沉积界面变化对大港油田低电阻率油层分布的影响

Influence of Two Depositional Interfaces Conversion on Distribution of Low Resistivity Oil Zone in Dagang Oilfield

大港油田是我国东部渤海湾油气区的重要组成部分。探索低电阻率油层分布与沉积界面转换之间的内在联系,对于预测低电阻率油层分布有着重要的应用价值,对于渤海湾盆地的油气挖潜有指导意义。尝试以沉积相在空间上的变化规律为线索,探讨2个重要沉积界面变化对低电阻率油层形成的影响,其中上第三系辫状河向曲流河转换界面之上分布以束缚水和泥质附加导电成因的低电阻率油层;下第三系冲积相向浅湖相转换界面之上分布以束缚水成因为主的低电阻率油层。沉积水动力的强弱变化、油气运移的充分性以及构造的继承性,是预测低电阻率油层分布与富集的3个不可或缺的因素。引用实例给予了说明。

Dagang oilfield is one of the important oil and gas areas in the eastern gulf of Bohai sea. It should not be ignored that the depositional interfaces conversion causes low resistivity oil zones distribute widely and abundantly in some parts of the layers. So research on the relationship between the low resistivity oil zones and depositional interfaces conversion will help us to forecast the low resistivity oil zones, and benefit finding oil and gas in the gulf of Bohal basin. We want to discuss the influence of the two depositional interfaces conversion on the low resistivity oil zones according to the law of steric varieties of sedimentary facies. Therefore, in neogene system, when the braid rivers converse to snaking streams, low resistivity oil zones are formed because of the bound water and additional conductive clay. On the other hand, in palaeogene system, alluvial facies converse to shallow lake facies, and the low resistivity oil zones are derived from the bound water.