DISTRIBUTION AND CONNECTIVITY OF THE JURASSIC SKELETAL SAND BODIES IN THE EAST OF HALA'ALATE MOUNTAIN, JUNGGAR BASIN

Skeletal sand body is one of the components of petroleum transportation system, in which the distribution of oil and gas is commonly affected by the sealing capacity of faults and the heterogeneity of sand. On the basis of regional stratigraphic framework and sedimentary facies, this paper studies the distribution and connectivity of the skeletal sand bodies in Jurassic Badaowan and Sangonghe formations. Analysis of the width-thickness ratio of sand body in the study area reveals that, when sand thickness in single well is above 30 m, the sand is considered as being connected between the wells. The regional connecting-well sections shows that the sand bodies in J₁b₁, J₁b₃ and J₁s₂ strata are large in size, with good connection. As the major Jurassic reservoir layer in the area, the differences of fault occurrences and sealing properties in the J₁b₁ is the main reason for the variability of oil-gas distribution. The variation tendency of permeability in J₁b₁ sand is consistent with that of porosity, but there is an obvious partition between the west and the east. The central junction zone has poor porosity. There is a good correlational dependence between the planar distribution of petroleum and the variation of micro-physical properties. This also proves that the micro-physical properties of sand body can affect the connection.