to top,there are sequence Ⅰ(lower segment of Chijinpu Formation),sequence Ⅱ(upper segment of Chijinpu Formation),sequence Ⅲ(lower segment of Xiagou Formation)and sequence Ⅳ(upper segment of Xiagou Formation).We lay special stress on dividing the system tracts of major developed sequence(sequence Ⅱ and sequence Ⅲ).Every sequence and system tracts has different response of lithological electric and seismic reflection characteristics.The sedimentary facies and lithological traps are distinguished by 3D seismic attribute inversion and seismic facies analysis etc.Three lithological traps are discovered by the research.Among them,sandbody No.1 has been chosen as a favorable exploration target.