QiXia Formation Sedimentary Facies Feature In The Northwest Sichuan Area

In this paper, as the research object is qixia group carbonate in northwest sichuan basin Permian, deepen the sichuan province Basin of Permian qixia group sedimentary system in the north west, in order to further the northwest region in sichuan in qixia group to looking for more favorable exploration area of sedimentary facies belt, it has important theoretical significance and practical value?Through the research, the main results are as follows;(1)Setted the Permian system in the northwest sichuan stratigraphic classification scheme, and contrasted the thickness of strata. Based on field profile observation,drilling core description, logging and seismic data, identify the qixia group is carbonate platform sedimentary system in the study area, further divided into open platform, platform edge, leading edge shelving and more than 4 subfacies and several microfacies of the basin type.Through the league well section and vertical evolution of sedimentary facies analysis, set up the "slow slope edge platform" depositional model in the region.(2)Qixia group in northwest sichuan province is a distribution of formation thickness and is thicker on both ends of the north and south, central things on both sides and thinner, the largest thickness in the bamboo garden dam area, more than 80 m in thick;West of the Gaochuan- Majiaoba- Yangjiayan and east of the Bazhong –Luduba have the thickness of thin, less than 40 m, other parts of the thickness between40 to 60 m.(3)The thickness change of the second segment of strata of Qixia group is bigger,the study area in the central to the north is thicker, and thinner on both sides of things and in the south.the Maximum thickness is still appear in the dam area and more than120 m, Zengjia region north of thickness > 80 m; the thickness of West of Long menshan fault and east of the pale Nanjiang- Cangwang region ? 40 m, other regions between 40 to 60 m.(4)Qixia formation sedimentary early, the main body is the open platform sedimentary environment in northwest sichuan province, the subject is located in the south of the region of Gaochuan- Tianjingshan and MiCangShan frontal zone;Platform edge is located in Guangyuanchaotian- Jiangeshangsi- Jiangyouhanzeng and Wangcangshuanghui- Bazhong area distribution, the body of nuclear of platformmargin beach distribute on Yangjiayan- Shangsi, Hangzeng- Gaochuan and shuang hui – long 17 well on the line, places such as Pingwu ?Qingchuan in the northwest and Luduba-Nanjiang in the northeast is the deepwater front slow slope and basinfacies in the study area.(5)Middle- late in qixia, deposition of subject of the study area consistent with the early, just due to influenced with Longmen ancient Breaking up plate edge,resulting in a decline in sea level, shallow water, a large number of biological debris piled up, and appear dolomitization, platform-margin beach body of core area and the thickness increase obviously, forming the favorable accumulation of oil and gas reservoir.