【作者】 李鸿军；

【导师】 徐望国； 彭军；

【作者基本信息】 湖南科技大学 ， 地质资源与地质工程， 2011， 硕士

【摘要】 针对四川盆地中西北部地区须家河组储层低孔、低渗、含水饱和度高等特征,以沉积岩石学、成岩作用原理等理论为指导,基于大量的薄片、扫描电镜、物性、区域地质及前人研究等资料,综合电子探针、包裹体测温、X-衍射分析等实验数据,系统研究了四川盆地中西北部须家河组第四段储层的成岩作用特征,详细论述了其主要类型,建立了成岩演化模式,划分了成岩相类型,并在此基础上探讨了成岩作用对储层物性的影响。通过对四川盆地中西北部八角场-充西地区岩石学特征、成岩作用及成岩相特征、成岩序列及演化特征综合研究认为:根据古地理环境表明,八角场-充西地区同属川中古隆中斜平缓带,其中充西地区位于南充背斜构造西段。四川盆地中西部晚三叠世须四期是一套河流-湖泊相的沉积,八角场-充西地区处于三角洲平原相区范围内。须四段储层岩石学特征表明,八角场-充西地区主要岩石岩性为结构成熟度与成分成熟度均较低的长石岩屑砂岩,局部发育钙质长石岩屑砂岩。碎屑颗粒组分具有高石英、高岩屑、低长石的特点;填隙物以泥质杂基、绿泥石、方解石、硅质为主。同时对八角场-充西地区须家河组第四段各亚段储层岩石学特征纵横向分布规律进行了阐述。须四段储层成岩作用复杂,主要发育压实、压溶、胶结、溶蚀和交代等成岩作用,在储层所经历主要的成岩作用中,绿泥石环边胶结和溶蚀作用是形成孔隙(含溶孔)型储层的主要原因,属于须四储层的建设性成岩作用范畴;而强压实作用、压溶作用是降低孔隙度的成岩作用,属于破坏性成岩作用范畴。成岩演化主要经历了同生成岩期、早成岩A期、早成岩B期、晚成岩A期四个阶段。目前,须四段储层成岩阶段总体处于晚成岩期,八角场地区演化程度相对较高,以晚成岩B期为主,充西地区为晚成岩A期。由于成岩作用在总体上控制着储层孔隙的形成与演化,故以某种成岩环境下发生的主要成岩作用来命名成岩相。通过大量的岩芯观察和薄片鉴定,结合扫描电镜、X一射线衍射、阴极发光等分析,将须家河组储层成岩相划分为:绿泥石胶结成岩相、强压实-溶蚀成岩相、强压实-弱溶蚀成岩相、钙质胶结成岩相、强压实成岩相、溶蚀成岩相和硅质胶结成岩相等七种成岩相类型。其中绿泥石胶结成岩相、强压实-溶蚀成岩相、溶蚀成岩相储层物性较好,为最有利的成岩相类型。钙质胶结成岩相和强压实成岩相储层物性很差。还研究了八角场-充西地区须家河组第四段各亚段成岩相的平面展布规律。须四段储层孔隙类型主要有剩余粒间孔、溶蚀粒间孔、粒内溶孔,总体上储层储集性较好。最后通过综合考虑成岩作用、成岩相、孔隙特征,指出了研究区储层储集性纵向上以须四段下部储集性较好;横向上,充西地区储集性相对较好。更多还原

【Abstract】 There are Characteristics such as low permeability, low saturation of Xujiahe Formation in Centre-northwestern of Sichuan Basin. guided by the theory and method of sedimentology and diagensis of reservoir,and based on observation of microsection, electron microscope, X-ray diffraction and cathodelu-minescence,diagenesis of Xujiahe Formation are studied in depth. diagenesis comprehensive research believes that:The reservoir rock type of research area is mainly feldspar, the local development of lithic sandstone calcareous feldspar lithic snastone. the main reason of porous type reservoir formation is developmental compaction, pressure dissolving, cementation, dissolution and explaination diagenesis, chlorite ring edge cementation and dissolition is porous type reservoir formed the main reason,while crush real pressure dissolve role is dense of reservoir formation of an important controlling factors. According to Comprehensive reservoir characteristics and diagenetic performance, research area can be divided into seven diagenetic phase such as chlorite cementation diagenetic phase, crush real - dissolution diagenetic phase, crush real - weak dissolution diagenetic phase, calcium cementation diagenetic phase, crush real diagenetic phase, dissolution diagenetic and siliceous cementation diagenetic. Chlorite cementation diagenetic phase, crush real - dissolution diagenetic phase, dissolution is the most advantageous to the diagenesis phase diagenesis phase among them. The degree of Reservoir diagenetic evolution is higher, the overall of them in late diagenetic stage and the degree of anise field evolution is relative taller, which is mainly the late of rock B period, while chongxi region is the late of rock A period. The important controlling factors of the reservoir of diagenesis is sedimentary microfacies, rock components, diagenesis changes and buried depth.Reservoir space type is mainly surplus grain holes, various solution pores.The pore types of T3x4 have mainly surplus grain, dissolution hole, grains hole, overall,the reservoir property of T3x4 is good.Finally, through comprehensive consideration of the diagenesis, diagenesis phase and pore features, it was pointed out that the reservoir of research on the reservoir that’s the vertical distribution of reservoir property in the lower of T3x4 better than the upper of T3x4 ;the plane distribution of reservoir property in the Chongxi area better than Bajiaochang area.更多还原