【作者】 张世广；

【导师】 卢双舫；

【作者基本信息】 大庆石油学院 ， 矿产普查与勘探， 2009， 博士

【摘要】 本项研究在经典层序地层学原理和方法指导下,综合利用地震、岩芯、录井、测井、地球化学等分析化验资料,建立了松辽盆地北部大庆长垣以西地区及松辽盆地南部邻区重点区块(红岗阶地)近1.5万平方公里的青山口组至准层序级所有探井及开发井统一层序地层格架,进而在该层序格架约束下对不同沉积体系及其储层特征、成藏条件进行了深入的分析,并预测了有利目标区带。本项研究对该区下一步油气勘探、开发具有重要的指导作用和借鉴价值。结合密井网解剖,首次对松辽盆地北部大庆长垣以西地区及松辽盆地南部重点区块青山口组所有钻遇探井、开发井按照经典层序地层学原理进行区域统一层序地层对比。将目的层位青山口组划分为3个三级层序,自下而上依次为SQ3、SQ4、SQ5。上述各个三级层序均由水进体系域和高位体系域2个体系域构成,均缺少低位体系域,故青山口组包含6个体系域。其中,SQ3进一步划分为7个准层序,SQ4划分为5个准层序,SQ5划分为7个准层序。首次建立了松辽盆地大庆长垣以西地区青山口组至准层序级层序地层分层与各油田开发区块油层分层的对应关系,并建立了地层沉积模式。首次应用重矿物等资料精细厘定了松辽盆地大庆长垣以西地区青山口组的物源体系。从区域沉积背景、物源体系分析及层序格架约束下的大比例尺沉积微相精细分析可知,工区主要受北部、西部和西北沉积体系控制。由于工区的北部是缓坡且属于远源沉积,北部沉积体系控制的三角洲体系的三角洲相带宽度明显比西部(属于陡坡且是相对远源沉积)和西北部(属于缓坡且是近源沉积)沉积体系控制的三角洲体系的三角洲相带宽。虽然同属三角洲前缘相带,但由于前述原因,造成北部沉积体系控制的地区沉积物粒度较细,多为粉砂岩、泥质粉砂岩(或各种含钙泥质粉砂岩)和泥岩组合,且上述各种岩性中介形虫含量特别多、还有部分成层介形虫;而西北沉积体系控制的沉积物的岩性则相应粗得多,甚至有很多井钻遇砾岩、含砾粗砂岩、粗砂岩等粒度较粗的岩性。工区内整个泰康隆起带和西部超覆带的大部分地区都受西北和西部沉积体系控制,沉积物粒度较北部沉积体系控制的沉积物粗,且西北部和西部沉积体系控制的地区平均砂地比比北部沉积体系控制的沉积体系高,砂体连通性好。但局部地区三角洲前缘末端及前三角洲在统一湖盆的改造下已经连在一起,很难区分;多物源、多沉积体系随时空演化的复杂性造成水域范围广大的古湖盆内沉积微相统一识别上的较大困难。通过层序及沉积特征的研究发现青山口组沉积时期,大庆长垣以西地区的沉积中心自下而上由北向南不断迁移,“最大湖泛面”对于不同沉积体系控制的大型湖盆来说是一个动态变化的理想面,并建立了统一湖盆不同沉积体系沉积模式。通过众多典型油气藏解剖确定了本区发育的油气藏类型及其与层序格架的关系,研究区目的层主要发育构造、构造-岩性、微幅度构造、岩性-断层遮挡、断层-岩性及岩性等油气藏;构造因素起主导作用的油气藏可发育于各体系域中,岩性起主导作用的油气藏主要发育于SQ3的水进体系域中,其它因素起主导作用的油气藏主要发育于高位体系域中。通过层序格架内的成藏组合特征研究可知,烃源岩主要发育于水进体系域,储层主要发育于高位体系域,最大湖泛面附近发育的泥岩对水进和高位体系域的砂体都有较好的封闭作用。以体系域为单元剖析了大庆长垣以西地区青山口组的成藏条件和主控因素,本区主要有自生自储持续性供烃原生油藏成藏模式、西斜坡远源微幅度鼻状构造和断层岩性油气藏成藏模式及油源断裂成藏模式。以准层序为单元预测了大庆长垣以西地区青山口组的有利区带。准层序级层序地层格架对油气藏预测具有较好的指导作用。更多还原

【Abstract】 Under the guidance of classic sequence stratigraphy principles and methods, this study comprehensively used seismic, core, logging, well logging, geochemical analytical data, etc. It established a unified sequence stratigraphic framework from Qingshankou formation to parasequence level including all exploration wells and development wells in the west of Daqing Placanticline north of Songliao Basin and adjacent key areas (Honggang terrace) south of Songliao Basin covered 15 thousand square kilometers. And within the constraints of the sequence framework we deeply analyzed different depositional systems, characteristics of the reservoir, and reservoir forming conditions. And then we forecast a favorable target zone. This study has an important guidance role and reference value on the next step oil-gas exploration and development in this area.It is the first time that regional uniform sequence stratigraphic correlation was carried out to all exploration wells, development wells in the west of Daqing Placanticline north of Songliao Basin and key areas south of Songliao Basin according to the classical principles of sequence stratigraphy. The target zone of Qingshankou formation is divided into three third-order sequences, followed by bottom-up SQ3, SQ4, SQ5. Each of these three sequences is constituted by transgressive system tract and highstand system tract. There is no low stand system tract. So there are six system tract in Qingshankou formation. Where, SQ3 is further divided into seven parasequence, SQ4 divided into five parasequence, SQ5 divided into seven parasequence. And also corresponding relation between sequence formation classification from Qingshankou formation to parasequence level in the west of Daqing Placanticline north of Songliao Basin and oil strata division of oil fields development block was established for the first time,and stratigraphic sedimentary pattern was also established.Data on heavy minerals was firstly applied to the redefinition of deposit source of Qingshankou formation in the west of Daqing Placanticline north of Songliao Basin. From regional deposition background, source analysis and large-scale sedimentary microfacies precise analysis constrained by sequence stratigraphic framework, we can find that, work area mainly affected by the north, northwest and western depositional system. As the northern part of work area is gentle slope and belongs to distant source deposition, delta phase zone width of delta system controlled by the north depositional system is wider than the west (of the steep slopes and is relatively far away from the source of deposition) and the north-west (of the gentle slope and is deposited near the source). Although same belongs to front delta facies zone, and the foregoing reasons, the north depositional system controlled areas sediment smaller grain size, mostly siltstone, shaly siltstone (or a variety of calcium-pelitic siltstone) and mudstone portfolio, and there are lots of ostracods in these lithology, some ostracods formed stratigraphy, and north-west of the lithology of depositional systems is correspondingly more coarse, coarse pebbly, coarse sandstone and fine sandstone, and so on. The whole Taikang uplift belt and the majority districts of the west overlap zone of work area are controlled by the north-west and west depositional systems. Sediment grain size is coarser than the north depositional system. Average sand versus ground value in the north-west and west depositional system controlled zones is higher than the north. Sandbody connectivity is good. However, some areas in the front delta phase zone have been linked together under a unified basin transformation, it is difficult to distinguish; the complexity of the multi-source, multi-sedimentary system evolution caused more difficult on the identification of a unified basin micro-facies. Through the study of sequence and sedimentary characteristics,we can find that during sedimentary period of Qingshankou formation,depocenter in the west of Daqing Placanticline gradually migrate from below to above and from north to south. While the“maximum flooding surface”is a dynamic changing ideal plane,as for large-scale lake basin controlled by different sedimentary system. We established sedimentary model of unified lake basin with different sedimentary system.We defined the relationship between reservoir types developed in the study area and sequence framework by dissecting many typical oil and gas reservoirs. The purpose layer of the study area mainly developed structure, structure-lithology, tiny structure, lithology-fault sheltered,fault-lithology,lithology reservoir, and so on. Reservoirs that structural factors play a leading role can develop in all system tracts; Reservoirs that lithology factors play a leading role mainly develop in transgressive system tract in SQ3; Reservoirs controlled by other factors mostly develop in highstand system tract. Through the study of characteristics of reservoir combination in sequence framework, we learned that source rocks mainly develop in transgressive system tract, reservoirs in highstand system tract, and mudstones developed near maximum flooding surface have good sealing ability for sandstone in transgressive system tract and highstand system tract. Based on the unit of system tract, we analyzed the reservoir forming condition and main controlling factors of Qingshankou formation in the west of Daqing Placanticline. It has a self-sustained self-storage continual hydrocarbon supply for the original reservoir accumulation model and distant source micro-amplitude nasal structure in the west slope, fault lithologic reservoir accumulation model, and oil-migrating fault reservoir accumulation model. Based on the unit of Parasequence, we predicted favorable zone of Qingshankou formation in the west of Daqing Placanticline. Parasequence level sequence stratigraphic framework has a good guidence effection on reservoir prediction.更多还原