Abstract: The Kuqa Area is a typical fractured tight sandstone reservoir with dense lithology and low porosity. Validity of fractures is a key factor in the formation of a good reservoir. Therefore, how to accurately identify fractures and evaluate their effectiveness is the primary problem in oilfield exploration and development. Due to the needs of drilling engineering, most wells in the Kuqa Area are drilled with oil-based mud. The electrical conductivity of oil-based mud is poor, and it is difficult to effectively identify fractures with early oil-based mud electrical imaging logging tools due their low resolution. Therefore, the combination of oil-based mud electrical imaging logging tools (EI) and ultrasonic imaging tools (UXPL) can be used to extract structures and pick up fractures with different opening degrees, effectively solving the problem of fine identification of bedding and fractures. This article also introduces the method of using non-conductive mud geological imaging (NGI) to identify fractures, and systematically analyzes the relationship between normal stress on the fracture surface, the angle between fracture direction and maximum principal stress, and production capacity. A quantitative standard for evaluating the effectiveness of oil-based mud fractures in the Kuqa Area is established. In practical applications, this set of crack fine identification of fracture and effectiveness evaluation methods effectively guides production operation measures and provides technical means for the evaluation and development of fractured tight oil and gas reservoirs.

Key words: oil-based mud, tight sandstone, electrical imaging, fracture normal stress, effectiveness evaluation