Characteristics of Tertiary reservoir in Kuqa depression of Tarim Basin

The thickness of Cenozoic sedimentary is tremendous,and the sedimentary systems are multiple in Kuqa depression of Tarim Basin.The reservoir petrography property shows that its compositional maturity and textural maturity are lower and various in the different areas and sedimentary environments.In addition,the matrix contents of the different sedimentories are generally high.The secondary pore is the main type of the reservoir pore space,mainly including intergranular dissolution pore,intragranular dissolution pore,ultra-large pore,micro-pore and structural crack.The Paleogene porosity in the southern part of Kuqa Depression is higher than that in the northern part,and it is also higher in the center than that in the eastern and western parts of Kuqa Depression.The permeability of Paleogene reservoir tends to be higher in the south than that in the north,and the change of porosity is not distinct in the eastern and western of Kuqa Depression.The physical properties of the base sandstones of Jidike Formation in the study area show that the porosity in the east is higher than that in the west,and that in the south is higher than that in the north,and that in the circumference is higher than that of the middle part.The general thickness distribution rule of the reservoir exhibits that the Paleogene reservoir is thick and coarse in the east,and it is thin and fine in the west.The thickness and grain sizes of Paleogene reservoir in the south are very lightly different from those in the north.The base sandstone of Jidike Formation is a set of stable and thin sandstone beds for making some tracks in the region of the study area.The development of the reservoir was controlled by sedimentary facies,diagenesis and tectonics.