渤海海域胜顺油田油气成藏规律及勘探潜力

OIL AND GAS ACCUMULATION AND EXPLORATION POTENTIAL IN THE SHENGSHUN OILFIELD,THE BOHAI SEA

胜顺油田位于渤海海域渤东凹陷东部斜坡带,近10年勘探处于停滞不前状态,勘探潜力及勘探方向不明,如何打开勘探局面成为当前面临的关键问题。研究区主要发育元古界、沙四段—孔店组、东营组及馆下段4套良好的储盖组合。利用地震、钻井等资料,对研究区断裂、圈闭、成藏条件进行了综合分析,落实了不同层系的勘探潜力。其中,元古界构造圈闭面积大,但储层非均质性强,内部构造复杂,可作为兼探层系;沙四段—孔店组具典型残留地层特征,岩性以火成岩为主,储层物性较差,勘探难度大;东营组和馆下段是本区主力勘探层系,受走滑断裂发育程度和规模的影响,构造圈闭表现为面积小、含油高度低的特点,地层超覆圈闭和断裂岩性圈闭具有较大勘探潜力。东营组底部不整合对油气大范围横向运移有重要作用;不同走向断层控制了油气富集差异。NNE向主油源断层+东营组底部不整合+NWW向次级油源断层构成了本区油气自西向东阶梯式运移的立体输导网络。依据油气运聚规律认识,近期突破应优先考虑近源勘探。

The Shengshun Oilfield lies on the east slope of the Bodong Sag.No obvious progress has been made during the last decade in oil and gas exploration and the exploration potential and direction remain a puzzle.How to break the deadlock is a key issue we are facing.There are four sets of reservoir-cap assemblages in the region based on the analysis of faults,traps and hydrocarbon accumulation conditions in different strata.Although the Proterozoic structural trap is widely distributed,the reservoir is serious heterogeneous and structure complicated,it might be considered as a subordinate choice in exploration.The Member Sha 4to Kongdian Formation is a kind of typical residual deposits,which mainly consists of igneous rock debris with poor physical properties.The Dongying Formation and Guantao Formation are the main exploration targets after an overall evaluation.Influenced by strike-slip faults,the structural traps in the Formations usually have low oil-bearing height and small oil-bearing area.However,the stratigraphic overlap traps and fault-lithology traps are of relatively large exploration potential.Within the system,the unconformity under the Dongying Formation may provide a pathway for lateral migration and the strike-slip fault control the vertical hydrocarbon movement.The NNE oil source faults,plus the unconformity and the NWW faults make of a three dimensional ladder-like migration network.According to this model,exploration close to source should be prioritized in the region.