Puguang Gas Field Group Of Feixianguan Reservoir Characteristics And Its Main Controlling Factors

Guided by the theories of carbonate sedimentology, reservoir geology, petroleum geology and the recent progress at home and abroad, taking the outcrops、drilling data and logging data as the main study objects, combining the field research and laboratory study, using the traditional and modern means, referring to previous research results, this paper has deeply studied the strata、sedimentary facies、reservoir characteristics and the control factors of the lower Triassic Feixianguan formation in PuGuang gas field of Northeastern Sichuan.It is researched that the Feixianguan formation in PuGuang gas field is caused by three sea-level decline. According to the sea level, lithology and Logging curves characteristics, the formation can be divided into three parts from the bottom to top.According to sedimentary feature, PuGuang and the surrounding areas can be further divided into six phases of evaporation platform, restricted platform, platform margin, slope and trough. The oolitic shoal facies which develop in platform margin areas is the most conducive to the formation and evolution of reservoirs.Also, on the basis of macroscopic and microscopic characteristics of drilling cores and the data of geochemical analysis, this paper studies the characteristics of the main reservoir lithology, reservoir space types, reservoir properties and pore structure. And on the basis of the above-mentioned study, it is thought that the formation and evolution of the reservoir mainly by the combined effect of deposition, digenesis and tectonics. The deposition is the basis which determines the approximate distribution of the reservoir; digenesis is the key to the formation of reservoir, in which the dolomitization is the basis for formation of secondary porosity, based on petrological characteristics and geochemical characteristics,the regional dolomitization is divided into three types-infiltration, mixing water and buried dolomitization.The burial dissolution is the main key to the formation of secondary pores, in particular, the dissolution of H2S generated by thermochemical sulfate reduction reaction (TSR) and related acidic water make a significant contribution to Today’s reservoir space in PaGuang gas field.finally,this paper studies the reservoir formation and evolution process, and establishes the reservoir formation and evolution model,classifies and evaluates the reservoirs, and analyzes the uniplanar distribution and change tendency of the different levels of reservoir.