Characteristics of seepage of Chang 6 reservoir in Jiyuan area of Ordos Basin

In this paper, the authors made a comprehensive study of reservoir characteristics, micro-flow characteristics and influencing factors of Chang 6 reservoir in Jiyuan area of the Ordos Basin so as to provide a scientific basis for exploitation and evaluation at early stages. New methods for reservoir evaluation were used to study the composition of the rocks and the pore structures which include rate-controlled mercury penetration and nuclear magnetic resonance technique based on the data of the cast slice and SEM. The results show that the characteristics of Chang 6 reservoir are relatively ideal in that the reservoir develops intergranular pores, the reservoir pore structure is relatively good, being mainly small pores with microthroat, upper movable fluid has high saturation, and the percolating capabilityis strong, thus favorable for efficient development. Reservoir pore structure, diagenetic facies and reservoir wet degree are considered to be the important factors influencing effective permeability.