Although buried over eight thousand meters, there is still developing high production from tight gas reservoir with low porosity and ultra-low permeability in the sandstones of Bashijiqike Formation of Cretaceous in Kelasu area of Kuqa depression. It is an interesting issue for the origin of the ultra-deep reservoirs. This paper aims to present the characteristics and origin of the nano-pore and nano fissures of that ultra-deep reservoirs using field emission scanning electron microscope, laser scanning confocal microscope and other high resolution measure experiments. There are developed two kinds of nano-pores with pore diameters between 40 nanometers to 1000 nanometers, and many nano fissures with width between 10 and 600 nanometers in this sandstone reservoir. Based on their petrophysical properties and microstructure characteristics, the nano pores are connected by those nano fissures that are also as valid pore throats. So, there is valid permeability in sandstones with even very low porosity. The effective combination between nano pores and pore throats is the key factors for high production in this tight gas sandstones. This point can help us to predict gas reservoirs with effective and recoverable reserve in this kind of ultra-deep gas field, also maybe in other similar gas field.

STUDY ON CHARACTERISTICS AND ORIGIN OF NANO-PORE AND FISSURES FOR DEEP BURIED CRETACEOUS TIGHT GAS RESERVOIR USING NANOTECHNOLOGY IN KUQA DEPRESSION- TARIM BASIN, CHINA, Carpathian Journal of Earth and Environmental Sciences February 2025, Vol. 20, No. 1, p. 77 – 84; DOI:10.26471/cjees/2025/020/315