南贝尔凹陷东次洼北洼槽南一段油藏类型及控制因素

Types and Controlling Factors of K1n1 Reservoir in Northern Trough of Eastern Sub-sag in Nanbeier Sag

南贝尔凹陷东次洼北洼槽区块断层复杂,油水分布关系复杂,成藏主控因素不清,部分油井投产初期呈现高含水特征。该区块南一段为一套扇三角洲沉积,沉积厚度大,泥岩有机质含量丰富,油气资源量大。依据测井、试油、录井资料及生产动态资料对区块的油水层进行综合分析研究,结果表明:洼槽内发育岩性-构造油藏和岩性油藏两大类型,其中反向正断层控制的岩性-构造油藏为区块主力产油区。南一段零油组成熟的烃源岩为油藏形成提供了丰富的物质基础,不整合面和断裂为油气运移提供了良好的通道,构造控制油水界面的高度。沉积相控制储层的物性及含油性,对油气平面和纵向分布范围和油层发育程度起到一定的控制作用。储层沉积为扇三角洲沉积,其中水下分流河道微相为主要储集体。应用该成果部署外扩井13口及首钻井2口,平均单井钻遇有效厚度28.9m,取得了较好的应用效果,为同类油田开发提供了借鉴及指导。

Faults and oil-water distribution relation are complex,main controlling factors of hydrocarbon accumulation are not clear,and high water cut appears at the stage of early production in partial oil wells at northern trough of eastern sub-sag in Nanbeier Sag.In Member One of Nantun Formation(K1n1),a set of fan delta deposits with large thickness,rich content of shale organic matter and large amount of oil and gas resources in this block.Oil and water layers in the block are analyzed comprehensively based on the data of well log,oil test,mud logging and production dynamic.The result presents that there are two types of oil reservoirs developed in the trough:lithologic-structural oil reservoirs and lithologic oil reservoirs,among them the lithologic-structural oil reservoirs controlled by reverse normal fault is the main oil producing area of the block.The mature source rocks of the Zero oil formation in K1n1 provide abundant material basis for the formation of oil reservoirs,and unconformity and fractures provide good channel for hydrocarbon migration.The structure controls the height of the oil-water interface.The sedimentary facies controls the physical properties and oil-bearing properties of the reservoirs,and controls oil-gas plane and vertical distribution range and development degree of the oil reservoirs at certain degree.Fan delta deposits in the reservoirs and underwater distributary channel micro-facies is the main reservoirs.Thirteen outstep wells and two new-drilled wells are explored according to the research results.The average effective thickness of single well drilling is 28.9 m.Good application results provide reference and guidance for the development of similar oilfields.