奥陶系马五5亚段有效储层主控因素分析——以苏里格气田Sd39-61井区为例

The main control factors of the ordovician M55 gas reservoir： a case of Sd39-61 borefield of Sulige gasfield

马五5亚段作为苏里格气田开发的新层系,其地质认识尚显薄弱,为此,特在Sd39-61井区利用单井岩芯观察与描述,结合单井岩芯的分析化验资料对马五5亚段储层沉积、成岩、形成机理及主控因素的研究.研究认为：Sd39-61井区马五5亚段为潮坪沉积相区,粒屑滩相和云坪相为该区有利沉积相带;研究区主要的白云岩化机理为准同生蒸发泵白云岩化、渗透回流白云岩化及埋藏白云岩化;沉积微相决定了气藏的分布,马五5亚段白云岩随着古地形的隆升、发育程度增加,准同生白云岩化未形成有利孔隙、埋藏形成了马五5储层重要的储集空间“晶间孔”,古残丘不仅是上组合气藏有利分布带也是中组合马五5亚段气藏有利分布区;马五5亚段上覆风化壳残余厚度在15～25m时最有利成藏;在构造鼻隆和鼻翼部位利于气体富集.

Ordovician M5^5 as a new layer of gas field development department,its geological knowledge still weak,through observation and description of a single well core,combined with the core of the single-well analysis data.To conduct M5^5 gas reservoir,diagenesis, mechanism and main control factors of research in Sd39-61 borefield.Studies suggest that：the M5^5 gas reservoir of Sd39-61 borefield is tidal flat facies,it＇s favorable sedimentary facies of the grain bank plateau phase and cloud phase.The main mechanism of dolomization shall prevail syn- genetic evaporation,seepage reflux pump dolomization buried dolomization and dolomization. Sedimentary microfacies determines the distribution of the gas reservoir, the M5^5 dolomite increasing the degree of development with ancient terrain uplift of, penecontemporaneous dolomitization do not form a favorable porosity,buried reservoir formed most important reser- voir space ＂intergranular holes＂ of the M5^5 gas reservoir, the ancient unaka gas reservoir is not only beneficial to the combination of the distribution is also in combination with the M5^5 gas reservoirs favorable distribution.The M5^5 gas reservoirs residual thickness of the overlying crust of weathering the most favorable accumulation during 15-25 m.The Nose-like uplift area and alae of the nose site in favor of gas enrichment.