Fine Sandbody Division Of Upper Paleozoic In Da17 Well Area From Daniudi Gas Field

Daniudi gas field is located in the northeastern part of Ordos Basin, is one of the main supply base of "west-east gas transmission", occupied an important position in China’s natural gas development strategy. The upper Paleozoic(Carboniferous Taiyuan Formation, Permian Shanxi Formation and Lower Shihezi Formation) is a giant complex lithology gas reservoir, has obvious characteristics of "facies controlled reservoir, near source accumulation", is the main gas producing layer of gas field with the features of stable structure, sandwich and a large area of contiguous transverse distribution.According to the characteristics of the upper Paleozoic lithologic gas reservoir in Daniudi gas field, under the guidance of sedimentary geology and petroleum geology theory, take the Da-17 well areain Daniudi gas field of the upper Paleozoic as study object, on the basis of the system analysis of the sedimentary facies, from the two aspects of macro development characteristics and internal differences of sand body architecture to fine description the sandstone of upper Paleozoic. Draw a few conclusions:Based on outcrop section, drilling core data, logging data and analysis of testing data, established 6 types of sedimentary microfacies of Da-17 well area in Daniudi gas field of upper Paleozoic, Taiyuan formation, Shanxi formation and He 1st member in Da-17 well area conducted in-depth study of the types and characteristics of sedimentary microfacies. Taiyuan formation is tidal flat facies, Shanxi formation is delta deposition, He 1st member is braided stream deposit. Based on the study and comparison of single well and thewells sedimentary microfacies, 10 small layers’ sedimentary microfacies distribution and vertical evolution characteristics of Taiyuan formation, Shanxi formation and He 1st member in Da-17 well area was studied systematically.Based on the study of sedimentary microfacies types and plane distribution characteristics, combine with identification method of facies- well logging Phase, established 3 types of reservoir sandstone which develop in the process of sedimentary evolution of tidal flat faciesâ†'delta depositionâ†'fluvial deposit in Da-17 well area’s Taiyuan formation and He 1st member. Taiyuan formation tidal sand dam sand body is divided into the main and flank sand bar sand body, Shanxi formation is divided into main distributary channel sand bodies and secondary distributary channel sand body, He 1st member’ high energy and low energy central bar sand body of the braided river. main sand bar, main distributary channel and high energy central bar sand body are the most favorable reservoir sand body of the study area, all have the smooth box-(gravel) coarse sandstone facies- logging facies features.Though analysis the division of different genetic types of sand body, by comparing the wells profile and the fine description of sand outcrop section, analysis of the internal structure characteristics of different genetic types of sand body. The result shows that Taiyuan formation tidal sand dam sand body is composed by multiple sets of sandbody superimposition, coarse granularity; Shanxi formation main distributary channel sand body and He 1st member’s high energy central bar sand body is composed by multiple stage sand superimposition, coarse granularity. Combined with sand material combination and development scale make the fine description of the Taiyuan formation tidal sand dam, Shanxi formation main distributary channel and He 1st member high energy central bar sand body.For the first time to carry out the modeling of different genetic types of sand bodies of the three-dimensional geological, display the three-dimensional space development characteristics of sand body. Through the small layer sand dam(River) development and connecting well section of the river, analysis of the distribution of the sand body and sand dam body, distributary channel and distributary channel sand body, central bar and high-energy. Finally established the development mode of tidal bar sand body, delta plain distributary channel sand body and the braided stream of sand body.