长春油田C区块双阳组二段油气藏特征及潜力分析

长春油田C区块双阳组二段是主要勘探层段,双二段划分出5个砂组,其中Ⅲ砂组和Ⅳ砂组是主要产油砂组。通过沉积特征研究,认为双二段为扇三角洲沉积。Ⅰ砂组和V砂组是扇三角洲前缘沉积,Ⅱ砂组-Ⅳ砂组为扇三角洲平原沉积,砂体的分布受沉积相带控制比较明显,砂体沿北西向展布。在明确该区地层沉积特征的基础上,开展了研究区油气藏成藏条件研究,认为大南凹陷具有供烃能力,双阳组是供烃层组,双三段暗色泥岩是区域盖层,17号断层及派生出的一系列近南北向正断层前期沟通油源、疏导油气,后期具有良好的封堵作用。C区块单井纵向上整体为油层-油水层-水层组合,上倾部位为油层,下倾部位为同层、水层。油水易于在构造圈闭范围内平衡,在-1 695 m形成统一的油水界面。双二段为一个成藏体系,整体为断块类型油气藏。低渗-中孔、低渗-低孔、特低渗-低孔储层是剩余油主要分布区,剩余油的形成受相控和构造控的影响,主要发育在河道储层中。

Hydrocarbon reservoirs characteristics and potentialities analysis of the second member of Shuangyang Formation in C Block of Changchun oil field

The second member of Shuangyang Formation in C Block of Changchun oil field is the main explo- ration layer． The second member has been divided into 5 sand groups，in which the sand groups III and IV are the main oil- produced groups． Based on the sedimentary characteristics，the second member is considered as the fan delta deposition． The groups I and V are the fan delta front deposition，and sand groups II- IV are the fan delta plain deposition． The distribution of sand bodies is obviously controlled by the sedimentary facies belts and shown along with the north- west direction． On the basis of defining the stratigraphically sedimentary characteristics in this area，the reservoir forming conditions of hydrocarbon reservoir in this area are studied． It is considered that the south depression has the hydrocarbon supplying ability， and the Shuangyang Formation is the hydrocarbon supplying formation． The dark mudstone in the third memeber of the Shuangyang Formation is regional caprocks． No. 17 fault and a series of derived faults with nearly SN- trending communicate oil source and dredge oil gas in the earlier stage， and act plugging effect in the later stage． Vertically in direction，the single well of C Block is a combination in general of the oil reservoir- oil and water reservoir- water reservoir in which overall，the updip is the oil reservoir and the downdiptraps is the oil- water and water reservoirs． The oil and water is easy to balance within the range of struc- tural trap，and the oil- water interface formed uniformly in －1 695 m． The second member of the Shuangyang For- mation is a reservoir forming system and is a hydrocarbon reservoir of fault block． The reservoirs of low permeabili- ty- middle porosity，low permeability- low porosity and ultra low permeability- low porosity are the main distributive areas of remaining oil． The formation of remaining oil is influenced by the facies control and structural control， which is mainly developed in the river reservoir．