论文部分内容阅读
通过22口井共计600.02m的岩心观察、125块普通薄片和16块铸体薄片的鉴定,153块普通薄片和235块铸体薄片的鉴定报告,12个扫描电镜观察,结合阴极发光、X射线衍射、荧光等手段,分析姬塬油田西部长8段储层岩性、物性特征,针对该地区成岩作用类型、成岩阶段、成岩演化序列、成岩环境的研究发现:岩石主要类型为长石质岩屑砂岩和岩屑质长石砂岩,结构成熟度中等,成分成熟度差—中等。储层经历了压实作用、压溶作用、胶结作用、交代作用和溶蚀作用等成岩作用,整体处于中成岩A期。典型成岩序列为压实作用-泥晶方解石胶结-石英加大、长石加大-绿泥石膜-长石、岩屑溶蚀、高岭石生成(油浸)-自生石英、自生长石-铁方解石胶结-长石、岩屑、铁方解石溶蚀。成岩过程中碱性和酸性环境交替出现。储集空间以原生粒间孔隙和粒内溶蚀孔隙为主,其中水下分流河道物性最好,孔隙度8%~18%,渗透率0.3×10~(-3)~14×10~(-3);分流间湾物性最差,孔隙度小于6%,渗透率小于0.1×10~(-3)。研究区原始沉积物具有初始孔隙度40.28%~41.55%。压实作用平均减少孔隙度30.53%,对储层影响最大;胶结、交代作用使孔隙度进一步平均降低了4.85%;后期的溶蚀作用新增平均孔隙度3.04%,对储层物性有一定改善作用,局部地区是储层物性改善的主要因素。
A total of 602 wells were observed in 22 wells, the identification of 125 normal and 16 castings, the identification of 153 ordinary and 235 castings, 12 scanning electron microscopy observations, combined with cathodoluminescence, X-ray Diffraction and fluorescence, the lithology and physical property of reservoir in Chang 8 section of west of Jiyuan oilfield are analyzed. According to the diagenesis type, diagenetic stage, diagenetic evolution sequence and diagenetic environment in this area, the main type of rock is lithic rock Sandstone and lithic feldspathic sandstone, the structure of medium maturity, poor maturity of composition - medium. The reservoirs underwent diagenesis such as compaction, pressure solution, cementation, metasomatism and dissolution. The whole reservoir was in the middle diagenetic stage A. Typical diagenetic sequences are compaction - cemented calcite cementation - increased quartz, feldspar - chlorite film - feldspar, kerogen erosion, kaolinite formation (oil immersion) - authigenic quartz, Iron calcite cement - feldspar, cuttings, iron calcite corrosion. During diagenesis alkaline and acidic environments alternate. The reservoir space is dominated by intergranular intergranular pores and intragranular dissolved pores, of which the underwater distributary channel has the best physical properties with porosity of 8% ~ 18% and permeability of 0.3 × 10 ~ (-3) ~ 14 × 10 ~ (- 3). The properties of the shunt bay are the worst with porosity less than 6% and permeability less than 0.1 × 10 -3. The original sediment in the study area has an initial porosity of 40.28% ~ 41.55%. Compaction reduces the porosity by 30.53% on average, which has the most significant effect on the reservoir. The cementation and replacement processes decrease the porosity by 4.85% on average, and the new mean porosity increases by 3.04% in the later period, which can improve the reservoir physical properties In some areas, the main factors for the improvement of reservoir physical properties are.