准噶尔盆地腹部三工河组二段层序界面厘定

准噶尔盆地腹部岩性油气藏油水关系复杂,解决这一问题的关键是层序划分对比。通过岩心、录井、测井、地震的综合研究发现,在下侏罗统三工河组二段内部可以识别出一个三级层序界面。该界面在岩性上以冲刷面及其之上砾岩或者含砾粗砂岩的出现为标志,在测井曲线上表现为突变接触,该界面在伽马反演剖面上能够识别并且能够追踪对比。界面之下的高水位体系域砂体连通性好、侧向封堵不好、不含油,层序界面之上的低水位体系域及水进体系域三角洲分流河道砂体储集层非均质性强、侧向封堵条件好、含油。厘定追踪该界面并寻找该界面之上的低水位体系域和水进体系域的三角洲分流河道砂体是勘探的关键。

Classification of Sequence Boundary of Member 2 of Sangonghe Formation in Hinterland of Junggar Basin

In view of the complex water-oil relations of lithology reservoir in hinterland of Junggar basin, the sequence stratigraphic classification and correlation are conducted by comprehensive researches of core, logging, well logging and seismic profile. The result shows that a sequence boundary is identified inside member 2 of Sangonghe formation of Lower Jurassic, which is characterized by lithology of scour surface and conglomerate and gravel bearing gritstone over it, and by well logs of abrupt contact. The boundary can be identified and traced for correlation on the gamma inverse profile. In HST beneath the boundary have good interconnecting sand body, poor lateral sealing, and no oil shows; in LST and TST above it have delta distributary channel sand reservoir with serious heterogeneity and good lateral sealing, being oil layer. Hence, tracing this boundary and searching for the delta distributary channel sands in LST and TST will be the key for petroleum exploration in this area.