【作者】 高丽华；

【导师】 韩作振；

【作者基本信息】 山东科技大学 ， 矿产普查与勘探， 2011， 博士

【摘要】 在石油地质成藏理论的指导下，综合应用地震、测井、岩心和分析化验资料，对临南洼陷断层封堵的类型和机理进行了研究，通过对研究区断面附近地层的系统取样，探讨了成岩作用、深部流体以及动力变质作用对断层封堵的影响，并采用断层封闭系数和模糊数学等方法对研究区断层封堵能力进行综合评价。影响断层封闭性的影响因素可分为断距、断移地层泥岩含量以及主应力三个因素。本文根据临南洼陷断层附近岩心详细取样分析，分别对岩性对接、泥岩涂抹、成岩作用、深部流体以及动力变质作用5个方面对断层封闭机理进行研究，重点是前人研究较少的成岩作用、深部流体以及动力变质作用等微观机理。通过取心井铸体薄片、扫描电镜、粘土矿物、全岩矿物、碳酸盐含量、同位素分析以及孔隙度、渗透率和压汞等测试，分析成岩作用对断层封堵的影响，以解释高砂地比情况下断层的封堵性。断层是流体运移的通道，不同温压条件下形成不同的成岩相、自生矿物组合，其孔隙度、渗透率等物性特征有明显的差别；因此，与正常砂岩相比，断层附近砂岩的自生矿物组合明显不同，物性明显变差，原因是碳酸盐胶结、粘土矿物胶结、沥青质和铁质胶结等成岩作用对储层的物性具有破坏作用。另外，与断层上盘目的层对接的下盘对接层往往是比较老的地层，两盘的压实程度不同，孔隙度和渗透率也不相同，因此，压实作用对断层封闭性有一定的影响。不同期次的深部流体，影响到沉积盆地尤其是断层附近的成岩作用。深部流体富含CO₂、CO、H₂、K⁺、Na⁺、卤素等，其中的K⁺、Mg²⁺的存在使碎屑岩、泥岩发生广泛的伊利石化、绿泥石化等；在C02流体参与下，碳酸盐岩发生白云岩化、铁白云岩化。这些化学反应均在较高温度下发生。在岩浆活动期熔融的岩浆沿断层运移，释放出所携带的C02与水反应形成HCO^3-和H⁺，增加的酸度引起长石等不稳定矿物的溶蚀溶解，流体中的HC03’与溶蚀溶解形成的Ca²⁺、Mg²⁺、Fe³⁺十结合则形成铁白云石。深部流体引起以上对温度变化敏感的砂岩填系物的重新分配，大大降低了储层的物性，增加了断层的封堵能力。在断层活动中，上下两盘相对错动，在巨大的应力作用下断面两侧发生动力变质作用。如碎裂岩中长英质矿物颗粒被错移并形成棋盘格式构造、断面附近砂岩发生了具有S-C组构的糜棱岩化等。断裂发育初期,断裂带表现为张裂缝发育的脆性变形,断裂带的物性较好,断层对油气具有垂向输导作用；随着断裂活动的进一步加强,断面附近发生糜棱岩化,颗粒受力破碎直至研磨、粉碎成细粒的糜棱岩,孔隙度也由正常地层向断面附近糜棱岩的逐渐减小,对油气起侧向封堵作用；其后,随着断裂活动的消亡,胶结充填带的裂缝被碳酸盐胶结充填,使孔隙不再具有连通性,断裂带的物性变差,断层在垂向和侧向均具有较好的封堵能力。在综合考虑断层带泥岩含量、区域应力、流体压力、断面产状等因素影响的基础上,提出断层封闭系数和断层封闭性模糊评价方法对断层封堵能力进行评价。断层所能封堵的油柱高度越高,则其封闭性越好；其所能封闭的油柱高度越低,则其封闭性较差。根据研究区大量实测数据分别回归出排驱压力与油柱高度、SGR、孔喉半径以及与孔隙度和渗透率的关系；泥岩含量与排驱压力之间呈正相关的关系,孔喉半径与排驱压力呈负相关关系,孔隙度和渗透率与排驱压力之间呈负相关性。断层是否具有封闭性,关键在于断层的活动时期与油气的运移时期的配置关系。惠民凹陷开始油气运移时间为东营末期,主要油气运移期为明化镇期—至今。当油气运移时断层处于静止期,断层在垂向上是封闭的,油气以侧向运移为主；当油气运移时断层仍旧活动时,在纵向上常常具有开启性,油气沿断裂自深部向浅部运移,在浅层适当的圈闭中聚集成藏,在垂向上形成多套含油层系。更多还原

【Abstract】 Under the guidance of petroleum geology reservoiring theory and comprehensive application of seismic, logging, core and analysis materials, the type of fault sealing ability and mechanism have been studied. The influence of diagenesis, deep fluids, dynamic metamorphism on fault sealing ability is discussed. By systematic sampling near the cross-section of research area, the fault sealing ability in the studied area is evaluated using fault sealing coefficient and fuzzy mathematics method.The factors of influencing the fault sealing ability can be divided into three factors:broken distance, broken move stratigraphic, mudstone content and principal stress. According to the detailed analysis of the fault sample of cored nearby Linnan subsag respectively, the lithologic docking, mudstone daub, diagenesis, deep fluids as well as dynamic metamorphismis studied to learn about the mechanism of the fault sealing ability. The key are microscopic mechanism such as deep fluids as well as dynamic metamorphism which were studied less before.By casting body chip, scanning electron microscope, clay mineral, full rock mineral, carbonate content, isotope analysis and porosity, permeability and pressure mercury and other test of coring wells, the influence of diagenesis on fault sealing ability, and texted row-flooding pressure and porosity, permeability were analysed to explain the fault sealing ability under the high sandstone content circumstances. Fault is the channel of fluid migration and different temperature, pressure conditions form different diagenetic authigenic mineral assemblage so that the porosity, permeability are obvious different. Therefore, compared with normal sandstone, the authigenic mineral assemblage near the fault are markedly different and the property become worse because of carbonate cementation, clay mineral cementation, bituminous and iron such diagenesis cemented have destroy the reservoir. In addition, the corresponding layer in the footwall which is compared to the purpose in the upper plate are old layers, the degree of compaction in the two plates is different and the porosity and permeability is not identical.They also can influence the sealinga ability.The deep fluids of different terms could effect the diagenesis in the sedimentary basin especially near the fault. Deep fluids mainly contains CO2, CO, H2, K+, Na+, halogen and so on. Because the existence of K+, Mg2+, both clastic rocks and mudstone extensively choritization and illitization; Carbonatite develop dolomitisation and parankerite in the presence of CO2 fulid. All the chemical reaction happened in high temperatures. The CO2 fluid associate with deep fluids participate in the diagenetic process and the molten rock magma move along the fault, releasing CO2 into water and forming HCO3-, H+. So it increase the acidity and caused feldspar mineral to disslove and the fluid of HCO3-, Ca2+, Mg3+, Fe3+ combined and ankerite is formed. Deep fluids cause the fillings sensitive to temperature to redistribute, which greatly reduce the petrophysics and increased the fault sealing capacity.Dynamical metamorphism is occurred on both sides of the cross section under high stress generated by the fluctuation two plates during fault activity. Such as quartz, sericite and feldspar mineral grains are split and disconnected, formed the chessboard format structure, and the sandstone near section is mylonitization mylonitized and so on. In the early stage of fracture development, fault zone shows brittle deformation with tension fissure development and its property is good, at this time the fault has vertical translocation to the oil and gas. Along with the further strengthen of fault activities, it happens mylonitization near the fracture surface, and so the particle changes into the miliolite because of broken, grinding and crushing; while the porosity gradually decreases from the normal formation to near the mylonite; so in this situation the fault plays lateral sealing effective to oil and gas; Thenceforward, with the death of fault activity, cracks in the cemented rock pack are filled by carbonate, and make pore have the bad connectivity,and so the fault has the good sealing capacity in vertical and lateral direction.On the basis of comprehensive consideration of the influnce of mudstone content of the belt, regional stress, fluid pressure, the shape of cross section, the fault sealing coefficient and fuzzy evaluation method are used to evaluate the sealing ability. The higher of oil column, the better of the sealing ability.The relationship between oil column height, SGR, pore throat radius porosity, permeability and flooding discharge pressure are figured out according to the large quantities of measured data in the studied area. Shale content is positively correlated with displacement pressure and radius of pore throat, porosity are negatively correlated with discharge pressure.Whether faults having sealing ability lies in the configuration between the fault activity period and hydrocarbon migrating period. The starting of the hydrocarbon migration of Huimin sag was at the end of Ed and since Nm. If the fault is static after hydrocarbon migration, faults are enclosed in the vertical,so oil and gas will migrate in the parallel direction;On the contary, vertical hydrocarbon are often open, then oil gas will move from the deep to the shallow along the fault, forming a series of oil formations in the vertical in shallow appropriate trap.更多还原