Sequence Stratigraphic For III Member In San-Gonghe Formation Early Jurassic Baolang Oil-Field Yanqi Basin. Northwest China

Abstract- Problem statement . The Yanqi Basin is located in the xinjaing district NW of China Sangonghe formation Early Jurassic consists mainly of several layers which are characterized by a complex geological landscape. The aim of the research is the characterization of sand Sequence stratigraphic for III member in Sangonghe Formation .Method Through create thickness maps which are essentially information well logs with data well and using petrel software was introduced information for a number 124 wells in the study area and by identifying the limits of sand vertical top and base per lithology unit In each well then investigate a correlation between these wells and then build maps sand thickness of the III member part in Sangonghe Formation. Result determines the five layers of small sand which clearly show the well logs curves return to main classes sand layers III1 and III2 that make up this part of the sangonghe formation. Characterized layer III11 continuity good cover most of the study area and up to a maximum thickness of have to 32 m. Also layer III12 covers most of the study area up to a maximum thickness of have to 48 m while the layer III13 is composed of two parts of the first located in the north of the study area and up thickness to 32 m and the second part in the south have a maximum thickness of 20 m up to a maximum thickness III21 to 26 m also III22. Overall All layers of sand accounts for 90 of the total content of classes that make up the third part of the composition of sangonghe formtion. the difference rapid levels thickness caused by the presence of a series of faults affected the structure of synthetic layers. That a gradual decrease in the thickness of the layers of sand and down the thickness to zero or nearly it suggests that the direction of flow of the river will be mainly from the northeast toward the southwest.